CN114175803A

CN114175803A - Sidelink feedback resource allocation

Info

Publication number: CN114175803A
Application number: CN202080054665.4A
Authority: CN
Inventors: 赛巴斯钦·华格纳
Original assignee: JRD Communication Shenzhen Ltd
Current assignee: JRD Communication Shenzhen Ltd
Priority date: 2019-08-04
Filing date: 2020-07-29
Publication date: 2022-03-11
Also published as: WO2021023081A1

Abstract

There is provided a method of allocating resources of a resource pool of a UE for PSFCH transmission, the method comprising: configuring at least one set of PSFCH resources in the resource pool consisting of one or more time-frequency resources for the PSFCH transmission. The step of configuring the at least one set of PSFCH resources in the resource pool may comprise: configuring the at least one set of PSFCH resources to be specific to a single or multiple PSFCH formats. The step of configuring the at least one set of PSFCH resources in the resource pool may comprise: the set is configured to consist of time-frequency resources (including period, slot cycle offset, time gap between the PSFCH and the associated PSSCH) for the PSFCH transmission.

Description

Sidelink feedback resource allocation

Technical Field

The following disclosure relates to resource allocation for sidelink feedback transmission in a cellular communication network.

Background

Wireless communication systems such as third generation (3G) mobile telephone standards and technologies are well known. Such 3G standards and techniques have been developed by the third generation partnership project (3 GPP). Third generation wireless has been developed generally to support macrocell mobile telephone communications. Communication systems and networks have evolved towards broadband and mobile systems.

In a cellular radio communication system, User Equipment (UE) is connected to a Radio Access Network (RAN) over a radio link. The RAN comprises a set of base stations providing radio links to UEs located in cells covered by the base stations and an interface providing overall network control to a Core Network (CN). As will be appreciated, the RAN and CN each perform corresponding functions with respect to the overall network. For convenience, the term "cellular network" will be used to refer to the combined RAN and CN, it being understood that this term is used to refer to the corresponding system for performing the disclosed functions.

The third generation partnership project has developed a so-called long term evolution system (i.e. evolved universal mobile telecommunications system terrestrial radio access network (E-UTRAN)) for mobile access networks, wherein one or more macro cells are supported by base stations called enodebs or enbs (evolved nodebs). Recently, LTE has evolved further towards so-called 5G or NR (new radio) systems, where one or more cells are supported by a base station called a gNB. NR is proposed to utilize an Orthogonal Frequency Division Multiplexing (OFDM) physical transmission format.

In conventional cellular communication networks, all signaling is between each mobile device and the base station rather than directly between the mobile devices, even though the mobile devices are within wireless communication range of each other. This may result in inefficient use of radio transmission resources and may increase base station resource utilization. Sidelink communications allow mobile devices to communicate directly rather than via a base station, potentially improving wireless and base station resource utilization. For machine-to-machine communications, specifically vehicle-to-vehicle (V2V) and vehicle-to-everything/anything (V2X), sidelink communications are considered particularly interesting.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

A method of allocating resources of a resource pool of a UE for PSFCH transmission is provided, the method comprising configuring at least one set of PSFCH resources in a resource pool consisting of one or more time-frequency resources for PSFCH transmission.

The step of configuring the at least one set of PSFCH resources in a resource pool may comprise configuring the at least one set of PSFCH resources to be specific to a single or more PSFCH formats.

The step of configuring the at least one set of PSFCH resources in the resource pool may comprise configuring the set to consist of time-frequency resources for PSFCH transmission, the time-frequency resources comprising a slot cycle, a slot cycle offset, a time gap between a PSFCH and an associated PSSCH. Configuring the at least one set of PSFCH resources in a resource pool may include configuring the set to support frequency hopping.

A method of multiplexing PSFCH resources for different PSFCH transmissions onto at least one set of PSFCH resources is also provided.

The step of multiplexing the PSFCH resources may comprise using an implicit mapping between the PSFCH resources and the associated PSCCH/PSCCH resources. The implicit mapping between the PSCCH resource and the associated PSCCH/PSCCH resource may include setting a PSCCH resource offset within the set of PSCCH resources equal to a subchannel number of a first subchannel of the associated PSCCH/PSCCH resource.

The step of multiplexing the PSFCH resources may comprise explicit signaling using the PSFCH resources. The PSFCH resources may be dynamically signaled in the DCI/SCI transmission.

The step of multiplexing the PSFCH resources may comprise dynamic signaling using a PSFCH resource offset. The step of multiplexing the PSFCH resources may comprise using a PSFCH resource multiplexing scheme that is configurable per resource pool. The step of multiplexing the PSFCH resources for different PSFCH transmissions may comprise allowing the UE to transmit multiple PSFCH transmissions in one time slot.

There is also provided a method of allocating resources of a resource pool of a UE for PSFCH transmission, the method comprising: configuring at least one set of PSFCH resources in a resource pool consisting of one or more time-frequency resources for PSFCH transmission; wherein the time-frequency resources are continuous or discontinuous in time-frequency; wherein configuring at least one PSFCH resource set in a resource pool comprises configuring the set together with a configuration of the resource pool.

A selection of optional features is set out in the dependent claims.

The non-transitory computer-readable medium may include at least one from the group consisting of a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an EPROM, an electrically erasable programmable read-only memory, and a flash memory.

Drawings

Further details, aspects and embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings. Elements shown in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. To facilitate understanding, like reference numerals have been included in the corresponding figures.

Fig. 1 shows a schematic diagram of a cellular network.

Fig. 2 shows an example of a sidelink slot structure in which the PSFCH resources are multiplexed with the PSCCH/PSCCH resources.

Fig. 3 shows an example of inter-slot PSFCH resource allocation for two resource pools.

Fig. 4 shows an example of a set of PFSCH resources with different periods and period offsets.

Fig. 5 shows an example of PFSCH resource set hopping.

Fig. 6 shows an example of possible sets of PSFCH resources with different time-frequency configurations.

Fig. 7 shows an example of a configuration of a set of PSFCH resources.

Fig. 8 shows an example of a PSFCH resource multiplexing using an implicit mapping between PSFCH resources and related PSCCH/PSCCH resources.

Fig. 9 shows an example of a multiplexing of a PSCCH resource using an implicit mapping between a PSCCH/PSCCH resource and an associated PSCCH/PSCCH resource by setting the PSCCH resource offset equal to the first sub-channel number of the associated PSCCH/PSCCH resource.

Fig. 10 illustrates an example of PSFCH resource reuse via explicit signaling of a PSFCH resource offset.

Fig. 11 shows an example of a PSFCH multiplexing in which PSFCH resources are configured every 2 slots for unicast transmission.

Fig. 12 shows an example of PFSCH resource multiplexing with a period equal to 2.

Detailed Description

Those skilled in the art will recognize and appreciate that the specifics of the described examples are merely illustrative of some embodiments and that the teachings set forth herein may be applied in a variety of alternative settings.

Fig. 1 shows a schematic diagram of three base stations (e.g., enbs or gnbs according to certain cellular standards and terminology) forming a cellular network. Typically, each base station will be deployed by one cellular network operator to provide geographic coverage for UEs in the area. The base stations form a wireless local area network (RAN). Each base station provides radio coverage for UEs in its area or cell. The base stations are interconnected via an X2 interface and connected to the core network via an S1 interface. As will be appreciated, only the basic details are shown in order to illustrate key features of the cellular network. In the proposed NR protocol, the Uu interface is between the base station and the UE. The PC5 interface is provided between UEs for sidelink (sl) communication. The interface and component names mentioned with respect to fig. 1 are used as examples only, and different systems operating according to the same principles may use different nomenclature.

The base stations each include hardware and software for performing the functions of the RAN, including communication with the core network and other base stations, transfer of control and data signals between the core network and the UEs, and maintaining wireless communication with the UEs associated with each base station. The core network includes hardware and software that implement network functions, such as overall network management and control, and routing of calls and data.

In order to achieve the reliability and delay required in SL communication (e.g., NR V2X communication) in such a network, a Hybrid Automatic Repeat Request (HARQ) scheme is used for SL communication. For SL communication between a transmitting UE and a receiving UE, the receiving UE receives data on a Physical Sidelink Shared Channel (psch) and receives Sidelink Control Information (SCI) on a Physical Sidelink Control Channel (PSCCH). For unicast SL communication, when SL Feedback is enabled, the receiving UE will send HARQ acknowledgement (HARQ-ACK) Feedback to the sending UE via a Physical Sidelink Feedback Channel (PSFCH) as part of the Sidelink Feedback Control Information (SFCI) when the receiving UE successfully receives and decodes the SCI and successfully receives the relevant data. When the receiving UE successfully receives and decodes the SCI but does not successfully receive the data, the receiving UE will send HARQ negative acknowledgement (HARQ-NACK) feedback to the transmitting UE via the PSFCH as part of the SFCI.

The sidelink transmission uses TDD (half duplex) on a dedicated carrier or TDD (half duplex) on a shared carrier using conventional Uu transmission between the base station and the UE. A resource pool of transmission resources is used to manage resources and allocation and to manage interference between potential concurrent transmissions. A resource pool is a set of time-frequency resources from which resources may be selected for transmission. The UE may be configured with multiple transmit and receive resource pools.

Two modes of operation are proposed for resource allocation for sidelink communications. The first mode (mode 1)) is applied when the UE is within the coverage of the base station and resources are allocated by the base station. When the UE is not within the coverage of the base station, the second mode (mode 2) is used, and the UE autonomously selects and utilizes resources, typically with a listen-before-transmit process.

The UE reserves the resources by sending a SCI message indicating the resources to be used for transmission. The SCI informs the receiving end (which may be a single UE in unicast, a group of UEs in multicast, or all reachable UEs in broadcast) of the details of the transmission it can expect. The UE may reserve transmission resources for the first transmission of a Transport Block (TB) of data and for repetitions of transmission TBs for improved reliability when the initial transmission fails.

The following protocol has been agreed upon with respect to scheduling and procedures for SFCI communications via the PSFCH. For at least sidelink HARQ feedback, the NR sidelink supports at least a PSFCH format that uses resources including one or more last symbols in a slot that are available for sidelink communications. At least TDM between PSCCH/PSCCH resources and PSFCH resources is allowed at least from the UE transmission perspective. An implicit mechanism is used to determine at least the frequency and/or code domain resources for the PSFCH within the resource pool, at least for the case when the PSFCH in the slot is responsive to a single PSSCH.

An example of a SL slot structure is shown in fig. 2, where the PSFCH resources are multiplexed with the PSCCH/PSCCH resources using TDM. Note that the PSFCH does not necessarily relate to the PSSCH in the same slot. If the UE is scheduled to receive on the PSSCH and then transmit on the PSFCH, a transition period is required to switch from receiving to transmitting. Similarly, if the UE receives PSFCH communications in the same slot as the slot of the PSSCH communications, a transition period is required.

With regard to inter-slot resource scheduling, the following protocol has been reached. The (pre) configuration indicates the time interval between the PSFCH resource and the associated PSSCH resource. Within the time slot associated with the resource pool, the PSFCH resource may be (pre-) configured with a period of N time slots. The PSFCH resources may be (pre-) configured to occur periodically every slot, every 2 slots, every 4 slots. The PSFCH resources may be (pre-) configured to not occur at all. The (pre) configuration is resource pool specific. The PSFCH transmission is transmitted only in the same resource pool as the resource pool of the associated PSSCH transmission.

An example of inter-slot resource scheduling for the PSFCH resources of two resource pools is shown in fig. 3. The time gap between the PSFCH resource and the related PSSCH resource is (pre-) configured (generally understood to be for each resource pool), which means that dynamic signaling is not supported. Resource pool 0 has a PSFCH resource occurrence every 2 sidelink slots (N ═ 2), and resource pool 1 has a PSFCH resource occurrence every 4 sidelink slots (N ═ 4).

The following protocol has been agreed on the payload of the PSFCH (i.e., HARQ-ACK/NACK feedback). HARQ feedback may be enabled or disabled for each UE through higher layer signaling. HARQ feedback can also be disabled in the resource pool configuration of the UE, i.e. no PSFCH resources are configured in the resource pool. In case of unicast communication, HARQ payload is simple, the UE sends HARQ ACK/NACK feedback on the relevant PSFCH. The situation is more complicated in multicast transmission because feedback has to be sent/received from multiple UEs. There are two options at this time: all UEs in a group transmission (i) HARQ-NACK-only feedback or (ii) HARQ-ACK/NACK feedback. For option 1, all UEs share one PSFCH resource. Since the TX-UE does not need to distinguish the UE from the feedback of the UE, all UEs can transmit the same HARQ-NACK feedback sequence. For option 2, each receiving UE uses separate PSFCH resources for HARQ ACK/NACK feedback. Each PSFCH is mapped to time, frequency and code resources.

Only a few agreements are made with respect to the physical structure of the PSFCH. A sequence-based PSFCH format with one symbol is supported. This applies to unicast and multicast including option 1 and option 2 described above. The sequence of PUCCH format 0 is the starting point for developing the 5G-V2X PSFCH format.

A problem with the protocol for PSFCH scheduling is that only one PSFCH resource is allocated within a time slot. Another problem is that the time interval between the (pre-) configured psch resource and the associated PSFCH resource results in that the (pre-) configured minimum delay for transmission and traffic types with different delay requirements cannot be supported within one resource pool.

The time-frequency resources may be contiguous in time-frequency. The time-frequency resources may be discontinuous in time-frequency. The UE may transmit the SFCI using time-frequency resources.

The step of configuring at least one set of PSFCH resources in the resource pool may comprise configuring the at least one set of PSFCH resources to be specific to a single PSFCH format. A set of PSFCH resources specific to a single PSFCH format may consist of time-frequency resources having the same format. A set of PSFCH resources specific to a single PSFCH format may consist of time-frequency resources having the same type. A set of PSFCH resources specific to a single PSFCH format may consist of time-frequency resources having the same size. For example, a first set of PSFCH resources may be specified for a sequence-based PSFCH format similar to PUCCH format 0, and a second set of PSFCH resources may be configured for an encoded PSFCH format similar to PUCCH format 2. Configuring the set of PSFCH resources to be specific to a single PSFCH format facilitates implicit PSFCH multiplexing and indicating the PSFCH resources using implicit signaling.

The step of configuring at least one set of PSFCH resources in the resource pool may comprise configuring the at least one set of PSFCH resources to be specific to a plurality of PSFCH formats. Multiple different PSFCH formats of a set of PSFCH resources will use the same number of symbols. A plurality of different PSFCH formats may be multiplexed in a set of PSFCH resources by explicit signaling of the PSFCH resources, e.g. explicit signaling for indicating frequency location.

The step of configuring at least one set of PSFCH resources in the resource pool may comprise configuring said set to consist of time-frequency resources for PSFCH transmission, said time-frequency resources comprising a slot cycle and a slot cycle offset. Multiple sets of PSFCH resources may be configured, each set consisting of a different periodicity and periodicity offset. This allows, for example, a first set of PSFCH resources to be available every even slot and a second set of PSFCH resources to be available every odd slot. Furthermore, the UE or the base station of the UE may schedule a PSFCH transmission that requires a large amount of PSFCH resources (e.g., a multicast transmission with ACK/NACK feedback) such that the PSFCH transmission occurs in a time slot with a large set of PSFCH resources. An example is shown in fig. 4, in which a PSFCH0 is configured in each SL slot (slot cycle 1), a PSFCH1 is configured in each even SL slot (slot cycle 2), and a PSFCH3 is configured in each odd SL slot (slot cycle 2, slot cycle offset 1).

The step of configuring at least one set of PSFCH resources in the resource pool may comprise configuring said set to consist of time-frequency resources for PSFCH transmission, including a time gap between a PSFCH and an associated PSSCH. This enables traffic types with different delay requirements. For example, in fig. 4, the resource set PSFCH0 occurs every slot, so the resource set PSFCH0 has the potential to support low latency services. If the PSSCH-PSFCH gap is configured to be 0 slots, the UE can receive the PSSCH and transmit the relevant PSFCH in the same slot (assuming sufficient UE capability). Meanwhile, mode-2 UEs that sense pscch transmissions are aware of the PSFCH resource set configuration and may implicitly infer the PSFCH resources for the corresponding PSFCH transmission. Thus, the UE resource pool with its different PSFCH resource set configurations can be shared between mode-1 and mode-2 users.

The step of configuring at least one set of PSFCH resources in the resource pool may comprise configuring said set to support frequency hopping according to a configurable pattern. An example is shown in fig. 5, where the PSFCH0 is changing frequency location with each SL slot.

The step of configuring at least one set of PSFCH resources in the resource pool may comprise configuring said set as UE group specific. The base station may configure the set of group-specific PSFCH resources, e.g., during group configuration. The resource set may then be configured according to the group feedback requirements. The multicast transmission will then automatically use the set of PSFCH resources.

The step of configuring at least one set of PSFCH resources in the resource pool may comprise configuring said set to allow CBG based feedback. Feedback for CBGs requires more PSFCH resources, so it may be beneficial to allow CBG feedback only for certain sets of PSFCH resources.

The step of configuring at least one set of PSFCH resources in a resource pool may comprise configuring said set as relating to a portion of frequency resources within said resource pool. A set of PSFCH resources may be associated with a particular frequency range within a resource pool. The set of PFSCH resources may define the relevant PSCCH/PSCCH frequency range. If the first assigned sub-channel for the PSCCH/PSCCH is located within a frequency range, the transmission is fed back using the corresponding pool of PSFCH resources. Note that multiple transmissions may be scheduled in the frequency range, so they will use the same set of PSFCH resources.

The step of configuring at least one set of PSFCH resources in the resource pool may comprise configuring said set to associate a PSSCH transmission to a set of PSFCH resources. The psch transmission may be implicitly associated to a set of PSFCH resources. The psch transmission may be explicitly associated with a set of PSFCH resources. The psch transmission may be directly associated to the set of PSFCH resources through dynamic signaling in the DCI/SCI. The dynamic signaling may include an ID of the set of PSFCH resources. The psch transmission may be implicitly associated to the set of PSFCH resources by the resource allocation of the relevant psch, e.g., if the set of PSFCH resources are sub-channel dependent. The psch transmission may be implicitly associated with the set of PSFCH resources by the PSFCH format for transmission, e.g., if the feedback requires PSFCH format 2, only the set of PSFCH resources that allow that format is considered. Psch transmissions may be implicitly associated with sets of PSFCH resources through CBG-based feedback, e.g., some sets of PSFCH resources may allow CBG feedback while others may not.

The step of configuring at least one PSFCH resource set in the resource pool may comprise configuring the set together with the configuration of the resource pool.

The method may also include configuring the resource pool to include a list of PSFCH resource sets. The list of PSFCH resource sets in the resource pool may be empty, i.e. HARQ feedback is not supported in the resource pool.

An example of possible sets of PSFCH resources with different time-frequency configurations is given in fig. 6. In this example, the set of resources consists of contiguous time-frequency resources. The resource set may also contain a list of time-frequency resources, each configured separately like NR PUCCH resource allocation.

An example of the configuration of the resource pool is given in fig. 7. Note that the set of PSFCH resources is configured per subchannel, as the remaining resources in the frequency domain may be used for PSSCHs allocated only at a subchannel-based granularity. The granularity of the sub-channels is the same as the granularity for the resource pool configuration and therefore is not part of the PSFCH resource set configuration.

As can be seen, a set of PSFCH resources may be defined as a set of PSFCH time-frequency resources that may be configured with different capabilities (e.g., periodicity offset, psch-PSFCH interval, frequency hopping, etc.). This allows a very flexible allocation of feedback resources tailored to various requirements, e.g. new V2X services (low latency, high throughput, etc.). The proposed set of PSFCH resources allows flexible allocation of HARQ feedback resources and improves feedback resource efficiency in 5G sidelink communications.

Methods of multiplexing PSFCH resources for different PSFCH transmissions onto at least one set of PSFCH resources are also provided.

When the relevant PSCCH/PSCCH transmissions occur on different sub-channels but on the same time slot, we first consider multiplexing the PSFCH resources. If the pscch transmissions are scheduled on different subchannels in the same slot, their associated PSFCH feedback transmissions must also be multiplexed.

The step of multiplexing the PSFCH resources may comprise using an implicit mapping between the PSFCH resources and the associated PSCCH/PSCCH resources.

Implicit allocation of PSFCH resources has the advantage of allowing the UE to sense the relevant PSCCH/PSCCH transmission and directly derive the location of the mapped PSFCH resources. However, implicit mapping is not resource efficient because it is not flexible. Implicit mapping of the PSFCH resources and the associated PSCCH/PSCCH resources is supported. One simple scheme is to map the PSFCH resources to the first sub-channel used by the associated PSCCH/PSCCH resource. Fig. 8 depicts an example in which four UEs transmit on different subchannels. Although the mapping is simple, it is clear from fig. 8 that the PSFCH resource utilization is poor. Of the available 20 PRBs, only 4 are used to send the PSFCH transmission.

The implicit mapping between the PSCCH resource and the associated PSCCH/PSCCH resource may include setting a PSCCH resource offset within the set of PSCCH resources equal to a subchannel number of a first subchannel of the associated PSCCH/PSCCH resource.

The association of the PSFCH resource offset with the subchannel number of the associated PSCCH/PSCCH transmission within the resource set improves the PSFCH resource utilization. For example, in fig. 9 there are five subchannels, the first subchannel for the transmission of UE2 is subchannel 3, and thus the PSFCH resource offset is 3. From FIG. 9, it can be seenThe set of PSFCH resources needs to be at least 5 PRBs (more typically n) in bandwidth_subCHsize RBs²). However, since the PSFCH resource allocation is likely to be sub-channel-wise, two sub-channels must be available. Thus, only 4 of the 8 PSFCH resources are used in this example. This scheme is effective if a large number of transmissions are scheduled, each occupying only a small number of subchannels. Conversely, it is less efficient if each transmission schedules only a small number of transmissions across multiple subchannels.

The step of multiplexing the PSFCH resources may comprise explicit signaling using the PSFCH resources. The PSFCH resources may be signaled in the DCI/SCI transmission.

Dynamic signaling is very efficient, but comes with the signaling overhead and the fact that the UE needs to decode the control information to know the exact PSFCH resource location. To improve resource efficiency, the PSFCH resources should be allocated as shown in fig. 10. In this example, the PSFCH resources for all four transmissions may be allocated to only 4 PRBs. The remaining resources may be used, for example, to schedule psch resources (if half duplex issues do not arise) or to configure another set of PSFCH resources. In the example UE0, assuming that UE1 and UE2 send feedback in another slot, UE1 and UE2 may use the last two symbols for the PSSCH resource. To implement this scheme, an offset must be associated with each transmission. In the example of fig. 10, the set of PSFCH resources is allocated on subchannels spanning PRB0 through PRB 3. The offset may be relative to the first PRB of the PSFCH resource set, i.e., UE0, UE1, UE2, and UE3 have an offset of 0 PRB, 1 PRB, 2 PRB, 3 PRB, respectively. To address each PSFCH resource in this resource set example, 2 bits are therefore required. In general, the number of bits of the PSFCH resource offset is given by:

wherein n is_subCHsizeIs the size of the sub-channel and,

being a subchannel of a set of PSFCH resourcesThe number is numbered,

is the number of PRBs per PSFCH resource.

Obviously, the larger the set of PSFCH resources, the more bits are needed for the offset. To achieve optimal multiplexing, the offset needs to be signaled dynamically, since the number of transmissions and their bandwidth can change every slot.

The step of multiplexing the PSFCH resources may comprise dynamic signaling using a PSFCH resource offset. The PSFCH resource offset may be dynamically signaled in the DCI/SCI transmission.

The step of multiplexing the PSFCH resources may comprise using a PSFCH resource multiplexing scheme that is configurable per resource pool. Implicit or explicit signaling of the PSFCH resources may be beneficial depending on the nature of the communication in the resource pool. Therefore, it is desirable to configure a multiplexing scheme for each resource pool.

We now discuss the multiplexing of PSFCH resources for transmissions that occur in different time slots.

The step of multiplexing the PSFCH resources for different PSFCH transmissions may comprise allowing the UE to transmit multiple PSFCH transmissions in one time slot.

If the PSFCH period N >1, then the feedback from the transmissions of different time slots needs to be multiplexed onto the PSFCH resources in one time slot. Fig. 11 depicts a simple example of PSFCH multiplexing, where the PSFCH resources are configured every 2 slots for unicast transmission. We assume that the time gap between the pscch resource and the associated PSFCH resource is configured to be 2 slots, i.e. the earliest feedback of the pscch transmission in slot n is in slot n + 2.

When a pscch transmission is received by the same UE in two consecutive slots, the UE receives the transmission in slot n and slot n + 1. The earliest feedback was n +2 and n +3, but since there is no PSFCH resource in slot n +2, the feedback for both transmissions must be sent in slot n + 3. The UE may send HARQ-ACK feedback on separate PSFCH resources. This requires that the UE be able to transmit multiple PSFCHs in the same slot. Alternatively, the UE may send HARQ-ACK feedback for two transmissions on the same PSFCH resource. This requires the possibility that the PSFCH may carry multiple bits. PUCCH format 0 carries only 2 bits and is therefore not sufficient for N > 2. Therefore, it is necessary to allow the UE to transmit multiple PSFCH transmissions in one slot.

When pscch transmissions are received by two different UEs in two consecutive slots, the two transmissions may use the same PSFCH resource, but each UE needs to know the sequence to transmit so that they do not interfere with each other.

The step of multiplexing the PSFCH resources for different PSFCH transmissions in different time slots may follow rule n_PSFCHN mod N, where N is the period of the PSFCH resource and N_PSFCHIs the PSFCH resource index and n is the number of slots in which the associated PSSCH is received.

The preceding section addresses the problem of multiplexing the PSFCH resources for PSFCH transmission that occurs in different time slots or in different sub-channels. However, in general, a set of PSFCH resources may be configured with N >1 and support multiple PSFCH transmissions per slot, i.e., a resource pool consisting of more than one subchannel.

Fig. 12 shows an example of N-2 PSFCH resource reuse. The mapping rules given above for multiplexing different transmissions in different time slots are combined with different methods for sub-channel to PSFCH resource mapping. Scheme S1 uses the direct subchannel mapping rule, while scheme S2 uses the first subchannel to PSFCH resource rule. Scheme S3 is a dynamic scheme with signaling of PSFCH offset. It can be observed that implicit mapping results in segmented PSFCH transmission, i.e., the UE needs to send multiple PSFCHs in non-adjacent PRBs. This is undesirable because it may cause interference from in-band spurs (in-band emissions). However, the implicit mapping of subchannel numbers to PSFCH resources is more resource efficient and results in fewer segments. Note that if N is larger than the subchannel size, the mapping rule in S2 needs to be modified. In this case, it is preferable to use the multiplexing scheme S1. Dynamic signaling of the PSFCH resource offset only may enable high resource efficiency and allow continuous PSFCH resources per UE. Therefore, we propose to extend the dynamic signaling of the offset to the case N > 1.

Multiplexing the PSFCH resources may include using dynamic signaling of the PSFCH resource offset when the periodicity of the PSFCH resources is greater than 1. This may include introducing an offset parameter that addresses different PSFCH resources within the set of PSFCH resources to map the PSFCH resources to the set of PSFCH resources. The offset parameter may be signaled in the DCI/SCI scheduling the transmission.

The minimum granularity of the offset parameter is the minimum frequency allocation of the PSFCH resource (e.g., one PRB), but this will result in high control overhead and is also unnecessary. In the multiplexing of PFSCH resources, the PSFCH transmission of one UE may be contiguous. This minimizes the in-band spurs. Thus, the psch resources of one UE in consecutive slots are mapped to neighboring PRBs in the PFSCH resource set.

The number of offsets N is defined by the size of the PSFCH resource set_offset：

Wherein n is_subCHsizeIs the sub-channel size of the resource pool,

and N are the number and period, respectively, of the subchannels of the set of PSFCH resources. The offset L should have granularity with respect to the PSFCH resource bandwidth of L ═ N.

There can only be as many parallel transmissions in the resource pool as there are subchannels in the resource pool. Therefore, the PSFCH resources must be as many as subchannels. In fig. 12, there are 5 subchannels and N is 2, so the PSFCH resource set should consist of 10(5 × 2 ═ 10) PSFCH resources. Therefore 5 offsets are required: 0. 2, 4, 6 and 8.

A special case is multicast transmission with ACK/NACK feedback, where one transmission must be sent to a group of users, but each user is required to send feedback on the PSFCH resources. It has been proposed to use the UE IDs within the group to derive the PSFCH resource location. In connection-based multicast, another solution may be to reserve a set of PSFCH resources for the group (as described earlier) and allocate dedicated PSFCH resources within the set for each group member. For example, an offset is signaled to the UEs in the group within the set of PSFCH resources.

The step of multiplexing the PSFCH resources may comprise allocating dedicated PSFCH resources to each group member during group configuration for SL multicast transmission.

To avoid collisions with the PSFCH of other transmissions, a dedicated set of PSFCH resources is allocated to the group. The same may be applied to hybrid feedback, i.e. some of the users use ACK/NACK feedback while other users use only NACK. In case the whole group is configured with NACK feedback only, the same PSFCH multiplexing and mapping as unicast is applied.

Advantages of the proposed method include: resource utilization: the PSFCH resources are minimized and the released resources may be used for different purposes. Flexibility: the PSFCH resources may be configured to meet the specific requirements of a transport or service. Coexistence of different services: for example, within a resource pool, two sets of PSFCH resources may be configured, a smaller set of PSFCH resources having a high periodicity and a short PSSCH-PSFCH resource interval for low latency services, and a larger set of PSFCH resources having a high multiplexing capacity, a low periodicity, a larger PSSCH-PSFCH interval for high connectivity services.

Although not shown in detail, any device or apparatus forming part of a network may comprise at least a processor, a memory unit and a communication interface, wherein the processor unit, the memory unit and the communication interface are configured to perform the method of any aspect of the invention. Further options and choices are described below.

The signal processing functions of embodiments of the present invention (specifically, the gNB and the UE) may be implemented using computing systems or architectures known to those skilled in the art. Computing systems (such as desktop, laptop or notebook computers, handheld computing devices (PDAs, cell phones, palmtops, etc.), mainframes, servers, clients, or any other type of special or general purpose computing device) may be used as may be desired or appropriate for a given application or environment. A computing system may include one or more processors, which may be implemented using a general-purpose or special-purpose processing engine (e.g., such as a microprocessor, microcontroller or other control module).

The computing system may also include a main memory, such as a Random Access Memory (RAM) or other dynamic memory, for storing information and instructions to be executed by the processor. Such main memory may also be used for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor. The computing system may also include a Read Only Memory (ROM) or other static storage device for storing static information and instructions for the processor.

The computing system may also include an information storage system that may include, for example, a media drive and a removable storage interface. The media drive may include a drive or other mechanism for supporting fixed or removable storage media, such as a hard disk drive, a floppy disk drive, a magnetic tape drive, an optical disk drive, a Compact Disc (CD) or Digital Video Drive (DVD) read or write drive (R or RW), or other removable or fixed media drive. The storage media may include, for example, a hard disk, floppy disk, magnetic tape, optical disk, CD or DVD, or other fixed or removable medium that is read by and written to by a media drive. The storage media may include a computer-readable storage medium having stored therein particular computer software or data.

In alternative embodiments, the information storage system may include other similar components for allowing computer programs or other instructions or data to be loaded into the computing system. Such components may include, for example, removable storage units and interfaces such as program cartridges and cartridge interfaces, removable memory (e.g., flash memory or other removable memory modules) and memory slots, and other removable storage units and interfaces that allow software and data to be transferred from the removable storage unit to the computing system.

The computing system may also include a communications interface. Such a communication interface may be used to allow software and data to be transferred between the computing system and external devices. Examples of a communication interface may include a modem, a network interface (such as an ethernet or other NIC card), a communication port (such as, for example, a Universal Serial Bus (USB) port), a PCMCIA slot and card, etc. Software and data transferred via the communication interface are in the form of signals which may be electrical, electromagnetic and optical, or other signals capable of being received by the communication interface medium.

In this document, the terms "computer program product," "computer-readable medium," and the like may be used generally to refer to tangible media such as memory, storage devices, or storage units. These and other forms of computer-readable media may store one or more instructions for use by a processor, including a computer system, to cause the processor to perform specified operations. Such instructions, generally referred to as "computer program code" (which may be grouped in the form of computer programs or other groupings), when executed, enable the computing system to perform functions of embodiments of the present invention. Note that the code may directly cause the processor to perform specified operations, be compiled to perform specified operations, and/or be combined with other software, hardware, and/or firmware elements (e.g., libraries for performing standard functions) to perform the specified operations.

The non-transitory computer-readable medium may include at least one from the group consisting of a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an EPROM, an electrically erasable programmable read-only memory, and a flash memory. In embodiments where the elements are implemented using software, the software may be stored in a computer-readable medium and loaded into the computing system using, for example, a removable storage drive. When executed by a processor in a computer system, the control module (in this example, software instructions or executable computer program code) causes the processor to perform the functions of the invention as described herein.

Furthermore, the inventive concept may be applied to any circuit for performing signal processing functions within a network element. It is further contemplated that, for example, a semiconductor manufacturer may employ the inventive concept in the design of a stand-alone device, such as a microcontroller or Application Specific Integrated Circuit (ASIC) of a Digital Signal Processor (DSP) and/or any other subsystem element.

It will be appreciated that the above description, for clarity, has described embodiments of the invention with reference to a single processing logic. The inventive concept may, however, equally be implemented by a plurality of different functional units and processors for providing signal processing functions. Hence, references to specific functional units are only to be seen as references to suitable means for providing the described functionality rather than indicative of a strict logical or physical structure or organization.

Aspects of the invention may be implemented in any suitable form including hardware, software, firmware or any combination of these. The invention may optionally be implemented (at least in part) as computer software running on one or more data processors and/or digital signal processors or configurable modular components, such as FPGA devices.

Thus, the elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the invention is limited only by the attached claims. In addition, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term "comprising" does not exclude the presence of other elements or steps.

Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Furthermore, the inclusion of a feature in one category of claims does not imply a limitation to this category but rather indicates that the feature is equally applicable to other claim categories as appropriate.

Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. In addition, singular references do not exclude a plurality. Thus, references to "a", "an", "first", "second", etc., do not preclude a plurality.

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the invention is limited only by the attached claims. In addition, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term "comprising" or "comprises" does not exclude the presence of other elements.

Claims

1. A method of allocating resources of a resource pool of a UE for PSFCH transmission, the method comprising:

configuring at least one set of PSFCH resources in the resource pool consisting of one or more time-frequency resources for the PSFCH transmission;

wherein the time-frequency resources are continuous or discontinuous in time-frequency;

wherein the step of configuring the at least one PSFCH resource set in the resource pool comprises: configuring the set with a configuration of the resource pool.

2. The method of claim 1, wherein the set of PSFCH resources relates to a frequency range within the resource pool and comprises a set of PRBs.

3. The method according to claim 1, wherein the step of configuring the at least one set of PSFCH resources in the resource pool comprises: configuring the at least one set of PSFCH resources to consist of time-frequency resources used for the PSFCH transmission such that a time gap exists between a PSFCH and an associated PSSCH.

4. The method of claim 3, wherein the time gap between PSSCH resources and associated PSFCH resources is defined as a number of slots.

5. The method of claim 4, wherein the number of the time slots is 0 or 2.

6. The method of claim 1, wherein multiplexing PSFCH resources for different PSFCH transmissions into the at least one set of PSFCH resources comprises mapping PSFCH resources to associated PSCCH/PSSCH resources, and wherein the mapping comprises setting a PSFCH resource offset equal to the subchannel number of a first subchannel of the associated PSCCH/PSSCH resources within the set of PSFCH resources.

7. The method of claim 1, wherein the at least one set of PSFCH resources consists of a number of subchannels multiplied by a PSFCH period.

8. The method according to claim 6, wherein the step of multiplexing PSFCH resources comprises: the UE is allowed to transmit multiple PSFCH transmissions in one slot.

9. The method according to claim 1, wherein the step of configuring the at least one set of PSFCH resources in the resource pool comprises: configuring the at least one set of PSFCH resources to support frequency hopping according to a configurable pattern.