WO2023123232A1

WO2023123232A1 - Methods and apparatuses for sl-prs transmission and measurement reporting

Info

Publication number: WO2023123232A1
Application number: PCT/CN2021/143177
Authority: WO
Inventors: Xiaodong Yu; Haipeng Lei; Zhennian SUN; Jie Hu; Xin Guo
Original assignee: Lenovo (Beijing) Limited
Priority date: 2021-12-30
Filing date: 2021-12-30
Publication date: 2023-07-06

Abstract

The present application relates to methods and apparatuses for sidelink Positioning Reference signal (SL-PRS) transmission and measurement reporting. One embodiment of the present disclosure provides a first user equipment (UE), which includes: a processor configured to determine sidelink control information (SCI) including a first time offset or a first resource for sidelink Positioning Reference signal (SL-PRS) measurement reporting; and a transceiver coupled to the processor and configured to transmit the sidelink control information via physical layer channel to the second UE.

Description

METHODS AND APPARATUSES FOR SL-PRS TRANSMISSION AND MEASUREMENT REPORTING

TECHNICAL FIELD

The present disclosure relates to sidelink (SL) communication, and more specifically relates to methods and apparatuses for sidelink positioning reference signal (SL-PRS) transmission and measurement reporting.

BACKGROUND OF THE INVENTION

Vehicle to everything (V2X) has been introduced into 5G wireless communication technology. In terms of a channel structure of V2X communication, a direct link between two user equipments (UEs) is called a sidelink (SL) . Sidelink is a long-term evolution (LTE) feature introduced in 3GPP Release 12, and enables a direct communication between proximal UEs, and data does not need to go through a base station (BS) or a core network.

In order to enhance the reliability and reduce latency of the requirement for positioning of SL UEs, it is desirable to further improve the SL-PRS transmission and measurement reporting.

SUMMARY

One embodiment of the present disclosure provides a first UE, which includes: a processor configured to determine sidelink control information (SCI) including a first time offset or a first resource for SL-PRS measurement reporting; and a transceiver coupled to the processor and configured to transmit the sidelink control information via physical layer channel to the second UE.

In some embodiments, the SCI further includes identity information to indicate an association between SL-PRS transmission of the first UE and SL-PRS measurement reporting of a second UE.

In some embodiments, the SCI includes at least one of the following: a size of the first time offset; a number of slots corresponding to the first time offset; a type of the first time offset; a type of slot corresponding to the first time offset; a type of SL-PRS transmission of the first UE and SL-PRS measurement reporting of a second UE; a SL-PRS measurement reporting latency requirement; or a SL-PRS measurement reporting configuration.

In some embodiments, at least one of the following is determined based on pre-configuration or definition per resource pool: the size of the first time offset; the number of slots corresponding to the first time offset; the type of the first time offset; the type of slot corresponding to the first time offset; the type of SL-PRS transmission of the first UE and SL-PRS measurement reporting of the second UE; the SL-PRS measurement reporting latency requirement; or the SL-PRS measurement reporting configuration.

In some embodiments, the SCI is determined based on downlink control information (DCI) received from a BS.

In some embodiments, the DCI includes a second time offset identical to the first time offset for the second UE to report the SL-PRS measurement to the first UE.

In some embodiments, the DCI includes a second time offset greater than the first time offset, the first time offset indicates a first maximum reporting delay tolerance for the second UE to report the SL-PRS measurement to the first UE, and the second time offset indicates a second maximum reporting delay tolerance for the first UE to report the SL-PRS measurement to a BS.

In some embodiments, the SCI further includes a first indication, which indicates the second UE whether the SL-PRS measurement is to be reported to the first UE or is to be reported to a BS.

In some embodiments, the first resource includes a time and/or frequency location of resource on SL or a time and/or frequency location of resource on UL and is used for the second UE to report the SL-PRS measurement.

In some embodiments, the SCI further includes a second indication which indicates the second UE on SL to report the SL-PRS measurement, or on UL to report the SL-PRS measurement.

Another embodiment of the present disclosure provides a first UE, which includes: a transceiver configured to receive SCI via physical layer channel from a second UE, wherein SCI includes a first time offset or a first resource for SL-PRS measurement reporting; and a processor configured to determine, based on the SCI, a maximum reporting delay tolerance for SL-PRS measurement reporting or the first resource for SL-PRS measurement reporting.

In some embodiments, the configuration information further includes identity information to indicate an association between SL-PRS transmission of the first UE and SL-PRS measurement reporting of a second UE.

In some embodiments, SCI includes at least one of the following: a size of the first time offset; a number of slots corresponding to the first time offset; a type of the first time offset; a type of slot corresponding to the first time offset; a type of SL-PRS transmission of the first UE and SL-PRS measurement reporting of a second UE; a SL-PRS measurement reporting latency requirement; or a SL-PRS measurement reporting configuration.

Yet another embodiment of the present disclosure provides a method performed by a first user UE, which includes: determining SCI including a first time offset or a first resource for SL-PRS measurement reporting; and transmitting the SCI via physical layer channel to the second UE.

In some embodiments, the at least one of the following is determined based on pre-configuration or definition per resource pool: the size of the first time offset; the number of slots corresponding to the first time offset; the type of the first time offset; the type of slot corresponding to the first time offset; the type of SL-PRS transmission of the first UE and SL-PRS measurement reporting of the second UE; the SL-PRS measurement reporting latency requirement; or the SL-PRS measurement reporting configuration.

In some embodiments, the SCI is determined based on DCI received from a BS.

Still another embodiment of the present disclosure provides a method performed by a first UE, which includes: receiving SCI via physical layer channel from a second UE, wherein the SCI includes a first time offset or a first resource for SL-PRS measurement reporting; and determining a maximum reporting delay tolerance for SL-PRS measurement reporting or the first resource for SL-PRS measurement reporting.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 illustrates an exemplary V2X communication system in accordance with some embodiments of the present disclosure.

Fig. 2A illustrates an exemplary measurement window and an exemplary reporting window according to some embodiments of the present disclosure.

Fig. 2B illustrates some exemplary SL-PRS measurement windows and some exemplary SL-PRS reporting windows according to some embodiments of the present disclosure.

Fig. 2C illustrates an exemplary one SL-PRS measurement transmission and one SL-PRS measurement reporting according to some embodiments of the present disclosure.

Fig. 2D illustrates an exemplary multiple SL-PRS measurement transmissions and one SL-PRS measurement reporting according to some embodiments of the present disclosure.

Fig. 3 illustrates an exemplary signalling exchange among BS, target UE, and Rx UEs according to some embodiments of the present disclosure.

Figs. 4A-4C illustrate some exemplary signalling exchange between target UE and Rx UE according to some embodiments of the present disclosure.

Fig. 5 illustrates an exemplary flow chart of SL-PRS transmission and measurement reporting according to some embodiments of the present disclosure.

Fig. 6 illustrates another exemplary flow chart of SL-PRS transmission and measurement reporting according to some embodiments of the present disclosure.

Fig. 7 illustrates another exemplary flow chart of SL-PRS transmission and measurement reporting according to some embodiments of the present disclosure.

Fig. 8 illustrates a method performed by target UE for wireless communication according to a preferred embodiment of the present disclosure.

Fig. 9 illustrates a method performed by Rx UE for wireless communication according to a preferred embodiment of the present disclosure.

Fig. 10 illustrates an exemplary block diagram of an apparatus according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of the currently preferred embodiments of the present invention, and is not intended to represent the only form in which the present invention may be practiced. It should be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present invention.

While operations are depicted in the drawings in a particular order, persons skilled in the art will readily recognize that such operations need not be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results, sometimes one or more operations can be skipped. Further, the drawings can schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing can be advantageous.

UE (s) under new radio (NR) V2X scenario may be referred to as V2X UE (s) . A V2X UE, which transmits data according to sidelink resource (s) scheduled by a base station (BS) , may be referred to as a UE for transmitting, a transmitting UE, a transmitting V2X UE, a Tx UE, a V2X Tx UE, a SL Tx UE, or the like. A V2X UE, which receives data according to sidelink resource (s) scheduled by a BS, may be referred to as a UE for receiving, a receiving UE, a receiving V2X UE, a Rx UE, a V2X Rx UE, a SL Rx UE, or the like.

V2X UE (s) may include computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, and modems) , internet of things (IoT) devices, or the like.

According to some embodiments of the present application, V2X UE (s) may include a portable wireless communication device, a smart phone, a cellular telephone, a flip phone, a device having a subscriber identity module, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a wireless network.

According to some embodiments of the present application, V2X UE (s) includes wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, V2X UE (s) may be referred to as a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terminology used in the art. V2X UE (s) may communicate directly with BS (s) via uplink (UL) communication signals.

A BS under NR V2X scenario may be referred to as a base unit, a base, an access point, an access terminal, a macro cell, a Node-B, an enhanced Node B (eNB) , a gNB, a Home Node-B, a relay node, a device, a remote unit, or by any other terminology used in the art. A BS may be distributed over a geographic region. Generally, a BS is a part of a radio access network that may include one or more controllers communicably coupled to one or more corresponding base stations.

A BS is generally communicably coupled to one or more packet core networks (PCN) , which may be coupled to other networks, like the packet data network (PDN) (e.g., the Internet) and public switched telephone networks, among other networks. These and other elements of radio access and core networks are not illustrated but are well known generally by those having ordinary skill in the art. For example, one or more BSs may be communicably coupled to a mobility management entity (MME) , a serving gateway (SGW) , and/or a packet data network gateway (PGW) .

A BS may serve a number of V2X UEs within a serving area, for example, a cell or a cell sector via a wireless communication link. A BS may communicate directly with one or more of V2X UEs via communication signals. For example, a BS may serve V2X UEs within a macro cell.

Sidelink communication between a Tx UE and an Rx UE under NR V2X scenario includes groupcast communication, unicast communication, or broadcast communication.

Embodiments of the present application may be provided in a network architecture that adopts various service scenarios, for example but is not limited to, 3GPP 3G, long-term evolution (LTE) , LTE-Advanced (LTE-A) , 3GPP 4G, 3GPP 5G NR (new radio) , 3GPP LTE Release 12 and onwards, etc. It is contemplated that along with the 3GPP and related communication technology development, the terminologies recited in the present application may change, which should not affect the principle of the present application.

Fig. 1 illustrates an exemplary V2X communication system in accordance with some embodiments of the present application.

As shown in Fig. 1, the V2X communication system includes a base station, i.e., BS 102 and some V2X UEs, i.e., UE 101-A, UE 101-B, UE 101-C, and UE 101-D. UE 101-A and UE 101-B are within the coverage of BS 102, while UE 101-C and UE 101-D are not. UE 101-A and UE 101-B may perform sidelink unicast transmission, sidelink groupcast transmission, or sidelink broadcast transmission. It is contemplated that, in accordance with some other embodiments of the present application, a V2X communication system may include more or fewer BSs, and more or fewer V2X UEs. Moreover, it is contemplated that names of V2X UEs (which represent a Tx UE, a Rx UE, and etc. ) as illustrated and shown in Fig. 1 may be different, e.g., UE 101c, UE 104f, and UE 108g or the like.

In addition, although each V2X UE as shown in Fig. 1 is illustrated in the shape of a phone, it is contemplated that a V2X communication system may include any type of UE (e.g., a car, a roadmap device, a cell phone, a computer, a laptop, IoT (internet of things) device or other type of device) in accordance with some other embodiments of the present application.

According to some embodiments of Fig. 1, UE 101-A functions as a Tx UE, and UE 101-B, UE 101-C, and UE101-D function as an Rx UE. UE 101-A may exchange V2X messages with UE 101-B, or UE 101-C through a sidelink, for example, PC5 interface as defined in 3GPP TS 23.303. UE 101-A may transmit information or data to other UE (s) within the V2X communication system, through sidelink unicast, sidelink groupcast, or sidelink broadcast. For instance, UE 101-A transmits data to UE 101-B in a sidelink unicast session. UE 101-A may transmit data to UE 101-B, UE 101-C, and UE101-D in a groupcast group by a sidelink groupcast transmission session. Also, UE 101-A may transmit data to UE 101-B, UE 101-C, and UE101-D by a sidelink broadcast transmission session.

Alternatively, according to some other embodiments of Fig. 1, UE 101-B functions as a Tx UE and transmits V2X messages, UE 101-A functions as a Rx UE and receives the V2X messages from UE 101-B.

Both UE 101-A and UE 101-B in the embodiments of Fig. 1 may transmit information to BS 102 and receive control information from BS 102, for example, via NR Uu interface. BS 102 may define one or more cells, and each cell may have a coverage area. As shown in Fig. 1, both UE 101-A and UE 101-B are within a coverage of BS 102, and UE 101-C and UE101-D are not.

BS 102 as illustrated and shown in Fig. 1 is not a specific base station, but may be any base station (s) in the V2X communication system. For example, if the V2X communication system includes two BSs 102, UE 101-A being within a coverage area of any one the two BSs 102 may be called as a case that UE 101-A is within a coverage of BS 102 in the V2X communication system; and UE 101-A being outside of coverage area (s) of both BSs 102 can be called as a case that UE 101-A is outside of the coverage of BS 102 in the V2X communication system.

The V2X UEs may operate in different modes. At least two sidelink resource allocation modes are defined for NR-V2X sidelink communication, which are: mode 1: BS schedules sidelink resource (s) to be used by UE for sidelink transmission (s) ; and mode 2: UE determines sidelink transmission resource (s) within sidelink resources configured by base station or network, or pre-configured sidelink resources, in mode 2, BS does not schedules the sidelink resources for the UE.

The mode 2 definition covers potential sidelink radio-layer functionality or resource allocation sub-modes where

a) UE autonomously selects sidelink resource for transmission;

b) UE assists sidelink resource selection for other UE (s) ;

c) UE is configured with NR configured grant (type-1) for sidelink transmission; and

d) UE schedules sidelink transmissions of other UEs.

Taking the positioning measurement accuracy requirement and/or measured value reporting (i.e. feedback) delay requirement into consideration, one or more measurement windows and/or reporting windows may be defined for SL positioning.

In Fig. 2A, there are a measurement window and a reporting window, and the horizontal axis represents the time. The size of measurement window and/or reporting window may be associated with the measurement accuracy requirement and/or measured value reporting delay requirement. For example, for higher measurement accuracy requirement, the size of measurement window can be larger, it can ensure multiple SL-PRS transmissions can be performed within the measurement window; for lower measured value reporting delay requirement, the size of reporting window can be smaller, it can ensure the reporting information can be received as soon as possible.

In the present disclosure, the UE which needs the SL-PRS measurement reporting from other UE (s) to assist the positioning of the UE is referred to as a target UE, and the target UE may perform one or more SL-PRS measurement transmissions to other UE (s) within a configured SL-PRS measurement window, which may be associated with some measurement accuracy requirements. The UE (s) that receive the SL-PRS measurement transmission are referred to the receiving (Rx) UE (s) . After receiving the SL-PRS measurement transmission from the target UE, the Rx UE (s) may measure the SL-PRS transmission and then perform a SL-PRS measurement reporting, which includes the measured value (s) , within the reporting window.

In the above procedure, an amount of higher layer signaling should be configured from network (for example, BS 102 in Fig. 1 or location management function (LMF) ) to UE (s) , or exchanged among multiple UEs. For example, suppose the target UE and other UE (s) are in mode 1, i.e. they are within the coverage of network, before performing a SL-PRS measurement transmission to other UE (s) , the target UE transmits a request to network, such that the network schedules the sidelink resources for the target UE to perform a SL-PRS measurement transmission. At other UE (s) side, before performing the SL-PRS measurement reporting, other UE (s) also request network for scheduling the sidelink resources.

Therefore, there may be too much the higher layer signalling for SL-PRS measurement transmission and SL-PRS measurement reporting.

In Fig. 2B, there are three pairs of measurement windows and reporting windows are configured for a resource pool, measurement window 1 and reporting window 1, measurement window 2 and reporting window 2, and measurement window 3 and reporting window 3.

As shown in the dashed box in Fig. 2B, the duration of the three measurement windows have an overlapped part. During the overlapped time, the Rx UE receives SL-PRS measurement transmission, and determines the corresponding measurements, but it may not know when the measurements should be transmitted. In other words, the UE does not know within which reporting window, the sidelink transmission with the measured value (s) should be transmitted.

Accordingly, overlapped measurement windows at the Rx UE side may lead to mismatch between measurement window (s) and reporting window (s) .

In Fig. 2C, one SL-PRS transmission, which may be referred to as one-time SL-PRS transmission, or one-shot SL-PRS transmission, is transmitted within the measurement window, the Rx UE can perform a measurement based on this one-time SL-PRS transmission and report the measured value (s) based on one-time SL-PRS transmission within the SL-PRS reporting window.

In Fig. 2D, multiple SL-PRS transmissions are transmitted in the measurement window, or multiple SL-PRS transmissions are configured to be transmitted within the measurement window, the Rx UE should perform a measurement based on received one or more SL-PRS transmission (s) and report the measured value (s) based on the received one or more SL-PRS transmission (s) .

However, when the link is unstable, the Rx UE may not receive all the multiple SL-PRS transmissions, for example, the first SL-PRS transmission is missing. In this case, the Rx UE cannot determine the reporting window correctly, and this might lead to incorrect measurements.

Therefore, the indexes of one or more SL-PRS transmissions and the various relative times between the transmissions and the corresponding reporting should be indicated to Rx UE for the calculation and reporting of Rx UE.

In Fig. 3, UE 101-A (mode 1) , UE 101-B (mode 1) , and UE 101-C (mode 2) measure the SL-PRS transmission, and perform the SL-PRS measurement reporting to target UE. Before performing the SL-PRS measurement reporting, UE 101-A (mode 1) , UE 101-B (mode 1) , and UE 101-C (mode 2) each transmits a scheduling request to the target UE, and receives a SL grant (the SL-PRS measurement reporting is to be transmitted to target UE) . Accordingly, SL resource may be occupied excessively. Similarly, the UL resource may also be occupied excessively.

The present disclosure proposes some technical solutions for the above technical problems.

Figs. 4A-4C illustrate some exemplary signalling exchange s between target UE and Rx UE according to some embodiments of the present disclosure.

In Fig. 4A, the target UE is in mode 1. That is, target UE is within the coverage of BS 102. After receiving the SL grant from the network, the target UE transmits SL-PRS transmission (s) to other UEs based on the SL grant.

In Fig. 4B, the target UE is in mode 2. That is, target UE is out of the coverage of BS 102, thus will not receive SL grant for the SL-PRS transmission (s) . Based on the previously received or pre-configured configuration information, the target UE transmits SL-PRS transmission (s) to other UEs, and other UEs transmit the SL-PRS measurement reporting to target UE.

In Fig. 4C, the target UE may be in mode 1 or mode 2, as can be seen, there may be a link between the target UE and BS 102 or not. After receiving the SL-PRS transmission (s) from the target UE, other UEs transmit the SL-PRS measurement reporting to target UEs either in mode 1 or mode 2.

Fig. 5 illustrates an exemplary flow chart of SL-PRS transmission and measurement reporting according to some embodiments of the present disclosure. In these embodiments, the control information for SL-PRS transmission and SL-PRS measurement reporting are included in the DCI or SCI, which are physical layer signallings, and are carried on physical layer channels, such as physical sidelink shared channel (PSSCH) or physical sidelink control channel (PSCCH) , instead of transmitted with higher layer signalling. Thus, the higher layer signalling for SL-PRS measurement transmission and SL-PRS measurement reporting can be reduced significantly.

Fig. 5 includes three components, network, target UE, and Rx UE. Target UE is the UE which needs to know its location information, and will transmit SL-PRS transmission to Rx UE. In Fig. 5, the positioning calculation entity is at target UE, the Rx UE shall perform SL-PRS measurement, and transmit SL-PRS measurement reporting to target UE.

In step 501, the network transmits downlink control information (DCI) to the target UE. The DCI includes the first time offset indication, which is used for the target UE to determine a sidelink control information field. The first time offset may indicate a max time gap, a max time window, a max slot gap, a max slot window, the last transmission slot, the last transmission time, or a parameter that is associated with the ending time for SL-PRS measurement reporting, etc. In other words, the first time offset indicates a deadline in time domain for SL-PRS measurement reporting.

The first time offset may be explicitly indicated. For example, a number of bits may be used for indicating the first time offset. Suppose the first time offset indicates a number of slots, and the total number of the slots that may be included in the slot gap is x, then log ₂ (x) bits may be used to indicate the slot gap between the SL-PRS transmission slot and the last time slot of SL-PRS measurement reporting. If the total number of slots is 8, then 3 bits may be used. Here the slot may be a logical slot, which is continuous in the time domain, but may or may not be continuous in the resource pool. The slot may be a physical slot, which is continuous in the resource pool, but may or may not be continuous in the time domain.

The first time offset may indicate a length of time with the unit of milliseconds, and the total number of the milliseconds that may be included in the time gap is x, then log ₂ (x) bits may be used to indicate the time gap between the SL-PRS transmission time and the last time of SL-PRS measurement reporting. If the total number of milliseconds is 8, then 3 bits may be used.

The slot, milliseconds, may be defined by other manners, and the present disclosure has no intention of limiting the same.

In some other scenarios, the first time offset may be implicitly indicated.

For example, the bits may be used to indicate different types of pre-defined or pre-configured slot gaps (or time gap) . For example, suppose there are 3 bits, then 8 different types may be defined or pre-configured per resource pool. Such as: the value "000" indicates the slot gap is 10 slots, the value "001" indicates the slot gap is 20 slots, the value "111" indicates the slot gap is 80 slots, etc.

The bits may be used to indicate different types of reporting configurations, measurement delay requirements, or SL PRS transmission/reporting configurations. Taking the measurement delay requirement as an example, suppose there are 3 bits, then 8 measurement delay requirements may be pre-configured per resource pool. For instance, the value "000" indicates the slot gap includes 10ms, the value "001" indicates the time gap includes 20ms, and the value "111" indicates the time gap includes 80ms, etc. Each reporting configuration, measurement delay requirement, or SL PRS transmission/reporting configuration may correspond to one value of the bits. Or, each set of reporting configuration, measurement delay requirement, or SL PRS transmission/reporting configuration may correspond to one value of the bits.

After a time offset, target UE receives the DCI from network, and obtains the first time offset indication.

The target UE then determines the second time offset based on the first time offset, and transmit the second time offset in the SCI to the Rx UE. The first time offset and the second time offset may be identical. That is, the two time offset indicate the same SL-PRS measurement reporting time. Or, the second time offset indicate a smaller time duration, a smaller time gap or the like, compared with the first time offset.

The second time offset may be configured in similar fashion as the first time offset. That is, the second time offset may be explicitly indicated. For example, a number of bits may be used for indicating the second time offset. Suppose the second time offset indicates a number of slots, and the total number of the slots that may be included in the slot gap is y, then log ₂ (y) bits may be used to indicate the slot gap between the SL-PRS transmission slot and the last time slot of SL-PRS measurement reporting. If the total number of slots is 8, then 3 bits may be used. Similarly, the second time offset may be indicated in the unit of milliseconds.

In some other scenarios, the second time offset may be implicitly indicated.

For example, the bits may be used to indicate different types of pre-defined or pre-configured slot gap (or time gap) . For example, suppose there are 3 bits, then 8 different types may be defined or pre-configured per resource pool. Such as: the value "000" indicates the slot gap includes 10 slots, the value "001" indicates the slot gap includes 20 slots, the value "111" indicates the slot gap includes 80 slots, etc.

The bits may be used to indicate different types of reporting configurations, or measurement delay requirements, or SL PRS transmission/reporting configurations. Taking the measurement delay requirement as an example, suppose there are 3 bits, then 8 measurement delay requirements may be pre-configured per resource pool. For instance, the value "000" indicates the slot gap includes 10ms, the value "001" indicates the time gap includes 20ms, and the value "111" indicates the time gap includes 80ms, etc. Each reporting configuration, measurement delay requirement, or SL PRS transmission/reporting configuration may correspond to one value of the bits. Or, each set of reporting configuration, measurement delay requirement, or SL PRS transmission/reporting configuration may correspond to one value of the bits.

Since in some cases, the second time offset is smaller than the first time offset, the bits required for indication the second time offset may be less than the bits for the first time offset.

In some other scenarios, target UE may be in mode 2, that is, target UE is out of coverage of the network. In this case, step 501 is not included in the procedure, and target UE does not receive the DCI including the first time offset indication. Target UE may determine the SCI including the time (slot) gap based on (pre-) configuration information. The configuration information may include: reporting configurations, or measurement delay requirements, or SL PRS transmission/reporting configurations, reporting configuration, or measurement delay requirement, or SL PRS transmission/reporting configuration corresponds to a time gap value) .

In step 502, target UE transmits sidelink control information (SCI) which includes the second time offset to Rx UE. The second time offset may be included in the first stage (1 ^st stage) SCI or in the second stage (2 ^nd stage) SCI, and is conveyed by PSCCH or PSSCH respectively.

At time t ₁, Rx UE receives SCI, and obtains the second time offset indication. Based on the second time offset indication, Rx UE determines the last measurement reporting time, which is marked as "t ₂" in Fig. 5. The last measurement reporting slot is the slot that is transmitted before time t ₂. The maximum time gap is from time t ₁ to t ₂, which is shown in Fig. 5, and the maximum slot gap between the slot at t ₁ to the slot at t ₂. When target UE transmits the SCI scheduling SL-PRS transmission, then the SL-PRS transmission need to be transmitted at time t ₁. In step 503, Rx UE transmits the SL-PRS measurement reporting before t ₂.

When Rx UE is in mode 1, Rx UE needs to request a SL resource for SL-PRS measurement reporting before the last time slot before step 503. When Rx UE is in mode 2, Rx UE performs a resource selection for SL-PRS measurement reporting before step 503. For example, when the Rx UE performs resource selection, the ending of the resource selection window is set before/to time t ₂

After receiving the SL-PRS measurement reporting, the target UE may perform the positioning calculation, so as to obtain the location information of the target UE. Alternatively, target UE may transmit the received SL-PRS measurement reporting to network, and let network perform the positioning calculation.

In Fig. 6, the positioning calculation entity is at network, the Rx UE measures the SL-PRS transmission from target UE, and transmit SL-PRS measurement reporting to network via target UE.

In step 601, network transmits DCI to target UE, and the first time offset indication is identical to the first time offset indication as transmitted in the DCI in step 501.

After determining the max time gap 1 based on the first time offset indication as shown in Fig. 6, target UE determines the second time offset indication. Since target UE needs to receive SL-PRS measurement reporting from Rx UE then forward it to the network, the second time offset indication may indicate a time earlier than that of the first time offset indication. In other word, the first time offset, which is included in DCI, indicates the first maximum reporting delay tolerance for target UE to perform the SL-PRS measurement reporting to network, and the second time offset, which is included in the SCI, indicates the second maximum reporting delay tolerance for the Rx UE to perform the SL-PRS measurement reporting to the target UE.

As can be seen in Fig. 6, the ending time of max time gap 1 is later in time than the ending time of the max time gap 2.

Before time t ₂, Rx UE transits the SL-PRS measurement reporting to target UE in step 603, and in step 604, before time t ₃, target UE transmits the SL-PRS measurement reporting to the network, such that the network may perform the positioning calculation. After determining the position information of target UE, network transmits the position information to target UE in step 605.

In Fig. 7, the positioning calculation entity is at network, the Rx UE measures the SL-PRS transmission from target UE, and directly performs SL-PRS measurement reporting to network.

In step 701, network transmits DCI to target UE, and the first time offset indication is similar to the first time offset indication as transmitted in the DCI in step 501.

Target UE determines the second time offset indication based on the first time offset indication, which may be identical to the first time offset indication, and in step 702, target UE transmits SCI including the second time offset indication to Rx UE. Rx UE receives the SCI at time t ₁, and determines the max time gap based on the second time offset indication, which is from time t ₁ to time t ₂ in Fig. 7.

In step 703, Rx UE transmits a scheduling request to network and receives UL grant in step 704.

In step 705, Rx UE transmits SL-PRS measurement reporting to the network, such that the network may perform the positioning calculation for target UE. After determining the position information of target UE, network transmits the position information to target UE in step 706.

In the solution of Fig. 5, Rx UE transmits the SL-PRS measurement reporting to target UE, and target UE performs the positioning calculation. In the solution of Fig. 6, Rx UE transmits the SL-PRS measurement reporting to target UE, and target UE transmits the SL-PRS measurement reporting to network, then network performs the positioning calculation. In Fig. 7, Rx UE transmits the SL-PRS measurement reporting directly to network, and network performs the positioning calculation.

As can be seen, Rx UE may transmit the SL-PRS measurement reporting to different objects, and thus an indication is needed, for indicating Rx UE whether to transmit the SL-PRS measurement reporting to target UE, or to network.

The present disclosure proposes an indication included in the DCI or SCI, which is used for indicating Rx UE whether to transmit the SL-PRS measurement reporting to target UE, or to network. For example, the indication may be included in SCI, and target UE may indicate Rx UE to select a resource (before indicated time deadline) on SL to transmit the SL-PRS measurement reporting to target UE on SL. Alternatively, target UE may indicate Rx UE to request a resource (before indicated time deadline) on UL to transmit the SL-PRS measurement reporting to network on UL.

The indication may be included in DCI, and network can configure/enable Rx UE transmit the SL-PRS measurement reporting to target UE or Rx UE transmit the SL-PRS measurement reporting to network. After receiving the indication in DCI, target UE may configure the indication in SCI correspondingly.

Alternatively, the indication may not be needed when it is pre-configured that Rx UE transmits the SL-PRS measurement reporting to target UE, or to network.

In some other embodiments, in order to reduce the scheduling request and its associated SL grant or UL grant for SL-PRS measurement reporting on SL or UL, the present disclosure proposes an indication for indicating resource for Rx UE to transmit the SL-PRS measurement reporting to target UE on SL, or to network on UL.

Specifically, when target UE is in mode 1, an indication is included in DCI and transmitted from network to target UE. The indication information is used to indicate that:

a) a time and/or frequency location of resource on SL for Rx UE to perform SL-PRS measurement reporting on SL;

b) a time/frequency location of resource on UL for Rx UE to perform SL-PRS measurement reporting on UL; or

c) a time/frequency location of resource on UL for target UE to perform SL-PRS measurement reporting on UL.

Specifically, when in mode 2, target UE selects a resource on SL and indicates the resource to Rx UE for Rx UE to perform SL-PRS measurement reporting from Rx UE to target UE on SL.

Correspondingly, an indication is included in SCI and transmitted from target UE to Rx UE. The indication may be included in the first stage (1 ^st stage) or second stage (2 ^nd stage) SCI, and is conveyed by PSCCH or PSSCH respectively. The indication information is used to indicate that:

i.a time and/or frequency location of resource on SL for Rx UE to perform SL-PRS measurement reporting on SL; or

ii. a time and/or frequency location of resource on UL for Rx UE to perform SL-PRS measurement reporting on UL.

In mode 1, the SL or UL resource in the above i) and ii) may be determined based on above DCI field. In mode 2, the SL resource can be determined or selected by target UE based on SL-PRS configuration information which may be pre-configured.

It should be noted that if the indication for indicating resource is applied, and when the time information is implicitly included in the indicated resource, for example, the indicated resource is within a time duration, then the above first time offset indication and the second time offset indication described in Figs. 5-7 are necessary in this solution.

In order to solve the mismatch between measurement window (s) and reporting window (s) as explained in Fig. 2B, the present disclosure proposes to introduce another indication in DCI or SCI, which is used to identify SL-PRS transmission and its associated configuration, including measurement windows and reporting windows.

For example, the indication may include source ID and destination ID, which are used to identify SL-PRS transmission and its associated configuration, measurement windows and reporting windows.

The indication may include the SL-PRS transmission index or SL-PRS transmission order among multiple SL-PRS transmissions in one configured measurement windows.

For example, suppose the three transmissions (marked by the black arrow) in Fig. 2B in the three measurement windows are indexed as 1, 2, and 3, and they are respectively associated with reporting

window

1, 2, and 3, then the mismatch between the measurement windows and the reporting windows are cured.

In operation 801, target UE determines SCI including a first time offset or a first resource for SL-PRS measurement reporting, and in operation 802, target UE transmit the sidelink control information via physical layer channel to the second UE. For example, in Fig. 5, target UE determines SCI including the second time offset, and in step 502, target UE transmits SCI via physical layer channel, i.e. PSCCH, to Rx UE.

In some embodiments, the SCI includes at least one of the following:

1) a size of the first time offset, such as 10ms;

2) a number of slots corresponding to the first time offset, such as 10 slots;

3) a type of the first time offset; for example, the type may correspond to a unit of the first time offset, the unit may be slot or millisecond, second, or the like. Type 1 may correspond to 10 slots or 10ms, there might be multiple pre-defined/pre-configured types, with each type corresponding to a certain number of slots or time (ms) ;

4) a type of slot corresponding to the first time offset, such as a physical slot;

5) a type of SL-PRS transmission of the first UE and SL-PRS measurement reporting of a second UE, for example, the type may correspond to a configuration of the measure window, reporting window, and a time gap there between. Type 1 may correspond to a combination of 10ms SL-PRS measurement window, 10ms SL-PRS reporting window and 10ms time gap between two windows. There might be multiple pre-defined/pre-configured types, with each type corresponding to a combination of a certain size of SL-PRS measurement window, a certain size of SL-PRS reporting windows and time gap between the ending time of SL-PRS measurement window and the starting time of SL-PRS reporting windows; or

6) a SL-PRS measurement reporting latency requirement; or

7) a SL-PRS measurement reporting configuration, for example, the SL-PRS measurement reporting configuration may include configuration of the length of the reporting window and the associated time gap. A configuration may correspond to 10ms time gap and 10ms SL-PRS reporting window. There might be multiple configurations, with each configuration corresponding to a combination of a certain size of SL-PRS reporting windows and time gap between received SL-PRS transmission and the starting time of SL-PRS reporting windows.

In some embodiments, the SCI is determined based on DCI received from a BS.

In some embodiments, the DCI includes a second time offset identical to the first time offset for the second UE to report the SL-PRS measurement to the first UE. For example, in Fig. 5, the first time offset, which is included in the SCI is identical to the second time offset included in the DCI.

In some embodiments, the DCI includes a second time offset greater than the first time offset, the first time offset indicates a first maximum reporting delay tolerance for the second UE to report the SL-PRS measurement to the first UE, and the second time offset indicates a second maximum reporting delay tolerance for the first UE to report the SL-PRS measurement to a BS. For example, in Fig. 6, the first time offset, which is included in the SCI is smaller to the second time offset included in the DCI.

In operation 901, Rx UE receives SCI via physical layer channel from a second UE, wherein SCI includes a first time offset or a first resource for SL-PRS measurement reporting; in operation 902, Rx UE determines, based on the SCI, a maximum reporting delay tolerance for SL-PRS measurement reporting or the first resource for SL-PRS measurement reporting.

The apparatus may be or include at least a part of a UE such as UE101-A, UE 101-B, or UE 101-C, as shown in Fig. 1, or other device with similar functionality.

The apparatus may include a processor and a transceiver coupled with the processor. In some embodiments, the transceiver may include a transmitter and a receiver. The processor is configured to perform any of the methods described in the present disclosure, for example, the method described with respect to Figs. 8 and 9. For example, when the apparatus is implemented as target UE, the processor may determine SCI including a first time offset or a first resource for SL-PRS measurement reporting, and the transceiver may transmit the sidelink control information via physical layer channel to the second UE. For example, in Fig. 5, target UE determines SCI including the second time offset, and in step 502, target UE transmits SCI to Rx UE.

When the apparatus is implemented as Rx UE, the receiver may receive SCI via physical layer channel from a target UE, wherein SCI includes a first time offset or a first resource for SL-PRS measurement reporting; and the processor may determine, based on the SCI, a maximum reporting delay tolerance for SL-PRS measurement reporting or the first resource for SL-PRS measurement reporting.

The method of the present disclosure can be implemented on a programmed processor. However, controllers, flowcharts, and modules may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, any device that has a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processing functions of the present disclosure.

While the present disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in other embodiments. Also, all of the elements shown in each Fig. are not necessary for operation of the disclosed embodiments. For example, one skilled in the art of the disclosed embodiments would be capable of making and using the teachings of the present disclosure by simply employing the elements of the independent claims. Accordingly, the embodiments of the present disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the present disclosure.

In this disclosure, relational terms such as "first, " "second, " and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises, " "comprising, " or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "a, " "an, " or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. Also, the term "another" is defined as at least a second or more. The terms "including, " "having, " and the like, as used herein, are defined as "comprising. "

Claims

A first user equipment (UE) , comprising:

a processor configured to determine sidelink control information (SCI) including a first time offset or a first resource for sidelink positioning reference signal (SL-PRS) measurement reporting; and

a transceiver coupled to the processor and configured to transmit the sidelink control information via physical layer channel to a second UE.
The first UE of Claim 1, wherein the SCI further includes identity information to indicate an association between SL-PRS transmission of the first UE and SL-PRS measurement reporting of the second UE.
The first UE of Claim 1, wherein the SCI includes at least one of the following:

a size of the first time offset;

a number of slots corresponding to the first time offset;

a type of the first time offset;

a type of slot corresponding to the first time offset;

a type of SL-PRS transmission of the first UE and SL-PRS measurement reporting of the second UE;

a SL-PRS measurement reporting latency requirement; or

a SL-PRS measurement reporting configuration.
The first UE of Claim 3, wherein at least one of the following is determined based on pre-configuration or definition per resource pool:

the size of the first time offset;

the number of slots corresponding to the first time offset;

the type of the first time offset;

the type of slot corresponding to the first time offset;

the type of SL-PRS transmission of the first UE and SL-PRS measurement reporting of the second UE;

the SL-PRS measurement reporting latency requirement; or

the SL-PRS measurement reporting configuration.
The first UE of Claim 1, wherein the SCI is determined based on downlink control information (DCI) received from a base station (BS) .
The first UE of Claim 5, wherein the DCI includes a second time offset identical to the first time offset for the second UE to report the SL-PRS measurement to the first UE.
The first UE of Claim 5, wherein the DCI includes a second time offset greater than the first time offset, the first time offset indicates a first maximum reporting delay tolerance for the second UE to report the SL-PRS measurement to the first UE, and the second time offset indicates a second maximum reporting delay tolerance for the first UE to report the SL-PRS measurement to a BS.
The first UE of Claim 1, wherein the SCI further includes a first indication, which indicates the second UE whether the SL-PRS measurement is to be reported to the first UE or is to be reported to a BS.
The first UE of Claim 1, wherein the first resource includes a time and/or frequency location of resource on SL or a time and/or frequency location of resource on UL and is used for the second UE to report the SL-PRS measurement.
The first UE of Claim 9, wherein the SCI further includes a second indication which indicates the second UE on SL to report the SL-PRS measurement, or on UL to report the SL-PRS measurement.
A first user equipment (UE) , comprising:

a transceiver configured to receive sidelink control information (SCI) via physical layer channel from a second UE, wherein SCI includes a first time offset or a first resource for sidelink positioning reference signal (SL-PRS) measurement reporting; and

a processor configured to determine, based on the SCI, a maximum reporting delay tolerance for SL-PRS measurement reporting or the first resource for SL-PRS measurement reporting.
The first UE of Claim 11, wherein the SCI further includes identity information to indicate an association between SL-PRS transmission of the first UE and SL-PRS measurement reporting of the second UE.
The first UE of Claim 11, wherein SCI includes at least one of the following:

a size of the first time offset;

a number of slots corresponding to the first time offset;

a type of the first time offset;

a type of slot corresponding to the first time offset;

a type of SL-PRS transmission of the first UE and SL-PRS measurement reporting of the second UE;

a SL-PRS measurement reporting latency requirement; or

a SL-PRS measurement reporting configuration.
The first UE of Claim 11, wherein the SCI further includes a first indication, which indicates the second UE whether the SL-PRS measurement is to be reported to the first UE or is to be reported to a BS.
A method performed by a first user equipment (UE) , comprising:

determining sidelink control information (SCI) including a first time offset or a first resource for sidelink positioning reference signal (SL-PRS) measurement reporting; and

transmitting the SCI via physical layer channel to a second UE.