CN117917148A

CN117917148A - Techniques for backward compatible side-uplink communications

Info

Publication number: CN117917148A
Application number: CN202280061294.1A
Authority: CN
Inventors: T·V·阮; S·杜塔; G·萨奇斯; 吴栓栓; K·古拉蒂; G·W·马什; S·帕蒂尔
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2021-09-21
Filing date: 2022-09-20
Publication date: 2024-04-19

Abstract

Methods, systems, and devices for wireless communications are described. A User Equipment (UE) may be configured to select a set of resources for one or more sidelink messages to be performed by the UE from a pool of resources for sidelink communications. The UE may select an additional resource for transmitting a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold. The UE may send an inter-UE (IUE) coordination message via the additional resources that includes an indication of an earliest resource within a first stage side uplink control information portion of the IUE coordination message, and the UE may send a first side uplink message of the one or more side uplink messages within the earliest resource indicated via the first stage side uplink control information portion of the IUE coordination message.

Description

Techniques for backward compatible side-uplink communications

Cross reference

This patent application claims the benefit of the following applications: U.S. provisional patent application Ser. No.63/246,436, entitled "TECHNIQUES FOR BACKWARDS-COMPATIBLE SIDELINK COMMUNICATIONS," filed by NGUYEN et al at 2021, 9, 21; U.S. patent application Ser. No.17/947,805, entitled "TECHNIQUES FOR BACKWARDS-COMPATIBLE SIDELINK COMMUNICATIONS," filed by NGUYEN et al at 2022, 9, 19; each of the above applications is assigned to the assignee of the present application.

Technical Field

The following relates to wireless communications, including techniques for backward compatible side-uplink communications.

Background

Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems are able to support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple access systems include fourth generation (4G) systems (e.g., long Term Evolution (LTE) systems, LTE-advanced (LTE-a) systems, or LTE-a Pro systems) and fifth generation (5G) systems (which may be referred to as New Radio (NR) systems). These systems may employ techniques such as: code Division Multiple Access (CDMA), time Division Multiple Access (TDMA), frequency Division Multiple Access (FDMA), orthogonal FDMA (OFDMA), or discrete fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple-access communication system may include one or more base stations or one or more network access nodes, each of which simultaneously support communication for multiple communication devices, which may be otherwise referred to as User Equipment (UE).

Some wireless communication systems may support side-uplink communications between UEs. However, in a wireless communication system including UEs with different capabilities, such as reduced capability UEs or release 16 (Re 16) UEs and non-reduced capability UEs or release 17 (Re 17) UEs, not all UEs are able to receive and decode messages reserving side-link resources, which may lead to increased interference.

Disclosure of Invention

The described technology relates to improved methods, systems, devices, and apparatus supporting techniques for backward compatible side-link communications. In summary, the present disclosure supports techniques for scheduling side-link communications for release 17 (Re 17) UEs that are backward compatible (e.g., understandable) by reduced capability UEs such as release 16 (Re 16) UEs. In particular, the techniques described herein enable Re17 UEs to send some side-uplink scheduling information via side-uplink control information (SCI) messages (e.g., SCI-1) such that Re16 UEs can receive and identify reservations of side-link resources by Re17 UEs. For example, a UE (e.g., re17 UE) may send a side uplink message using a set of resources to be selected by the UE or another UE. In some cases, the UE may send an inter-UE (IUE) coordination message (e.g., IUE coordination message or IUE message) reserving the set of resources, where the IUE coordination message may be decoded by a Re17 UE but may not be decoded by a Re16 UE. In addition, the UE may select additional resources for transmitting the SCI-1 message reserving the first resource (e.g., the earliest resource) in the selected set of resources. In particular, the UE may select additional resources for SCI-1 to meet timing constraints associated with SCI-1 such that SCI-1 is not transmitted more than 32 symbols prior to the first selected resource.

A method for wireless communication at a UE is described. The method may include: selecting a set of resources for one or more sidelink messages to be performed by the UE from a pool of resources for sidelink communications; selecting an additional resource for sending a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold; transmitting an IUE coordination message via the additional resource, the IUE coordination message including an indication of the earliest resource within a first stage SCI portion of the IUE coordination message; and transmitting a first one of the one or more side-link messages within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

An apparatus for wireless communication at a UE is described. The apparatus may include a processor, a memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to: selecting a set of resources for one or more sidelink messages to be performed by the UE from a pool of resources for sidelink communications; selecting an additional resource for sending a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold; transmitting an IUE coordination message via the additional resource, the IUE coordination message including an indication of the earliest resource within a first stage SCI portion of the IUE coordination message; and transmitting a first one of the one or more side-link messages within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

Another apparatus for wireless communication at a UE is described. The apparatus may include: means for selecting a set of resources for one or more sidelink messages to be performed by the UE from a pool of resources for sidelink communications; means for selecting an additional resource for transmitting a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold; means for sending an IUE coordination message via the additional resources, the IUE coordination message comprising an indication of the earliest resource within a first stage SCI portion of the IUE coordination message; and means for transmitting a first side-link message of the one or more side-link messages within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to: selecting a set of resources for one or more sidelink messages to be performed by the UE from a pool of resources for sidelink communications; selecting an additional resource for sending a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold; transmitting an IUE coordination message via the additional resource, the IUE coordination message including an indication of the earliest resource within a first stage SCI portion of the IUE coordination message; and transmitting a first one of the one or more side-link messages within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: based on selecting the set of resources, IUE coordination information is sent via a second stage SCI portion of the IUE coordination message, a data portion of the IUE coordination message, or both, the IUE coordination information including an indication of the set of resources for the one or more side uplink messages.

In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the second stage SCI portion, the data portion, or both may not be decodable by reduced capability UEs, and the indication of the earliest resource within the first stage SCI portion may be decodable by reduced capability UEs.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: transmitting a second IUE coordination message comprising a second indication of the earliest resource in a first stage SCI portion of the second IUE coordination message, wherein the second IUE coordination message may be transmitted prior to the IUE coordination message; and transmitting the IUE coordination message via the additional resources based on a second time interval between transmission of the second IUE coordination message and the earliest resource in the set of resources failing to meet the time threshold.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: an indication of a set of a plurality of sub-channels of the earliest resource is sent via the first stage SCI portion of the IUE coordination message, wherein a last sub-channel of the set of the plurality of sub-channels may be within the resource pool in a frequency domain, wherein the first side-link message may be sent via the set of the plurality of sub-channels.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: one or more FDRI field values including an indication of a subchannel of the earliest resource are sent via the first stage SCI portion of the IUE coordination message, where the first side uplink message may be sent via at least the subchannel.

In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the subchannel includes an initial subchannel of the earliest resource.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: one or more Time Domain Resource Indication (TDRI) field values associated with the earliest resource, one or more Frequency Domain Resource Indication (FDRI) field values associated with the earliest resource, or both are sent via the first stage SCI portion of the IUE coordination message.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: transmitting an indication of a second resource in the set of resources via the first side uplink message; and transmitting a second side-link message via the second resource based on transmitting the indication of the second resource via the first side-link message.

In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the time interval satisfies the time threshold if the time interval may be less than or equal to the time threshold.

In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the time threshold comprises thirty-two time slots.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: receiving a second IUE coordination message comprising an indication of second resources for one or more additional side-link messages to be performed by a second UE; and relaying the second IUE coordination message to at least a third UE.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: receive, via the second IUE coordination message, one or more TDRI field values associated with a relative timing of the one or more additional side uplink messages; and transmitting one or more additional TDRI field values associated with the relative timing of the one or more additional side uplink messages via the relayed second IUE coordination message.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: selecting a second set of resources for the one or more sidelink messages to be performed by the UE from the pool of resources for sidelink communications, wherein selecting the second set of resources occurs before selecting the set of resources; and determining that a second additional resource for transmitting a resource reservation for an earliest resource in the second set of resources may not be identified, wherein selecting the set of resources, selecting the additional resource, or both may be based on determining that the second additional resource for transmitting a resource reservation for an earliest resource in the second set of resources may not be identified.

In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first stage SCI portion of the IUE coordination message includes one or more bit field values indicating that the first stage SCI portion may be associated with the IUE coordination message.

A method for wireless communication at a first UE is described. The method may include: selecting a set of resources for one or more sidelink messages from a second UE to the first UE from a pool of resources for sidelink communications; selecting an additional resource for sending a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold; transmitting an IUE coordination message via the additional resource, the IUE coordination message including an indication of the earliest resource within a first stage SCI portion of the IUE coordination message; and receiving a first side-link message of the one or more side-link messages from the second UE within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

An apparatus for wireless communication at a first UE is described. The apparatus may include a processor, a memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to: selecting a set of resources for one or more sidelink messages from a second UE to the first UE from a pool of resources for sidelink communications; selecting an additional resource for sending a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold; transmitting an IUE coordination message via the additional resource, the IUE coordination message including an indication of the earliest resource within a first stage SCI portion of the IUE coordination message; and receiving a first side-link message of the one or more side-link messages from the second UE within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

Another apparatus for wireless communication at a first UE is described. The apparatus may include: means for selecting a set of resources for one or more sidelink messages from a second UE to the first UE from a pool of resources for sidelink communications; means for selecting an additional resource for transmitting a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold; means for sending an IUE coordination message via the additional resources, the IUE coordination message comprising an indication of the earliest resource within a first stage SCI portion of the IUE coordination message; and means for receiving a first side-link message of the one or more side-link messages from the second UE within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

A non-transitory computer-readable medium storing code for wireless communication at a first UE is described. The code may include instructions executable by a processor to: selecting a set of resources for one or more sidelink messages from a second UE to the first UE from a pool of resources for sidelink communications; selecting an additional resource for sending a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold; transmitting an IUE coordination message via the additional resource, the IUE coordination message including an indication of the earliest resource within a first stage SCI portion of the IUE coordination message; and receiving a first side-link message of the one or more side-link messages from the second UE within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: based on selecting the set of resources, IUE coordination information is sent to the second UE via a second stage SCI portion of the IUE coordination message, a data portion of the IUE coordination message, or both, the IUE coordination information including an indication of the set of resources for the one or more sidelink messages.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: transmitting a second IUE coordination message comprising a second indication of the earliest resource within a first stage SCI portion of the second IUE coordination message, wherein the second IUE coordination message may be transmitted prior to the IUE coordination message; and transmitting the IUE coordination message via the additional resources based on a second time interval between transmission of the second IUE coordination message and the earliest resource in the set of resources failing to meet the time threshold.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: one or more TDRI field values associated with the earliest resource, one or more FDRI field values associated with the earliest resource, or both are sent via the first stage SCI portion of the IUE coordination message.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: receiving an indication of a second resource in the set of resources via the first side uplink message; and receiving a second side uplink message from the second UE via the second resource based on sending the indication of the second resource via the first side uplink message.

In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the selection of the additional resource may be based on the time interval between the additional resource and the earliest resource being greater than or equal to a second time threshold associated with processing capabilities of the first UE, the second UE, or both.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: selecting a second set of resources for the one or more sidelink messages to be performed by the second UE from the pool of resources for sidelink communications, wherein selecting the second set of resources occurs before selecting the set of resources; and determining that a second additional resource for transmitting a resource reservation for an earliest resource in the second set of resources may not be identified, wherein selecting the set of resources, selecting the additional resource, or both may be based on determining that the second additional resource for transmitting a resource reservation for an earliest resource in the second set of resources may not be identified.

A method for wireless communication at a second UE is described. The method may include: receiving an IUE coordination message from a first UE, the IUE coordination message comprising an indication of an earliest resource in a set of resources for one or more sidelink messages from the second UE to the first UE, the indication of the earliest resource being included in a first stage SCI portion of the IUE coordination message, the set of resources being included in a pool of resources for sidelink communications, wherein a time interval between receipt of the SCI message and the earliest resource meets a time threshold; and transmitting a first one of the one or more side-link messages within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

An apparatus for wireless communication at a second UE is described. The apparatus may include a processor, a memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to: receiving an IUE coordination message from a first UE, the IUE coordination message comprising an indication of an earliest resource in a set of resources for one or more sidelink messages from the second UE to the first UE, the indication of the earliest resource being included in a first stage SCI portion of the IUE coordination message, the set of resources being included in a pool of resources for sidelink communications, wherein a time interval between receipt of the SCI message and the earliest resource meets a time threshold; and transmitting a first one of the one or more side-link messages within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

Another apparatus for wireless communication at a second UE is described. The apparatus may include: means for receiving an IUE coordination message from a first UE, the IUE coordination message comprising an indication of an earliest resource in a set of resources for one or more sidelink messages from the second UE to the first UE, the indication of the earliest resource being included within a first stage SCI portion of the IUE coordination message, the set of resources being included within a pool of resources for sidelink communications, wherein a time interval between receipt of the SCI message and the earliest resource meets a time threshold; and means for transmitting a first side-link message of the one or more side-link messages within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

A non-transitory computer-readable medium storing code for wireless communication at a second UE is described. The code may include instructions executable by a processor to: receiving an IUE coordination message from a first UE, the IUE coordination message comprising an indication of an earliest resource in a set of resources for one or more sidelink messages from the second UE to the first UE, the indication of the earliest resource being included in a first stage SCI portion of the IUE coordination message, the set of resources being included in a pool of resources for sidelink communications, wherein a time interval between receipt of the SCI message and the earliest resource meets a time threshold; and transmitting a first one of the one or more side-link messages within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: IUE coordination information is received from the first UE via a second stage SCI portion of the IUE coordination message, a data portion of the IUE coordination message, or both, the IUE coordination information including an indication of the set of resources used to send the one or more sidelink messages based on the selection of the set of resources.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: receiving a second IUE coordination message comprising a second indication of the earliest resource within a first stage SCI portion of the second IUE coordination message, wherein the second IUE coordination message may be sent prior to the IUE coordination message; and receiving the IUE coordination message via the additional resources based on a second time interval between transmission of the second IUE coordination message and the earliest resource in the set of resources failing to meet the time threshold.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: an indication of a set of a plurality of sub-channels of the earliest resource is received via the first stage SCI portion of the IUE coordination message, wherein a last sub-channel of the set of the plurality of sub-channels may be within the resource pool in a frequency domain, wherein the first side-link message may be transmitted via the set of the plurality of sub-channels.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: one or more FDRI field values including an indication of a subchannel of the earliest resource are received via the first stage SCI portion of the IUE coordination message, wherein the first side uplink message may be sent via at least the subchannel.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: one or more TDRI field values associated with the earliest resource, one or more FDRI field values associated with the earliest resource, or both are received via the first stage SCI portion of the IUE coordination message.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: transmitting an indication of a second resource in the set of resources via the first side uplink message; and transmitting a second side-link message from the second UE via the second resource based on transmitting the indication of the second resource via the first side-link message.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: the IUE coordination message is relayed to at least a third UE.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: receive, via the IUE coordination message, one or more TDRI field values associated with a relative timing of the one or more additional side uplink messages; and transmitting one or more additional TDRI field values associated with the relative timing of the one or more additional side-link messages via the relayed IUE coordination message.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: performing one or more blind decoding processes, wherein receiving the IUE coordination message may be based on performing the one or more blind decoding processes.

Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions to: one or more decoding processes for the IUE coordination message are performed regardless of one or more parameters indicated via the inter-UE coordination message, including a broadcast type, a destination identifier, a source identifier, feedback distance information, or any combination thereof.

Drawings

Fig. 1 illustrates an example of a wireless communication system supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure.

Fig. 2 illustrates an example of a wireless communication system supporting techniques for backward compatible side-link communication in accordance with aspects of the present disclosure.

Fig. 3 illustrates an example of a process flow supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure.

Fig. 4 illustrates an example of a process flow supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure.

Fig. 5 and 6 illustrate block diagrams of devices supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure.

Fig. 7 illustrates a block diagram of a communication manager supporting techniques for backward compatible side-uplink communication in accordance with aspects of the disclosure.

Fig. 8 illustrates a diagram of a system including a device supporting techniques for backward compatible side-link communications in accordance with aspects of the present disclosure.

Fig. 9-12 show flowcharts illustrating methods of supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure.

Detailed Description

Some wireless communication systems may support side-uplink communications between User Equipment (UEs). In such a system, the base station may select resources for side-link communication between UEs (e.g., a "mode 1" resource selection), or the UE may autonomously select resources for side-link communication (e.g., a "mode 2" resource selection). For release 16 (Re 16) UEs, all side-link reservation information (e.g., an indication of the selected side-link resources) may be transmitted via a side-link control information (SCI) message (e.g., SCI-1). In the case of SCI-1, the time gap between any two consecutive reserved resources may not exceed 32 slots (e.g., SCI-1 may reserve resources only for the next 32 slots). In contrast, release 17 (Re 17) UEs may support IUE coordination messages to reserve side uplink resources, where IUE coordination messages are not timing limited (e.g., side uplink resources may be reserved for any number of time slots in the future). However, re16 UEs cannot decode IUE coordination messages. The lack of backward compatibility with the Re17 IUE coordination message may result in increased interference because the Re16 UE may not identify the resources reserved via the IUE coordination message and may transmit on the previously reserved resources, resulting in interference.

Accordingly, aspects of the present disclosure relate to techniques for scheduling side-uplink communications for Re17 UEs that are backward compatible (e.g., understandable) by Re16 UEs. In particular, the techniques described herein enable Re17 UEs to send some side-link scheduling information in the SCI-1 portion of an IUE coordination message (e.g., IUE message) such that Re16 UEs can receive and identify reservations of side-link resources by Re17 UEs. For the purposes of this disclosure, the terms "IUE coordination message" and "IUE message" may be used interchangeably and may refer to a side-link message that includes control portions, such as a first stage SCI portion (SCI-1 portion) and a second stage SCI portion (SCI-2 portion), as well as data portions. The data portion of the IUE coordination message may include information (e.g., an indication of preferred and/or non-preferred resources) for assisting other UEs in selecting resources for side-link communication. It is suggested to carry reservation information in the SCI-1 part of the IUE message.

For example, a UE (e.g., re17 UE) may select a set of resources for a side-uplink message to be performed by the UE or another UE. In some cases, the UE may send an IUE coordination message reserving the set of resources, where some portions of the IUE coordination message (e.g., data portion, SCI-2 portion) are decodable by Re17 UEs but not Re16 UEs. In addition, the IUE coordination message may reserve a first resource (e.g., the earliest resource) in the selected set of resources in its SCC-1 part. In other words, the UE may include an indication of the earliest selected resource in the SCI-1 portion of the IUE coordination message so that the Re16 UE knows about the reservation of the earliest resource. Further, the UE may select additional resources for sending the IUE coordination message to meet timing constraints associated with the SCI-1 portion of the IUE coordination message. In other words, the UE may select additional resources for transmitting the IUE coordination message such that the IUE coordination message is transmitted no more than 32 slots before the first selected resource. In this regard, the UE may send an IUE coordination message that includes an indication of additional resources within the SCI-1 portion of the IUE coordination message so that the Re16 UE is aware of the reservation of the first/earliest resources.

Aspects of the present disclosure are first described in the context of a wireless communication system. Additional aspects of the present disclosure are described in the context of example process flows. Aspects of the disclosure are further illustrated by, and described with reference to, apparatus diagrams, system diagrams, and flowcharts relating to techniques for backward compatible side-link communications.

Fig. 1 illustrates an example of a wireless communication system 100 supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure. The wireless communication system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a Long Term Evolution (LTE) network, an LTE-advanced (LTE-a) network, an LTE-a Pro network, or a New Radio (NR) network. In some examples, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable communications, low latency communications, or communications with low cost and low complexity devices, or any combination thereof.

The base stations 105 may be dispersed throughout a geographic area to form the wireless communication system 100 and may be devices of different forms or with different capabilities. The base station 105 and the UE 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110 and ues 115 and base stations 105 may establish one or more communication links 125 over the coverage area 110. Coverage area 110 may be an example of such a geographic area: over the geographic area, base stations 105 and UEs 115 may support transmitting signals in accordance with one or more radio access technologies.

The UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary, or mobile, or both at different times. The UE 115 may be a different form or device with different capabilities. Some example UEs 115 are shown in fig. 1. The UEs 115 described herein are capable of communicating with various types of devices, such as other UEs 115, base stations 105, or network devices (e.g., core network nodes, relay devices, integrated Access and Backhaul (IAB) nodes, or other network devices), as shown in fig. 1.

The base stations 105 may communicate with the core network 130, or with each other, or both. For example, the base station 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 may communicate with each other directly (e.g., directly between the base stations 105) over the backhaul link 120 (e.g., via an X2, xn, or other interface), indirectly (e.g., via the core network 130), or both. In some examples, the backhaul link 120 may be or include one or more wireless links.

One or more of the base stations 105 described herein may include or may be referred to by those skilled in the art as a base station transceiver, a radio base station, an access point, a radio transceiver, a node B, an evolved node B (eNB), a next generation node B or giganode B (either of which may be referred to as a gNB), a home node B, a home evolved node B, or some other suitable terminology.

The UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where a "device" may also be referred to as a unit, station, terminal, or client, among other examples. The UE 115 may also include or be referred to as a personal electronic device, such as a cellular telephone, a Personal Digital Assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, the UE 115 may include or be referred to as a Wireless Local Loop (WLL) station, an internet of things (IoT) device, a internet of things (IoE) device, or a Machine Type Communication (MTC) device, among other examples, which may be implemented in various items such as appliances, or vehicles, meters, among other examples.

The UEs 115 described herein are capable of communicating with various types of devices, such as other UEs 115 that may sometimes act as relays, as well as base stations 105 and network devices, including macro enbs or gnbs, small cell enbs or gnbs, or relay base stations, among other examples, as shown in fig. 1.

The UE 115 and the base station 105 may communicate wirelessly with each other over one or more carriers via one or more communication links 125. The term "carrier" may refer to a collection of radio frequency spectrum resources having a defined physical layer structure for supporting the communication link 125. For example, the carriers for the communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth portion (BWP) that operates according to one or more physical layer channels for a given radio access technology (e.g., LTE-A, LTE-A Pro, NR).

In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers. The carrier may be associated with a frequency channel, e.g., an evolved universal mobile telecommunications system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN), and may be placed according to a channel grid for discovery by the UE 115. The carrier may operate in an independent mode, where the UE 115 makes initial acquisition and connection via the carrier, or the carrier may operate in a non-independent mode, where different carriers (e.g., of the same or different radio access technologies) are used to anchor the connection.

The communication link 125 shown in the wireless communication system 100 may include an uplink transmission from the UE 115 to the base station 105, or a downlink transmission from the base station 105 to the UE 115. The carrier may carry downlink or uplink communications (e.g., in FDD mode) or may be configured to carry downlink and uplink communications (e.g., in TDD mode).

The carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples, the carrier bandwidth may be referred to as the "system bandwidth" of the carrier or wireless communication system 100. For example, the carrier bandwidth may be one of a determined number of bandwidths (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)) for a number of carriers of a particular radio access technology. Devices of wireless communication system 100 (e.g., base station 105, UE 115, or both) may have a hardware configuration that supports communication over a particular carrier bandwidth or may be configurable to support communication over one of a set of carrier bandwidths. In some examples, wireless communication system 100 may include a base station 105 or UE 115 that supports simultaneous communication via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate over part (e.g., sub-band, BWP) or all of the carrier bandwidth.

The signal waveform transmitted on the carrier may be composed of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as Orthogonal Frequency Division Multiplexing (OFDM) or discrete fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may include one symbol period (e.g., the duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Thus, the more resource elements received by the UE 115 and the higher the order of the modulation scheme, the higher the data rate for the UE 115 may be. The wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity for communication with the UE 115.

One or more digital schemes (numerology) for the carrier may be supported, where the digital schemes may include a subcarrier spacing (Δf) and a cyclic prefix. The carrier wave may be divided into one or more BWP with the same or different digital schemes. In some examples, UE 115 may be configured with multiple BWP. In some examples, a single BWP for a carrier may be active at a given time, and communication for UE 115 may be limited to one or more active BWPs.

The time interval for the base station 105 or UE 115 may be represented in a multiple of a basic time unit (which may be referred to, for example, as T _s＝1/(Δf_max·N_f) seconds, where Δf _max may represent the maximum supported subcarrier spacing and N _f may represent the maximum supported Discrete Fourier Transform (DFT) size). The time intervals of the communication resources may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a System Frame Number (SFN) (e.g., ranging from 0 to 1023).

Each frame may include a plurality of consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on the subcarrier spacing. Each slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix added before each symbol period). In some wireless communication systems 100, a time slot may be further divided into a plurality of minislots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N _f) sampling periods. The duration of the symbol period may depend on the subcarrier spacing or the operating frequency band.

A subframe, slot, minislot, or symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a Transmission Time Interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in the form of bursts of shortened TTIs (sTTIs)).

The physical channels may be multiplexed on the carrier according to various techniques. For example, the physical control channels and physical data channels may be multiplexed on the downlink carrier using one or more of Time Division Multiplexing (TDM), frequency Division Multiplexing (FDM), or hybrid TDM-FDM techniques. The control region (e.g., control resource set (CORESET)) for the physical control channel may be defined by the number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESET) may be configured for a group of UEs 115. For example, one or more of UEs 115 may monitor or search for control regions for control information according to one or more sets of search spaces, and each set of search spaces may include one or more control channel candidates at one or more aggregation levels arranged in a cascade. The aggregation level for control channel candidates may refer to the number of control channel resources (e.g., control Channel Elements (CCEs)) associated with coding information for a control information format having a given payload size. The set of search spaces may include a common set of search spaces configured to transmit control information to a plurality of UEs 115 and a UE-specific set of search spaces configured to transmit control information to a particular UE 115.

In some examples, the base station 105 may be mobile and, thus, provide communication coverage for a mobile geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but different geographic coverage areas 110 may be supported by the same base station 105. In other examples, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of base stations 105 use the same or different radio access technologies to provide coverage for respective geographic coverage areas 110.

The wireless communication system 100 may be configured to support ultra-reliable communication or low-latency communication, or various combinations thereof. For example, the wireless communication system 100 may be configured to support ultra-reliable low latency communications (URLLC). The UE 115 may be designed to support ultra-reliable, low latency, or critical functions. Ultra-reliable communications may include private communications or group communications, and may be supported by one or more services such as push-to-talk, video, or data. Support for ultra-reliable low latency functions may include prioritization of services, and such services may be used for public safety or general commercial applications. The terms ultra-reliable, low latency, and ultra-reliable low latency are used interchangeably herein.

In some examples, the UE 115 is capable of communicating directly (e.g., using peer-to-peer (P2P) or D2D protocols) with other UEs 115 over a device-to-device (D2D) communication link 135. One or more UEs 115 utilizing D2D communication may be within the geographic coverage area 110 of the base station 105. Other UEs 115 in such a group may be outside of the geographic coverage area 110 of the base station 105 or otherwise unable to receive transmissions from the base station 105. In some examples, groups of ues 115 communicating via D2D communication may utilize a one-to-many (1:M) system in which each UE 115 transmits to each other UE 115 in the group. In some examples, the base station 105 facilitates scheduling of resources for D2D communications. In other cases, D2D communication is performed between UEs 115 without involving base station 105.

In some systems, D2D communication link 135 may be an example of a communication channel (such as a side-link communication channel) between vehicles (e.g., UEs 115). In some examples, the vehicle may communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these. The vehicle may signal information related to traffic conditions, signal scheduling, weather, safety, emergency, or any other information related to the V2X system. In some examples, a vehicle in the V2X system may communicate with a roadside infrastructure, such as a roadside unit, or with a network via one or more network nodes (e.g., base station 105) using vehicle-to-network (V2N) communication, or both.

The core network 130 may provide user authentication, access authorization, tracking, internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an Evolved Packet Core (EPC) or a 5G core (5 GC), which may include at least one control plane entity (e.g., a Mobility Management Entity (MME), an access and mobility management function (AMF)) that manages access and mobility, and at least one user plane entity (e.g., a serving gateway (S-GW), a Packet Data Network (PDN) gateway (P-GW), or a User Plane Function (UPF)) that routes packets to or interconnects to an external network. The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the core network 130. The user IP packets may be transmitted through a user plane entity that may provide IP address assignment as well as other functions. The user plane entity may be connected to IP services 150 for one or more network operators. IP services 150 may include access to the internet, intranets, IP Multimedia Subsystem (IMS), or packet switched streaming services.

Some of the network devices (e.g., base stations 105) may include subcomponents such as access network entity 140, which may be an example of an Access Node Controller (ANC). Each access network entity 140 may communicate with UEs 115 through one or more other access network transport entities 145, which may be referred to as radio heads, smart radio heads, or transmit/receive points (TRPs). Each access network transport entity 145 may include one or more antenna panels. In some configurations, the various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or incorporated into a single network device (e.g., base station 105).

The wireless communication system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Typically, the region from 300MHz to 3GHz is referred to as the Ultra High Frequency (UHF) region or decimeter band, because wavelengths range in length from approximately one decimeter to one meter. UHF waves may be blocked or redirected by building and environmental features, but the waves may be sufficiently transparent to the structure for a macrocell to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter distances (e.g., less than 100 kilometers) than transmission of smaller and longer waves using the High Frequency (HF) or Very High Frequency (VHF) portions of the spectrum below 300 MHz.

The wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may employ Licensed Assisted Access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology in unlicensed frequency bands, such as the 5GHz industrial, scientific, and medical (ISM) frequency bands. When operating in the unlicensed radio frequency spectrum band, devices such as base station 105 and UE 115 may employ carrier sensing for collision detection and avoidance. In some examples, operation in the unlicensed band may be based on a carrier aggregation configuration that incorporates component carriers operating in the licensed band (e.g., LAA). Operations in the unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

Base station 105 or UE 115 may be equipped with multiple antennas that may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of base station 105 or UE 115 may be located within one or more antenna arrays or antenna panels (which may support MIMO operation or transmit or receive beamforming). For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with base station 105 may be located in different geographic locations. The base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming for communication with the UE 115. Also, UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals transmitted via the antenna ports.

Base station 105 or UE 115 may utilize multipath signal propagation using MIMO communication and improve spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. For example, the transmitting device may transmit multiple signals via different antennas or different combinations of antennas. Also, the receiving device may receive multiple signals via different antennas or different combinations of antennas. Each of the plurality of signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or a different data stream (e.g., a different codeword). Different spatial layers may be associated with different antenna ports for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) (in which multiple spatial layers are transmitted to the same receiving device) and multi-user MIMO (MU-MIMO) (in which multiple spatial layers are transmitted to multiple devices).

Beamforming (which may also be referred to as spatial filtering, directional transmission or directional reception) is a signal processing technique as follows: the techniques may be used at a transmitting device or a receiving device (e.g., base station 105, UE 115) to form or steer antenna beams (e.g., transmit beams, receive beams) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by: signals transmitted via antenna elements of the antenna array are combined such that some signals propagating in a particular direction relative to the antenna array experience constructive interference while other signals experience destructive interference. The adjusting of the signal transmitted via the antenna element may include: the transmitting device or the receiving device applies an amplitude offset, a phase offset, or both to the signal carried via the antenna element associated with the device. The adjustment associated with each of the antenna elements may be defined by a set of beamforming weights associated with a particular orientation (e.g., relative to an antenna array of the transmitting device or the receiving device, or relative to some other orientation).

As part of the beamforming operation, the base station 105 or UE 115 may use beam scanning techniques. For example, the base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with the UE 115. The base station 105 may transmit some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) multiple times in different directions. For example, the base station 105 may transmit signals according to different sets of beamforming weights associated with different transmission directions. Transmissions in different beam directions may be used (e.g., by a transmitting device (such as base station 105) or by a receiving device (such as UE 115)) to identify the beam direction for subsequent transmission or reception by base station 105.

The base station 105 may transmit some signals (e.g., data signals associated with a particular receiving device (e.g., UE 115)) in a single beam direction (e.g., a direction associated with the receiving device). In some examples, the beam direction associated with transmissions along a single beam direction may be determined based on signals transmitted in one or more beam directions. For example, the UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions and may report an indication to the base station 105 of the signal received by the UE 115 with the highest signal quality or otherwise acceptable signal quality.

In some examples, transmissions by a device (e.g., by base station 105 or UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from base station 105 to UE 115). The UE 115 may report feedback indicating precoding weights for one or more beam directions and the feedback may correspond to a configured number of beams spanning a system bandwidth or one or more subbands. The base station 105 may transmit reference signals (e.g., cell-specific reference signals (CRSs), channel state information reference signals (CSI-RS)) that may or may not be precoded. The UE 115 may provide feedback for beam selection, which may be a Precoding Matrix Indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals transmitted by the base station 105 in one or more directions, the UE 115 may employ similar techniques to transmit signals multiple times in different directions (e.g., to identify a beam direction for subsequent transmission or reception by the UE 115) or in a single direction (e.g., to transmit data to a receiving device).

Upon receiving various signals, such as synchronization signals, reference signals, beam selection signals, or other control signals, from the base station 105, a receiving device (e.g., UE 115) may attempt multiple receive configurations (e.g., directed listening). For example, the receiving device may attempt multiple directions of reception by receiving via different antenna sub-arrays, by processing received signals according to different antenna sub-arrays, by receiving according to different sets of receive beamforming weights (e.g., different sets of directional listening weights) applied to signals received at multiple antenna elements of the antenna array, or by processing received signals according to different sets of receive beamforming weights applied to signals received at multiple antenna elements of the antenna array (any of the above operations may be referred to as "listening" according to different receive configurations or receive directions). In some examples, the receiving device may use a single receiving configuration to receive along a single beam direction (e.g., when receiving a data signal). The single receive configuration may be aligned on a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or otherwise acceptable signal quality based on listening according to multiple beam directions).

The wireless communication system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. The Radio Link Control (RLC) layer may perform packet segmentation and reassembly for transmission over logical channels. The Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels to transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, a Radio Resource Control (RRC) protocol layer may provide for the establishment, configuration, and maintenance of an RRC connection between the UE 115 and the base station 105 or core network 130, which supports radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels.

The UE 115 and the base station 105 may support retransmission of data to increase the likelihood that the data is successfully received. Hybrid automatic repeat request (HARQ) feedback is a technique for increasing the likelihood that data is properly received over the communication link 125. HARQ may include a combination of error detection (e.g., using Cyclic Redundancy Check (CRC)), forward Error Correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ may improve throughput at the MAC layer under poor radio conditions (e.g., low signal and noise conditions). In some examples, a device may support the same slot HARQ feedback, where the device may provide HARQ feedback in a particular slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent time slot or according to some other time interval.

The UE 115 and the base station 105 of the wireless communication system 100 may be configured to support techniques for selecting and reserving side-uplink resources that may be understood by both reduced-capability UEs 115 (e.g., re16 UEs) and non-reduced-capability UEs 115 (e.g., re17 UEs 115). In this regard, the wireless communication system 200 may support techniques for scheduling side-link communications for Re17 UEs 115 that are backward compatible (e.g., understood) by Re16 UEs 115. In particular, the techniques described herein enable Re17UE 115 to send some side-link scheduling information in the first stage SCI portion (e.g., SCI-1 portion) of the IUE coordination message, enabling Re16 UE 115 to receive and identify reservations of side-link resources by Re17UE 115. By implementing backward compatibility in the context of scheduling side uplink communications, aspects of the present disclosure may improve coordination between UEs 115, thereby reducing interference and improving efficiency and reliability of wireless communications.

For example, a UE 115 (e.g., re17 UE 115) of the wireless communication system 100 may select a set of resources for a side-link message to be performed by the UE 115 (e.g., self-scheduled or self-reserved) or another UE 115. In some cases, UE 115 may send an IUE coordination message reserving a set of resources, where some portions of the IUE coordination message (e.g., SCI-2 portion, data portion) may be decoded by Re17 UE 115 but may not be decoded by Re16 UE 115. In addition, the IUE message may reserve a first resource (e.g., the earliest resource) in the selected set of resources via an indication within a first stage SCI portion (e.g., SCI-1 portion) of the IUE coordination message. In particular, UE 115 may select additional resources for the IUE coordination message to satisfy the timing constraint associated with the SCI-1 portion such that the IUE coordination message (e.g., SCI-1 portion of the IUE coordination message) is not sent more than 32 slots prior to the first selected resource. Subsequently, UE 115 may send an IUE coordination message within the additional resources, wherein the SCI-1 portion of the IUE coordination message is decodable by Re16 UE 115 and indicates reservation of the first/earliest reserved resources.

Techniques described herein may improve sidelink network coordination to reduce collisions within sidelink resources. In particular, by sending some information related to reserved side-link resources via the SCI-1 portion of the IUE coordination message, the techniques described herein may enable backward compatibility for side-link reservations between Re17 UE 115 and Re16 UE 115. By enabling reservation of side-link resources to be understood by both Re17 UE 115 and Re16 UE 115, the techniques described herein may reduce potential collisions within side-link resources and may enable more efficient and reliable communications within wireless communication system 100.

Fig. 2 illustrates an example of a wireless communication system 200 supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure. In some examples, wireless communication system 200 may implement aspects of wireless communication system 100 or by aspects of wireless communication system 100. The wireless communication system 200 may support techniques for reserving side-uplink resources that may be understood by UEs 115 with different capabilities.

The wireless communication system 200 may include a base station 105 (not shown), a first UE 115-a, and a second UE 115-b, which may be examples of UEs 115, base stations 105, and other wireless devices as described with reference to fig. 1. In some aspects, one or more of the UEs 115 may communicate with the base station 105 using a communication link, which may be an example of an NR or LTE link between the base station 105 and the respective UE 115. In some aspects, the communication links between the base stations 105 and the respective UEs 115 may include examples of access links (e.g., uu links), which may include bi-directional links that enable both uplink and downlink communications. Further, in some aspects, the first UE 115-a and the second UE 115-b may communicate with each other using a communication link 205, which communication link 205 may be an example of a side-link communication link or a PC5 link.

In some aspects, the communication links 205 between respective UEs 115 (e.g., sidelink communication links) may be included within a sidelink network of the wireless communication system 200. The sidelink network (e.g., the sidelink network including communication links 205-a, 205-b) may be configured to operate in "mode 1" and/or "mode 2". When operating in mode 1, the side-link network (e.g., communication link 205) may be managed (e.g., coordinated) by the base station 105. In this regard, during mode 1 operation, the base station 105 may manage resource allocation over the communication link 205 and may allocate sets of resources within the communication link 205 to respective UEs 115. In some cases, the base station 105 may allocate the set of side downlink resources to the respective ues 115 during mode 1 operation via RRC signaling, a Downlink Control Information (DCI) message (e.g., DCI 3_0), or both. During mode 1 operation, the base station 105-a may allocate side uplink resources via dynamic grants, configured grants (e.g., type 1 configured grants, type 2 configured grants), or both. Within mode 1 operation, the Modulation and Coding Scheme (MCS) for communications over the communication link 210 (e.g., a side-link communication link) may be determined by the respective UE 115 within the constraints pre-configured at the UE 115 and/or signaled by the base station 105-a.

In contrast, when operating in mode 2, the side-link network (e.g., communication link 205) may not be managed by base station 105 (e.g., may not be coordinated by base station 105). Without coordinating or managing resources of the sidelink network during mode 2 operation, UE 115 may be configured to monitor the sidelink network (e.g., monitor sidelink communication link 205 and/or other sidelink communication links) and determine a set of sidelink resources available for transmitting sidelink messages via sidelink communication link 205. For example, the first UE 115-a may determine the side-link resources to be used within the communication link 205 "autonomously" by: the sidelink network, including the sidelink communication link, is monitored and all Physical Sidelink Control Channels (PSCCHs) and Physical Sidelink Shared Channels (PSSCHs) within the communication link 205 and the sidelink network are decoded to identify sidelink resources that have been reserved by other UEs 115. Subsequently, the first UE 115-a may report available sidelink resources to an upper layer and may send sidelink control information (e.g., SCI) reserving a set of sidelink resources for sidelink communications to be performed (e.g., transmitted, received) at the first UE 115-a. In this regard, mode 2 operation of the sidelink network including the communication link 205 may follow a contention-based access procedure in which various UEs 115 "contend" for use of the sidelink network (including the communication link 205).

Within the mode 2 side-link operation, there are several different "types" of side-link reservations that may be performed. For example, according to "IUE coordination scheme 1" ("scheme 1"), the first UE 115-a may send to the second UE 115-b a set of resources that are preferred or non-preferred for the second UE 115-b side uplink message. In other words, the coordination information transmitted in scheme 1 may include an indication of preferred resources and/or non-preferred resources. In some cases, IUE coordination information may be transmitted within the second stage SCI portion (e.g., SCI-2 portion) of the IUE coordination message, the data portion of the IUE coordination message, or both. The indication of the preferred/non-preferred resource set may be based on a sensing result of the side-uplink network performed by the first UE 115-a, an expected or potential resource conflict, or any combination thereof. Some wireless communication systems may support techniques for selecting between a preferred set of resources and a non-preferred set of resources in the context of scheme 1.

Additionally or alternatively, according to "IUE coordination scheme 2" ("scheme 2"), the first UE 115-a may identify a resource conflict (e.g., within a side-uplink resource set) and may send an indication of the detected conflict to the second UE 115-b. For example, the first UE 115-a may receive a SCI message from the second UE 115-b reserving a set of side uplink resources for the side uplink message to be performed by the second UE 115-b and may identify an expected or potential collision on the reserved resources. In this case, the first UE 115-a may transmit an indication of time/frequency resources for the detected conflict, a type of resource conflict, information associated with a sensing operation performed to detect the conflict, broadcast type information, and the like. In other words, the coordination information transmitted in scheme 2 may include an indication of past and/or future collisions, which may be transmitted within a second stage SCI portion (e.g., SCI-2 portion) of the IUE coordination message, a data portion of the IUE coordination message, or both. Some wireless communication systems may support techniques for selecting between anticipated/potential collisions and detected resource collisions in the context of scheme 1.

In some implementations, the UE 115 may be configured to implement scheme 1 and scheme 2 in different scenarios and/or when certain conditions or parameters are met. In other cases, the use of scheme 1 and/or scheme 2 may be configured via higher layer signaling (e.g., RRC signaling, MAC-CE signaling), may be based on certain conditions or UE 115 capabilities. In other cases, the signaling used in schemes 1 and 2 may be limited to certain geographic ranges, such as in the intended receivers within range of the respective UEs 115-a, 115-b. These signaling mechanisms within mode 2 operation (e.g., the signaling performed within scheme 1 and scheme 2) may help facilitate coordination (e.g., IUE coordination) between UEs 115-a, 115-b, which may improve efficiency and reliability of wireless communications within the side-link network of wireless communication system 200.

When the second UE 115-b receives IUE coordination information (e.g., an indication of a preferred/non-preferred collision in scheme 1, an indication of a detected collision in scheme 2) from the first UE 115-a, the second UE 115-b may utilize the received information in various ways to improve the side-link reservation. For example, in the context of scheme 1, the second UE 115-b may select or reselect which resources to use for its own sidelink message based on both the sensing results of the second UE 115-b (if available) and the received coordination information (e.g., received indications of preferred/non-preferred resources). In other cases, the second UE 115-b may select or reselect which resources to use for its own sidelink message based solely on the received coordination information, or may reselect resources based on the received coordination information. In contrast, in the context of scheme 1, the second UE 115-b may select or reselect which resources to use for its own sidelink message based on the received indication of the expected/potential collision and/or may determine the necessity of retransmission based on the received indication of the expected/potential collision.

Some wireless communication systems, such as wireless communication systems 100 and 200, may support UEs 115 with different capabilities, such as reduced capability UEs 115 (e.g., re16 UEs 115) and non-reduced capability UEs 115 (e.g., re17 UEs 115). In other words, re16 UE 115 and Re17 UE 115 may coexist and communicate within the same resource pool. For example, in some cases, the first UE 115-a may include a non-reduced capability UE 115 (e.g., re17 UE 115), and the second UE 115-b may include a reduced capability UE 115 (e.g., re16 UE 115). In other cases, both the first UE 115-a and the second UE 115-b may include non-reduced capability UEs 115.

However, UEs 115 with different capabilities may utilize different mechanisms to reserve and communicate on side-link resources. Furthermore, not all UEs 115 are able to receive and decode messages reserving side-uplink resources, which may lead to increased interference.

For example, in the context of Re16, re16 UE 115 may select a set of side uplink resources 220 for its own side uplink message at time 1, as shown in fig. 2. According to Re16 behavior, UE 115 may not perform any other actions until the first/earliest side uplink message is sent within earliest side uplink resource 215-a (e.g., first transmission of aperiodic transmission, first semi-persistent scheduling (SPS) transmission) within reserved side uplink resource set 220. In other words, after the selection of the side-link resource 220 at time 1, the Re16 ue 115 may not send any indication of the reservation of the side-link resource 220, such that the resources of the transmission are selected but not signaled. This may result in interference when other UEs 115 reserve resources that overlap with the selected set of side uplink resources 220.

In contrast, in the context of Re17, re17 UE 115 may signal resources selected for its own side-uplink messages (e.g., self-reservation) and/or resources selected for side-uplink messages to be performed by other UEs 115. For example, as previously noted herein, re17 UE 115 may reserve initial transmission resources as preferred or non-preferred resources by sending an IUE coordination message. Such IUE coordination information may be used by UE 115 to schedule its own side-uplink messages (e.g., self-reservations). In some aspects, the UE 115 may transmit a self-reservation in the event that the UE 115 has selected resources but has not signaled a reservation of resources. In other cases, one UE 115 (or another wireless device) may select resources that are preferred/non-preferred for a side-uplink message to be performed by another UE 115 (e.g., tx UE 115), and may notify the Tx UE 115 of the preferred/non-preferred resources. Such indication of preferred/non-preferred resources may be distributed (where Rx UEs 115 schedule Tx UEs 115) or centralized (where scheduling UEs 115 schedule transmitting UEs 115 (where scheduling UEs 115 may or may not be UEs 115 set to receive side-uplink messages)).

However, not all UEs 115 are able to receive and decode IUE coordination messages reserving side uplink resources. In particular, re16UE 115 cannot decode or understand the content of the IUE coordination message used by Re17UE 115. Thus, where Re17 UEs 115 coordinate with each other with respect to reserved side-uplink resources, re16 UEs 115 may not be aware of such coordination and may transmit on resources previously reserved by Re17 UEs 115. In other words, despite the existence of Re17 IUE coordination, re16 side downlink communications may still collide with Re17 side downlink communications. This results in increased interference, which reduces performance of both Re16 communication and Re17 communication.

Accordingly, aspects of the present disclosure relate to techniques for scheduling side-uplink communications for Re17 UEs that are backward compatible (e.g., understandable) by Re16 UEs. Aspects of the present disclosure relate to signaling and other configurations that enable Re16 UE 115 to be aware of intended Re17 side-link communications, which may affect several parameters of Re17 for indicating side-link reservations via IUE coordination information (including IUE coordination containers, IUE coordination signaling designs, and IUE coordination procedures). Further, aspects of the present disclosure may enable Re16 UEs 115 to understand reservation of side-uplink resources for initial transmission as preferred/non-preferred resources (e.g., self-scheduling) as well as signaling, where Re17 UEs 115 are scheduled and/or recommended resources for different, scheduled Re17 UEs 115.

In particular, the techniques described herein enable Re17 UEs to send some side-link control information in the SCI-1 portion (e.g., the first stage SCI) of the IUE coordination message, enabling Re16 UEs to receive and identify reservations of side-link resources by Re17 UEs. SCI-1 is the only form of resource reservation that can be understood (e.g., decoded) by some Re16 UEs 115, as previously described herein. Furthermore, in the case of SCI-1, the time gap between any two consecutive reserved resources may not exceed 32 slots (e.g., SCI-1 may reserve resources only for the next 32 slots). Thus, in some implementations, aspects of the present disclosure may enable Re17 side uplink reservations sent via the SCI-1 portion of IUE coordination messages to adhere to SCG-1 reservation time gap constraints to the extent possible. In other words, aspects of the present disclosure may enable Re17 UE 115 to send some side-link reservation information via the SCI-1 portion of the IUE coordination message, wherein the time gap between SCI-1 portions of the corresponding IUE coordination message and/or the time gap between consecutive resources reserved via the SCI-1 portion of the IUE coordination message is less than 32 slots.

For example, in the context of self-scheduling in which the first UE 115-a reserves initial transmission resources (e.g., non-preferred resources) for its own sidelink message 240, the first UE 115-a may be configured to select the sidelink resource set 220 for its own sidelink message 240. For example, as shown in fig. 2, a first UE 115-a may select a set of side uplink resources 220 for a side uplink message 240 from the first UE 115-a to a second UE 115-b at time 1. The first UE 115-a may additionally be configured to select additional resources to be used for sending the IUE coordination message 230, the IUE coordination message 230 indicating a reservation of a first resource (e.g., earliest resource) in the set of contralateral uplink resources 220 within a first stage SCI portion (e.g., SCI-1 portion) of the IUE coordination message 230. In other words, at time 2, the first UE 115-a may select additional resources to be used for transmitting the IUE coordination message 230, which IUE coordination message 230 reserves the earliest side uplink resource 215-a in the side uplink resource set 220 via the SCI-1 portion of IUE coordination message 230.

When selecting additional resources to be used for transmitting the IUE coordination message 230 reserving the earliest side uplink resource 215-a (e.g., indicating non-preferred resources), the first UE 115-a may be configured to select the additional resources such that the additional resources meet timing requirements for the SCI-1 portion of the IUE coordination message 230. In other words, the first UE 115-a may be configured to select additional resources for the IUE coordination message 230 such that the earliest side uplink resource 215-a is less than 32 slots after the additional resources for transmitting the IUE coordination message 230 including the non-preferred resource indication.

In this regard, the first UE 115-a may select the additional resources for the IUE coordination message 230 such that a time interval 235 between the additional resources (e.g., the additional resources for the IUE coordination message 230) and the earliest side uplink resource 215-a meets a time threshold. More specifically, the first UE 115-a may select the additional resources for the IUE coordination message 230 such that the time interval 235 between the additional resources (e.g., the additional resources for the IUE coordination message 230) and the earliest side uplink resource 215-a is less than 32 time slots (e.g., the time interval 235 between the SCI-1 portion of the IUE coordination message 230 and the earliest side uplink resource 215-a is less than 32 time slots).

In some aspects, the second UE 115-b may attempt to decode the IUE coordination message 230 without regard to one or more parameters indicated via the SCI (e.g., SCI-1 portion, SCI-2 portion, or both) of the IUE coordination message 230, such as a broadcast type, destination identifier, source identifier, feedback distance information, and the like. In particular, where the second UE 115-b identifies the IUE coordination message 230 as an IUE message (e.g., via one or more bit fields of the IUE coordination message 230 or via restrictions), the second UE 115-b may attempt to decode the IUE coordination message 230 without regard to the broadcast type, destination identifier information, source identifier information, and/or feedback distance information indicated via SCI (e.g., SCI-1 portion and/or SCI-2 portion) of the IUE coordination message 230. By attempting to decode the IUE coordination message without consideration of these parameters, the techniques described herein may enable each UE 115 within wireless communication system 200 to receive IUE coordination message 230 as broadcast information even if IUE coordination message 230 is piggybacked to data and thus shares the same broadcast type characteristics as the data.

There are several implementations that may be implemented by the first UE 115-a such that the additional resources for the IUE coordination message 230 meet the timing requirements for the SCI-1 message (e.g., the timing requirements for the SCI-1 portion of the IUE coordination message 230). For example, in some cases, the first UE 115-a may repeat the R16 resource selection process multiple times until the earliest side uplink resource 215-a is less than 32 slots from the additional resources selected for sending the non-preferred resource indication (e.g., less than 32 slots from the additional resources for IUE coordination message 230). As another example, the first UE 115-a may exhaust all possible combinations of resources selected for transmitting the non-preferred resource indication and the earliest side uplink resource 215-a and may then uniformly sample each respective combination of resources that meets the 32 slot time constraint.

In some cases, the first UE 115-a may wait to send the scheduled side-link message 240 (e.g., may select a new set of side-link resources 220) if the first UE 115-a cannot find/select additional resources for the IUE coordination message 230 that satisfy the timing constraint for SCI-1 signaling. Additionally or alternatively, if the first UE 115-a cannot find/select additional resources for the IUE coordination message 230 that satisfy the timing constraint for SCI-1 signaling, the first UE 115-a may refrain from reserving the earliest side uplink resources 215-a and/or include IUE coordination information within the IUE coordination message 230, as will be discussed in further detail herein. However, it should be noted herein that the 32-slot time constraint for SCL-1 signaling may not be an absolute requirement (e.g., may not be binding). In this way, the first UE 115-a may perform a reasonable search to select additional resources that will meet the time constraint, but not be required to do so in all cases. For example, with a large amount of side-link traffic, there may not be any available resources for IUE coordination message 230, which may be selected to meet SCI-1 timing constraints.

After selecting the additional resources for IUE coordination message 230 at time 2 (e.g., additional resources to be used to send an indication of earliest side uplink resource 215-a), first UE 115-a may send IUE coordination message 230 within the selected additional resources. For example, the first UE 115-a may select the additional resources at time 2 and may then send the IUE coordination message via the additional resources. In some aspects, IUE message 230 may include an indication of the earliest side uplink resource 215-a in the selected set of side uplink resources 220.

In some cases, the first UE 115-a may be configured to send multiple IUE coordination messages 230 in order to satisfy SCI-1 timing constraints. In particular, if the additionally selected resources for IUE coordination messages 230 do not meet the 32-slot time constraint (e.g., if time interval 235 is greater than 32 slots), then first UE 115-a may "daisy-chain" multiple IUE coordination messages 230 until one of IUE coordination messages 230 meets the 32-slot timing constraint. In other words, if the initial gap (time interval 235) between the additional resources selected for transmitting IUE coordination message 230 and the earliest side uplink resource 215-a is too large (e.g., greater than 32 slots), the first UE 115-a may select/schedule additional resources to transmit a non-preferred resource indication (e.g., select additional resources for transmitting additional IUE coordination message 230). For example, if the time interval 235 between the earliest side uplink resource 215-a and the SCI-1 portion of IUE coordination message 230 is greater than 32 time slots, the first UE 115-a may transmit an additional IUE coordination message 230 reserving the earliest side uplink resource 215-a until the time interval between SCI-1 portions of IUE coordination message 230 transmitted satisfies the time constraint (e.g., until the SCI-1 portion of IUE coordination message 230 transmitted is less than 32 time slots before the earliest side uplink resource 215-a).

As another example, the first UE 115-a may perform a resource selection procedure to select resources for transmitting the IUE coordination message 230. If the earliest side uplink resource 215-a for side uplink message 240 is less than 32+ t slots from the resource selected for IUE coordination message 230, UE 115-a may trigger another resource selection procedure to find another resource for IUE coordination message 230 that will satisfy the applicable timing constraint (e.g., another resource within 32 slots of earliest side uplink resource 215-a). In contrast, if the earliest side uplink resource 215-a for side uplink message 240 is more than 32+T slots from the resource selected for IUE coordination message 230, UE 115-a may wait until 32+T slots before earliest side uplink resource 215-a to trigger another resource selection procedure in order to find another resource for IUE coordination message before earliest side uplink resource 215-a. In other words, the UE 115-a may begin resource selection at 32+t slots before the earliest side uplink resource 215-a and may seek to select resources for IUE coordination message 230 within the 32 slots of the earliest side uplink resource 215-a. In these examples, T may indicate a time period or additional time interval (e.g., one or more slots, symbols, etc.) for taking into account resource selection, implementation, and processing constraints at the first UE 115-a and/or the second UE 115-b. The value of T may be configured via the network (e.g., via RRC signaling), preconfigured at UE 115-a, or may be decided by UE 115 implementation. Further, the value of T may be defined by an upper limit T _max, where T _max may be preconfigured, configured or signaled via the network (e.g., via RRC signaling, SIB broadcast), preconfigured at UE 115-a, or may be decided by UE 115 implementation.

In the event that the earliest side uplink resource 215-a is less than 32 time slots from the additional resources used to transmit IUE coordination message 230 including the non-preferred resource indication, IUE coordination message 230 may include an indication of earliest side uplink resource 215-a. In other words, the SCI-1 portion of IUE coordination message 230 may reserve the earliest side uplink resource 215-a in the event that a timing constraint (e.g., a 32 slot timing constraint) is met. In this case, the IUE coordination message 230 (e.g., SCI-1 portion of IUE coordination message 230) may include an indication of the set of subchannels for the earliest side uplink resource 215-a. The number of reserved subchannels may indicate the number of subchannels for the earliest side uplink resource 215-a to be used for transmitting data (e.g., to be used for transmitting the first/earliest side uplink message 240-a). However, in some cases, the indication may be undesirable (e.g., may be considered "cheating") for R16 UE 115 because the non-preferred resource indication message for Re16 UE 115 may be only one subchannel. However, the impact is negligible. The indication of the subchannel for the earliest side uplink resource 215-a may not have any effect on the side uplink resource selection because the reserved resources in the current time slot are not used as input to the resource selection process and the resource selection process (e.g., the resource selection algorithm) uses only future resources to determine the resource selection. Furthermore, the indication of the subchannel for the earliest side uplink resource 215-a may have limited impact on the demodulation process at the second UE 115-b because the second UE 115-b may not attempt to decode the data after failing to decode SCI-2.

On the other hand, re17 UEs may need to know that IUE coordination message 230 is only 1 subchannel, even if the SCI-1 portion of IUE coordination message 230 indicates that the message is more than one subchannel, such Re17 UEs 115 may not be able to decode the SCI-2 portion of IUE coordination message 230 and the corresponding data portion to recover the rest of IUE coordination information (except for the initial reserved resources). In some aspects, the resources used to send IUE coordination message 230 may be limited to a certain fixed time and/or fixed frequency location (e.g., resources that are preconfigured or indicated via control signaling). For example, IUE coordination message 230 may be sent via a single subchannel. In this regard, by transmitting IUE coordination message 230 within fixed time/frequency resources (e.g., via a single subchannel), re17 UE 115 may be configured to identify that signals received within the respective resources may be associated with potential IUE coordination message 230 and, thus, may attempt to decode SCI-2 on a single subchannel. In an additional or alternative implementation, re17 UE 115 may be configured to perform a blind decoding process to decode SCI-2 on a single subchannel (e.g., blind decoding for the SCI-2 portion of IUE coordination message 230). In this case, if the Re17 UE 115 decodes a valid SCI-2 payload, the Re17 UE 115 will know that it is a potential IUE coordination message 230. Furthermore, in some cases, reserved bits in the SCI-1 payload (e.g., reserved bits within the SCI-1 portion of IUE coordination message 230) may be used to indicate that this is IUE coordination message 230, such that Re17 UE 115 may attempt to decode SCI-2 in one subchannel (e.g., decode the SCI-2 portion of IUE coordination message 230 within one subchannel).

If the indicated last subchannel for the earliest side-link resource 215-a end (last, final) subchannel and/or non-preferred resource indication message is outside of the resource pool for side-link communication, some UEs 115 (e.g., re16 UEs 115) may not be able to interpret the reserved subchannel and may therefore ignore the reservation information. In other words, the last subchannel used to send IUE coordination message 230 and the last subchannel of the earliest reserved sidelink resource 215-a must be located within the resource pool used for sidelink communications in order for some Re16 ues 115 to understand the reservation. Thus, where IUE coordination message 230 indicates a set of subchannels for earliest side-link resource 215-a, the last subchannel in the set of subchannels may be within a resource pool for side-link communication in the frequency domain. In some implementations, the constraint may cause the first UE 115-a to send the IUE coordination message 230 within resources away from the end of the resource pool (e.g., within resource 0 of the resource pool in the frequency domain).

In other cases, IUE coordination message 230 may indicate/reserve a single subchannel for the earliest side uplink resource 215-a. In this case, the number of reserved subchannels for the earliest side-link resource 215-a would be 1 and may be included in the resource pool for side-link communication. R16 UE 115 may desire to reserve a single subchannel (e.g., a "non-cheating" option) and there may be no restriction as to where IUE coordination message 230 may be sent in the frequency domain of the resource pool. However, by indicating only a single subchannel for the earliest side uplink resource 215-a, the full side uplink message 240-a to be transmitted within the earliest side uplink resource 215-a may not be reserved or protected. That is, only a portion of the data transmissions sent within a single indicated sub-channel may be reserved/protected.

In some cases, the Frequency Domain Resource Indication (FDRI) field within the SCI-1 portion of IUE coordination message 230 may point to (e.g., indicate) the first/initial subchannel of the earliest side uplink resource 215-a (e.g., the first/initial subchannel of the first side uplink message 240-a to be transmitted via the earliest side uplink resource 215-a). By indicating the first/initial subchannel, the techniques described herein may protect at least the first subchannel in which the side-uplink message 240-a of SCI-1 is to be carried. In some cases, SCI-2 may be transmitted across multiple sub-channels. Additionally or alternatively, the FDRI field within IUE coordination message 230 may point to (e.g., indicate) any subchannel of the earliest side uplink resource 215-a (e.g., any subchannel of the first side uplink message 240-a that is to be transmitted via the earliest side uplink resource 215-a). In some aspects, a decision may be made by the UE 115-a whether the first UE 115-a indicates a first/initial subchannel or any subchannel of the earliest side uplink resource 215-a, may be indicated to the first UE 115 via the network, or both.

In some aspects, assuming SCI-1 timing constraints are met, the first UE 115-a may send an indication of reserved resources (e.g., an indication of side link resources 220) on the IUE coordination message 230 and copy the corresponding SCI-1 portion via the IUE coordination message 230. In other words, when IUE coordination message 230 (e.g., SCI-1 portion of IUE coordination message 230) is transmitted less than 32 time slots away from earliest side uplink resource 215-a, first UE 115-a may transmit an indication of the earliest side uplink resource via SCI-1 portion of IUE coordination message 230 and, at the same time, include the earliest side uplink resource in the set of non-preferred resources indicated in IUE coordination information included within IUE coordination message 230 (e.g., the IUE coordination information included within SCI-2 and/or data portion of IUE coordination message 230). In contrast, if the timing constraint is not met, the first UE 115-a may send an indication of the earliest side uplink resource (e.g., an indication within the SCI-2 portion and/or the data portion but not in the SCI-1 portion) in the non-preferred set of resources indicated in the IUE coordination message without reservation via SCI-1. In other words, if the IUE coordination message 230 is sent more than 32 time slots away from the earliest side uplink resource 215-a (e.g., SCI-1 portion of IUE coordination message 230), the first UE 115-a may send an indication of non-preferred resources via the IUE coordination message and no SCI-1 replication.

In additional or alternative implementations, the first UE 115-a may send an indication of reserved resources (e.g., an indication of side uplink resources 220) via only the SCI-1 portion (e.g., no duplication) of the IUE coordination message 230. In such a case, if the SCI-1 portion of IUE coordination message 230 is sent more than 32 slots away from the earliest side uplink resource 215-a, the first UE 115-a may be configured to avoid sending a reservation of the earliest side uplink resource 215-a (e.g., fallback to Re16 behavior) or wait until a later time when it is possible to send IUE coordination message 230 reserving the initial side uplink resource 215-a that satisfies the timing constraint.

In some cases, the UE 115 of the wireless communication system 200 may be configured to forward or relay the IUE coordination message 230 and other messages reserving side uplink resources to other UEs 115. By forwarding/relaying the initial resource reservation in IUE coordination message 230 to other UEs 115 within wireless communication system 200, the techniques described herein may enable receive-side protection of scheduled side-uplink message 240, particularly in the context of a unicast link. For example, upon receiving the IUE coordination message 230 reserving the earliest side uplink resource 215-a, the second UE 115-b may forward or relay the initial resource reservation in the IUE coordination message 230 to other UEs 115, such as UEs 115 that are out of range from the first UE 115-a. The initial resource reservation (e.g., SCI-1 portion) in relay IUE coordination message 230 may enable other UEs 115 to be aware of reserved side-link resources 220, which may further reduce interference and collisions within wireless communication system 200. In such cases, the UE 115-b may be configured to relay the entire IUE coordination message 230 and/or relay only the portion of the IUE coordination message 230 indicating the reservation of the earliest side uplink resource 215-a (e.g., relay only the SCI-1 portion of IUE coordination message 230). The first UE 115-a may be similarly configured to forward/relay the initial resource reservation in the IUE coordination message 230 and other resource reservations received by the first UE 115-a to other wireless devices within the wireless communication system 200.

In the case of forwarding/relaying initial resource reservations in IUE coordination message 230 and other signaling for reservation of side-uplink resources in UE 115 of wireless communication system 200, the Time Domain Resource Indication (TDRI) field within the SCI-1 portion of IUE coordination message 230 may be repackaged or reset to point to the same relative timing of the reserved resources. In other words, TDRI fields may be reset to account for the time difference between the first time of initially sending IUE coordination message 230 and the second time of initial resource reservation in relay IUE coordination message 230. For example, the IUE coordination message 230 sent by the first UE 115-a may include a TDRI field indicating a time difference (e.g., time gap) between transmission of the IUE coordination message 230 and the earliest side uplink resource 215-a. Upon receiving the IUE coordination message 230, the second UE 115-b may relay the initial resource reservation in the IUE coordination message 230 to other UEs 115 (e.g., relay the entire IUE coordination message 230 and/or SCI-1 portion of the IUE coordination message 230) and may repackage (e.g., reset) TDRI fields within the relayed IUE coordination message 230 such that TDRI fields point to the same relative timing of the earliest side uplink resource 215-a. In other words, the second UE 115-b may reset the TDRI field within the relay IUE coordination message 230 such that the reset TDRI field indicates a time gap between the time of the relay IUE coordination message 230 and the time of the same earliest side uplink resource 215-a. Furthermore, the SCI-2 portion and/or the data portion of the relay IUE coordination message 230 may or may not include a copy indication of reserved resources, as previously described herein, depending on whether the IUE coordination message 230 originally sent by the first UE 115-a includes a copy indication within the corresponding SCI-2/data portion.

Subsequently, the first UE 115-a may send the first side-link message 240-a via the earliest side-link resource 215-a indicated by the IUE coordination message 230. In some cases, the first side-link message 240-a may indicate time/frequency resources for a subsequent side-link message 240. For example, in some cases, the first side-link message 240-a may include time/frequency resources for the subsequent side-link resource 215-b that will be used to transmit the second side-link message 240-b. For example, the first side-link message 240-a may include SCI-1 and/or SCI-2 that schedule a subsequent (second) side-link message 240-b. Similarly, the second sidelink message 240-b may indicate time/frequency resources for a subsequent sidelink message 240 (e.g., indicating time/frequency resources for sidelink resource 215-c).

In addition to supporting backward compatible side-link reservations in the context of self-reservations (e.g., by self-scheduling indicating non-preferred resources), the techniques of this disclosure may also be used for backward compatible signaling to schedule/recommend resources for another UE 115. In other words, the techniques described herein may be used in the case where a first UE 115-a schedules a side-link message 240 to be performed by a second UE 115-b.

For example, the first UE 115-a may be configured to select a set of side uplink resources 220 for a side uplink message 240 to be performed/transmitted by the second UE 115-b. In this regard, a first UE 115-a (e.g., scheduling UE 115-a) may select resources to be used by a second UE 115-b (e.g., scheduled UE 115-b) to send side uplink messages 240-a and/or 240-b. For example, as shown in fig. 2, a first UE 115-a may select a set of side uplink resources 220 for a side uplink message 240 from a second UE 115-b to the first UE 115-a (or another UE 115) at time 1. The first UE 115-a may be additionally configured to select additional resources to be used for sending an IUE coordination message 230 (e.g., SCI-1 portion of IUE coordination message 230) indicating a reservation of a first resource (e.g., an earliest resource) in the set of side uplink resources 220. In other words, at time 2, the first UE 115-a may select additional resources to be used for transmitting the IUE coordination message 230 that reserve the earliest side uplink resource 215-a in the side uplink resource set 220 within the SCI-1 portion of the IUE coordination message 230, as previously described herein.

As noted previously herein in the context of reserving non-preferred resources for self-selection, the first UE 115-a may be configured to select additional resources to be used for reserving the earliest side uplink resource 215-a such that the additional resources meet timing requirements for SCC-1. In other words, the first UE 115-a may be configured to select additional resources for the IUE coordination message 230 such that the earliest side uplink resource 215-a is less than (or equal to) 32 slots after the additional resources for transmitting the IUE coordination message 230 including the non-preferred resource indication.

Further, the first UE 115-a may require a certain amount of time (e.g., time interval 245, T slots) for processing and handshaking between transmission of the IUE coordination message 230 and receipt of the earliest IUE coordination message 230. The amount of time required for the first UE 115-a to process and handshake may depend on how the handshake procedure is designed. Thus, in some cases, the first UE 115-a may select additional resources for transmitting the resource reservation in a manner that satisfies an additional time interval 245 (e.g., T slots) associated with processing capability at the first UE 115-a and/or a handshake procedure to be performed between the first UE 115-a and the second UE 115-b. If the IUE coordination message 230 is sent more than T time slots before the earliest side uplink resource, then the additional time interval 245 for processing and handshaking may be met. Thus, the first UE 115-f may select additional resources for the transmission resource reservation such that the additional resources are more than T Time slots before the earliest side uplink resource, but less than 32 Time slots before the earliest side uplink resource (e.g., t+.Time _SCI +.ltoreq.32).

There are several implementations that can be implemented by the first UE 115-a such that the additional resources for IUE coordination message 230 meet the timing requirements for SCI-1 messages and additional time intervals 245 for processing and handshaking. For example, in some cases, the first UE 115-a may repeat the R16 resource selection process multiple times until the earliest side uplink resource 215-a is less than 32 slots from the additional resources selected for transmitting the non-preferred resource indication, but more than T slots (e.g., less than 32 slots of time interval 245 from the additional resources for IUE coordination message 230, but more than T slots), and more than T slots. As another example, the first UE 115-a may search through all possible combinations of resources selected for transmitting the non-preferred resource indication and the earliest side uplink resource 215-a and may then uniformly sample each respective combination of resources that satisfies the 32 slot time constraint and the additional time interval 245.

As previously described herein, the first UE 115-a may be configured to transmit reservation resource information via the IUE coordination message 230 (e.g., via the SCI-1 portion of IUE coordination message 230), via IUE coordination information included within the SCI-2 and/or data portion of IUE coordination message 230, or both, based on whether certain conditions are met. Thus, any discussion associated with techniques for self-reservation may also be applied to cases where a first UE 115-a schedules/recommends for a second UE 115-b resource, unless otherwise stated herein.

After selecting the additional resources for IUE coordination message 230 at time 2 (e.g., additional resources to be used to send an indication of earliest side uplink resource 215-a), first UE 115-a may send IUE coordination message 230 within the selected additional resources. For example, the first UE 115-a may select the additional resources at time 2 and may then send the IUE coordination message 230 via the additional resources. In some aspects, the SCI-1 portion of IUE coordination message 230 may include an indication of the earliest side uplink resource 215-a in the selected set of side uplink resources 220. Further, as previously described herein, the first UE 115-a may be configured to transmit a plurality of IUE coordination messages 230 (e.g., daisy chain IUE coordination messages 230) in the event that the previously transmitted IUE coordination message 230 fails to meet one or more time thresholds or time constraints.

Subsequently, the second UE 115-b may send the first side-link message 240-c via the earliest side-link resource 215-a indicated by the IUE coordination message 230. In some cases, the first side-link message 240-c may indicate time/frequency resources for a subsequent side-link message 240. For example, in some cases, the first side-link message 240-c may include time/frequency resources for the subsequent side-link resource 215-b that will be used to transmit the second side-link message 240-d. For example, the first side-link message 240-c may include SCI-1 and/or SCI-2 of a subsequent (second) side-link message 240-d to be scheduled for execution by the second UE 115-d. Similarly, the second sidelink message 240-d may indicate time/frequency resources for a subsequent sidelink message 240 (e.g., indicating time/frequency resources for sidelink resource 215-c).

Techniques described herein may improve sidelink network coordination to reduce collisions within sidelink resources. In particular, by sending some information related to reserved side-link resources via the first stage SCI portion (e.g., SCI-1 portion) of the IUE coordination message, the techniques described herein may enable backward compatibility for side-link reservation between Re17 UE 115 and Re16 UE 115. By enabling both Re17 UE 115 and Re16 UE 115 to understand reservation of side-link resources, the techniques described herein may reduce potential collisions within side-link resources and may enable more efficient and reliable communications within wireless communication system 100.

Fig. 3 illustrates an example of a process flow 300 supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure. In some examples, process flow 300 may implement or be implemented by aspects of wireless communication system 100, wireless communication system 200, or both. For example, process flow 300 may illustrate first UE 115-c selecting resources for its own sidelink message, selecting additional resources for sending an IUE coordination message for reserving the earliest reserved resources, and sending a SCI to reserve the earliest reserved resources, as described with reference to fig. 1-2.

In some cases, the process flow 300 may include a first UE 115-c, a second UE 115-d, and a third UE 115-e, which may be examples of corresponding devices as described herein. For example, the first and second UEs 115-c and 115-d shown in fig. 3 may include examples of first and second UEs 115-a and 115-b, respectively, as shown in fig. 2. The first UE 115-c may include a UE 115 reserving resources (e.g., performing self-reservation) for its own sidelink message. Further, in some cases, the first UE 115-c may include a non-reduced capability UE 115 (e.g., re17UE 115). In some implementations, the second UE 115-d may include a reduced capability UE 115 (e.g., re16 UE 115), and the third UE 115-e may include a non-reduced capability UE 115 (e.g., re17UE 115).

In some examples, the operations shown in process flow 300 may be performed by hardware (e.g., including circuitry, processing blocks, logic components, and other components), code executed by a processor (e.g., software or firmware), or any combination thereof. The following alternative examples may be implemented in which some steps are performed in a different order than described or not performed at all. In some cases, steps may include additional features not mentioned below, or additional steps may be added.

At 305, the first UE 115-c may select a set of resources (e.g., self-scheduling) for one or more side-uplink messages to be performed by the first UE 115-c. The first UE 115-c may select a set of resources from a pool of resources for side-uplink communications. For example, as shown in fig. 2, the first UE 115-c may select the set of side uplink resources 220 for the side uplink message 240 to be performed by the first UE 115-c.

At 310, the first UE 115-c may select additional resources for transmitting a resource reservation for the earliest resource in the set of resources selected at 305. For example, as shown in fig. 2, the first UE 115-c may select additional resources (e.g., via a first stage SCI portion of the IUE coordination message) to be used for sending the IUE coordination message indicating the resource reservation of the earliest side uplink resource 215-a in the selected set of side uplink resources 220.

In some aspects, the first UE 115-c may select additional resources for the transmission resource reservation such that a time interval between the additional resources and the earliest resource meets a time threshold. For example, as shown in FIG. 2, the first UE 115-c may select the additional resources for transmitting SCI-1 such that the time interval 235 between the additional resources and the earliest side uplink resource 215-a meets a time threshold. In some cases, the time threshold may include 32 time slots, and if the time interval (e.g., time interval 235) is less than or equal to the time threshold, the time interval may satisfy the time threshold (e.g., if time interval 235 is less than or equal to 32 time slots, the time threshold is satisfied).

At 315, the first UE 115-c may send an IUE coordination message. In some aspects, the IUE coordination message may include an indication of the earliest resource in the set of resources selected at 305. In particular, the IUE coordination message may include a first stage SCI portion (e.g., SCI-1 portion) that indicates/reserves the earliest resource in the set of resources selected at 305. Further, an IUE coordination message may be sent within the additional resources selected at 310. For example, as shown in fig. 2, the IUE coordination message sent at 315 may include an indication of the earliest side uplink resource 215-a in the set of side uplink resources 220.

In some aspects, the indication of the earliest side uplink resource within the IUE coordination message sent at 315 can be decoded by non-reduced capability UEs 115 and reduced capability UEs 115. In other words, the SCI-1 portion of the IUE coordination message reserving the earliest resources may be decoded by both non-reduced capability UEs 115 and reduced capability UEs 115. For example, the SCI-1 portion of the IUE coordination message can be decoded by both the second UE 115-d (e.g., re16 UE 115-d) and the third UE 115-e (e.g., re17 UE 115-d).

In some aspects, the IUE coordination message may include IUE coordination information including an indication of the set of resources selected at 305. For example, as shown in fig. 2, the IUE coordination message may include an indication of the set of side-link resources within the second stage SCI portion (e.g., SCI-2 portion) and/or the data portion of the IUE coordination message. IUE coordination information may not be decoded by reduced capability UEs 115, as compared to an indication of the earliest resource that can be decoded by both non-reduced capability UEs 115 and reduced capability UEs 115. In other words, the SCI-2 portion and/or the data portion of the IUE coordination message may not be decoded by the reduced capability UE 115. For example, in some cases, IUE coordination information (e.g., an indication of the set of resources selected at 305) may not be decoded by the second UE 115-d (e.g., re16 UE 115-d).

In some aspects, the IUE coordination message may indicate the time/frequency resources of the earliest resource. In particular, the SCI-1 portion of the IUE coordination message may indicate the time/frequency resources of the earliest resource. The time and frequency resources associated with the earliest resource may be indicated via FDRI field values, TDRI field values, or both. In some aspects, the IUE coordination message may include an indication of the set of subchannels of the earliest resource. For example, as shown in FIG. 2, the SCI-1 portion of the IUE coordination message may include an indication of the set of subchannels for the earliest side uplink resource 215-a. In some aspects, the last subchannel in the set of subchannels may be included in a resource pool for side-link communication in the frequency domain. In particular, if the last indicated subchannel is outside of the pool of resources for side-uplink communications, re16 ue 115 may not be able to understand/decode the IUE coordination message, as described herein. Thus, by ensuring that the last subchannel is within the resource pool, the techniques described herein may ensure that Re16 UE 115 is able to decode the IUE coordination message. In an additional or alternative implementation, the IUE coordination message may indicate a single subchannel of the earliest resource. For example, as shown in fig. 2, the SCI-1 portion of the IUE coordination message may include one or more FDRI field values that indicate the subchannel (e.g., the first/initial subchannel) of the earliest side uplink resource 215-a.

In some implementations, the UEs 115-c, 115-d, and 115-e may be configured to forward or relay IUE coordination messages and other communications that schedule/reserve side uplink resources. UE 115 may be configured to forward/relay the entire received IUE coordination message and/or only the portion of the received IUE coordination message indicating the earliest reserved resource (such as the SCC-1 portion). For example, in some cases, the second UE 115-d and the third UE 115-e may be configured to forward or relay the received IUE coordination message to other UEs 115 within the wireless communication system. By forwarding/relaying IUE coordination message 230 to other UEs 115 within wireless communication system 200, the techniques described herein may enable receive-side protection of scheduled side-uplink message 240, particularly in the context of a unicast link. In some implementations, the second UE 115-d and/or the third UE 115-e may be configured to repackage or reset TDRI fields within the relayed IUE coordination message to point to the same relative timing of the reserved resources when forwarding/relaying the received IUE coordination message to other UEs 115. In other words, the TDRI field may be reset to account for the time difference between the first time that the first UE 115-c initially sent the IUE coordination message and the second time that the corresponding UE 115-c, 115-d relays the IUE coordination message. The first UE 115-c may be similarly configured to forward/relay the IUE coordination message and other resource reservations received by the first UE 115-c to other wireless devices within the wireless communication system.

In some implementations, as previously described herein, the first UE 115-c may be configured to transmit multiple IUE coordination messages if the previously transmitted IUE coordination message does not meet a time threshold (e.g., does not meet a 32 slot time constraint). Thus, in the event that the SCI-1 portion of the IUE coordination message sent at 315 does not meet the time threshold (e.g., in the event that the SCI-1 portion of the IUE coordination message at 315 is sent more than 32 time slots prior to the earliest resource), process flow 300 may proceed to 320. Otherwise, where the IUE coordination message sent at 315 meets the time threshold (e.g., where the SCI-1 portion of the IUE coordination message at 315 is sent less than 32 time slots prior to the earliest resource), process flow 300 may proceed to 325.

At 320, the first UE 115-c may send an additional IUE coordination message, wherein the additional IUE coordination message includes an indication of the earliest resource in the set of resources selected at 305 (e.g., within the SCI-1 portion of the additional IUE coordination message). In particular, the first UE 115-c may send an additional IUE coordination message at 320 to bridge the gap between the IUE coordination message and the earliest resource at 315 such that a time interval (e.g., time interval 235) between the additional IUE coordination message and the earliest side uplink resource at 320 meets a time threshold. In other words, the first UE 115-c may send an additional IUE coordination message at 320 based on the time interval between the SCI-1 portion of the IUE coordination message at 315 and the earliest side uplink resource failing to meet the time threshold. In this regard, any description associated with the IUE coordination message at 315 may be understood as applied to the IUE coordination message at 320.

At 325, the first UE 115-c may send the first side link message at 320 and/or 325 within the earliest resources indicated via the IUE coordination message (e.g., via the SCI-1 portion of the corresponding IUE coordination message). For example, as shown in fig. 2, the first UE 115-c may send a first side-link message 240-a (e.g., a side-link data message) via the earliest side-link resource 215-a. In some cases, the first side-link message at 325 may indicate time/frequency resources for a subsequent side-link message. For example, in some cases, the first side-link message at 325 may indicate the time/frequency resources of the second side-link message to be performed at 330. For example, the first side-link message at 325 may include SCI-1 and/or SCI-2 that schedule a subsequent (second) side-link message at 330.

At 330, the first UE 115-c may send a second sidelink message within the second resource selected at 305. For example, as shown in fig. 2, the first UE 115-c may send a second sidelink message 240-b (e.g., a sidelink data message) within a second sidelink resource 215-b of the sidelink resource set 220. Further, as described with reference to the first side-link message at 325, the second side-link message at 330 may indicate time/frequency resources for subsequent side-link messages.

Fig. 4 illustrates an example of a process flow 400 supporting techniques for backward compatible side-uplink communications in accordance with aspects of the disclosure. In some examples, process flow 400 may implement or be implemented by aspects of wireless communication system 100, wireless communication system 200, or both. For example, process flow 400 may illustrate a first UE 115-f (e.g., scheduling UE 115-f) selecting resources of a side-link message to be performed/transmitted by a second UE 115 (e.g., scheduled UE 115-g), selecting additional resources for transmitting an IUE coordination message for reserving earliest reserved resources, and transmitting a SCI to reserve earliest reserved resources, as described with reference to fig. 1-3.

In some cases, the process flow 400 may include a first UE 115-g and a second UE 115-g, which may be examples of corresponding devices as described herein. For example, the first and second UEs 115-f, 115-g shown in fig. 4 may include examples of the first and second UEs 115-a, 115-b, respectively, as shown in fig. 2. The first UE 115-c may include a scheduling UE 115-f that schedules/recommends resources for side-uplink messages to be performed by the second scheduling UE 115-g. In some cases, the first UE 115-f may include a non-reduced capability UE 115 (e.g., re17 UE 115). Further, the second UE 115-g may include a reduced capability UE 115 (e.g., re16 UE 115) or a non-reduced capability UE 115 (e.g., re17 UE 115).

In some examples, the operations shown in process flow 400 may be performed by hardware (e.g., including circuitry, processing blocks, logic components, and other components), code executed by a processor (e.g., software or firmware), or any combination thereof. The following alternative examples may be implemented in which some steps are performed in a different order than described or not performed at all. In some cases, steps may include additional features not mentioned below, or additional steps may be added.

At 405, the first UE 115-f may select a set of resources (e.g., non-self-scheduling) for one or more sidelink messages to be performed by the second UE 115-g. The first UE 115-f may select a set of resources from a pool of resources for side-uplink communications. For example, as shown in fig. 2, the first UE 115-f may select a set of side uplink resources 220 for a side uplink message 240 to be performed by the second UE 115-g.

At 410, the first UE 115-f may select additional resources for transmitting a resource reservation for the earliest resource in the set of resources selected at 405. For example, as shown in fig. 2, the first UE 115-f may select additional resources to be used for transmitting the IUE coordination message that indicate the resource reservation of the earliest side uplink resource 215-a in the selected side uplink resource set 220 within the SCI-1 portion of the IUE coordination message.

In some aspects, the first UE 115-f may select additional resources for the transmission resource reservation such that a time interval between the additional resources and the earliest resource meets a time threshold. For example, as shown in fig. 2, the first UE 115-f may select the additional resources for transmitting the IUE coordination message such that the time interval 235 between the additional resources and the earliest side uplink resource 215-a meets a time threshold. In particular, the first UE 115-f may select additional resources for transmitting the IUE coordination message such that the time interval 235 between the SCI-1 portion of IUE coordination message 230 and the earliest side uplink resource 215-a meets a time threshold. In some cases, the time threshold may include 32 time slots, and if the time interval (e.g., time interval 235) is less than or equal to the time threshold, the time interval may satisfy the time threshold (e.g., if time interval 235 is less than or equal to 32 time slots, the time threshold is satisfied).

In some implementations, the first UE 115-f may require a certain amount of time for processing and handshaking between transmission of the IUE coordination message and receiving the earliest IUE coordination message. Thus, as shown in fig. 2, the first UE 115-f may select additional resources for transmitting the resource reservation in a manner that satisfies an additional time interval 245 (e.g., T slots) associated with processing capability at the first UE 115-f and/or a handshake procedure to be performed between the first UE 115-f and the second UE 115-g. Additional time intervals for processing and handshaking may be met if the SCI message is sent more than T slots before the earliest side uplink resource. Thus, the first UE 115-f may select additional resources for the transmission resource reservation such that the additional resources are more than T Time slots before the earliest side uplink resource, but less than 32 Time slots before the earliest side uplink resource (e.g., t+.Time _SCI +.ltoreq.32).

At 415, the first UE 115-f may send a SCI message. In some aspects, the IUE coordination message may include an indication of the earliest resource in the set of resources selected at 405. In particular, the first stage SCI portion (e.g., SCI-1 portion) of the IUE coordination message may include an indication of the earliest resource in the set of resources selected at 405. Further, an IUE coordination message may be sent within the additional resources selected at 410. For example, as shown in FIG. 2, the SCI-1 portion of the IUE coordination message sent at 415 may include an indication of the earliest side uplink resource 215-a in the set of side uplink resources 220.

In some aspects, the indication of the earliest side uplink resource within the IUE coordination message sent at 415 can be decoded by non-reduced capability UEs 115 and reduced capability UEs 115. In other words, the SCI-1 portion of the IUE coordination message indicating the earliest reserved resources may be decoded by both non-reduced capability UEs 115 and reduced capability UEs 115. For example, the SCI-1 portion of the IUE coordination message can be decoded by both the second UE 115-g (e.g., re16 UE 115-g) and the third UE 115-e (e.g., re17 UE 115-g). In some aspects, the IUE coordination message may include IUE coordination information including an indication of the set of resources selected at 405. In particular, the IUE coordination information may include additional IUE coordination information within the second stage SCI portion (e.g., SCI-2 portion) and/or the data portion of the IUE coordination message. For example, as shown in fig. 2, the IUE coordination message may include an indication of the set of side uplink resources within the SCI-2 portion and/or the data portion of IUE coordination message 230. IUE coordination information indicated via SCI-2 and/or data portions may not be decoded by reduced capability UEs 115, as compared to the indication of the earliest resources indicated via SCI-1 portions that can be decoded by both non-reduced capability UEs 115 and reduced capability UEs 115. For example, in some cases, the IUE coordination information (e.g., an indication of the set of resources selected at 405) indicated via SCI-2 and/or data portion of the IUE coordination message may not be decoded by the second UE 115-g (e.g., re16 UE 115-g).

In some aspects, the IUE coordination message may indicate the time/frequency resources of the earliest resource. In particular, the SCI-1 portion of the IUE coordination message may indicate the time/frequency resources of the earliest resource. The time and frequency resources associated with the earliest resource may be indicated via FDRI field values, TDRI field values, or both, as described with reference to fig. 1-3. Furthermore, as previously described herein, UEs 115-f and 115-g may be configured to forward or relay IUE coordination messages and other communications that schedule/reserve side uplink resources for receiver side protection.

In some implementations, as previously described herein, the first UE 115-f may be configured to transmit multiple IUE coordination messages if the previously transmitted IUE coordination message does not meet a time threshold (e.g., does not meet a 32 slot time constraint). Thus, in the event that the IUE coordination message sent at 415 does not meet the time threshold (e.g., in the event that the SCI-1 portion of the IUE coordination message at 415 is sent more than 32 time slots prior to the earliest resource), process flow 400 may proceed to 420. Otherwise, where the IUE coordination message sent at 415 meets the time threshold (e.g., where the SCI-1 portion of the IUE coordination message at 415 is sent less than 32 time slots prior to the earliest resource), process flow 400 may proceed to 425.

At 420, the first UE 115-f may send an additional IUE coordination message, wherein the additional IUE coordination message includes an indication of the earliest resource in the set of resources selected at 405 (e.g., within the SCI-1 portion of the additional IUE coordination message). In particular, the first UE 115-f may send an additional IUE coordination message at 420 to bridge the gap between the IUE coordination message and the earliest resource at 415 such that a time interval (e.g., time interval 245) between the additional IUE coordination message and the earliest side uplink resource at 420 meets a time threshold. In other words, the first UE 115-f may send an additional IUE coordination message at 420 based on the time interval between the IUE coordination message and the earliest side uplink resource at 415 failing to meet the time threshold. In this regard, any description associated with the IUE coordination message at 415 may be understood as applied to the SCI message at 420.

At 425, the second UE 115-g may send the first side link message within the earliest resources indicated at 420 and/or 425 via the SCI-1 portion of the IUE coordination message. For example, as shown in fig. 2, the second UE 115-g may send a first side-link message 240-c (e.g., a side-link data message) via the earliest side-link resource 215-a. The second UE 115-g may send a first side-link message to the first UE 115-f and/or the further UE 115 at 425.

In some cases, the first side-link message at 425 may indicate time/frequency resources for a subsequent side-link message. For example, in some cases, the first side-link message at 425 may indicate the time/frequency resources of the second side-link message to be performed at 430. For example, the first side-link message at 425 may include SCI-1 and/or SCI-2 that scheduled the subsequent (second) side-link message at 430.

At 430, the second UE 115-g may send a second sidelink message within the second resource selected at 405. For example, as shown in FIG. 2, the second UE 115-g may send a second sidelink message 240-d (e.g., a sidelink data message) within a second sidelink resource 215-b of the sidelink resource set 220. Further, as described with reference to the first side-link message at 425, the second side-link message at 430 may indicate time/frequency resources for subsequent side-link messages.

Fig. 5 illustrates a block diagram 500 of a device 505 supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure. The device 505 may be an example of aspects of the UE 115 as described herein. The device 505 may include a receiver 510, a transmitter 515, and a communication manager 520. The device 505 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

The receiver 510 may provide means for receiving information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels related to techniques for backward compatible side-link communications). Information may be passed to other components of the device 505. The receiver 510 may utilize a single antenna or a set of multiple antennas.

The transmitter 515 may provide a means for transmitting signals generated by other components of the device 505. For example, the transmitter 515 may transmit information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels related to techniques for backward compatible side-link communications). In some examples, the transmitter 515 may be co-located with the receiver 510 in a transceiver module. The transmitter 515 may utilize a single antenna or a set of multiple antennas.

The communication manager 520, receiver 510, transmitter 515, or various combinations thereof, or various components thereof, may be examples of means for performing aspects of the techniques described herein for backward compatible side-link communication. For example, the communication manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof may support methods for performing one or more of the functions described herein.

In some examples, the communication manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof may be implemented in hardware (e.g., in communication management circuitry). The hardware may include processors, digital Signal Processors (DSPs), application Specific Integrated Circuits (ASICs), field Programmable Gate Arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combinations thereof, configured or otherwise supporting units for performing the functions described in the present disclosure. In some examples, a processor and memory coupled with the processor may be configured to perform one or more of the functions described herein (e.g., by the processor executing instructions stored in the memory).

Additionally or alternatively, in some examples, the communication manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof may be implemented in code (e.g., as communication management software or firmware) that is executed by a processor. If implemented in code executed by a processor, the functions of the communication manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof, may be performed by a general purpose processor, a DSP, a Central Processing Unit (CPU), an ASIC, an FPGA, or any combination of these or other programmable logic devices (e.g., configured or otherwise supporting units for performing the functions described in this disclosure).

In some examples, the communication manager 520 may be configured to perform various operations (e.g., receive, monitor, transmit) using the receiver 510, the transmitter 515, or both, or otherwise in cooperation with the receiver 510, the transmitter 515, or both. For example, communication manager 520 may receive information from receiver 510, send information to transmitter 515, or be integrated with receiver 510, transmitter 515, or both to receive information, send information, or perform various other operations as described herein.

According to examples as disclosed herein, the communication manager 520 may support wireless communication at the UE. For example, the communication manager 520 may be configured or otherwise support means for selecting a set of resources for one or more sidelink messages to be performed by the UE from a pool of resources for sidelink communications. The communication manager 520 may be configured or otherwise support means for selecting additional resources for transmitting a resource reservation for an earliest resource in a set of resources, the selection of the additional resources being based on a time interval between the additional resources and the earliest resource meeting a time threshold. The communication manager 520 may be configured or otherwise support a means for sending an IUE coordination message via additional resources, the IUE coordination message including an indication of the earliest resource within the first stage SCI portion of the IUE coordination message. The communication manager 520 may be configured or otherwise enabled to transmit a first one of the one or more side-link messages within an earliest resource indicated via the first stage SCI portion of the IUE coordination message.

Additionally or alternatively, according to examples as disclosed herein, the communication manager 520 may support wireless communication at the first UE. For example, the communication manager 520 may be configured or otherwise support means for selecting a set of resources for one or more sidelink messages from the second UE to the first UE from a pool of resources for sidelink communications. The communication manager 520 may be configured or otherwise support means for selecting additional resources for transmitting a resource reservation for an earliest resource in a set of resources, the selection of the additional resources being based on a time interval between the additional resources and the earliest resource meeting a time threshold. The communication manager 520 may be configured or otherwise support a means for sending an IUE coordination message via additional resources, the IUE coordination message including an indication of the earliest resource within the first stage SCI portion of the IUE coordination message. The communication manager 520 may be configured or otherwise support means for receiving a first one of the one or more side-link messages from the second UE within the earliest resources indicated via the first stage SCI portion of the IUE coordination message.

Additionally or alternatively, according to examples as disclosed herein, the communication manager 520 may support wireless communication at the second UE. For example, the communication manager 520 may be configured or otherwise support means for receiving an IUE coordination message from a first UE, the IUE coordination message comprising means for indicating an earliest resource in a set of resources for one or more sidelink messages from a second UE to the first UE, the indication of earliest resource being included in a first stage SCI portion of the IUE coordination message, the set of resources being included in a pool of resources for sidelink communications, wherein a time interval between receipt of the SCI message and the earliest resource meets a time threshold. The communication manager 520 may be configured or otherwise enabled to transmit a first one of the one or more side-link messages within an earliest resource indicated via the first stage SCI portion of the IUE coordination message.

By including or configuring the communication manager 520 according to examples as described herein, the device 505 (e.g., a processor controlling or otherwise coupled to the receiver 510, the transmitter 515, the communication manager 520, or a combination thereof) can support techniques for backward compatible sidelink reservation to improve sidelink network coordination and reduce collisions within sidelink resources. In particular, by sending some information related to reserved side-link resources via SCI messages, the techniques described herein may enable backward compatibility for side-link reservation between Re17 UE 115 and Re16 UE 115. By enabling both Re17 UE 115 and Re16 UE 115 to understand reservation of side-link resources, the techniques described herein may reduce potential collisions within side-link resources and may enable more efficient and reliable communications within wireless communication system 100.

Fig. 6 illustrates a block diagram 600 of an apparatus 605 supporting techniques for backward compatible side-link communications in accordance with aspects of the disclosure. The device 605 may be an example of aspects of the device 505 or UE 115 as described herein. The device 605 may include a receiver 610, a transmitter 615, and a communication manager 620. The device 605 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

The receiver 610 may provide means for receiving information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels related to techniques for backward compatible side-link communications). Information may be passed to other components of the device 605. The receiver 610 may utilize a single antenna or a set of multiple antennas.

The transmitter 615 may provide a means for transmitting signals generated by other components of the device 605. For example, the transmitter 615 may transmit information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels related to techniques for backward compatible side-link communications). In some examples, the transmitter 615 may be co-located with the receiver 610 in a transceiver module. The transmitter 615 may utilize a single antenna or a set of multiple antennas.

The device 605 or various components thereof may be an example of a means for performing aspects of the techniques for backward compatible side-uplink communications as described herein. For example, the communication manager 620 may include a side uplink resource manager 625, an IUE coordination messaging manager 630, a side uplink messaging manager 635, a side uplink message reception manager 640, an IUE coordination messaging manager 645, or any combination thereof. The communication manager 620 may be an example of aspects of the communication manager 520 as described herein. In some examples, the communication manager 620 or various components thereof may be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise in cooperation with the receiver 610, the transmitter 615, or both. For example, the communication manager 620 may receive information from the receiver 610, send information to the transmitter 615, or be integrated with the receiver 610, the transmitter 615, or both to receive information, send information, or perform various other operations as described herein.

According to examples as disclosed herein, the communication manager 620 may support wireless communication at the UE. For example, the sidelink resource manager 625 may be configured or otherwise enabled to select a set of resources for one or more sidelink messages to be performed by the UE from a pool of resources for sidelink communications. The side uplink resource manager 625 may be configured or otherwise support means for selecting additional resources for transmitting resource reservations for earliest resources in the set of resources, the selection of the additional resources being based on the time interval between the additional resources and the earliest resources meeting a time threshold. IUE coordination message transmission manager 630 may be configured or otherwise support a unit for transmitting IUE coordination messages via additional resources, the IUE coordination messages including an indication of the earliest resource within the first stage SCI portion of the IUE coordination messages. The side-uplink message transmission manager 635 may be configured or otherwise enabled to transmit a first side-link message of the one or more side-link messages within the earliest resources indicated via the first stage SCI portion of the IUE coordination message.

Additionally or alternatively, according to examples as disclosed herein, the communication manager 620 may support wireless communication at the first UE. The sidelink resource manager 625 may be configured or otherwise enabled to select a set of resources for one or more sidelink messages from the second UE to the first UE from a pool of resources for sidelink communications. The side uplink resource manager 625 may be configured or otherwise support means for selecting additional resources for transmitting resource reservations for earliest resources in the set of resources, the selection of the additional resources being based on the time interval between the additional resources and the earliest resources meeting a time threshold. IUE coordination message transmission manager 630 may be configured or otherwise support a unit for transmitting IUE coordination messages via additional resources, the IUE coordination messages including an indication of the earliest resource within the first stage SCI portion of the IUE coordination messages. The sidelink message receipt manager 640 may be configured or otherwise enabled to receive a first sidelink message of the one or more sidelink messages from the second UE within an earliest resource indicated via the first stage SCI portion of the IUE coordination message.

Additionally or alternatively, according to examples as disclosed herein, the communication manager 620 may support wireless communication at the second UE. The IUE coordination message reception manager 645 may be configured or otherwise support means for receiving an IUE coordination message from a first UE, the IUE coordination message including means for indicating an earliest resource in a set of resources for one or more sidelink messages from a second UE to the first UE, the indication of earliest resource being included in a first stage SCI portion of the IUE coordination message, the set of resources being included in a pool of resources for sidelink communications, wherein a time interval between reception of the SCI message and the earliest resource meets a time threshold. The side-uplink message transmission manager 635 may be configured or otherwise enabled to transmit a first side-link message of the one or more side-link messages within the earliest resources indicated via the first stage SCI portion of the IUE coordination message.

Fig. 7 illustrates a block diagram 700 of a communication manager 720 supporting techniques for backward compatible side-uplink communication in accordance with aspects of the disclosure. Communication manager 720 may be an example of aspects of communication manager 520, communication manager 620, or both, as described herein. The communication manager 720, or various components thereof, may be an example of a means for performing aspects of the techniques for backward compatible side-uplink communication as described herein. For example, communication manager 720 may include a side uplink resource manager 725, an IUE coordination messaging manager 730, a side uplink messaging manager 735, a side uplink message reception manager 740, an IUE coordination messaging manager 745, a message decoding manager 750, or any combination thereof. Each of these components may communicate with each other directly or indirectly (e.g., via one or more buses).

According to examples as disclosed herein, the communication manager 720 may support wireless communication at the UE. For example, the sidelink resource manager 725 may be configured or otherwise support means for selecting a set of resources for one or more sidelink messages to be performed by the UE from a pool of resources for sidelink communications. In some examples, the side uplink resource manager 725 may be configured or otherwise support means for selecting additional resources for transmitting a resource reservation for an earliest resource in the set of resources, the selection of the additional resources being based on a time interval between the additional resources and the earliest resource meeting a time threshold. IUE coordination message transmission manager 730 may be configured or otherwise support a means for transmitting an IUE coordination message via additional resources, the IUE coordination message including an indication of the earliest resource within the first stage SCI portion of the IUE coordination message. The side-uplink message transmission manager 735 may be configured or otherwise enabled to transmit a first side-link message of the one or more side-link messages within an earliest resource indicated via the first stage SCI portion of the IUE coordination message.

In some examples, IUE coordination message transmission manager 730 may be configured or otherwise enabled to transmit IUE coordination information based on selecting a set of resources, via a second stage SCI portion of the IUE coordination message, a data portion of the IUE coordination message, or both, the IUE coordination information including an indication of a set of resources for one or more side-link messages. In some examples, the second stage SCI portion, the data portion, or both cannot be decoded by the reduced capability UE. In some examples, the indication of the earliest resource within the first stage SCI portion can be decoded by the reduced capability UE.

In some examples, IUE coordination message transmission manager 730 may be configured or otherwise enabled to transmit a second IUE coordination message comprising a second indication of the earliest resource in a first stage SCI portion of the second IUE coordination message, wherein the second IUE coordination message is transmitted prior to the IUE coordination message. In some examples, IUE coordination message transmission manager 730 may be configured or otherwise support means for transmitting IUE coordination messages via additional resources based on a second time interval between transmission of a second IUE coordination message and an earliest resource in a set of resources failing to meet a time threshold.

In some examples, IUE coordination message transmission manager 730 may be configured or otherwise support means for transmitting, via a first stage SCI portion of an IUE coordination message, an indication of a set of a plurality of subchannels of an earliest resource, wherein a last subchannel of the set of the plurality of subchannels is within a resource pool in a frequency domain, wherein a first side-link message is transmitted via the set of the plurality of subchannels. In some examples, IUE coordination message transmission manager 730 may be configured or otherwise enabled to transmit, via a first stage SCI portion of an IUE coordination message, a unit comprising one or more FDRI field values of an indication of a subchannel of an earliest resource, wherein the first side-link message is transmitted via at least the subchannel. In some examples, the subchannels include initial subchannels of earliest resources.

In some examples, IUE coordination message transmission manager 730 may be configured or otherwise support means for transmitting an indication of one or more TDRI field values associated with an earliest resource, one or more FDRI field values associated with an earliest resource, or both via a first stage SCI portion of an IUE coordination message.

In some examples, the side-uplink message transmission manager 735 may be configured or otherwise support means for transmitting, via the first side-uplink message, an indication of a second resource in the set of resources. In some examples, the side-uplink message transmission manager 735 may be configured or otherwise support means for transmitting a second side-uplink message via a second resource based on transmitting an indication of the second resource via the first side-link message.

In some examples, the time interval satisfies the time threshold if the time interval is less than or equal to the time threshold. In some examples, the time threshold includes thirty-two time slots. In some examples, IUE coordination message reception manager 745 may be configured or otherwise support a unit for receiving a second IUE coordination message that includes an indication of a second resource for one or more additional side uplink messages to be performed by a second UE. In some examples, IUE coordination messaging manager 730 may be configured or otherwise support means for relaying the second IUE coordination message to at least a third UE.

In some examples, IUE coordination message reception manager 745 may be configured or otherwise support means for receiving one or more TDRI field values associated with the relative timing of one or more additional side uplink messages via a second IUE coordination message. In some examples, IUE coordination message transmission manager 730 may be configured or otherwise support means for transmitting one or more additional TDRI field values associated with the relative timing of one or more additional side-link messages via the relayed second IUE coordination message.

In some examples, the sidelink resource manager 725 may be configured or otherwise support means for selecting a second set of resources for one or more sidelink messages to be performed by the UE from a pool of resources for sidelink communications, wherein the selecting the second set of resources occurs before the selecting the set of resources. In some examples, the side uplink resource manager 725 may be configured or otherwise support means for determining that a second additional resource for transmitting a resource reservation for an earliest resource in the second set of resources cannot be identified, wherein selecting the set of resources, selecting the additional resource, or both is based on determining that the second additional resource for transmitting the resource reservation for the earliest resource in the second set of resources cannot be identified. In some examples, the IUE coordination message is sent via a single subchannel. In some examples, the first stage SCI portion of the IUE coordination message includes one or more bit field values indicating that the first stage SCI portion is associated with the IUE coordination message.

Additionally or alternatively, according to examples as disclosed herein, the communication manager 720 may support wireless communication at the first UE. In some examples, the sidelink resource manager 725 may be configured or otherwise support means for selecting a set of resources for one or more sidelink messages from the second UE to the first UE from a pool of resources for sidelink communications. In some examples, the side uplink resource manager 725 may be configured or otherwise support means for selecting additional resources for transmitting a resource reservation for an earliest resource in the set of resources, the selection of the additional resources being based on a time interval between the additional resources and the earliest resource meeting a time threshold. In some examples, IUE coordination message transmission manager 730 may be configured or otherwise support a unit for transmitting IUE coordination messages via additional resources, the IUE coordination messages including an indication of the earliest resource within the first stage SCI portion of the IUE coordination message. The sidelink message receipt manager 740 may be configured or otherwise enabled to receive a first sidelink message of the one or more sidelink messages from the second UE within the earliest resources indicated via the first stage SCI portion of the IUE coordination message.

In some examples, IUE coordination message transmission manager 730 may be configured or otherwise enabled to transmit IUE coordination information to the second UE via a second stage SCI portion of the IUE coordination message, a data portion of the IUE coordination message, or both, based on selecting the set of resources, the IUE coordination information including an indication of the set of resources for the one or more side uplink messages. In some examples, the second stage SCI portion, the data portion, or both cannot be decoded by the reduced capability UE. In some examples, the indication of the earliest resource within the first stage SCI portion can be decoded by the reduced capability UE.

In some examples, IUE coordination message transmission manager 730 may be configured or otherwise enabled to transmit a second IUE coordination message including a second indication of the earliest resource within the first stage SCI portion of the second IUE coordination message, wherein the second IUE coordination message is transmitted prior to the IUE coordination message. In some examples, IUE coordination message transmission manager 730 may be configured or otherwise support means for transmitting IUE coordination messages via additional resources based on a second time interval between transmission of a second IUE coordination message and an earliest resource in a set of resources failing to meet a time threshold. In some examples, IUE coordination message transmission manager 730 may be configured or otherwise support means for transmitting, via a first stage SCI portion of an IUE coordination message, an indication of a set of a plurality of subchannels of an earliest resource, wherein a last subchannel of the set of the plurality of subchannels is within a resource pool in a frequency domain, wherein a first side-link message is transmitted via the set of the plurality of subchannels.

In some examples, IUE coordination message transmission manager 730 may be configured or otherwise enabled to transmit, via a first stage SCI portion of an IUE coordination message, a unit comprising one or more FDRI field values of an indication of a subchannel of an earliest resource, wherein the first side-link message is transmitted via at least the subchannel. In some examples, the subchannels include initial subchannels of earliest resources. In some examples, IUE coordination message transmission manager 730 may be configured or otherwise support means for transmitting an indication of one or more TDRI field values associated with an earliest resource, one or more FDRI field values associated with an earliest resource, or both via a first stage SCI portion of an IUE coordination message.

In some examples, side uplink message reception manager 740 may be configured or otherwise support means for receiving an indication of a second resource in the set of resources via the first side uplink message. In some examples, side-uplink message reception manager 740 may be configured or otherwise enabled to receive, based on sending an indication of a second resource via the first side-uplink message, a second side-uplink message from a second UE via the second resource.

In some examples, the time interval satisfies the time threshold if the time interval may be less than or equal to the time threshold. In some examples, the time threshold includes thirty-two time slots.

In some examples, IUE coordination message reception manager 745 may be configured or otherwise support a unit for receiving a second IUE coordination message that includes an indication of a second resource for one or more additional side uplink messages to be performed by a second UE. In some examples, IUE coordination messaging manager 730 may be configured or otherwise support means for relaying the second IUE coordination message to at least a third UE.

In some examples, IUE coordination message reception manager 745 may be configured or otherwise support means for receiving one or more TDRI field values associated with the relative timing of one or more additional side uplink messages via a second IUE coordination message. In some examples, IUE coordination message transmission manager 730 may be configured or otherwise support means for transmitting one or more additional TDRI field values associated with the relative timing of one or more additional side-link messages via the relayed second IUE coordination message. In some examples, the selection of the additional resource is based on a time interval between the additional resource and the earliest resource being greater than or equal to a second time threshold associated with the processing capability of the first UE, the second UE, or both.

In some examples, the sidelink resource manager 725 may be configured or otherwise support means for selecting a second set of resources for one or more sidelink messages to be performed by the second UE from a pool of resources for sidelink communications, wherein the selecting the second set of resources occurs before the selecting the set of resources. In some examples, the side uplink resource manager 725 may be configured or otherwise support means for determining that a second additional resource for transmitting a resource reservation for an earliest resource in the second set of resources cannot be identified, wherein selecting the set of resources, selecting the additional resource, or both is based on determining that the second additional resource for transmitting the resource reservation for the earliest resource in the second set of resources cannot be identified.

In some examples, the IUE coordination message is sent via a single subchannel. In some examples, the first stage SCI portion of the IUE coordination message includes one or more bit field values indicating that the first stage SCI portion is associated with the IUE coordination message.

Additionally or alternatively, according to examples as disclosed herein, the communication manager 720 may support wireless communication at the second UE. The IUE coordination message reception manager 745 may be configured or otherwise support means for receiving an IUE coordination message from a first UE, the IUE coordination message comprising means for indicating an earliest resource in a set of resources for one or more sidelink messages from a second UE to the first UE, the indication of earliest resource being included in a first stage SCI portion of the IUE coordination message, the set of resources being included in a pool of resources for sidelink communications, wherein a time interval between reception of the SCI message and the earliest resource meets a time threshold. In some examples, the side-uplink message transmission manager 735 may be configured or otherwise enabled to transmit a first side-link message of the one or more side-link messages within an earliest resource indicated via the first stage SCI portion of the IUE coordination message.

In some examples, IUE coordination message reception manager 745 may be configured or otherwise support means for receiving IUE coordination information from the first UE via a second stage SCI portion of the IUE coordination message, a data portion of the IUE coordination message, or both, the IUE coordination information including an indication of a set of resources for transmitting one or more side uplink messages based on the selected set of resources. In some examples, the second stage SCI portion, the data portion, or both cannot be decoded by the reduced capability UE. In some examples, the indication of the earliest resource within the first stage SCI portion can be decoded by the reduced capability UE.

In some examples, IUE coordination message reception manager 745 may be configured or otherwise enabled to receive a second IUE coordination message including a second indication of the earliest resource within the first stage SCI portion of the second IUE coordination message, wherein the second IUE coordination message is sent prior to the IUE coordination message. In some examples, IUE coordination message reception manager 745 may be configured or otherwise enabled to receive IUE coordination messages via additional resources based on a second time interval between transmission of a second IUE coordination message and an earliest resource in a set of resources failing to meet a time threshold.

In some examples, IUE coordination message reception manager 745 may be configured or otherwise enabled to receive, via a first stage SCI portion of an IUE coordination message, an indication of a set of a plurality of subchannels of an earliest resource, wherein a last subchannel of the set of the plurality of subchannels is within a resource pool in a frequency domain, wherein a first side-link message is transmitted via the set of the plurality of subchannels.

In some examples, IUE coordination message reception manager 745 may be configured or otherwise enabled to receive, via a first stage SCI portion of an IUE coordination message, a unit comprising one or more FDRI field values of an indication of a subchannel of an earliest resource, wherein the first side uplink message is sent via at least the subchannel. In some examples, the subchannels include initial subchannels of earliest resources.

In some examples, IUE coordination message reception manager 745 may be configured or otherwise support means for receiving one or more TDRI field values associated with an earliest resource, one or more FDRI field values associated with an earliest resource, or both via a first stage SCI portion of an IUE coordination message.

In some examples, the side-uplink message transmission manager 735 may be configured or otherwise support means for transmitting, via the first side-uplink message, an indication of a second resource in the set of resources. In some examples, the side-uplink message transmission manager 735 may be configured or otherwise support means for transmitting, based on transmitting the indication of the second resource via the first side-uplink message, a second side-uplink message from the second UE via the second resource.

In some examples, the time interval satisfies the time threshold if the time interval may be less than or equal to the time threshold. In some examples, the time threshold includes thirty-two time slots. In some examples, IUE coordination messaging manager 730 may be configured or otherwise support means for relaying IUE coordination messages to at least a third UE.

In some examples, IUE coordination message reception manager 745 may be configured to or otherwise support means for receiving one or more TDRI field values associated with the relative timing of one or more additional side uplink messages via IUE coordination messages. In some examples, IUE coordination message transmission manager 730 may be configured or otherwise support means for transmitting one or more additional TDRI field values associated with the relative timing of one or more additional side-link messages via the relayed IUE coordination message.

In some examples, message decoding manager 750 may be configured or otherwise support a unit for performing one or more blind decoding processes, wherein receiving the IUE coordination message is based on performing the one or more blind decoding processes.

Fig. 8 illustrates a diagram of a system 800 including a device 805 that supports techniques for backward compatible side-uplink communications in accordance with aspects of the disclosure. Device 805 may be or include an example of device 505, device 605, or UE 115 as described herein. The device 805 may communicate wirelessly with one or more base stations 105, UEs 115, or any combination thereof. Device 805 may include components for bi-directional voice and data communications, including components for sending and receiving communications, such as a communications manager 820, an input/output (I/O) controller 810, a transceiver 815, an antenna 825, a memory 830, code 835, and a processor 840. These components may be coupled in electronic communication or in other ways (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., bus 845).

The I/O controller 810 may manage input and output signals for the device 805. The I/O controller 810 may also manage peripheral devices that are not integrated into the device 805. In some cases, I/O controller 810 may represent a physical connection or port to an external peripheral device. In some cases, I/O controller 810 may utilize a controller such as, for example Such as an operating system or another known operating system. Additionally or alternatively, the I/O controller 810 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, I/O controller 810 may be implemented as part of a processor, such as processor 840. In some cases, a user may interact with device 805 via I/O controller 810 or via hardware components controlled by I/O controller 810.

In some cases, device 805 may include a single antenna 825. However, in some other cases, the device 805 may have more than one antenna 825 that is capable of sending or receiving multiple wireless transmissions simultaneously. The transceiver 815 may communicate bi-directionally via one or more antennas 825, wired or wireless links as described herein. For example, transceiver 815 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 815 may also include a modem for modulating packets, providing the modulated packets to one or more antennas 825 for transmission, and demodulating packets received from the one or more antennas 825. The transceiver 815 or transceiver 815 and one or more antennas 825 may be examples of a transmitter 515, a transmitter 615, a receiver 510, a receiver 610, or any combination or component thereof, as described herein.

Memory 830 may include Random Access Memory (RAM) and Read Only Memory (ROM). The memory 830 may store computer-readable, computer-executable code 835, the code 835 comprising instructions that when executed by the processor 840 cause the device 805 to perform the various functions described herein. Code 835 can be stored in a non-transitory computer-readable medium such as a system memory or other type of memory. In some cases, code 835 may not be directly executable by processor 840, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein. In some cases, memory 830 may contain, among other things, a basic I/O system (BIOS) that may control basic hardware or software operations, such as interactions with peripheral components or devices.

Processor 840 may include intelligent hardware devices (e.g., general purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combinations thereof). In some cases, processor 840 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into the processor 840. Processor 840 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 830) to cause device 805 to perform various functions (e.g., functions or tasks that support techniques for backward compatible side-uplink communications). For example, device 805 or components of device 805 may include a processor 840 and a memory 830 coupled to processor 840, processor 840 and memory 830 configured to perform the various functions described herein.

According to examples as disclosed herein, communication manager 820 may support wireless communication at a UE. For example, communication manager 820 may be configured or otherwise support means for selecting a set of resources for one or more sidelink messages to be performed by a UE from a pool of resources for sidelink communications. The communication manager 820 may be configured or otherwise support means for selecting additional resources for transmitting a resource reservation for an earliest resource in a set of resources, the selection of the additional resources being based on a time interval between the additional resources and the earliest resource meeting a time threshold. Communication manager 820 may be configured or otherwise support a means for sending an IUE coordination message via additional resources, the IUE coordination message including an indication of the earliest resource within the first stage SCI portion of the IUE coordination message. Communication manager 820 may be configured or otherwise support means for transmitting a first side-link message of the one or more side-link messages within the earliest resources indicated via the first stage SCI portion of the IUE coordination message.

Additionally or alternatively, according to examples as disclosed herein, the communication manager 820 may support wireless communication at the first UE. For example, communication manager 820 may be configured or otherwise support means for selecting a set of resources for one or more sidelink messages from a second UE to a first UE from a pool of resources for sidelink communications. The communication manager 820 may be configured or otherwise support means for selecting additional resources for transmitting a resource reservation for an earliest resource in a set of resources, the selection of the additional resources being based on a time interval between the additional resources and the earliest resource meeting a time threshold. Communication manager 820 may be configured or otherwise support a means for sending an IUE coordination message via additional resources, the IUE coordination message including an indication of the earliest resource within the first stage SCI portion of the IUE coordination message. The communications manager 820 may be configured or otherwise support means for receiving a first one of the one or more side-link messages from the second UE within the earliest resources indicated via the first stage SCI portion of the IUE coordination message.

Additionally or alternatively, according to examples as disclosed herein, the communication manager 820 may support wireless communication at the second UE. For example, communication manager 820 may be configured or otherwise support means for receiving an IUE coordination message from a first UE, the IUE coordination message comprising means for indicating an earliest resource in a set of resources for one or more sidelink messages from a second UE to the first UE, the indication of earliest resource being included in a first stage SCI portion of the IUE coordination message, the set of resources being included in a pool of resources for sidelink communications, wherein a time interval between receipt of the SCI message and the earliest resource meets a time threshold. Communication manager 820 may be configured or otherwise support means for transmitting a first side-link message of the one or more side-link messages within the earliest resources indicated via the first stage SCI portion of the IUE coordination message.

By including or configuring the communication manager 820 according to examples as described herein, the device 805 can support techniques for backward compatible sidelink reservation to improve sidelink network coordination and reduce collisions within sidelink resources. In particular, by sending some information related to reserved side-link resources via SCI messages, the techniques described herein may enable backward compatibility for side-link reservation between Re17 UE 115 and Re16 UE 115. By enabling both Re17 UE 115 and Re16 UE 115 to understand reservation of side-link resources, the techniques described herein may reduce potential collisions within side-link resources and may enable more efficient and reliable communications within wireless communication system 100.

In some examples, communication manager 820 may be configured to perform various operations (e.g., receive, monitor, transmit) using or in cooperation with transceiver 815, one or more antennas 825, or any combination thereof. Although communication manager 820 is shown as a separate component, in some examples, one or more of the functions described with reference to communication manager 820 may be supported or performed by processor 840, memory 830, code 835, or any combination thereof. For example, code 835 may include instructions executable by processor 840 to cause device 805 to perform aspects of techniques for backward compatible side-uplink communications as described herein, or processor 840 and memory 830 may be otherwise configured to perform or support such operations.

Fig. 9 shows a flow chart illustrating a method 900 of supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure. The operations of method 900 may be implemented by a UE or components thereof as described herein. For example, the operations of method 900 may be performed by UE 115 as described with reference to fig. 1-8. In some examples, the UE may execute a set of instructions to control a functional unit of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functionality.

At 905, the method may include: a set of resources for one or more sidelink messages to be performed by the UE is selected from a pool of resources for sidelink communications. The operations of 905 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 905 may be performed by the side-uplink resource manager 725 as described with reference to fig. 7.

At 910, the method may include: the method further comprises selecting an additional resource for transmitting a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold. The operations of 910 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 910 may be performed by the side-uplink resource manager 725 as described with reference to fig. 7.

At 915, the method may include: an IUE coordination message is sent via the additional resources, the IUE coordination message including an indication of the earliest resource within the first stage SCI portion of the IUE coordination message. The operations of 915 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 915 may be performed by IUE coordination messaging manager 730 as described with reference to fig. 7.

At 920, the method may include: a first one of the one or more side-link messages is sent within an earliest resource indicated via the first stage SCI portion of the IUE coordination message. The operations of 920 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 920 may be performed by the side-uplink messaging manager 735 as described with reference to fig. 7.

Fig. 10 shows a flow chart illustrating a method 1000 of supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure. The operations of method 1000 may be implemented by a UE or components thereof as described herein. For example, the operations of method 1000 may be performed by UE 115 as described with reference to fig. 1-8. In some examples, the UE may execute a set of instructions to control a functional unit of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functionality.

At 1005, the method may include: a set of resources for one or more sidelink messages to be performed by the UE is selected from a pool of resources for sidelink communications. Operations of 1005 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1005 may be performed by the side-uplink resource manager 725 as described with reference to fig. 7.

At 1010, the method may include: the method further comprises selecting an additional resource for transmitting a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold. The operations of 1010 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1010 may be performed by the side-uplink resource manager 725 as described with reference to fig. 7.

At 1015, the method may include: an IUE coordination message is sent via the additional resources, the IUE coordination message including an indication of the earliest resource within the first stage SCI portion of the IUE coordination message. The operations of 1015 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1015 may be performed by IUE coordination messaging manager 730 as described with reference to fig. 7.

At 1020, the method may include: based on selecting the set of resources, IUE coordination information is sent via a second stage SCI portion of the IUE coordination message, a data portion of the IUE coordination message, or both, the IUE coordination information including an indication of the set of resources for one or more side-link messages. Operations of 1020 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1020 may be performed by IUE coordination messaging manager 750 as described with reference to fig. 7.

At 1025, the method may include: a first one of the one or more side-link messages is sent within an earliest resource indicated via the first stage SCI portion of the IUE coordination message. The operations of 1025 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1025 may be performed by side-uplink messaging manager 735 as described with reference to fig. 7.

Fig. 11 shows a flow chart illustrating a method 1100 of supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure. The operations of method 1100 may be implemented by a UE or components thereof as described herein. For example, the operations of method 1100 may be performed by UE 115 as described with reference to fig. 1-8. In some examples, the UE may execute a set of instructions to control a functional unit of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functionality.

At 1105, the method may include: a set of resources for one or more sidelink messages from the second UE to the first UE is selected from a pool of resources for sidelink communications. The operations of 1105 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1105 may be performed by the side-uplink resource manager 725 as described with reference to fig. 7.

At 1110, the method may include: the method further comprises selecting an additional resource for transmitting a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based on a time interval between the additional resource and the earliest resource meeting a time threshold. The operations of 1110 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1110 may be performed by the side-uplink resource manager 725 as described with reference to fig. 7.

At 1115, the method may include: an IUE coordination message is sent via the additional resources, the IUE coordination message including an indication of the earliest resource within the first stage SCI portion of the IUE coordination message. The operation of 1115 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1115 may be performed by IUE coordination messaging manager 730 as described with reference to fig. 7.

At 1120, the method may include: a first one of the one or more side-link messages is received from the second UE within an earliest resource indicated via the first stage SCI portion of the IUE coordination message. The operations of 1120 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1120 may be performed by side uplink message reception manager 740 as described with reference to fig. 7.

Fig. 12 shows a flow chart illustrating a method 1200 of supporting techniques for backward compatible side-uplink communications in accordance with aspects of the present disclosure. The operations of method 1200 may be implemented by a UE or components thereof as described herein. For example, the operations of method 1200 may be performed by UE 115 as described with reference to fig. 1-8. In some examples, the UE may execute a set of instructions to control a functional unit of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functionality.

At 1205, the method may include: receiving a SCI message from a first UE, the SCI message comprising an indication of an earliest resource in a set of resources for one or more sidelink messages from a second UE to the first UE, the indication of the earliest resource being included in a first stage SCI portion of an IUE coordination message, the set of resources being included in a pool of resources for sidelink communications, wherein a time interval between receipt of the SCI message and the earliest resource meets a time threshold. Operations of 1205 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operation of 1205 may be performed by SCI message receipt manager 745 as described with reference to fig. 7.

At 1210, the method may include: a first one of the one or more side-link messages is sent within an earliest resource indicated via the first stage SCI portion of the IUE coordination message. The operations of 1210 may be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1210 may be performed by the side-uplink messaging manager 735 as described with reference to fig. 7.

The following provides a summary of various aspects of the disclosure:

Aspect 1: a method for wireless communication at a UE, comprising: selecting a set of resources for one or more sidelink messages to be performed by the UE from a pool of resources for sidelink communications; selecting an additional resource for transmitting a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based at least in part on a time interval between the additional resource and the earliest resource meeting a time threshold; transmitting an IUE coordination message via the additional resource, the IUE coordination message including an indication of the earliest resource within a first stage SCI portion of the IUE coordination message; and transmitting a first one of the one or more side-link messages within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

Aspect 2: the method of aspect 1, further comprising: based at least in part on selecting the set of resources, IUE coordination information is sent via a second stage SCI portion of the IUE coordination message, a data portion of the IUE coordination message, or both, the IUE coordination information including an indication of the set of resources for the one or more sidelink messages.

Aspect 3: the method of aspect 2 wherein the second stage SCI portion, the data portion, or both cannot be decoded by reduced capability UEs and the indication of the earliest resource within the first stage SCI portion can be decoded by reduced capability UEs.

Aspect 4: the method of any one of aspects 1 to 3, further comprising: transmitting a second IUE coordination message comprising a second indication of the earliest resource in a first stage SCI portion of the second IUE coordination message, wherein the second IUE coordination message is transmitted prior to the IUE coordination message; and transmitting the IUE coordination message via the additional resources based at least in part on a second time interval between transmission of the second IUE coordination message and the earliest resource in the set of resources failing to meet the time threshold.

Aspect 5: the method of any one of aspects 1 to 4, further comprising: an indication of a plurality of sub-channels of the earliest resource is sent via the first stage SCI portion of the IUE coordination message, wherein a last sub-channel of the plurality of sub-channels is within the resource pool in a frequency domain, wherein the first side-link message is sent via the plurality of sub-channels.

Aspect 6: the method of any one of aspects 1 to 5, further comprising: one or more FDRI field values including an indication of a subchannel of the earliest resource are sent via the first stage SCI portion of the IUE coordination message, wherein the first side uplink message is sent via at least the subchannel.

Aspect 7: the method of aspect 6, wherein the subchannel includes an initial subchannel of the earliest resource.

Aspect 8: the method of any one of aspects 1 to 7, further comprising: one or more TDRI field values associated with the earliest resource, one or more FDRI field values associated with the earliest resource, or both are sent via the first stage SCI portion of the IUE coordination message.

Aspect 9: the method of any one of aspects 1 to 8, further comprising: transmitting an indication of a second resource in the set of resources via the first side uplink message; and transmitting a second side-link message via the second resource based at least in part on transmitting the indication of the second resource via the first side-link message.

Aspect 10: the method of any one of aspects 1 to 9, wherein the time interval satisfies the time threshold if the time interval is less than or equal to the time threshold.

Aspect 11: the method of any one of aspects 1 to 10, wherein the time threshold comprises thirty-two time slots.

Aspect 12: the method of any one of aspects 1 to 11, further comprising: receiving a second IUE coordination message comprising an indication of second resources for one or more additional side-link messages to be performed by a second UE; and relaying the second IUE coordination message to at least a third UE.

Aspect 13: the method of aspect 12, further comprising: receive, via the second IUE coordination message, one or more TDRI field values associated with a relative timing of the one or more additional side uplink messages; and transmitting one or more additional TDRI field values associated with the relative timing of the one or more additional side uplink messages via the relayed second IUE coordination message.

Aspect 14: the method of any one of aspects 1 to 13, further comprising: selecting a second set of resources for the one or more sidelink messages to be performed by the UE from the pool of resources for sidelink communications, wherein selecting the second set of resources occurs before selecting the set of resources; and determining that a second additional resource for transmitting a resource reservation for an earliest resource in the second set of resources may not be identified, wherein selecting the set of resources, selecting the additional resource, or both is based at least in part on determining that the second additional resource for transmitting a resource reservation for an earliest resource in the second set of resources is not identified.

Aspect 15: the method of any of claims 1-14, wherein the first stage SCI portion of the IUE coordination message comprises one or more bit field values indicating that the first stage SCI portion is associated with the IUE coordination message.

Aspect 16: a method for wireless communication at a first UE, comprising: selecting a set of resources for one or more sidelink messages from a second UE to the first UE from a pool of resources for sidelink communications; selecting an additional resource for transmitting a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based at least in part on a time interval between the additional resource and the earliest resource meeting a time threshold; transmitting an IUE coordination message via the additional resource, the IUE coordination message including an indication of the earliest resource within a first stage SCI portion of the IUE coordination message; and receiving a first side-link message of the one or more side-link messages from the second UE within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

Aspect 17: the method of aspect 16, further comprising: based at least in part on selecting the set of resources, IUE coordination information is sent to the second UE via a second stage SCI portion of the IUE coordination message, a data portion of the IUE coordination message, or both, the IUE coordination information including an indication of the set of resources for the one or more side-link messages.

Aspect 18: the method of claim 17, wherein the second stage SCI portion, the data portion, or both are not decodable by reduced capability UEs and the indication of the earliest resource within the first stage SCI portion is decodable by reduced capability UEs.

Aspect 19: the method of any one of aspects 16 to 18, further comprising: transmitting a second IUE coordination message comprising a second indication of the earliest resource within a first stage SCI portion of the second IUE coordination message, wherein the second IUE coordination message is transmitted prior to the IUE coordination message; and transmitting the IUE coordination message via the additional resources based at least in part on a second time interval between transmission of the second IUE coordination message and the earliest resource in the set of resources failing to meet the time threshold.

Aspect 20: the method of any one of aspects 16 to 19, further comprising: an indication of a plurality of sub-channels of the earliest resource is sent via the first stage SCI portion of the IUE coordination message, wherein a last sub-channel of the plurality of sub-channels is within the resource pool in a frequency domain, wherein the first side-link message is sent via the plurality of sub-channels.

Aspect 21: the method of any one of aspects 16 to 20, further comprising: one or more FDRI field values including an indication of a subchannel of the earliest resource are sent via the first stage SCI portion of the IUE coordination message, wherein the first side uplink message is sent via at least the subchannel.

Aspect 22: the method of claim 21, wherein the subchannel includes an initial subchannel of the earliest resource.

Aspect 23: the method of any one of aspects 16 to 22, further comprising: one or more TDRI field values associated with the earliest resource, one or more FDRI field values associated with the earliest resource, or both are sent via the first stage SCI portion of the IUE coordination message.

Aspect 24: the method of any one of aspects 16 to 23, further comprising: receiving an indication of a second resource in the set of resources via the first side uplink message; and receive a second side uplink message from the second UE via the second resource based at least in part on sending the indication of the second resource via the first side uplink message.

Aspect 25: the method of any of aspects 16-24, wherein the time interval satisfies the time threshold if the time interval is less than or equal to the time threshold.

Aspect 26: the method of any of claims 16-25, wherein the time threshold comprises thirty-two time slots.

Aspect 27: the method of any one of aspects 16 to 26, further comprising: receiving a second IUE coordination message comprising an indication of second resources for one or more additional side-link messages to be performed by a second UE; and relaying the second IUE coordination message to at least a third UE.

Aspect 28: the method of aspect 27, further comprising: receive, via the second IUE coordination message, one or more TDRI field values associated with a relative timing of the one or more additional side uplink messages; and transmitting one or more additional TDRI field values associated with the relative timing of the one or more additional side uplink messages via the relayed second IUE coordination message.

Aspect 29: the method of any of claims 27-28, wherein the selection of the additional resource is based at least in part on the time interval between the additional resource and the earliest resource being greater than or equal to a second time threshold associated with processing capabilities of the first UE, the second UE, or both.

Aspect 30: the method of any one of aspects 16 to 29, further comprising: selecting a second set of resources for the one or more sidelink messages to be performed by the second UE from the pool of resources for sidelink communications, wherein selecting the second set of resources occurs before selecting the set of resources; and determining that a second additional resource for transmitting a resource reservation for an earliest resource in the second set of resources cannot be identified, wherein selecting the set of resources, selecting the additional resource, or both is based at least in part on determining that the second additional resource for transmitting a resource reservation for the earliest resource in the second set of resources cannot be identified.

Aspect 31: the method of any of claims 16-30, wherein the first stage SCI portion of the IUE coordination message comprises one or more bit field values indicating that the first stage SCI portion is associated with the IUE coordination message.

Aspect 32: a method for wireless communication at a second UE, comprising: receiving an IUE coordination message from a first UE, the IUE coordination message comprising an indication of an earliest resource in a set of resources for one or more sidelink messages from the second UE to the first UE, the indication of the earliest resource being included in a first stage SCI portion of the IUE coordination message, the set of resources being included in a pool of resources for sidelink communications, wherein a time interval between receipt of the SCI message and the earliest resource meets a time threshold; and transmitting a first one of the one or more side-link messages within the earliest resource indicated via the first stage SCI portion of the IUE coordination message.

Aspect 33: the method of aspect 32, further comprising: IUE coordination information is received from the first UE via a second stage SCI portion of the IUE coordination message, a data portion of the IUE coordination message, or both, the IUE coordination information including an indication of the set of resources for transmitting the one or more side-link messages based at least in part on selecting the set of resources.

Aspect 34: the method of aspect 33 wherein the second stage SCI portion, the data portion, or both cannot be decoded by reduced capability UEs and the indication of the earliest resource within the first stage SCI portion can be decoded by reduced capability UEs.

Aspect 35: the method of any one of aspects 32 to 34, further comprising: receiving a second IUE coordination message comprising a second indication of the earliest resource within a first stage SCI portion of the second IUE coordination message, wherein the second IUE coordination message is sent prior to the IUE coordination message; and receiving the IUE coordination message via the additional resource based at least in part on a failure of the time threshold to be met by a second time interval between transmission of the second IUE coordination message and the earliest resource in the set of resources.

Aspect 36: the method of any one of aspects 32 to 35, further comprising: an indication of a plurality of sub-channels of the earliest resource is received via the first stage SCI portion of the IUE coordination message, wherein a last sub-channel of the plurality of sub-channels is within the resource pool in a frequency domain, wherein the first side-link message is transmitted via the plurality of sub-channels.

Aspect 37: the method of any one of aspects 32 to 36, further comprising: one or more FDRI field values including an indication of a subchannel of the earliest resource are received via the first stage SCI portion of the IUE coordination message, wherein the first side uplink message is sent via at least the subchannel.

Aspect 38: the method of claim 37, wherein the subchannel includes an initial subchannel of the earliest resource.

Aspect 39: the method of any one of aspects 32 to 38, further comprising: one or more TDRI field values associated with the earliest resource, one or more FDRI field values associated with the earliest resource, or both are received via the first stage SCI portion of the IUE coordination message.

Aspect 40: the method of any one of aspects 32 to 39, further comprising: transmitting an indication of a second resource in the set of resources via the first side uplink message; and transmitting a second side-uplink message from the second UE via the second resource based at least in part on transmitting the indication of the second resource via the first side-uplink message.

Aspect 41: the method of any one of aspects 32 to 40, wherein the time interval satisfies the time threshold if the time interval is less than or equal to the time threshold.

Aspect 42: the method of any one of aspects 32 to 41, wherein the time threshold comprises thirty-two time slots.

Aspect 43: the method of any one of aspects 32 to 42, further comprising: the IUE coordination message is relayed to at least a third UE.

Aspect 44: the method of aspect 43, further comprising: receive, via the IUE coordination message, one or more TDRI field values associated with a relative timing of the one or more additional side uplink messages; and transmitting one or more additional TDRI field values associated with the relative timing of the one or more additional side-link messages via the relayed IUE coordination message.

Aspect 45: the method of any of claims 32-44, wherein the first stage SCI portion of the IUE coordination message comprises one or more bit field values indicating that the first stage SCI portion is associated with the IUE coordination message.

Aspect 46: the method of any one of aspects 32 to 45, further comprising: one or more blind decoding processes are performed, wherein receiving the IUE coordination message is based at least in part on performing the one or more blind decoding processes.

Aspect 47: the method of any one of aspects 32 to 46, further comprising: one or more decoding processes for the IUE coordination message are performed regardless of one or more parameters indicated via the IUE coordination message, including a broadcast type, a destination identifier, a source identifier, feedback distance information, or any combination thereof.

Aspect 48: an apparatus for wireless communication at a UE, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method according to any one of aspects 1 to 15.

Aspect 49: an apparatus for wireless communication at a UE, comprising at least one unit to perform the method of any one of aspects 1-15.

Aspect 50: a non-transitory computer-readable medium storing code for wireless communication at a UE, the code comprising instructions executable by a processor to perform the method of any one of aspects 1-15.

Aspect 51: an apparatus for wireless communication at a first UE, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method according to any one of aspects 16 to 31.

Aspect 52: an apparatus for wireless communication at a first UE, comprising at least one means for performing the method of any one of aspects 16-31.

Aspect 53: a non-transitory computer-readable medium storing code for wireless communication at a first UE, the code comprising instructions executable by a processor to perform the method of any one of aspects 16-31.

Aspect 54: an apparatus for wireless communication at a second UE, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method according to any one of aspects 32 to 47.

Aspect 55: an apparatus for wireless communication at a second UE, comprising at least one means for performing the method of any one of aspects 32-47.

Aspect 56: a non-transitory computer-readable medium storing code for wireless communication at a second UE, the code comprising instructions executable by a processor to perform the method of any one of aspects 32-47.

It should be noted that the methods described herein describe possible implementations, and that the operations and steps may be rearranged or otherwise modified, and that other implementations are possible. Further, aspects from two or more methods may be combined.

Although aspects of the LTE, LTE-A, LTE-a Pro or NR system may be described for purposes of example, and LTE, LTE-A, LTE-a Pro or NR terminology may be used in much of the description, the techniques described herein are applicable to areas outside of the LTE, LTE-A, LTE-a Pro or NR network. For example, the described techniques may be applicable to various other wireless communication systems such as Ultra Mobile Broadband (UMB), institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

The information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, DSP, ASIC, CPU, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software for execution by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwired or a combination of any of these items. Features that implement the functions may also be physically located at various locations including being distributed such that each portion of the functions is implemented at a different physical location.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. Non-transitory storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media can comprise RAM, ROM, electrically Erasable Programmable ROM (EEPROM), flash memory, compact Disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Further, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, includes CD, laser disc, optical disc, digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein (including in the claims), an "or" as used in a list of items (e.g., a list of items ending with a phrase such as "at least one of" or "one or more of" indicates an inclusive list, such that a list of at least one of, for example A, B or C means a or B or C or AB or AC or BC or ABC (i.e., a and B and C). Furthermore, as used herein, the phrase "based on" should not be construed as a reference to a closed set of conditions. For example, example steps described as "based on condition a" may be based on both condition a and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on" is interpreted.

The term "determining (determine)" or "determining (determining)" includes a wide variety of actions, and thus, "determining" may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Further, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), and so forth. Further, "determining" may include parsing, selecting, establishing, and other such like actions.

In the drawings, similar components or features may have the same reference numerals. Furthermore, various components of the same type may be distinguished by following the reference label by a dash and a second label that is used to distinguish between similar components. If only a first reference label is used in the specification, the description applies to any one of the similar components having the same first reference label, irrespective of second or other subsequent reference labels.

The description set forth herein in connection with the appended drawings describes example configurations and is not intended to represent all examples that may be implemented or within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration," rather than "preferred" or "advantageous over other examples. The detailed description includes specific details for the purpose of providing an understanding of the described technology. However, the techniques may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus for wireless communication at a User Equipment (UE), comprising:

A processor;

a memory coupled with the processor; and

Instructions stored in the memory and executable by the processor to cause the apparatus to:

selecting a set of resources for one or more sidelink messages to be performed by the UE from a pool of resources for sidelink communications;

Selecting an additional resource for transmitting a resource reservation for an earliest resource in the set of resources, the selection of the additional resource being based at least in part on a time interval between the additional resource and the earliest resource meeting a time threshold;

Transmitting an inter-UE coordination message via the additional resources, the inter-UE coordination message including an indication of the earliest resource within a first stage side uplink control information portion of the inter-UE coordination message; and

A first side-link message of the one or more side-link messages is sent within the earliest resource indicated via the first stage side-link control information portion of the inter-UE coordination message.

2. The apparatus of claim 1, wherein the processor is further configured to:

based at least in part on selecting the set of resources, inter-UE coordination information is sent via a second stage side uplink control information portion of the inter-UE coordination message, a data portion of the inter-UE coordination message, or both, the inter-UE coordination information including an indication of the set of resources for the one or more side uplink messages.

3. The apparatus of claim 2, wherein the second stage side uplink control information portion, the data portion, or both are not decodable by reduced capability UEs, and wherein the indication of the earliest resource within the first stage side uplink control information portion is decodable by the reduced capability UEs.

4. The apparatus of claim 1, wherein the processor is further configured to:

An indication of a plurality of subchannels of the earliest resource is sent via the first-stage side uplink control information portion of the inter-UE coordination message, wherein a last subchannel of the plurality of subchannels is within the resource pool in a frequency domain, wherein the first side uplink message is sent via the plurality of subchannels.

5. The apparatus of claim 1, wherein the processor is further configured to:

One or more frequency domain resource indication field values comprising an indication of a sub-channel of the earliest resource are transmitted via the first stage side uplink control information portion of the inter-UE coordination message, wherein the first side uplink message is transmitted via at least the sub-channel.

6. The apparatus of claim 5, wherein the subchannel comprises an initial subchannel of the earliest resource.

7. The apparatus of claim 1, wherein the processor is further configured to:

One or more time domain resource indication field values associated with the earliest resource, one or more frequency domain resource indication field values associated with the earliest resource, or both are sent via the first stage side uplink control information portion of the inter-UE coordination message.

8. The apparatus of claim 1, wherein the time interval satisfies the time threshold if the time interval is less than or equal to the time threshold.

9. The apparatus of claim 1, wherein the time threshold comprises thirty-two time slots.

10. The apparatus of claim 1, wherein the processor is further configured to:

Selecting a second set of resources for the one or more sidelink messages to be performed by the UE from the pool of resources for sidelink communications, wherein selecting the second set of resources occurs before selecting the set of resources; and

Determining a second additional resource for transmitting a resource reservation for an earliest resource in the second set of resources may not be identified, wherein selecting the set of resources, selecting the additional resource, or both is based at least in part on determining that the second additional resource for transmitting the resource reservation for the earliest resource in the second set of resources is not identified.

11. An apparatus for wireless communication at a first User Equipment (UE), comprising:

A processor;

a memory coupled with the processor; and

Selecting a set of resources for one or more sidelink messages from a second UE to the first UE from a pool of resources for sidelink communications;

A first side-link message of the one or more side-link messages is received from the second UE within the earliest resources indicated via the first stage side-link control information portion of the inter-UE coordination message.

12. The apparatus of claim 11, wherein the processor is further configured to:

Based at least in part on selecting the set of resources, inter-UE coordination information is sent to the second UE via a second stage side uplink control information portion of the inter-UE coordination message, a data portion of the inter-UE coordination message, or both, the inter-UE coordination information including an indication of the set of resources for the one or more side uplink messages.

13. The apparatus of claim 12, wherein the second stage side uplink control information portion, the data portion, or both are not decodable by reduced capability UEs, and wherein the indication of the earliest resource within the first stage side uplink control information portion is decodable by the reduced capability UEs.

14. The apparatus of claim 11, wherein the processor is further configured to:

15. The apparatus of claim 11, wherein the processor is further configured to:

16. The apparatus of claim 15, wherein the subchannel comprises an initial subchannel of the earliest resource.

17. The apparatus of claim 11, wherein the processor is further configured to:

18. The apparatus of claim 11, wherein the time threshold comprises thirty-two time slots.

19. The apparatus of claim 11, wherein the processor is further configured to:

selecting a second set of resources for the one or more sidelink messages to be performed by the second UE from the pool of resources for sidelink communications, wherein selecting the second set of resources occurs before selecting the set of resources; and

Determining that a second additional resource for sending a resource reservation for an earliest resource in the second set of resources cannot be identified, wherein selecting the set of resources, selecting the additional resource, or both is based at least in part on determining that the second additional resource for sending the resource reservation for the earliest resource in the second set of resources cannot be identified.

20. An apparatus for wireless communication at a second User Equipment (UE), comprising:

A processor;

a memory coupled with the processor; and

Receiving an inter-UE coordination message from a first UE, the inter-UE coordination message comprising an indication of an earliest resource in a set of resources for one or more side-uplink messages from the second UE to the first UE, the indication of the earliest resource being included within a first stage side-uplink control information portion of the inter-UE coordination message, the set of resources being included within a resource pool for side-uplink communications, wherein a time interval between receipt of a side-uplink control information message and the earliest resource meets a time threshold; and

21. The apparatus of claim 20, wherein the processor is further configured to:

inter-UE coordination information is received from the first UE via a second stage side uplink control information portion of the inter-UE coordination message, a data portion of the inter-UE coordination message, or both, the inter-UE coordination information including an indication of the set of resources for transmitting the one or more side uplink messages based at least in part on selecting the set of resources.

22. The apparatus of claim 21, wherein the second stage side uplink control information portion, the data portion, or both are not decodable by reduced capability UEs, and wherein the indication of the earliest resource within the first stage side uplink control information portion is decodable by reduced capability UEs.

23. The apparatus of claim 20, wherein the processor is further configured to:

an indication of a plurality of subchannels of the earliest resource is received via the first-stage side uplink control information portion of the inter-UE coordination message, wherein a last subchannel of the plurality of subchannels is within the resource pool in a frequency domain, wherein the first side uplink message is transmitted via the plurality of subchannels.

24. The apparatus of claim 20, wherein the processor is further configured to:

One or more frequency domain resource indication field values comprising an indication of a sub-channel of the earliest resource are received via the first stage side uplink control information portion of the inter-UE coordination message, wherein the first side uplink message is sent via at least the sub-channel.

25. The apparatus of claim 20, wherein the processor is further configured to:

One or more time domain resource indication field values associated with the earliest resource, one or more frequency domain resource indication field values associated with the earliest resource, or both are received via the first stage side uplink control information portion of the inter-UE coordination message.

26. The apparatus of claim 20, wherein the time threshold comprises thirty-two time slots.

27. The apparatus of claim 20, wherein the processor is further configured to:

One or more blind decoding processes are performed, wherein receiving the inter-UE coordination message is based at least in part on performing the one or more blind decoding processes.

28. The apparatus of claim 20, wherein the processor is further configured to:

One or more decoding processes for the inter-UE coordination message are performed regardless of one or more parameters indicated via the inter-UE coordination message, including a broadcast type, a destination identifier, a source identifier, feedback distance information, or any combination thereof.

29. A method for wireless communication at a User Equipment (UE), comprising:

30. The method of claim 29, further comprising: