RTT-based sidelink ranging and positioning

Abstract

A method implemented by a first user equipment (UE), the method comprising: transmitting a first sidelink positioning reference signal (SL Pos-RS) to a second UE at a first time (t1), and transmitting a second sidelink positioning reference signal (SL Pos-RS) to the second UE at a second time (t2), receiving a second SL Pos-RS from the second UE at a fourth time (t4); receiving a timing measurement report from the second UE, the timing measurement report including information about a second time (t2) when the second UE receives the first SL Pos-RS and about a third time (t3) when the second UE transmits the second SL Pos-RS to the first UE; and calculating the distance between the first UE and the second UE based on the first time, the fourth time and the timing measurement report.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the benefit of U.S. Provisional Patent Application No. 63 / 336,124, filed on April 28, 2022, entitled “Methods and Apparatus of RTT Based Sidelink Ranging And Positioning,” which is incorporated herein by reference. Technical Field

[0003] The present invention relates generally to telecommunications, and more particularly to round trip time (RTT) based sidelink (SL) ranging and positioning. Background Art

[0004] Sidelink (SL) communication is a communication scheme in which a direct link is established between user equipment (UE) and the UEs exchange voice and data directly with each other without intervention of the gNodeB (gNB). SL communication is being considered as a scheme for reducing the overhead of gNB caused by the rapidly increasing data traffic.

[0005] The 3rd generation partnership project (3GPP) has been developing and standardizing several important features of the fifth generation (5G) new radio (NR) access technology. In Release 16, a work item on NR vehicle-to-everything (V2X) wireless communication was completed, with the goal of providing 5G-compatible high-speed and reliable connections for vehicle communications. This work item provides the basis for NR sidelink communications for applications such as safety systems and autonomous driving. In Release 16, a work item on NR positioning support was completed. In Release 18, a study item on extended and improved NR positioning was approved, which includes the study of sidelink positioning schemes. It is hoped that the technology and signaling will be provided to achieve sidelink positioning. Summary of the invention

[0006] In one aspect, the present invention includes a method implemented by a first user equipment (UE), comprising: sending a first sidelink position reference signal (SL Pos-RS) to a second UE at a first time (t1); receiving a second SL Pos-RS from the second UE at a fourth time (t4); receiving a timing measurement report from the second UE, wherein the timing measurement report includes information about a second time (t2) when the second UE receives the first SL Pos-RS and a third time (t3) when the second UE sends the second SL Pos-RS to the first UE; and calculating the distance between the first UE and the second UE based on the first time, the fourth time and the timing measurement report.

[0007] Optionally, according to any of the above aspects, in another implementation of this aspect, the distance is calculated using the following formula:

[0008]

[0009] Among them, D 1,2 represents distance and c represents the speed of light.

[0010] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the first UE includes a target UE, the second UE includes an anchor UE, and the timing measurement report includes a time value representing a difference between the third time and the second time.

[0011] Optionally, according to any of the above aspects, in another implementation of this aspect, the first UE sends two or more first SL Pos-RSs according to a first semi-static configuration, wherein the first semi-static configuration includes a period, a number of transmissions of the first SL Pos-RS, and parameters for generating two or more first SL Pos-RSs; the first UE receives two or more second SL Pos-RSs according to a second semi-static configuration, wherein the second semi-static configuration includes a period, a number of transmissions of the second SL Pos-RS, and parameters for generating two or more second SL Pos-RSs.

[0012] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the timing measurement report includes a value of each of the second time and the third time.

[0013] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the timing measurement report includes a value representing a difference between the second time and the third time, and the difference represents a portion of a subframe or a time slot.

[0014] Optionally, according to any of the above aspects, in another implementation of this aspect, the first time, the second time, the third time and the fourth time respectively correspond to reference orthogonal frequency-division multiplexing (OFDM) symbols.

[0015] Optionally, according to any of the above aspects, in another implementation of this aspect, the timing measurement report includes the number of orthogonal frequency-division multiplexing (OFDM) symbols and a relative timing offset corresponding to the second time and the third time.

[0016] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the timing measurement report is included in the second SL Pos-RS.

[0017] In one aspect, the present invention includes a method implemented by a first user equipment (UE), comprising: sending a first sidelink position reference signal (SL Pos-RS) to a second UE at a first time (t1); receiving a PSFCH sequence sent by the second UE on a physical sidelink feedback channel (PSFCH) at a fourth time (t4); receiving a timing measurement report from the second UE, wherein the timing measurement report includes information about the difference between a second time (t2) when the second UE receives the first SL Pos-RS and a third time (t3) when the second UE sends the second SL Pos-RS to the first UE; and calculating the distance between the first UE and the second UE based on the first time, the fourth time and the timing measurement report.

[0018] Optionally, according to any of the above aspects, in another implementation of this aspect, the PSFCH sequence includes multiple PSFCHs in a single physical resource block (PRB) set.

[0019] Optionally, according to any of the above aspects, in another implementation of this aspect, a hybrid automatic repeat request acknowledgement (HARQ-ACK) is excluded from a single PRB set.

[0020] Optionally, according to any of the above aspects, in another implementation of this aspect, a hybrid automatic repeat request acknowledgement (HARQ-ACK) is included in a single PRB set and is used to calculate the distance.

[0021] Optionally, according to any of the above aspects, in another implementation of this aspect, a cyclic shift is applied to HARQ-ACK to shift HARQ-ACK from a PSFCH channel to a different PSFCH channel.

[0022] Optionally, according to any of the above aspects, in another implementation of this aspect, a set of physical resource blocks (PRBs) not configured for HARQ-ACK is used in a PSFCH sequence.

[0023] In one aspect, the present invention includes a method implemented by a target user equipment (UE), comprising: selecting one or more anchor UEs for positioning; sending a positioning request to the selected one or more anchor UEs; receiving an affirmative response from the one or more anchor UEs in response to the positioning request; sending a first sidelink position reference signal (SL Pos-RS) to the one or more anchor UEs, the affirmative response being received from the one or more anchor UEs; receiving a second SL Pos-RS from each of the one or more anchor UEs, the affirmative response being received from the one or more anchor UEs; receiving a timing measurement report from each of the one or more anchor UEs, the affirmative response being received from the one or more anchor UEs; and calculating the distance between the target UE and one or more UEs based on the timing measurement report received from the one or more anchor UEs.

[0024] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the selecting further includes: identifying one or more anchor UEs that support positioning based on multiple round trip times (RTTs).

[0025] Optionally, according to any of the above aspects, in another implementation manner of the aspect, one or more available candidate anchor point UEs are discovered, and one or more UEs are selected from the one or more available candidate anchor point UEs.

[0026] Optionally, according to any of the above aspects, in another implementation of this aspect, one or more anchor UEs are selected for positioning based on one or more of the synchronization source, received signal strength, anchor characteristics, location area and mobility of the one or more anchor UEs.

[0027] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the target UE receives a second SL Pos-RS from one or more anchor UEs before sending the first SL Pos-RS to one or more anchor UEs.

[0028] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the timing measurement report is encoded in the second SL Pos-RS or multiplexed with the second SL Pos-RS.

[0029] In one aspect, the present invention includes a method implemented by a target user equipment (UE), comprising: sending a positioning request to a first anchor UE and a second anchor UE; receiving an affirmative response from the first anchor UE and the second anchor UE in response to the positioning request; sending a first sidelink position reference signal (SL Pos-RS) of the target UE to the first anchor UE and the second anchor UE; receiving a second SL Pos-RS of the first anchor UE and a third SL Pos-RS of the second anchor UE in a time slot; receiving a timing measurement report from at least one of the first anchor UE or the second anchor UE; and calculating a distance between the target UE and at least one of the first anchor UE or the second anchor UE based on the timing measurement report.

[0030] Optionally, according to any of the above aspects, in another implementation of this aspect, the second SL Pos-RS is interlaced with the third SL Pos-RS.

[0031] Optionally, according to any of the above aspects, in another implementation of this aspect, the second SL Pos-RS and the third SL Pos-RS do not intersect.

[0032] Optionally, according to any of the above aspects, in another implementation of this aspect, the second SL Pos-RS and the third SL Pos-RS are separated by one or more protection symbols.

[0033] Optionally, according to any of the above aspects, in another implementation of this aspect, the number of orthogonal frequency-division multiplexing (OFDM) symbols of each of the second SL Pos-RS and the third SL Pos-RS is four.

[0034] Optionally, according to any of the above aspects, in another implementation of this aspect, the timing measurement report is based on the measured receiver-transmitter (Rx-Tx) time difference, or based on the version 16 or version 17 definition of the gNodeB (gNB) Rx-Tx time difference measurement or the UE Rx-Tx time difference in Uu.

[0035] Optionally, according to any of the above aspects, in another implementation of this aspect, the sidelink positioning measurement report is reported to a location management function (LMF) and a UE whose position is determined.

[0036] Optionally, according to any of the above aspects, in another implementation of this aspect, for positioning based on multiple round trip time (RTT), one or more transmissions of a first SL Pos-RS from a first UE and one or more transmissions of a second SL Pos-RS and a second UE have no order restriction between multiple rounds of SL Pos-RS transmissions.

[0037] Optionally, according to any of the above aspects, in another implementation of this aspect, the UE is used to receive SL PRS resource allocation signaling from the gNB through dynamic authorization to send SL Pos-RS.

[0038] Optionally, according to any of the above aspects, in another implementation of this aspect, comb-tooth based SL Pos-RS transmission is multiplexed from one or more UEs in a time slot in a sidelink resource pool.

[0039] Optionally, according to any of the above aspects, in another implementation of this aspect, the configuration of the SL Pos-RS includes a single (M, N) value for comb-based multiplexing in time slots of two or more SL Pos-RSs from two or more UEs, where M is the number of OFDM symbols in the time slot scheduled for the SL Pos-RS, and N is the comb size.

[0040] Optionally, according to any of the above aspects, in another implementation of this aspect, the comb tooth size includes 2 and 4.

[0041] Optionally, according to any of the above aspects, in another implementation of this aspect, the sidelink positioning measurement report includes measurements, and the measurements include line-of-sight (LOS) paths or all non-line-of-sight (NLOS) paths.

[0042] Optionally, according to any of the above aspects, in another implementation of this aspect, the UE is used to execute any one of the first resource allocation scheme or the second resource allocation scheme applicable to all resource pools, wherein SLPRS unicast, groupcast or broadcast occurs in the resource pool.

[0043] Optionally, according to any of the above aspects, in another implementation of this aspect, the transmission of the SL Pos-RS is in response to a trigger, wherein the trigger is provided by a high layer of the UE or a low layer signaling provided by a second UE, and wherein the low layer signaling includes sidelink control information (SCI) or a sidelink media access control-control element (SL MAC-CE).

[0044] Optionally, according to any of the above aspects, in another implementation of this aspect, the configuration of SL PRS includes: SL PRS resource identifier (ID), SL PRS comb tooth offset and associated SL-PRS comb tooth size (N), SL PRS start symbol and the number of SL-PRS symbols (M), and SL PRS frequency domain allocation.

[0045] Optionally, according to any of the above aspects, in another implementation of this aspect, anchor UE location information is provided to LMF or UE to provide auxiliary information for absolute SL positioning.

[0046] Optionally, according to any of the above aspects, in another implementation of this aspect, the UE receives a physical sidelink control channel (PSCCH) and an SL Pos-RS time-division multiplexed in the same time slot.

[0047] Optionally, according to any of the above aspects, in another implementation of this aspect, the transmission of the SL PosRS in the resource pool is in response to a Release 16 resource selection or reselection process with periodic and aperiodic reservation.

[0048] In one aspect, the present invention includes a user equipment (UE), comprising: one or more processors; a transmitter coupled to the one or more processors; and a receiver coupled to the one or more processors, wherein the one or more processors, the transmitter, and the receiver are used to perform any of the disclosed methods.

[0049] In one aspect, the present invention includes a non-transitory computer-readable medium, which includes a computer program product for use by a user equipment (UE), the computer program product including computer executable instructions stored in the non-transitory computer-readable medium, and the computer executable instructions, when executed by one or more processors, cause the UE to perform any of the disclosed methods.

[0050] In one aspect, the present invention includes a target user equipment (UE), comprising: a sending component for sending a positioning request directly to one or more anchor UEs via sidelink communication; a receiving component for receiving positioning data from the anchor UE via sidelink communication; and a calculating component for calculating a range or positioning measurement based on the positioning data.

[0051] For clarity, any of the embodiments described above may be combined with any one or more of the other embodiments described above to create new embodiments within the scope of the present invention.

[0052] These and other features will become more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] For a more complete understanding of the present invention, reference is made to the following brief description, taken in conjunction with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

[0054] Figure 1 is a graph of in-coverage / out-of-coverage operations.

[0055] Figure 2 is a graphic representation of resource pools in a resource grid.

[0056] Figure 3 is a diagram of a resource grid with a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSCCH) and a physical sidelink feedback channel (PSCCH).

[0057] Figure 4 It is a diagram of the structure of a sidelink synchronization signal block (S-SSB).

[0058] Figure 5It is a diagram of an uplink (UL) sounding reference signal (SRS).

[0059] Figure 6 is a diagram of an example of a downlink positioning reference signal (PRS).

[0060] Figure 7 FIG. 1 is a diagram of the perception and resource selection window in release 16 (Rel-16) new radio (NR) vehicle-to-everything (V2X) communication. ...

[0061] Figure 8 is a diagram of round trip time (RTT) based ranging in the sidelink.

[0062] Fig. 9 is a diagram of multi-RTT positioning in the sidelink.

[0063] Fig.10 This is a flow chart of SL ranging.

[0064] Fig.11 It is a diagram of the transmission of the sidelink position reference signal (SL Pos-RS) in SL ranging.

[0065] Fig.12 is a diagram of the message flow in RTT-based SL ranging.

[0066] Fig.13 is a diagram of RTT timing in SL ranging and positioning.

[0067] Fig.14 It is a diagram of the mapping of the physical sidelink shared channel (PSSCH) and the physical sidelink feedback channel (PSFCH) hybrid automatic repeat request acknowledgement (HARQ-ACK).

[0068] Fig.15 is a diagram of a PSFCH channel in a PSFCH HARQ-ARK physical resource block (PRB) set for RTT-based SL positioning.

[0069] Fig.16 is a diagram of an additional PRB set used to respond to Pos-RS in RTT-based SL positioning.

[0070] Fig.17 This is a flowchart of positioning based on SL multi-RTT.

[0071] Fig.18 is an illustration of two UL SRS (as SL PRS) transmissions on the same time slot in the sidelink.

[0072] Fig.19 is a diagram of a network used to transmit data.

[0073] Fig. 20 is a diagram of the processing system.

[0074] Fig.21 is a diagram of a transceiver used to send and receive signaling on a telecommunications network.

[0075] Fig. 22 It is a graphical illustration of the effect of angle of arrival (AOA) and angle of departure (AOD) on non-line-of-side (NLOS) propagation.

[0076] Fig.23 is a diagram of resource slot offset.

[0077] Fig.24 is a diagram of UL PRS resource configuration.

[0078] Fig.25 It is a diagram of S-SSB.

[0079] Fig.26 This is a method implemented by a first UE according to an embodiment of the present invention.

[0080] Fig. 27 This is a method implemented by a first UE according to an embodiment of the present invention.

[0081] Fig.28 It is a method implemented by the target UE according to an embodiment of the present invention.

[0082] Fig.29 It is a method implemented by the target UE according to an embodiment of the present invention. DETAILED DESCRIPTION

[0083] First, it should be understood that although illustrative implementations of one or more embodiments are provided below, the disclosed systems and / or methods can be implemented using any number of techniques, whether currently known or existing. The present invention is in no way limited to the illustrative implementations, drawings, and techniques described below, including the exemplary designs and implementations illustrated and described herein, but can be modified within the scope of the appended claims and the full scope of their equivalents.

[0084] The 3rd generation partnership project (3GPP) uses a parallel "release" system that provides developers with a stable platform for implementing functionality at a given point, and then supports adding new features in subsequent releases. The 3rd generation partnership project (3GPP) Release 18 (Rel.18) recently set the initial phase for enhanced 5G as the midpoint of 5G standardization. In this regard, 3GPP has announced its decision to recognize Rel.18 as the first release of enhanced 5G.

[0085] One problem with 5G networks is the congestion and overhead that occurs at the BS (e.g., gNB). Sidelink (SL) communication is a communication scheme in which a direct link is established between UEs so that the UEs can exchange voice and data directly with each other without the intervention of the gNB. SL communication is being considered as a scheme for reducing the overhead problem of gNB caused by the rapidly increasing data traffic.

[0086] The 3GPP Technical Specification Group (TSG) Radio Access Network (RAN) is responsible for the technical coordination of specification work done in the following working groups: RAN1 - Radio Layer 1 (Physical Layer), RAN2 - Radio Layer 2 and Radio Layer 3 Radio Resource Control. As part of Rel.18, a Positioning Study Item Description (SID) was established for RAN1 and RAN2 with the goal of studying and evaluating the performance and feasibility of potential solutions for SL positioning considering relative positioning, ranging and absolute positioning. Specifically, the RAN1 working group is tasked with studying positioning methods (e.g., time difference of arrival (TDOA), round trip time (RTT), angle of arrival (AOA), angle of departure (AOD), etc.), including the combination of SL positioning measurements with other radio access technology (RAT) related positioning measurements (e.g., Uu-based measurements). The RAN1 working group's tasks also include studying the sidelink reference signals for positioning purposes from the perspective of the physical layer, including signal design resource allocation, measurement, association procedures, etc., as well as reusing existing reference signals, procedures, etc. in sidelink communications and positioning as much as possible.

[0087] Unfortunately, there is no solution to implement sidelink positioning in 5G NR networks as described in the enhanced work item description (WID) of Rel.18. In other words, SL communication is not yet compatible with the enhanced 5G standard.

[0088] This document discloses technologies for implementing SL communication in an enhanced 5G network. Specifically, these technologies cover RTT-based SL ranging and multi-RTT-based SL positioning. By making SL communication compatible with the enhanced 5G standard, UEs are able to communicate directly with each other without gNB overhead. This improves communication between UEs. The disclosed embodiments also improve the ranging accuracy of the UE and the performance of UE positioning. For high-mobility UEs, distance changes can be captured through multiple measurements, and the estimate of the latest distance can also be improved.

[0089] The making and use of embodiments of the present invention are discussed in detail below. However, it should be understood that the concepts disclosed herein can be embodied in a wide range of specific contexts, and the specific embodiments discussed herein are merely illustrative and are not intended to limit the scope of the claims. Furthermore, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the spirit and scope of the present invention as defined by the appended claims.

[0090] introduction.

[0091] The 3rd generation partnership project (3GPP) has been developing and standardizing several important features of the fifth generation (5G) new radio (NR) access technology. In Release 16, the work item NR vehicle-to-everything (V2X) wireless communication was completed with the goal of providing 5G-compatible high-speed and reliable connectivity for vehicular communications. This work item provides the basis for NR sidelink communications for applications such as safety systems and autonomous driving. High data rates, low latency, and high reliability are some of the key areas of research and standardization. In Release 17, the work item Sidelink enhancement was completed to further enhance the capabilities and performance of sidelink communications. One of the important goals of this work item is to introduce an inter-UE coordination mechanism where one UE shares preferred or non-preferred resources for another UE to use in its resource selection, or sends a conflict indication to another UE when there is a conflict on its reserved resources.

[0092] In Release 16, a work item on NR positioning support was completed, which provides positioning support in 5G NR, including downlink (DL) and uplink (UL) reference signals for various positioning techniques (DL-time difference of arrival (TDOA), DL-AOD, UL-TDOA, UL-AOA, multi-cell RTT, and E-CID), and UE and gNodeB (gNB) measurements for NR positioning. In Release 17, a work item on NR positioning enhancements was completed, with the goal of supporting high accuracy, low latency, network efficiency, and device efficiency requirements for commercial use cases. This work item provides methods, measurements, signaling, and procedures to improve positioning accuracy in Release 16 positioning methods.

[0093] In Release 18, a study project on extended and improved NR positioning was approved, which includes the study of sidelink positioning schemes.

[0094] In this disclosure, techniques and signaling to achieve sidelink positioning are described.

[0095] Figure 1 It is a diagram of in-coverage / out-of-coverage operation. Sidelink communication can be in-coverage or out-of-coverage: In in-coverage (IC) operation, a central node (e.g., gNB) exists and can be used to manage the sidelink (Mode 1). In Mode 2 operation, the system operation is fully distributed and the UE selects its own resources. In the present invention, it can also facilitate / help some UEs to select their resources. It should be noted that in Mode 2, the UE can be in-coverage or out-of-coverage (OOC).

[0096] For the purpose of sidelink communications, the LTE sidelink introduced the concept of resource pools and is being reused for the NR sidelink. A resource pool is a set of resources that can be used for sidelink communications. The resources in the resource pool are used for different channels, including control channels, shared channels, feedback channels, synchronization signals, reference signals, broadcast channels (e.g., master information blocks), etc. The 3GPP standard (technical specification (TS) 38.331) defines the rules for how resources are shared and for specific configurations of resource pools.

[0097] The sidelink resource pool can be configured in units of time slots in the time domain and in units of physical resource blocks (PRBs) or subchannels in the frequency domain. A subchannel consists of one or more PRBs. Figure 3 is an example of a resource grid with a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSCCH) and a physical sidelink feedback channel (PSCCH).

[0098] For NR mobile broadband (MBB), each physical resource block (PRB) in the grid is defined as a slot of 14 consecutive orthogonal frequency-division multiplexing (OFDM) symbols in the time domain and 12 consecutive subcarriers in the frequency domain, that is, each resource block includes 12×14 resource elements (RE). When used as a frequency domain unit, a PRB is 12 consecutive subcarriers. When a normal cyclic prefix (CP) is used, a slot has 14 symbols, and when an extended cyclic prefix (ECP) is used, a slot has 12 symbols. The duration of a symbol is inversely proportional to the subcarrier spacing (SCS). For SCSs of {15, 30, 60, 120} kilohertz (kHz), the duration of the slot is {1, 0.5, 0.25, 0.125} milliseconds (ms), respectively. Each PRB can be allocated to a combination of control channel (CCH), shared channel (SCH), feedback channel, reference signal (RS), etc. In addition, some REs of PRB can be reserved. A similar structure is used on the sidelink. Communication resources occupy PRBs, PRB sets, and use codes (if code-division multiple access (CDMA) is used, similar to PUCCH), physical sequences, RE sets, etc.

[0099] The physical sidelink control channel (PSCCH) carries sidelink control information (SCI). The source UE uses the SCI to schedule data transmission on the physical sidelink shared channel (PSSCH). The SCI can transmit the time and frequency resources of the PSSCH, parameters of the hybrid automatic repeat request (HARQ) process, such as the redundancy version, process identifier (identifier, ID), new data indicator, and resources of the physical sidelink feedback channel (PFSCH). The PFSCH can carry an indication (HARQ-ACK) of whether the receiving [destination] UE correctly decodes the payload carried on the PSSCH (e.g., an acknowledgement (ACK) or a negative acknowledgement (NACK)). The SCI can also carry a bit field indicating a representation of the identity of the source UE. In addition, the SCI can also carry a bit field indicating a representation of the identity of one or more destination UEs. Other fields include the modulation coding scheme (MCS) used to encode the payload and modulate the coded payload bits; the demodulation reference signal (DMRS) mode, antenna port, and priority of the payload (transmission).

[0100] NR sidelink control information (SCI) can be transmitted in two levels. The first level (as shown below) can use SCI format 1-A, and the second level can use SCI format 2-A, 2-B or 2-C. The first level indicates the resources used for the second level SCI.

[0101] SCI format 1-A (from TS 38.212).

[0102] SCI format 1-A is used for scheduling PSSCH and secondary SCI on PSSCH.

[0103] The following information is transmitted via SCI Format 1-A:

[0104] – Priority – 3 bits as defined in clause 5.4.3.3 of [12, TS23.287].

[0105] – Frequency resource allocation – When the value of the higher-level parameter sl-MaxNumPerReserve is configured as 2

[0106] bit; otherwise, when the value of the higher-level parameter sl-MaxNumPerReserve is configured as 3,

[0107] bits, as defined in clause 8.1.2.2 of [6, TS 38.214].

[0108] – Time resource allocation – 5 bits when the value of the higher-level parameter sl-MaxNumPerReserve is configured as 2; otherwise,

[0109] The value of MaxNumPerReserve is configured to be 9 bits when it is 3, as defined in clause 8.1.2.1 of [6, TS 38.214].

[0110] – Resource reservation period – If the higher-level parameter sl-MultiReserveResource is configured, bits, as defined in clause 8.1.4 of [6, TS 38.214], where is the number of entries in the higher-level parameter sl-ResourceReservePeriodList; otherwise, it is 0 bit.

[0111] –DMRS Mode– bits, as defined in clause 8.4.1.1.2 of [4, TS 38.211], where N pattern It is the number of DMRS patterns configured by the higher-level parameter sl-PSSCH-DMRS-TimePatternList; if sl-PSSCH-DMRS-TimePatternList is not configured, it is 0 bit.

[0112] – Second level SCI format – 2 bits, as defined in Table 8.3.1.1-1.

[0113] – Beta_offset indicator – 2 bits, as provided by the higher layer parameter sl-BetaOffsets2ndSCI and Table 8.3.1.1-2.

[0114] – DMRS port number – 1 bit, as defined in Table 8.3.1.1-3.

[0115] – Modulation and coding scheme – 5 bits, as defined in clause 8.1.3 of [6, TS 38.214].

[0116] – Additional MCS table indicator – as defined in clause 8.1.3.1 of [6, TS 38.214]: 1 bit if the higher layer parameter sl-Additional-MCS-Table configures one MCS table; 2 bits if the higher layer parameter sl-Additional-MCS-Table configures two MCS tables; otherwise 0 bit.

[0117] –PSFCH Overhead Indication – 1 bit if higher layer parameter sl-PSFCH-Period = 2 or 4, as defined in clause 8.1.3.2 of [6, TS38.214]; otherwise 0 bit.

[0118] – Reserved – The number of bits determined by the higher layer parameter sl-NumReservedBits, whose value is set to zero.

[0119] SCI format 2-A (from TS38.212).

[0120] SCI format 2-A is used for decoding PSSCH, and HARQ operation is used when HARQ-ACK information includes ACK or NACK, or when HARQ-ACK information is not fed back.

[0121] The following information is transmitted via SCI Format 2-A:

[0122] –HARQ process number– bits, as defined in clause 16.4 of [5, TS 38.213].

[0123] – New data indicator – 1 bit, as defined in clause 16.4 of [5, TS 38.213].

[0124] – Redundancy version – 2 bits, as defined in clause 16.4 of [6, TS 38.214].

[0125] – Source ID – 8 bits, as defined in clause 8.1 of [6, TS 38.214].

[0126] – Destination ID – 16 bits, as defined in clause 8.1 of [6, TS 38.214].

[0127] – HARQ feedback enable / disable indicator – 1 bit, as defined in [5, TS 38.213] clause 16.3.

[0128] – Broadcast type indicator – 2 bits, as defined in Table 8.4.1.1-1.

[0129] – Channel state information (CSI) request – 1 bit, as defined in clause 8.2.1 of [6, TS38.214].

[0130] Table 8.4.1.1-1: Broadcast type indicator

[0131] The value of the broadcast type indicator Broadcast Type 00 broadcast 01 Multicast 10 Unicast 11 Reserve

[0132] SCI format 2-B (from TS38.212).

[0133] SCI format 2-B is used for decoding PSSCH, and HARQ operation is used when HARQ-ACK information includes only NACK, or when no HARQ-ACK information is fed back.

[0134] The following information is transmitted via SCI Format 2-B:

[0135] –HARQ process number– bits, as defined in clause 16.4 of [5, TS 38.213].

[0136] – New data indicator – 1 bit, as defined in clause 16.4 of [5, TS 38.213].

[0137] – Redundancy version – 2 bits, as defined in clause 16.4 of [6, TS 38.214].

[0138] – Source ID – 8 bits, as defined in clause 8.1 of [6, TS 38.214].

[0139] – Destination ID – 16 bits, as defined in clause 8.1 of [6, TS 38.214].

[0140] – HARQ feedback enable / disable indicator – 1 bit, as defined in [5, TS 38.213] clause 16.3.

[0141] – Area ID – 12 bits, as defined in clause 5.8.1.1 of [9, TS 38.331].

[0142] – Communication range requirement – ​​4 bits, as defined in [9, TS 38.331].

[0143] SCI format 2-C (from TS38.212).

[0144] SCI format 2-C is used to decode the PSSCH and to provide or request inter-UE coordination information.

[0145] The following information is transmitted via SCI Format 2-C:

[0146] –HARQ process number – 4 bits

[0147] – New data indicator – 1 bit

[0148] – Redundancy version – 2 bits, as defined in Table 7.3.1.1.1-2

[0149] – Source ID – 8 bits, as defined in clause 8.1 of [6, TS 38.214]

[0150] – Destination ID – 16 bits, as defined in clause 8.1 of [6, TS 38.214]

[0151] – HARQ feedback enable / disable indicator – 1 bit, as defined in clause 16.3 of [5, TS 38.213]

[0152] – CSI request – 1 bit, as defined in clause 8.2.1 of [6, TS 38.214] and clause 8.1 of [6, TS 38.214]

[0153] – Provide / request indicator – 1 bit, where a value of 0 indicates that SCI format 2-C is used to provide inter-UE coordination information and a value of 1 indicates that SCI format 2-C is used to request inter-UE coordination information

[0154] If the Offer / Request Indicator field is set to 0, all remaining fields are set as follows:

[0155] – Resource Portfolio – bits, as defined in clause 8.1.5A of [6, TS 38.214], where

[0156] - If the higher-level parameter sl-MultiReserveResource is configured, then and N rsv _ period is the number of entries in the higher-level parameter sl-ResourceReservePeriodList; otherwise Y = 0

[0157] - The number of subchannels in the resource pool provided by the higher-level parameter sl-NumSubchannel

[0158] – First resource location – 8 bits, as defined in clause 8.1.5A of [6, TS 38.214].

[0159] – Reference slot positions – bits, as defined in clause 8.1.5A of [6, TS 38.214], where μ is defined in Table 4.2-1 of clause 4.2 of [4, TS 38.211].

[0160] – Resource set type – 1 bit, where a value of 0 indicates a preferred resource set and a value of 1 indicates a non-preferred resource set.

[0161] – Lowest Subchannel Index – bits, as defined in clause 8.1.5A of [6, TS 38.214].

[0162] If the Offer / Request Indicator field is set to 1, all remaining fields are set as follows:

[0163] – Priority – 3 bits, as specified in clause 5.4.3.3 of [12, TS 23.287] and clause 5.22.1.3.1 of [8, TS 38.321]. A value of “000” in the “Priority” field corresponds to a priority value of “1”, a value of “001” in the “Priority” field corresponds to a priority value of “2”, and so on.

[0164] – Number of subchannels – bits, as defined in clause 8.1.4A of [6, TS 38.214].

[0165] – Resource reservation period – If the higher-level parameter sl-MultiReserveResource is configured, bits, as defined in clause 8.1.4A of [6, TS 38.214], where N rsv _ period is the number of entries in the higher-level parameter sl-ResourceReservePeriodList; otherwise, it is 0 bit.

[0166] – Resource Selection Window Location – bits, as defined in clause 8.1.4A of [6, TS 38.214], where μ is defined in Table 4.2-1 of clause 4.2 of [4, TS 38.211].

[0167] – Resource set type – If the higher layer parameter determineResourceSetTypeScheme1 is configured as “UE-B’s request”, it is 1 bit, where the value 0 indicates a request to provide inter-UE coordination information of a preferred resource set, and the value 1 indicates a request to provide inter-UE coordination information of a non-preferred resource set, otherwise it is 0 bit.

[0168] – Padding bits.

[0169] High-level message (from TS38.331).

[0170]

[0171]

[0172] Sidelink inter-UE coordination.

[0173] In Rel-17, sidelink inter-UE coordination (IUC) is specified to improve the reliability of Mode 2 by overcoming the problems of hidden nodes, exposed nodes and half-duplex that affect the sidelink performance. Specifically, two IUC schemes are defined, namely,

[0174] – Solution 1: Inter-UE coordination information signaling from UE-A to UE-B

[0175] – Preferred resource set for UE-B transmission

[0176] – Non-preferred resource set for UE-B transmission

[0177] – Solution 2: Inter-UE coordination information signaling from UE-A to UE-B

[0178] – There is an expected / potential resource conflict on the resources indicated by UE-B’s SCI

[0179] In IUC scheme 1, two IUC triggering scenarios are considered and specified, namely: (1) coordination triggered by explicit request, in which UE-B sends an explicit request to UE-A, and UE-A generates coordination information (preferred resource set or non-preferred resource set) according to the request and sends it to UE-B; (2) coordination triggered by conditions other than explicit request, in which UE (UE-A) that meets one or more specific conditions generates coordination information and sends it to UE-B.

[0180] Conditions for two IUC triggering scenarios are also specified. For IUC triggered by explicit request, one of the two conditions is configured for resource pool level, i.e., option 1 - until UE-B's implementation, and option 2 - the request can be triggered only if UE-B has data to send to UE-A. Similarly, for IUC triggered by condition, there are two conditions, one of which is enabled by resource pool level (pre) configuration, i.e., option 1 - until UE-A's implementation, and option 2 - coordination can be triggered only if UE-A has data to send to UE-B together with coordination information.

[0181] The generation criteria of the coordination information, i.e., the preferred resource set and the non-preferred resource set are defined as follows.

[0182] – Preferred resource set:

[0183] – Condition 1-A-1: One or more resources other than one or more overlapping reserved resources whose reference signal received power (RSRP) in other UEs is greater than a threshold

[0184] – Condition 1-A-2: When UE-A (as the receiver (Rx) of UE-B) does not expect to perform SL reception from UE-B, one or more resources other than the time slot

[0185] – Non-preferred resource set:

[0186] – Condition 1-B-1: One or more reserved resources and RSRP measurements of other identified UEs

[0187] – Option 1: One or more reserved resources of one or more other UEs identified by UE-A, whose RSRP measurement is greater than a (pre-)configured RSRP threshold

[0188] – Option 2: When UE-A is the destination of a TB sent by one or more UEs, one or more reserved resources of other UEs identified by UE-A, and the RSRP measurement of UE-A is less than the (pre-)configured RSRP threshold

[0189] – Condition 1-B-2: One or more resources (e.g., one or more time slots) where SL reception is not expected from UE-B when UE-A is the intended recipient of UE-B

[0190] To send explicit request and coordination information, the media access control-control element (MAC-CE) is used as a container. If configured, the second level SCI (SCI format 2C) is also used for explicit request or coordination information.

[0191] For coordination triggered by explicit request, the transmission of explicit request and coordination information only supports unicast. For coordination triggered by condition, the transmission of both coordination information supports unicast. Non-preferred resource sets only support broadcast and multicast.

[0192] Coordination information and explicit requests can be multiplexed with data transmission only when the source / destination identifier (ID) pair is the same.

[0193] Sidelink synchronization signal block (S-SSB).

[0194] The synchronization time slot in the sidelink, i.e., the sidelink synchronization signal block (S-SSB), is designated for one UE to synchronize with another UE. Figure 4 As shown, the first OFDM symbol is used for the physical sidelink broadcast channel (PSBCH). But as with a conventional sidelink time slot, the first symbol is used to establish the automatic control gain (AGC). After that, there are two symbols for the sidelink primary synchronization signal (S-PSS) and two symbols for the sidelink secondary synchronization signal (S-SSS). Eight of the remaining nine symbols are used for PSBCH transmission. The last symbol is the guard period (GP), which is the same as in a conventional sidelink time slot.

[0195] In the frequency domain, S-SSB occupies 11 PRBs, a total of 132 subcarriers. PSBCH occupies all 11 PRBs, and the synchronization signal size is 127, so the sidelink primary synchronization signal (S-PSS) and sidelink secondary synchronization signal (S-SSS) occupy 127 subcarriers.

[0196] The period of S-SSB is 160ms. The frequency position of S-SSB is preconfigured. For frequency range 1 (FR1), the number of S-SSB transmissions is set to 1, and for frequency range 2 (FR2), the number of S-SSB transmissions is configurable.

[0197] Sounding reference signal (SRS).

[0198] In NR, as specified in 38.211, SRS resources for 1, 2, and 4 antenna ports are supported. SRS resources can be mapped to The transmission comb (kTC) is supported on every 2, 4 or 8 REs in the frequency domain. In addition, cyclic shift is supported. When the comb size is 2, 4 or 8, the maximum number of cyclic shifts is 8, 12 and 6 respectively. The SRS sequence ID is configured by high-level parameters. The starting OFDM symbol l0 in the time domain is offset by l relative to the end of the time slot. offset Definition, where l offset ∈{0,1,…,13} indicates that the starting position can be any OFDM symbol in the time slot. The frequency starting position is also specified. For positioning, an additional offset in the frequency domain is specified The offset also depends on the OFDM symbol configured for SRS transmission. SRS resources can be configured for periodic, semi-static, and aperiodic SRS transmission. In the frequency domain, the SRS allocation is aligned with the 4PRB grid. Frequency hopping is supported, the same as in long-term evolution (LTE). Through the same design approach, the NR SRS bandwidth and frequency hopping configuration are designed to cover a larger span of values ​​compared to LTE.

[0199] As specified in 38.211, the SRS resources are configured by the SRS-Resource Information Element (IE) (for UL channel sounding) or by the SRS-Pos-Resource IE (for positioning purposes). Figure 5 Shows the time slot OFDM symbol comb size K TC =4 UL SRS.

[0200] The UE may be configured with one or more SRS resource sets. For each SRS resource set, the UE may be configured with multiple SRS resources. The use cases of SRS resource sets (e.g., beam management, codebook-based uplink multiple-input and multiple-output (MIMO), non-codebook uplink MIMO, antenna switching, which is actually used for general downlink CSI acquisition) are configured by high-level parameters.

[0201] In the time domain at the time slot level, SRS resources can be periodically configured with a period T SRS (in time slots) and the time slot offset T Offset .

[0202] Table 6.4.1.4.2-1: As K TC The maximum number of cyclic shifts of a function (TS 38.211)

[0203]

[0204] Table 6.4.1.4.3-2: As K TC SRS offset as a function of l′

[0205]

[0206] Positioning reference signal (PRS)

[0207] A positioning reference signal (PRS) is a downlink reference signal used for positioning purposes. A PRS is also called a DL-PRS, while a UL SRS configured for positioning is sometimes called a UL-PRS.

[0208] DL-PRS is designated with a starting symbol The size of the PRS (the number of OFDM symbols) is L PRS ∈{2,4,6,12}, from The frequency domain spacing (i.e., comb tooth size) of two DL-PRS resource elements selected from a specified subset of combinations Initial frequency domain offset And similar to UL-SRS for positioning, an additional frequency domain offset k′ specified in the table (Table 7.4.1.7.3-1 of TS38.211) varies from one OFDM symbol to another.

[0209] Table 7.4.1.7.3-1: As The frequency shift k′ of the function.

[0210]

[0211] In the time domain, at the time slot level, DL-PRS can be configured with a period and slot offset and additional slot offset The bandwidth of DL-PRS can be configured from 24 to 275 PRBs with a step size of 4 PRBs.

[0212] Figure 6 is the comb tooth size in the time slot and L PRS = Example of DL PRS of 12 OFDM symbols.

[0213] SL positioning in 3GPP Rel-18.

[0214] The need for 3GPP to develop a sidelink positioning solution has been discussed during the planning phase of 3GPP Rel-18. It has been shown that various important use cases can benefit from SL positioning, such as V2x and public safety use cases in technical report (TR) 38.845, ranging-based services in TS 22.261, and industrial internet of things (IIoT) use cases (TS 22.104).

[0215] In RANP #94, a Rel-18 study project (RP-213588) on extended and improved NR positioning was agreed, which included the objectives of SL positioning:

[0216] – Study and evaluate the performance and feasibility of potential solutions for SL positioning, considering relative positioning, ranging and absolute positioning: [RAN1,

[0217] RAN2]

[0218] – Evaluate the bandwidth requirements needed to meet the determined accuracy requirements [RAN1]

[0219] – Study positioning methods (e.g. TDOA, RTT, AOA / D, etc.), including the combination of SL positioning measurements with other RAT related positioning measurements (e.g. Uu based measurements) [RAN1]

[0220] – Study the sidelink reference signals for positioning purposes from the physical layer perspective, including signal design, resource allocation, measurement, association procedures, etc., and reuse existing reference signals, procedures, etc. from sidelink communications and from positioning as much as possible [RAN1]

[0221] – Study the positioning architecture and signalling procedures (e.g. configuration, measurement reporting, etc.) to enable sidelink positioning, including UE-based positioning and network-based positioning [RAN2, including coordination and alignment with RAN3 and SA2 as required]

[0222] Background Information

[0223] Sidelink Mode 1 Resource Allocation

[0224] In Rel-16 NR V2X sidelink mode 1, the gNB performs the scheduling of the sidelink, i.e. the gNB allocates SL resources for SL communication, which are sent to the UE via the NR Uu interface. Therefore, sidelink mode 1 is applicable to UEs within the coverage of the gNB. The resources allocated by mode 1 can be on the same carrier as the cellular NR or on a dedicated sidelink carrier.

[0225] There are three types of mode 1 resource allocation, namely, dynamic allocation, type 1 configured grant (CG), and type 2 configured grant. In dynamic allocation, the UE first sends a scheduling request (SR) for each TB to the gNB through PUCCH. Then, the gNB sends the SL resource allocation to the UE through DCI format 3_0 through the physical downlink control channel (PDCCH). In CG-based resource allocation, the UE first sends a message to the gNB with the expected SL traffic, such as periodicity, maximum TB size, and QoS information. The gNB provides resource allocation, i.e., the gNB provides the CG to the UE through RRC signaling. In type 1 CG, the UE can use the resource allocation immediately. In type 2 CG, the UE uses the allocated resources after the gNB activates the allocated resources through downlink control information (DCI).

[0226] Sidelink Mode 2 Resource Allocation

[0227] In Rel-16 sidelink, Mode 2 UE can send and receive information without network management. UE allocates resources from resource pool for sidelink transmission. Resource allocation relies on sensing and reservation process, such as Figure 7 As shown. During the sensing process, the monitoring UE detects the SCI sent in each time slot in the sensing window and measures the RSRP of the resources indicated in the SCI. The monitoring UE can also receive the transmission of data (also a receiving UE). For periodic traffic, resources reserved for sidelink transmission, if the UE occupies time slot s k If the UE has resources on the time slot s, the UE will also occupy the time slot s k +q*RRI k The resources on the k The interval is reserved for the resources of UE m detected by the sensing UE. Detecting SCI includes the steps of receiving and decoding PSCCH and processing SCI in PSCCH.

[0228] For aperiodic or dynamic transmissions, the transmitting UE reserves multiple resources and indicates the next resource in the SCI. Thus, based on the sensing results, the monitoring UE can determine which resources may be occupied in the future and avoid using these resources for its own transmission if the RSRP measured on the occupied resources during the sensing period is greater than the RSRP threshold in the resource exclusion process, as described in TS38.214.

[0229] Figure 7The timing information of sensing and resource selection for Rel-16NR sidelink transmission is shown, which is usually called full sensing. When resource selection is triggered on time slot n, based on the sensing result in the sensing window (i.e., on time slot [n-T0, n-Tproc, 0]), the sending UE selects resources in the resource pool in the resource selection window (i.e., on time slot [n+T1, n+T2]), where:

[0230] T0: time slot number with a value determined by the resource pool configuration;

[0231] T proc,0 : The time required for UE to complete the sensing process;

[0232] T1: The processing time required for candidate resource identification and resource selection, T1≤T proc,1 ;

[0233] T2: The last time slot of the resource pool used for resource selection, for UE implementation, but in [T 2min , packet delay budget (PDB)], where T 2min is the minimum value of T2, and PDB represents the packet delay budget, that is, the remaining time for the UE to send a data packet.

[0234] T proc,1 : The maximum time required for the UE to identify candidate resources and select new sidelink resources.

[0235] NR positioning method

[0236] Several positioning methods have been agreed upon in NR (TS 38.305), including DL-based schemes, UL-based schemes, and DL and UL-based schemes.

[0237] DL-based solutions

[0238] Timing-based techniques - downlink time difference of arrival (DL-TDOA): Similar to OTDOA in LTE, NR-specified DL-TDOA positioning measures the timing difference of DL-PRS on the LOS path from different gNBs.

[0239] Angle-based technology - downlink angle of departure (DL-AOD): NR introduces angle-based positioning technology. In DL-AOD, the UE measures the received power based on the DL-PRS and estimates the AOD from different gNBs based on the power difference between the measured PRS / beams from the same transmission / reception point (TRP).

[0240] UL-based solutions

[0241] Timing-based technology - uplink time difference of arrival (UL-TDOA): Unlike LTE, NR introduces UL positioning technology using UL positioning signal, which is the configured UL SRS. The gNB measures the UL timing difference from the UE.

[0242] Angle-based techniques - uplink angle of arrival (UL-AOA): Similar to DL-AOD, the gNB measures the AOA of the UE using the UL SRS configured for positioning purposes. The gNB measures the zenith AOA and azimuth AOA to obtain the 3D position.

[0243] DL-based solution and UL-based solution

[0244] Timing-based techniques - multi-cell round trip time (multi-RTT): In multi-RTT, the UE measures the UE receive-transmit (Rx-Tx) time difference and the gNB measures the gNB Rx-Tx time difference. For each UE-gNB pair, two Rx-Tx time differences can be used to estimate the RTT. For Rx-Tx time difference measurement, the DL PRS and UL SRS are configured and sent by the gNB and UE, respectively.

[0245] Enhanced cell-ID (E-CID): E-CID based positioning is based on RRM measurements, i.e. RSRP, RSRQ, through synchronization signals (i.e. SSB measurements) and CSI-RS. UL AOA is also supported.

[0246] The selection of positioning methods, configuration of reference signals (SRS, PRS) and collection of measurements are orchestrated by a location management function (LMF) residing in the network (TS 38.305). The LMF manages the support of different location services for the target UE, including positioning of the UE and delivery of assistance data to the UE. The LMF may interact with the serving gNB or serving ng-eNB of the target UE to obtain positioning measurements for the UE, including uplink measurements performed by the NG-RAN and downlink measurements performed by the UE, which are provided to the NG-RAN as part of other functions, for example to support handover.

[0247] question.

[0248] For radio access technology (RAT)-dependent positioning in cellular systems, the process has been studied and specified in detail starting from LTE. For NR positioning, the functions and procedures are basically the same as LTE. Some new technologies and UL reference signals are introduced. However, for SL positioning, although the positioning methods can be reused, the procedures and reference signaling are not yet defined. In addition, ranging (i.e. estimating the distance of a remote object to its own position, or in NR, estimating the distance between the gNB and the UE) is not specifically addressed in NR positioning because there are not many use cases for ranging between gNB and UE. However, it is different in the sidelink, especially for V2x and public safety use cases, ranging is very important. Although ranging can be solved by positioning (e.g. knowing the reference position and your own position), ranging requires fewer measurements and position references, so its design can be simpler.

[0249] As described herein, multi-RTT is specified in NR positioning, which is a timing-based positioning technique that utilizes DL measurements and UL measurements. In multi-RTT, positioning reference signals (e.g., DL PRS and UL SRS) are transmitted in DL and UL, respectively. The UE measures the UE Rx-Tx time difference and the gNB measures the gNB Rx-Tx time difference, where the Rx-Tx time difference is the difference between the time when a wireless node (UE or gNB) receives a positioning signal from another node (gNB or UE) and the time when the wireless node subsequently sends a positioning signal. Both Rx-Tx measurements are sent to the location management function (LMF) for position estimation. By measuring the Rx-Tx time difference of both sides of the node pair twice, the round trip time (RTT) can be obtained and the distance can be estimated. With multiple RTTs and the reference position of the gNB (as in multi-RTT), the position of the UE can be estimated. The distance between two wireless nodes (e.g. UE to UE or UE to gNB) is measured based on the RTT between the two nodes, without measuring the timing difference of another node as a reference. Therefore, multi-RTT is robust to synchronization between gNBs. In the sidelink, synchronization between multiple UEs may be difficult, which makes multi-RTT based positioning more attractive in the sidelink.

[0250] In ranging, what is needed is the distance between two nodes, not the exact location of the UE. Therefore, in the case of measuring the RTT between two nodes, a single RTT-based protocol is sufficient. Because RTT is the propagation time of light between two nodes, the distance between two nodes is half the distance that light propagates during the RTT. In the wireless fidelity (WiFi) 802.11 wireless local area network (WLAN) standard, a point-to-point single-user protocol is specified for fine timing measurement (FTM) and RTT. This protocol enables two wireless local area network (WLAN) stations to measure their distance relative to each other, i.e., ranging.

[0251] SL positioning (including ranging) is a new area for 5G NR. So far, in general, 3GPP has not specified signals and methods for SL positioning. First, there is no dedicated SL signaling for positioning. Second, SL resource selection does not support SL positioning RS transmission and information exchange including location information and measurements. Specifically, the existing SL specification does not support RTT-based ranging and multi-RTT-based positioning.

[0252] In the present invention, a design of SL ranging and positioning based on RTT is provided.

[0253] System description of RTT-based ranging and positioning in the sidelink.

[0254] RTT-based ranging in the sidelink.

[0255] Figure 8 A schematic diagram of sidelink ranging with a pair of UEs is shown, wherein one UE (the requesting UE or ranging source UE) wishes to estimate its distance from another UE (the responding UE or ranging remote UE). For RTT-based ranging, the two UEs send sidelink reference signals to each other in turn. The reference signaling used for SL ranging or positioning measurements is typically represented as a SL positioning reference signal (SL Pos-RS, or SL PRS). Each UE records the timestamp of its transmission and measures the time to receive the SLPos-RS from the other UE (to obtain the timestamp). The Rx-Tx timing difference can be calculated based on the two timestamps measured at each UE. If the Rx-Tx timing difference at the two UEs is known, the round-trip time (RTT) can be derived, and the distance between the two UEs can be estimated. As shown in the figure, the RTT-based technology requires bidirectional transmission of Pos-RS between the two UEs, as well as the transmission of Rx-Tx time difference measurements from one UE to another UE (particularly from the responding UE to the requesting UE). Both types of transmission use SL resource allocation. It should be noted that, since Pos-RS signaling may have multiple options or types (as described herein), the types of Pos-RS from the UE may be different.

[0256] Multi-RTT based positioning in sidelink.

[0257] like Fig. 9 As shown, a sidelink positioning system including multiple location reference UEs (i.e., anchor UE and target UE) is considered. The sidelink positioning will obtain the location of the target UE based on the location information of the anchor UE through SL Pos-RS measurement between the target UE and the anchor UE.

[0258] For multi-RTT based positioning, the single RTT of the UE in SL ranging is extended to multiple RTT measurements of all pairs of anchor UEs and target UEs. The position of the target UE can be estimated by the distance between the target UE and each anchor UE and the position information of each anchor UE.

[0259] Same as RTT-based ranging, such as Fig. 9As shown, multi-RTT SL positioning requires bidirectional SL Pos-RS transmission, i.e., SL Pos-RS transmission from anchor UE to target UE and from target UE to anchor UE. For SL Pos-RS from anchor UE to target UE, separate transmission is required. For SL Pos-RS from target UE to anchor UE, SL Pos-RS can be combined into one multicast or broadcast transmission.

[0260] Unlike NR Uu links, sidelink transmissions are opportunistic and multiple transmit and receive links coexist in the same resource pool. As described in this article, sidelink transmissions are based on resource reservation to avoid resource allocation conflicts between different UE-to-UE links (resource allocation conflicts will cause interference). Resource reservation is achieved through central planning by the gNB under the coverage of the gNB or through UE sensing in mode 2 operation. Resource reservation may also be required for the transmission of SL reference signals for positioning purposes. Another issue with SL positioning is that the anchor UE may be mobile or may be dynamically deployed, which means that the location of the anchor UE may change frequently. Therefore, the anchor UE may need to update its location to the target UE. It is also necessary to exchange Rx-Tx measurements between the anchor UE and the target UE based on the position estimate of the target UE. These transmissions also require resource allocation.

[0261] In order to achieve a certain positioning accuracy, sufficient bandwidth should be allocated to the SL Pos-RS, especially for timing-based positioning techniques, which use a lot of resources in one time slot, which is more serious for multi-RTT-based positioning because it requires SL Pos-RS transmissions from both sides. In order to avoid the SL resource pool being occupied by unnecessary SL Pos-RS transmissions, efficient protocols and resource allocation are required.

[0262] Next, we first consider the design based on RTT ranging, and then extend the design to multi-RTT based SL positioning. Before describing the detailed design, alternative terminology for UE in SL ranging and positioning is provided below.

[0263] For SL ranging, the following alternative terminology may be used:

[0264] – UE requesting ranging for a remote UE: requesting UE, (ranging) source UE, ranging initiating UE

[0265] – Remote UE that responds to the request: responding UE, remote UE, target UE.

[0266] For SL positioning, as described above, the UE providing the location reference is called the anchor UE, and the UE whose location is to be estimated (either at the UE itself or at the anchor UE) is called the target UE. Alternatively, the following terms for these two types of UEs may be used.

[0267] –UEs with location reference: anchor UE, reference UE, location reference UE, responding UE, source UE

[0268] – UEs whose positions are to be estimated: positioning UE, target UE, (position) requesting UE, initiating UE

[0269] It should be noted that there are some differences in issuing "requests" or "initiations" in SL ranging and positioning. As will be described below, in SL ranging, the UE requesting ranging usually initiates the ranging process, and the request is sent to the target (remote) UE to estimate the distance to the target UE. In SL positioning, the request is usually sent by the target UE whose position is to be estimated. However, in SL positioning, the anchor UE can initiate the positioning process. The anchor UE (referred to as the serving anchor UE) can send an explicit request to the target UE and request the transmission of the SL Pos-RS. At the same time, the anchor UE may need to send different requests to other anchor UEs (coordinating anchor UEs) to coordinate measurements. In this scenario, the definition of "request" / "initiation" is consistent with that in SL ranging. However, in this scenario, the anchor UE can still be referred to as the serving anchor UE without changing it to a "requesting" or "initiation" UE, but the target UE is not referred to as a requesting UE or an initiating UE to avoid confusion.

[0270] RTT-based SL ranging

[0271] SL ranging process and timestamp.

[0272] In SL ranging, an RTT is established between two UEs (a requesting UE for ranging estimation and a responding UE which is a reference UE for ranging).

[0273] like Fig.10 As shown, first, the source UE or ranging requesting UE sends an explicit ranging request to the target remote UE. The target UE responds to the source UE. Thereafter, the transmission of the SL Pos-RS for time measurement starts from one party to the other. The requesting UE can transmit the request with the SL Pos-RS on the same time slot or the same resource reservation. The responding UE can also send the SL Pos-RS with a response message, or only send the SL Pos-RS without a response message. The responding UE then sends a timing measurement to the requesting or source UE so that the UE estimates the range based on the RTT. The request can be dynamically sent to the remote UE via a second SCI or MAC-CE.

[0274] Fig.10 This is a flow chart of SL ranging. The Rx-Tx measurement report can be multiplexed with the SL Pos-RS or encoded in the SL Pos-RS. If encoded in the SL Pos-RS, there is no need to transmit the measurement report separately.

[0275] In one embodiment, a transmission from the requesting UE is followed by a transmission from the responding UE. This sequence may be repeated a fixed number of times, which is for example (pre)configured, or indicated by the requesting UE. In a different embodiment, the requesting UE does not specify the number of such exchanges, but rather the time limit within which such exchanges are allowed.

[0276] Fig.11 is an illustration of SL Pos-RS transmissions in SL ranging, e.g., multiple SL Pos-RS transmissions from a requesting UE prior to a transmission from a responding UE. In different embodiments, the requesting UE and the responding UE may send different numbers of SL Pos-RS transmissions. For example, the requesting UE may send two to three such transmissions, followed by, for example, a single SL Pos-RS transmission from a responding UE, such as Fig.11 As shown. The responding UE will measure the time difference from each received signal to each SLPos-RS signal it transmits and provide these time differences to the requesting UE. In this embodiment, the requesting UE can indicate to the responding UE how many SL Pos-RS transmissions to send and how many SL Pos-RS transmissions are expected to be received. In this embodiment, as long as the measurement of each received SL Pos-RS to each transmitted SL Pos-RS is provided, there is no need to regularly interleave the transmission signals, i.e., one after another.

[0277] In RTT-based SL ranging, signal or information exchange is performed between two SL UEs. Unicast is a suitable broadcast type for transmission. The request or configuration for SL Pos-RS transmission can be sent to the Radio Resource Control (PC5-RRC) through the PC5 interface. The remote UE and the requesting UE can send SL Pos-RS on multiple time slots, for example, periodically at a certain interval within a certain time. The remote UE can send multiple Rx-Tx (or Tx-Rx) measurements to the requesting UE sequentially or in one transmission.

[0278] Indication of responding UE: The remote UE may indicate whether it supports RTT-based ranging and / or positioning, or whether it may be the responding UE at this time. The indication may be an RRC signal interaction or in a response message. For example, if the requesting UE indicates and reserves HARQ feedback, the response may be indicated in the PSFCH. Examples of these indications may be different codes (spreading codes).

[0279] Fig.12 The message flow of RTT-based SL ranging is shown. Fig.12The message flow in RTT-based SL ranging is shown: (A) the requesting UE sends the SL Pos-RS first, (B) the responding UE sends the SL Pos-RS first, and (C) the requesting UE and the responding UE send the SL Pos-RS within a certain period of time. Fig.12 In (A) and (B), an RTT with two Pos-RS transmissions is described, one for each UE. Fig.12 As shown in (A), the SL Pos-RS is first sent from the requesting UE, and Fig.12 In (B), the SL Pos-RS is first transmitted from the responding UE. After one round of SL Pos-RS transmission, the responding UE sends Rx-Tx timing measurements to the requesting UE. Fig.12 In (C), each UE sends multiple SL Pos-RS. Multiple timing measurements are obtained, which can improve ranging accuracy. For high mobility UEs, distance changes can be captured through multiple measurements, and the estimation of the latest distance can also be improved.

[0280] Without loss of generality, Fig.12 (A) shows a round of RTT for discussing the timing of the current proposal in the sequel. Below are four timestamps in a round of RTT transmission.

[0281] –Request the UE to first send the SL Pos-RS signal at t1.

[0282] – The responding UE receives the SL Pos-RS at t2 and sends a response signal, eg, SL Pos-RS, at t3.

[0283] – The requesting UE receives a signal from the responding UE at t4.

[0284] – After t4, the responding UE then sends an Rx-Tx timing (t3–t2) measurement report to the requesting UE.

[0285] The Rx-Tx measurement of the responding UE 2 is measurement t3-t2. The Rx-Tx measurement of the requesting UE 1 is measurement t4-t1. The ranging or distance between the requesting UE and the responding UE is then calculated as follows:

[0286]

[0287] Where c is the speed of light.

[0288] If the fine timing measurement (FTM) protocol in the Institute of Electrical and Electronics Engineers (IEEE) 802.11 specification is followed, the values ​​of timestamps t2 and t3 are reported to the requesting UE. In multi-RTT, for NR positioning, the Rx-Tx measurement t3-t2 is reported to the LMF.

[0289] For absolute position estimation, i.e. positioning, multiple RTT (multi-RTT) measurements from different responding UEs are required. The minimum requirement for positioning is three RTTs.

[0290] Broadcast type: In RTT-based SL ranging, SL Pos-RS transmissions and measurement reports are between the requesting UE and the responding UE. Therefore, the appropriate broadcast type for these transmissions is unicast, which may be sufficient for ranging purposes.

[0291] RTT timing analysis and measurement reporting.

[0292] The timestamp can be the time of the reference OFDM symbol. Fig.13 As shown, the reference symbols at the requesting UE and the responding UE may be different, that is, and Then, the timestamp can be the OFDM symbol relative to the reference time T sym,i The offset plus the OFDM symbol duration τ 0i Therefore, the overall description of these four timestamps is:

[0293]

[0294] For transmission, t1 and t3 are the timestamps of the transmitted OFDM symbols, which can be aligned with the reference OFDM symbol, where τ 0,i = 0. When OFDM symbol samples are also aligned within the OFDM symbol interval, the delay τ 0,i The relative line of sight (LOS) channel path delay from one UE to another can be expressed as . However, the general expression in (1) is considered.

[0295] The Rx-Tx measurement is obtained at the responding UE and the requesting UE respectively and is given by:

[0296] t3-t2=T sym,3 +τ 0,3 -(T sym,2 +τ 0,2 )=N sym,rsp -τ 0,rsp ,

[0297] t4-t1=T sym,4 +τ 0,4 -(T sym,1 +τ 0,1 )=N sym,req +τ 0,req ,

[0298] Among them, N sym,rsp =T sym,3 -T sym,2 , N sym,req =T sym,4 -T sym ,1,τ 0,rsp =τ 0,2 -τ 0,3 And τ 0,req =τ 0,4 -τ 0,1 As discussed above, if τ 0,1 =τ 0,3 =0, then τ 0,rsp =τ 0,2 And τ 0,req =τ 0,4 .Then:

[0299]

[0300] If D 1,2 is small enough and the RTT is within the OFDM symbol duration, then N sym,req =N sym,rsp . Then the distance depends entirely on the two relative timing offsets, namely,

[0301]

[0302] For RTT-based SL ranging and positioning methods, for each RTT, the responding UE needs to send t2 and t3 or a direct quantization of the Rx-Tx timing difference (t3-t2) to the requesting UE. By decoupling the Rx-Tx timing difference, the responding UE can alternately send the number of OFDM symbols N to the ranging / positioning requesting UE. sym,rsp and the relative timing offset τ 0,rsp If we assume that N sym,req =N sym,rsp , then the responding UE can only shift the timing by τ 0,rsp The two SL Pos-RS transmissions may be located on different bandwidth parts (BWP) and have different SCSs. In this case, the responding UE and the requesting UE can use different reference SCSs to calculate the number of OFDM symbols. Since the SCS is specified as 15*2 μkHz, so the number of symbols can be converted to the number with the same reference SCS, for example, the SCS with μ = 0, for example to convert it to the number of OFDM symbols for 15kHz SCS.

[0303] Coded timing measurement reports for SL ranging and positioning.

[0304] Phase encoding.

[0305] In addition to sending τ 0,rsp , the responding UE can also encode the timing offset information in the SL Pos-RS signal without additional transmission. Assuming that the SL Pos-RS in the OFDM symbol is s k , where k∈S Pos-RS is the subcarrier index. The UE does not send s k , but instead send:

[0306]

[0307] Assume that the LOS channel has a first path delay τ 0,req ,

[0308] In the time domain OFDM signal carries s′ rsp,k In the case of , the received signal at the requesting UE is:

[0309]

[0310] The first path now has an effective delay component τ 0,rsp +τ 0,req The requesting UE can now measure τ without the need for information exchange 0,rsp +τ 0,req .

[0311] Sequence / cover code encoding.

[0312] Instead of encoding the timing offset on the phase, a sequence can be used to encode the timing offset. Given a timing offset τ 0,rsp The specified quantization granularity of the present invention has a maximum number of bits, for example, B bits. The maximum value is 2 B . You can specify a length of M for 2 B A sequence, denoted as a i =[a i,1 ,…,a i,M ],i=1,…,2 B Then, for each τ 0,rsp , there is a mapping a i . The transmitted symbol is then encoded as:

[0313] s′ rsp,k =s rsp,k a i,k .

[0314] The received signal in the frequency domain of the requesting UE is given by:

[0315]

[0316] For the received signal The receiver can perform joint sequence detection and channel estimation to estimate a i and τ 1,req or a i and τ 1,req By estimating a i , the requesting UE or target UE then obtains τ 0,rsp information.

[0317] It can be seen that a i The design is related to the length (i.e., size) of the positioning signal, which can be variable. A code sequence set can be specified to cover every change in the positioning signal reference. It is also possible to specify a sequence set with fewer choices and use it in M <M Pos-RS When applied, M Pos-RS is the size of the SL Pos-RS in an OFDM symbol. Leaving some SL Pos-RS REs unmasked will reduce the complexity and / or improve the performance of channel / delay estimation and sequence detection at the receiving UE.

[0318] Signal selection for SL ranging and positioning based on RTT

[0319] As mentioned above, SL Pos-RS is used to represent the general positioning reference signal. Potential configurations of these reference signals and RTT-based SL ranging and positioning are discussed.

[0320] S-SSB and SL CSI-RS.

[0321] S-SSB and SL CSI-RS can be used as SL Pos-RS. For timing-based techniques, such as RTT-based SL ranging and positioning, the small bandwidth of S-SSB or the sparsity of CSI-RS have a greater impact on ranging and positioning accuracy. However, the two reference signals can still be used to provide some rough estimate of ranging distance and position.

[0322] In one embodiment, the requesting UE sends a request to the responding UE, which indicates a request for S-SSB-based RTT ranging. In this embodiment, S-SSB transmissions from either side (requesting and responding UEs) are used for ranging purposes. The responding UE will measure the time interval between the last S-SSB received from the requesting UE and its own S-SSB transmission. This measurement will be provided to the requesting UE for distance estimation purposes. The requesting UE will measure the time difference between the S-SSB sent by itself and the subsequent S-SSB received from the responding UE, which is used together with the measurement from the responding UE to estimate the distance (range) between the two devices. In this embodiment, the requesting UE can indicate to the responding UE the number of times to request the responding UE to send the measurement.

[0323] In different embodiments, similar operations may be defined by using a CSI-RS from a requesting UE and a CSI-RS from a responding UE, or a combination of an S-SSB from a request and a CSI-RS from a response, or vice versa, etc.

[0324] SL Pos-RS positioning based on UL SRS (SL PRS or SL SRS).

[0325] Since S-SSB has a smaller bandwidth and CSI-RS has a lower density, they may not be suitable as SL Pos-RS for positioning with higher accuracy requirements. A new SL Pos-RS is needed. In Rel-16, UL SRS is extended with more signals for positioning purposes. Since UL SRS is designed for UE transmission, UL SRS can be used for RTT-based SL ranging and positioning, which is one of the SL Pos-RS.

[0326] As described herein, the following may be configured on the UL SRS for positioning.

[0327] Comb size K TC : 2, 4, 8

[0328] Number of UL SRS OFDM symbols

[0329] By offset l offse Define the starting OFDM symbol

[0330] Frequency Domain Offset

[0331] SRS Sequence ID

[0332] Time Domain Period and Offset

[0333] SRS bandwidth (BW) or number of PRBs

[0334] The SRS as SL Pos-RS can be configured by one of the following alternative methods.

[0335] - The SRS configuration is provided in the request message.

[0336] - Various (pre-)configurations of SRS for SL ranging and / or positioning, e.g. in SL-SRS-PosResourceSet or multiple SL-

[0337] In SRS-PosResourceSets, when SL ranging is requested or SL positioning is triggered, the (pre-)configured SL SRS for positioning is sent.

[0338] As an alternative to pre-configuration, the configuration may be set using PC5 RRC signaling or indicated in a request message.

[0339] Since the BW of the reference signal is important for timing estimation, and therefore, for positioning accuracy in RTT-based ranging and positioning, the configuration of the SRS BW or the number of PRBs for SRS as SL Pos-RS is important. The number of subchannels for SL SRS transmission can be (pre)configured. For SL positioning, the number of subchannels used for SRS can be specified within a lower limit of the minimum number of subchannels (or minimum number of PRBs) and an upper limit of the maximum number of subchannels (or maximum number of PRBs). The upper limit can be the total number of subchannels or PRBs in the SL resource pool. The anchor UE needs to reserve resources for transmitting the SL PRS. For efficient transmission, the configuration of the BW / PRB number for SL PRS can be within a range or can be the minimum number of subchannels (or minimum number of PRBs). The responding UE or the anchor UE can decide the actual number of subchannels used for SL PRS transmission.

[0340] PSFCH signaling

[0341] In RTT-based ranging and positioning, in response to the SL Pos-RS transmitted from the ranging request UE or the target UE within a certain time interval, the responding UE or the anchor UE needs to send the SL Pos-RS, for example, the SL PRS. Alternatively, the responding UE or the anchor UE may send the SL Pos-RS using the PSFCH sequence and transmit it in the PSFCH channel resources instead of sending the SL-PRS.

[0342] like Fig.14As shown, for PSFCH, there is a time slot gap based on the PSSCH to PSFCH timing specified in TS38.213 to determine the PSFCH time opportunity. Since the SL PRS is sent in the PSSCH, the PSSCH to PSFCH timing can be used to determine the time slot opportunity of the response signal. The PSFCH sequence on the PSFCH channel is then used as the SL Pos-RS.

[0343] But, also Fig.14 and Fig.15 As shown in (A), the PSFCH used for HARQ-ACK and conflicting reports in Rel-17 occupies one PRB in the PRB set used for HARQ-ACK or conflicting reports in IUC, which is far from the bandwidth required for timing measurement.

[0344] The present invention provides a solution to increase the bandwidth of PSFCH signaling on PSFCH symbols in a resource pool. For the subchannel of the initial SL PRS transmission, there are multiple PRB sets, which form a PSFCH PRB pool, also as Fig.14 and Fig.15 (A) is shown. The PSFCH PRB pool is expanded in the code domain by different cyclic shifts of the PSFCH sequence. For PSFCH HARQ-ACK, a PSFCH PRB is selected, where the PSFCH index is derived based on the configuration, as shown in Fig.15 (A) As shown. For RTT-based SL ranging and positioning, Fig.15 As shown in (B), instead of using one PSFCH PRB, other PSFCHs in the same PRB set can also be used as SL Pos-RS.

[0345] If there is data, the mapped PSFCH HARQ-ACK can be excluded. Or alternatively, the PSFCH HARQ-ACK can also be reused for positioning / ranging purposes after being decoded. Alternatively, in order to avoid collision between PSFCH HARQ-ACK and PSFCH used for SL ranging / positioning, a cyclic shift (which is different on PSFCH HARQ-ACK in the code domain) can be used, i.e., parameter m0 specified in TS38.213. For example, in Fig.15 In (B), if PRB 7 is used for HARQ-ACK, instead of using PSFCH channels 0 to 9 for SL Pos-RS, PSFCH channels 10 to 19 are used for PSFCH as SL Pos-RS.

[0346] In addition, the PRB set not configured for HARQ-ACK can be used as SL Pos-RS resources. Fig.16As shown, an additional PRB set {1, 3, 6, 11, 12} is used to respond to SL Pos-RS in RTT-based ranging and positioning.

[0347] In PSFCH HARQ-ACK, the ACK or NACK status is based on the additional cyclic shift parameter m CS , that is, ACK m CS = 0, NACK m CS =1. As SL Pos-RS, if these two states can share resources on the same time slot, these two states can be used to configure two response signals for different initial SL Pos-RS transmissions. Or alternatively, for simplicity, m CS The setting can be fixed, for example, m CS =0.

[0348] Since the UE has a maximum transmit power, power may be the limiting factor for the number of PSFCH PRBs configured for positioning reference signals. Using multiple RBs reduces the transmit power per resource element (RE). Therefore, the configuration of the number of PSFCH PRBs should consider the balance between the transmit power per RE and the positioning accuracy. This issue is not limited to PSFCH as SL Pos-RS. It generally applies to any SL Pos-RS in an OFDM symbol where PRBs can be configured.

[0349] Sidelink positioning based on multi-RTT.

[0350] Indication and availability of anchor UE for multi-RTT positioning.

[0351] The anchor UE acts as a reference UE with a known position. A UE that supports sidelink positioning and can act as an anchor UE for positioning functions may be an anchor UE. As described below, the target UE may request positioning reference signaling, location information, or measurements from the anchor UE. In one embodiment, the anchor UE (or positioning reference UE) indicates to another UE that it may be an anchor UE.

[0352] If a UE is capable of acting as an anchor UE, the UE may not always wish to act as an anchor UE. The UE may also not meet certain conditions for becoming an anchor UE. Therefore, an indication of an anchor UE is proposed, that is, the UE can indicate through periodic, semi-static or dynamic signaling that it can be an anchor UE for sidelink positioning. In order to obtain better positioning accuracy, the target UE is preferably able to synchronize with each anchor UE. However, this is not necessary for some positioning methods such as multi-RTT. SL synchronization can be achieved through S-SSB. Since the S-SSB is sent periodically, the anchor UE can indicate its availability for positioning as an anchor UE through a reserved bit in the PSBCH transmitted in the S-SSB. The PSBCH carries the SL master information block (SL-MIB), for example, a reserved bit in the PSBCH in the S-SSB indicates whether the UE can act as an anchor UE. Alternatively, in order to achieve a more dynamic indication, the UE can use the reserved bit in SCI format 1-A. The indication can also be provided through RRC signaling.

[0353] The anchor indication can be enabled / disabled by (pre) configuration, which is mainly used for dynamic indication, for example, using reserved bits in SL-MIB or PSCCH SCI-1A. It should be noted that this indication is a supplement to the signal exchange of UE capabilities.

[0354] The anchor point availability indication and support for a specific positioning method can be indicated in a variety of ways. For example, the anchor point indication can be used for all supported SL positioning technologies. Alternatively, it can be specified as a subset of positioning technologies, such as timing-based and / or angle-based technologies. In E-SID positioning based on signal strength (e.g., RSRP) measurements, dynamic indication may not be required. Capability signaling interaction of UE characteristics between the target UE and the anchor UE can be used for the above signaling. RTT-based ranging or multi-RTT-based positioning requires more signaling interactions, such as Rx-Tx time difference measurement. RTT-based capabilities are different from timing-based technologies. The indication can be different. The indication may be different for different positioning technologies. If there are separate indications, more bits need to be specified. Examples of these indications may be bitmaps, entries in a table indicating each combination, and the like.

[0355] An alternative is to use the reserved bits in the SL-MIB as a general indication that the UE can be an anchor UE. The request from the target UE can be a specific request for a specific positioning technology or a general request for positioning. Depending on the request, the potential anchor UE can send a response message or an affirmative acknowledgement, where it can be an anchor UE for a specific positioning technology requested by the UE (e.g., multi-RTT-based SL positioning), or in the case where the target UE sends a general request for positioning, it is an indication of the list of positioning technologies it supports. The response message from the responding UE can be sent in a second-level SCI (SCI format 2-x) or MAC-CE. For a simple response, the responding UE can send an acknowledgment via the PSFCH. The PSFCH timing for the affirmative acknowledgement can be on the same timeslot as the timing for the PSFCH HARQ-ACK, i.e., the same PSSCH-PSFCH mapping of the PSSCH used to send the request. The PSFCH PRB or cyclic shift can be different from the PSFCH HARQ-ACK.

[0356] In one embodiment, the anchor UE announces its availability to one or more positioning procedures / techniques by responding to the positioning RS request through RRC exchange, MAC CE, HARQ on PSFCH, or exchange of UE characteristics. Optionally, the anchor UE may also broadcast its absolute position. Such an anchor UE expects to broadcast its S-SSB. When in partial coverage, the anchor UE may also indicate the synchronization source used for its position estimate, such as GNSS or gNB.

[0357] In one embodiment, a UE in SL discontinuous reception (DRX) mode may announce its availability in the time domain, such as the SL DRX activation time (e.g., in a system information block (SIB)), so that the target UE may decide whether the UE can become its anchor UE given its availability. The SL DRX activation time of the candidate anchor UE may also be sent in a response message to the target UE requesting SL positioning or multi-RTT based positioning.

[0358] Multi-RTT SL positioning process and Pos-RS transmission.

[0359] RTT-based SL ranging can be extended to multi-RTT SL positioning.

[0360] like Fig.17 As shown, first, the target UE discovers candidate anchor UEs that can be used for positioning or multi-RTT SL positioning based on the UE's indication or the positioning capability of the candidate anchor UEs. The target UE selects a group of candidate anchor UEs.

[0361] In one embodiment, the selection of anchor devices is based on their synchronization source, their received signal strength, their support for anchor features, location area, mobility (Doppler shift), etc. In one embodiment, the target UE sends a positioning request, or specifically, a multi-RTT SL positioning request, to each UE in the group and waits for a response message or an acknowledgement message from each UE. Alternatively, the target UE multicasts the request to the group or broadcasts the request. If the target UE broadcasts the request, the target UE does not need to first select a set of candidate anchor UEs.

[0362] The target UE selects the group of anchor UEs for multi-RTT SL positioning based on the response message from the candidate anchor UE. Before the SL Pos-RS transmission from each UE, another round of information exchange may be completed, for example, the SL Pos-RS configuration of each anchor UE from the requesting UE. For Rx-Tx measurement, one round of SL Pos-RS may be sufficient. The SL Pos-RS transmission can be initiated from the target UE or the anchor UE based on the configuration. This configuration can be in the request message, the response message or the (pre) configuration of the resource pool. Multiple SL Pos-RS transmissions (periodic or aperiodic) from either side within the (pre) configured duration can be specified. For multiple SL Pos-RS transmissions, the Rx-Tx measurement report needs to include Rx and Tx SL Pos-RS information, for example, Rx and Tx SL Pos-RS time slots or Rx and Tx SL Pos-RS OFDM symbols.

[0363] The RTT process of SL Pos-RS transmission and obtaining Rx-Tx measurement report can be performed sequentially between the target UE and each anchor UE (one anchor UE to another anchor UE). The request and response for each RTT estimation can be based on unicast. Then, in order to obtain better positioning accuracy, the RTT process of each pair is subject to the specified maximum delay. However, for medium or high mobility, the RTT process can be performed in parallel, that is, the target UE sends SL Pos-RS to each anchor UE without completing the RTT process or Rx-Tx measurement for the anchor UE, and the anchor UE can also send a response SL Pos-RS before or after receiving the SL Pos-RS from the target UE. Then, the anchor UE sends an Rx-Tx measurement report to the target UE. The request and response for each RTT between the target UE and the anchor UE can still be based on unicast. However, alternatively, the target UE can multicast or broadcast the SL Pos-RS to the anchor UE, and allocate resources to all anchor UEs once for one SL Pos-RS transmission. This may be more efficient for multiple SL Pos-RS transmissions within a certain duration.

[0364] The efficient encoding of relative timing offsets (i.e., fractional timing of the OFDM symbol duration) described in this article can also be applied to multi-RTT SL positioning to achieve efficient Rx-Tx measurement reporting. For efficient encoding, if positioning (position estimation) is performed at the target UE, the target UE should first start the SL Pos-RS transmission. If positioning is performed at the anchor UE (referred to as the serving anchor UE), the anchor UE should first send the SL Pos-RS. Also in this case, the target UE needs to send the SLPos-RS separately to the serving anchor UE, where each transmission is encoded with the timing offset from one anchor UE.

[0365] The PSFCH as a response to SL Pos-RS described in this paper can be applied to multi-RTT SL positioning. Using PSFCH as SL Pos-RS ensures the timing gap between Rx SL Pos-RS and SL PSFCH transmission. Therefore, the number of OFDM symbol durations N is known to the PSFCH receiver sym,rsp Since the PSFCH sequence is known to the PSFCH receiver, the timing offset τ can also be calculated. 0,rsp For efficient encoding. 0,rsp , efficient coding is performed, so no additional resources are required for Rx-Tx measurement reporting at each anchor UE.

[0366] Instead of SL PRS as SL Pos-RS, the target UE and anchor UE rely on S-SSB for multi-RTTSL positioning instead. The target UE requests the anchor UE to send its UE Rx-Tx timing with respect to S-SSB. Upon request, the anchor UE provides UE Rx-Tx measurements to the target UE. The target UE also relies on S-SSB from the anchor UE to obtain Rx-Tx measurements. Using the Rx-Tx measurement report from the anchor UE, the target calculates its position.

[0367] Instead of one type of SL Pos-RS, Rx-Tx measurements may be obtained based on a combination of other SL signals (eg, S-SSB and CSI-RS, or CSI-RS and SL PRS, etc.).

[0368] Multi-target ranging in the sidelink.

[0369] Multi-target ranging can be achieved by multiple single-target ranging as described separately in this article. However, it is more efficient to apply these procedures (specifically SL Pos-RS (request and response) transmission designed for multi-RTT SL positioning). The main difference is that the location information of the anchor UE (now the ranging remote UE) is not required at the ranging requesting UE.

[0370] Broadcast type in multi-RTT SL positioning.

[0371] For the broadcast type of the requested transmission from the requesting UE, one or more of the following alternatives are supported.

[0372] Unicast: The target UE sends a request to each anchor UE independently.

[0373] - Multicast: After the anchor UE is selected, a group of anchor UEs is formed by the upper layer. The target UE multicasts the request to the group of anchor UEs.

[0374] - Broadcast: The UE may broadcast its request. A UE that supports SL positioning, or specifically, multi-RTT based SL positioning, and that meets certain (pre-)configured constraints / conditions (location area, RSRP, requirements for its synchronization source / location information) may respond to the target UE.

[0375] For response messages or positive acknowledgements, unicast is supported.

[0376] For SL Pos-RS transmission from either side, unicast is supported. In addition, if SL PRS is used, the Pos-RS sent by the target UE to the anchor UE can be multicast or broadcast.

[0377] For Rx-Tx measurement reports from anchor UE to target UE, unicast is used due to different Rx-Tx timing. In some scenarios, such as a roadside unit (RSU) acting as an anchor UE, broadcast is also useful, so broadcast is preferred when the interaction between the anchor UE and the target UE on other information is limited. The location information of the anchor UE can also be broadcast to each UE by multiplexing with the SL PRS transmission or in a separate transmission. Through multicast or broadcast of the SL Pos-RS from the target UE, each anchor UE can send Rx-Tx measurements to the target UE on one received SL Pos-RS (e.g., the most recent one from the target UE), and the SL Pos-RS references one of the transmitted Pos-RS (e.g., the most recent one). For multiple target UEs within the coverage area, the anchor UE needs to send Rx-Tx measurement reports to each target UE via unicast.

[0378] In the sidelink, no SIB message is used to convey the location information of the UE. For SL positioning, the location information of the anchor UE needs to be shared with the target UE. The location information can be sent to the target UE via unicast, multicast or broadcast. If the broadcast type of the two transmissions is the same, it can be multiplexed with the SL Pos-RS sent to the target UE.

[0379] SL resource allocation.

[0380] During the SL positioning process, various transmissions require allocation of resources, such as:

[0381] - Transmission of positioning request

[0382] - Transmission of SL Pos-RS (SL PRS, SL CSI-RS)

[0383] - Transmission of Rx-Tx measurement reports

[0384] - Transmission of anchor UE location information

[0385] Typically, each Tx UE may select resources for its own transmission based on (pre-)configured transmission settings (eg, periodicity, etc.) The Rx-Tx measurement reports or location information may be multiplexed with the SL Pos-RS transmission.

[0386] Resources may be reserved for periodic SL Pos-RS transmissions. A special indication may be specified on the resources reserved for SL Pos-RS transmissions via a reserved bit in SCI 1-A or the second level SCI.

[0387] To avoid conflicts, the target UE may send a preferred resource set for each anchor UE to transmit the SL Pos-RS or the location information of the anchor UE. The priorities of the SL Pos-RS and the location information may be (pre)configured. The priority of the location information may be associated with or determined based on its synchronization source.

[0388] For multi-RTT, the maximum timing interval between Rx and Tx is specified. The timing gap can be used as a PDB to reserve the Tx transmission after the most recent Rx from the other end of the SL Pos-RS. For multiple or periodic SL Pos-RS transmissions, the interval between two transmissions is also limited by the maximum timing interval.

[0389] In multi-RTT based sidelink positioning, due to the SL Pos-RS transmission from both sides (anchor UE and target UE), it may be more efficient if some anchor UEs can group their SL Pos-RS (e.g. SL PRS / SRS) and transmit them in the same resource on the same time slot. For example, based on the SL PRS configuration, the serving anchor UE or the target UE sends a request so that the anchor UE can send SL Pos-RS synchronized in one or several time slots.

[0390] Fig.18 Two UL SRS transmissions (as SL PRS) on the same time slot in the sidelink are shown: (A) interleaved (eg, overlapping pattern) SRS (in the time slot The comb size K on the OFDM symbol TC=4); (B) Disjoint SRS in the time domain (eg, independent regions) (comb size K TC =4, each in the time slot OFDM symbols). SLPRS can also achieve similar mapping.

[0391] like Fig.18 As shown, two configured SRS are transmitted in one reserved resource block (i.e., in shared resources). In this case, one of the anchor UEs may send a PSCCH indicating the reserved resources. The configuration of such grouped SRS is known to the target UE (e.g., requested by the target UE) or is notified to the target UE via a second SCI or MAC-CE multiplexed in the SL PRS transmission. To mitigate interference on SRS from different UEs, the grouping may be based on the approximate distance of the anchor UE from the target UE, e.g., via RSRP measurements from S-SSB transmissions. As shown Fig.18 As shown in (B), another solution is to configure different offsets for each SRS so that there are one or more guard symbols between two SRSs in the time domain. In this case, the number of OFDM symbols for each SRS is 4 or less.

[0392] Resource allocation for positioning in unlicensed spectrum.

[0393] In unlicensed spectrum, in order to access the channel, a clear channel assessment (CCA) based on listen before talk (LBT) is required before transmission. However, an exception is short control signaling transmission, which the UE uses to send management and control frames without sensing the presence of other signals on the channel. If the SL Pos-RS is short enough, that is, the number of OFDM symbols used for the SL PRS is less than the threshold, it can be regarded as a short control signaling transmission. By treating the SL Pos-RS as short control signaling, LBT-based CCA can be avoided.

[0394] The restrictions on short control signaling transmissions are: (1) the number of short control signaling transmissions shall be equal to or less than 50 within a 50ms observation period; (2) the total duration of short control signaling transmissions within the observation period shall be less than 2500ms. For some scenarios, such as RTT-based SL ranging (with few SL PRS transmissions) or SL positioning (with few high-quality anchors) (good LOS channel quality, high-level synchronization source, etc.), the restrictions may not be a problem because it does not require many or long SLPos-RS transmissions.

[0395] Fig.19A network 100 for transmitting data is shown. The network 100 includes a base station 110 having a coverage area 101, a plurality of mobile devices 120, and a backhaul network 130. As shown, the base station 110 establishes an uplink (dashed line) connection and / or a downlink (dotted line) connection with the mobile device 120, which is used to carry data from the mobile device 120 to the base station 110, and vice versa. The data carried by the uplink connection / downlink connection may include data transmitted between the mobile devices 120, and data transmitted with a remote terminal (not shown) through the backhaul network 130. As used herein, the term "base station" refers to any component (or collection of components) for providing wireless access to a network, such as a gNB, a macro cell, a micro cell, a Wi-Fi access point (access point, AP) or other wireless enabling device. The base station can provide wireless access according to one or more wireless communication protocols, such as long term evolution (long term evolution, LTE), advanced LTE (LTE advanced, LTE-A), high speed packet access (high speed packet access, HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. As used herein, the term "mobile device" refers to any component (or collection of components) capable of establishing a wireless connection with a base station, such as user equipment (UE), mobile station (STA), and other wireless-enabled devices. In some embodiments, the network 100 may include various other wireless devices, such as repeaters, low-power nodes, etc.

[0396] Embodiments of the present invention may be implemented as computer-implemented methods. These embodiments may be executed by a processing system. Fig. 20 1 is a block diagram of an embodiment processing system 2000 for executing the methods described herein, which can be installed in a host device. As shown in the figure, the processing system 2000 includes a processor 2004, a memory 2006, and interfaces 2010-2014, which may (or may not) be as described in the embodiment of the present invention. Fig. 20Arrangement shown. Processor 2004 can be any component or collection of components for performing calculations and / or other processing-related tasks, and memory 2006 can be any component or collection of components for storing programs and / or instructions executed by processor 2004. In one embodiment, memory 2006 includes a non-transitory computer-readable medium. Interfaces 2010, 2012, and 2014 can be any component or collection of components that support communication between processing system 2000 and other devices / components and / or users. For example, one or more of interfaces 2010, 2012, and 2014 can be used to send data, control, or management messages from processor 2004 to applications installed in a host device and / or a remote device. As another example, one or more of interfaces 2010, 2012, and 2014 can be used to support users or user devices (e.g., personal computers (PCs), etc.) to interact / communicate with processing system 2000. Processing system 2000 may include Fig. 20 Additional components not shown, such as long-term storage (e.g., non-volatile memory, etc.).

[0397] In some embodiments, the processing system 2000 is included in a network device that accesses a telecommunication network or otherwise becomes part of a telecommunication network. In one example, the processing system 2000 is located in a network-side device in a wireless or wired telecommunication network, such as a base station, a relay station, a scheduler, a controller, a gateway, a router, an application server, or any other device in a telecommunication network. In other embodiments, the processing system 2000 is located in a user-side device that accesses a wireless or wired telecommunication network, such as a mobile station, a user equipment (UE), a personal computer (PC), a tablet computer, a wearable communication device (e.g., a smart watch, etc.), or any other device for accessing a telecommunication network.

[0398] In some embodiments, one or more of interfaces 2010, 2012, 2014 connects processing system 2000 to a transceiver for sending and receiving signaling over a telecommunications network. Fig.21A block diagram of a transceiver 2100 for sending and receiving signaling through a telecommunications network is shown. The transceiver 2100 can be installed in a host device. As shown, the transceiver 2100 includes a network side interface 2102, a coupler 2104, a transmitter 2106, a receiver 2108, a signal processor 2110, and a device side interface 2112. The network side interface 2102 may include any component or component set for sending or receiving signaling through a wireless or wired telecommunications network. The coupler 2104 may include any component or component set for facilitating bidirectional communication through the network side interface 2102. The transmitter 2106 may include any component or component set (e.g., upconverter, power amplifier, etc.) for converting a baseband signal into a modulated carrier signal suitable for sending through the network side interface 2102. The receiver 2108 may include any component or component set (e.g., downconverter, low noise amplifier, etc.) for converting a carrier signal received through the network side interface 2102 into a baseband signal. The signal processor 2110 may include any component or set of components for converting baseband signals to data signals suitable for communication through the device-side interface 2112 or vice versa. The one or more device-side interfaces 2112 may include any component or set of components for transmitting data signals between the signal processor 2110 and components within a host device (e.g., the processing system 2000, a local area network (LAN) port, etc.).

[0399] The transceiver 2100 can send and receive signaling through any type of communication medium. In some embodiments, the transceiver 2100 sends and receives signaling through a wireless medium. For example, the transceiver 2100 can be a wireless transceiver for communicating according to a wireless telecommunication protocol, such as a cellular protocol (e.g., long-term evolution (long-termevolution, LTE), etc.), a wireless local area network (wireless local area network, WLAN) protocol (e.g., Wi-Fi, etc.), or any other type of wireless protocol (e.g., Bluetooth, near field communication (near field communication, NFC), etc.). In these embodiments, the network side interface 2102 includes one or more antenna / radiation units. For example, the network side interface 2102 may include a single antenna, multiple independent antennas, or a multi-antenna array for multi-layer communication, such as single input multiple output (single input multiple output, SIMO), multiple input single output (multiple input single output, MISO), multiple input multiple output (multiple input multiple output, MIMO), etc. In other embodiments, the transceiver 2100 sends and receives signaling via a wired medium such as twisted pair cable, coaxial cable, optical fiber, etc. A particular processing system and / or transceiver may utilize all of the components shown, or only a subset of these components, and the level of integration may vary from device to device.

[0400] Although the present invention has been described with reference to illustrative embodiments, this description is not intended to be understood in a restrictive sense. Those skilled in the art will appreciate various modifications and combinations of the illustrative embodiments and other embodiments of the present invention after reference to this description. Therefore, the appended claims are intended to cover any such modifications or embodiments.

[0401] More details are provided below.

[0402] In RAN#94e, the SID "Study and Improve NR Positioning" was approved [RP-213588]. The first objectives of the SI are:

[0403] “Study the sidelink positioning scheme from the following aspects: [RAN1, RAN2]

[0404] -Scenario / Requirements

[0405] – Coverage scenarios: within coverage, partially covered, and outside coverage

[0406] – Requirements: Based on the requirements determined in TR38.845 and TS22.261 and TS22.104

[0407] – Use cases: V2X (TR38.845), public safety (TR38.845), commercial (TS22.261), IIOT (TS22.104)

[0408] – Spectrum: ITS, licensing

[0409] - Identify specific target performance requirements to be considered in the evaluation, based on existing 3GPP work and input from industry forums [RAN1]

[0410] - Define evaluation methods to assess SL positioning for use cases and coverage scenarios, reusing existing methods in sidelink communication and positioning as much as possible [RAN1].

[0411] -Study and evaluate the performance and feasibility of potential solutions for SL positioning, considering relative positioning, ranging and absolute positioning: [RAN1,

[0412] RAN2]

[0413] – Evaluate the bandwidth requirements needed to meet the determined accuracy requirements [RAN1]

[0414] – Study positioning methods (e.g. TDOA, RTT, AOA / D, etc.), including the combination of SL positioning measurements with other RAT related positioning measurements (e.g. Uu based measurements) [RAN1]

[0415] – Study the sidelink reference signals for positioning purposes from the physical layer perspective, including signal design, resource allocation, measurement, association procedures, etc., and reuse existing reference signals, procedures, etc. from sidelink communications and from positioning as much as possible [RAN1]

[0416] – Study the positioning architecture and signalling procedures (e.g. configuration, measurement reporting, etc.) to enable sidelink positioning, including UE-based positioning and network-based positioning [RAN2, including coordination and alignment with RAN3 and SA2 as required]

[0417] To be clear: When bandwidth requirements have been determined and research into sidelink communications in unlicensed spectrum has progressed, further work could examine whether the use of unlicensed spectrum could be considered. At RAN#97, a checkpoint will be made to see if there is sufficient information available for this review.”

[0418] The first goal of examining SI SL positioning is to examine potential solutions for SL positioning, considering relative positioning, ranging and absolute positioning. To this end, the design of reference signals for positioning is studied, including signal design, measurement, and association processes, with an emphasis on reusing existing reference signals and processes in sidelink communication and positioning as much as possible.

[0419] Factors affecting positioning accuracy.

[0420] Signal bandwidth and SNR: Channel bandwidth and received SNR determine the positioning accuracy of methods based on time-of-flight / arrival (TOF / TOA) distance measurement. According to the Cramer-Rao lower bound (CRLB) analysis, the variance of TOA measurement in LOS channel is approximately the lower bound:

[0421]

[0422] Where β is the effective signal bandwidth.

[0423]

[0424] SNR is the signal-to-noise ratio, f is the frequency, and S(f) is the Fourier transform of the transmitted signal. The above inequality means that higher signal bandwidth can improve TOA measurement accuracy. Studies on the impact of bandwidth on positioning accuracy can indicate whether SL positioning schemes need to be extended to unlicensed spectrum.

[0425] LOS and NLOS channel propagation.

[0426] If there is a direct path (LOS) between the anchor point and the target node, the larger positioning signal bandwidth supports better resolution of multipath components, which improves the accuracy of finding the first path, thereby reducing the error caused by multipath bias in TOA, RTT and TDOA based methods. However, if such a direct path (LOS) does not exist and the communication between the anchor point and the target node is done by reflection (non-LOS, NLOS), the range between the anchor point and the target node will be overestimated due to the increase in TOF.

[0427] Fig. 22 is a graphical illustration of the effect of angle of arrival (AOA) and angle of departure (AOD) on non-line-of-sight (NLOS) propagation.

[0428] like Fig. 22 As shown, angle of arrival (AOA) and angle of departure (AOD) estimates may also be affected by NLOS propagation, which results in lower accuracy of position estimates.

[0429] Time synchronization.

[0430] When using a positioning method based on TOF or TOA, the receiver can use the timestamp from the transmitter to estimate the TOF and thus the distance between the transmitter and the receiver. However, even when the channel is LOS, if the clocks of the transmitter and receiver are not synchronized, additional errors will be introduced, affecting the ranging and position estimation. In TR38.855, the network synchronization error is defined as the truncated Gaussian distribution of the root mean square (rms) value (T1 nanoseconds (ns)) between the anchor node and the timing reference source assumed to have perfect timing, subject to the maximum timing difference of T2ns, where T2 = 2*T1. In other words, the range of the timing error is [–T2, T2]. The two values ​​of T1 are 0ns (perfect synchronization) and 50ns.

[0431] Some positioning methods (e.g., multi-RTT) are robust in terms of time synchronization, provided that the clock drift is negligible during the period of measuring the difference between the reception time and the transmission time of the positioning signal, while other methods are more sensitive to synchronization errors (e.g., TOA). Therefore, when studying SL positioning schemes, the synchronization error between the target node and the anchor node should be considered.

[0432] Proposal 1: SL positioning research should study the impact of BW size, non-ideal synchronization and NLOS propagation on SL positioning accuracy.

[0433] Location determination method.

[0434] The RAT-dependent positioning methods defined in Rel 16 and Rel 17 [TR38.855, TS 38.305] are based on the exchange of reference signals (RS) between an anchor node (gNB) and a target node (UE). In this context, a target UE is a UE for which positioning (location) needs to be determined, while anchor nodes are those nodes (UE, gNB, RSU) that can be considered as a reference for relative or absolute positioning of the target UE. In addition to RAT-independent methods for positioning such as GNSS, Wi-Fi, Bluetooth, terrestrial beacon systems (TBS) and motion-based sensors, RAT-dependent positioning methods are defined in Rel 16 and Rel 17. The RAT-dependent methods are:

[0435] -NR Enhanced Cell ID method based on NR signal (NR E-CID)

[0436] -Multi-round trip time positioning (multi-RTT based on NR signals)

[0437] -Downlink angle-of-departure (DL-AoD) based on NR signals

[0438] -Downlink time difference of arrival (DL-TDOA) based on NR signals

[0439] -Uplink time difference of arrival (UL-TDOA) based on NR signals;

[0440] -Uplink angle-of-arrival (UL-AoA), including A-AoA and Z-AoA based on NR signals.

[0441] - Also supports mixed positioning using multiple methods from the above positioning method list

[0442] - Measurements supporting the above methods are defined in TS 38.215.

[0443] -Downlink PRS reference signal received power (DL PRS RSRP)

[0444] - Downlink PRS reference signal received path power (DL PRS reference signal received path power, DL PRSRSRPP)

[0445] -Downlink PRS reference signal time difference (DL PRS RSTD)

[0446] -UE Rx-Tx time difference

[0447] For the sidelink positioning scenario, at least one positioning reference signal is provided through the sidelink (PC5), so the SL UE may be required to combine and measure the sidelink PRS and DL PRS, and send the sidelink PRS and UL PRS.

[0448] For sidelink Mode 2 (intended for out-of-coverage scenarios), the reference node (anchor node) may be less reliable than the in-coverage anchor nodes such as the gNB. In these scenarios, it is better to use positioning methods such as multi-RTT, which are more robust for clock synchronization between the anchor node and the target node.

[0449] Observation 1: For sidelink Mode 2 operation, robust positioning methods (e.g., multi-RTT) are preferred.

[0450] Proposal 2: RAN1 should discuss SL UE support for positioning methods and measurements defined in Rel-16 and Rel 17.

[0451] Proposal 3: For position determination, SL UE should support aggregation of DL PRS resources with SL positioning resources.

[0452] In 5G services, a basic requirement for positioning is to support positioning in OOC scenarios when all devices involved in SL positioning are out of the coverage of LMF.

[0453] OOC scenario positioning is part of the SID and is required by the 5G specification as in TS22.104.

[0454] “The 5G system should provide positioning information for UEs out of network coverage, with a positioning accuracy of < [1m] relative to other UEs that are nearby and within network coverage.”

[0455] TS22.261 requires that positioning support data be available to the UE, which enables UE-based positioning and positioning in OOC scenarios.

[0456] “5G systems should be able to make location-related data available to applications or application servers within the 5G network, external to the 5G network or in the user’s device.”

[0457] In the OOC case, it is not clear whether an entity similar to the LMF is still needed, and if so, where it should be located. Obviously, the target UE should support its function of calculating the position estimate. This function and complexity may depend on the scenario covered by the OOC, such as ranging, relative positioning or absolute positioning.

[0458] The SL positioning solution for OOC scenarios should be able to select a positioning method to: configure and enable sidelink reference signal transmission per request or triggered by an event; select an anchor node and enable an RRC connection when necessary; obtain location information or request S-PRS transmission; provide or exchange location information (if requested); configure and enable a set of SL positioning measurements to estimate relative or absolute position.

[0459] Some positioning methods involve an exchange between the target node and the anchor node. For example, in UE-based positioning multi-RTT, the anchor node should provide Rx-Tx measurements to the SL UE target node, which will be combined with the Rx-Tx measurements at the target node to obtain the final position estimate. Another example of data exchange between the target node and the anchor node can be the absolute position coordinates provided by the anchor node to the target node. This exchange can only be performed after an RRC connection is established between the target node and the anchor node, which can enable data encryption and thus privacy.

[0460] Proposal 4: The SL positioning solution should support the necessary configuration and control of OOC SL positioning.

[0461] These requirements for OOC SL positioning schemes can be achieved by two possible approaches. One option is to start from scratch and define new protocols and new signaling to support the necessary SL positioning methods.

[0462] Another option is to build on the existing SL design and extend the existing protocol with the necessary signaling to implement the SL positioning method. The inter UE coordination (IUC) feature defined in Rel17 is a good candidate to be considered and extended to support the SL positioning scheme for OOC scenarios. IUC provides the necessary framework to request and respond to measurement and location information, configure and trigger the necessary signaling, and coordinate the transmission of anchor nodes. In addition, reusing IUC can minimize the specification impact.

[0463] Proposal 5: Consider reusing or extending the IUC framework defined in Rel 17 for OOC SL positioning solutions.

[0464] 4.Rel 17 positioning reference signal.

[0465] The RAT-dependent positioning methods defined in Rel 16 and Rel 17 [TR38.855, TR 38.305] are based on the exchange of reference signals (RS) between the anchor node (gNB) and the target UE. More precisely, the gNB sends the DL positioning RS (DL PRS) signal. The UE sends the UL sounding reference signal (UL PRS) based on the configuration provided by SRS-PosResourceSet, which is different from the SRS used for UL channel estimation based on the configuration given by SRS-ResourceSet.

[0466] 4.1DL PRS.

[0467] The DL PRS signal defined in TS38.211 is a length-31 Gold QPSK sequence, in which the pseudo-random sequence generator is based on the time slot number, DL PRS sequence ID, The PRS sequence ID is initialized with the OFDM symbol index in the time slot to which the sequence is mapped. The PRS sequence ID supports frequency reuse, while the time slot and symbol index supports TOF, TOA, TDOA, and RTT determination.

[0468] In the time domain, the size of the DL PRS source is L PRS ∈{2,4,6,12} symbols, given by the higher-layer parameter dl-PRS-NumSymbols.

[0469] In the frequency domain, the PRS resource has a comb-tooth distribution (i.e., the resource element (RE) spacing in each symbol of the DL-PRS resource), where the comb-tooth size is Given by the higher-layer parameter dl-PRS-CombSizeN-AndReOffset of the downlink PRS resource configured for RTT-based propagation delay compensation, otherwise given by the higher-layer parameter dl-PRS-CombSizeN, so that the combination Is one of {2, 2}, {4, 2}, {6, 2}, {12, 2}, {4, 4}, {12, 4}, {6, 6}, {12, 6} and {12, 12}.

[0470] The comb distribution supports RS signals with wider bandwidth and thus better accuracy for TOA estimation. However, the gaps in frequency produce aliasing in time, which can be compensated by repetition and coherent combination of PRS in time. For example, if two symbols with comb-4 are coherently combined, the result is equivalent to a PRS signal with comb-2.

[0471] The frequency offset from symbol to symbol is chosen so that there is no step pattern. This has the main advantage of improving robustness (e.g., against Doppler shift) when only the first symbol is used for coherent combining. In addition, the comb design and the frequency offset between consecutive symbols increase robustness to broadband fading, as well as orthogonality with respect to other PRS signals from other transmission / reception points (TRPs).

[0472] PRS resources consist of ID, sequence ID {0...4095}, comb size {2, 4, 6, 12} and RE offset of remaining symbols, resource slot offset ( Fig.23 ), resource symbol offset and quasi-colocation (QCL) information definition.

[0473] The DL PRS resource set is configured by NR-DL-PRS-ResourceSet and consists of one or more DL PRS resources, where each resource has an associated spatial transmission filter (transmission direction).

[0474] A PRS resource set [TS 38.214] is characterized by: ID, subcarrier spacing, periodicity (of resource set transmission), resource list, resource repetition factor (number of times each resource is repeated during an instance of a resource set), resource time gap (number of slots between consecutive repetitions of a resource), comb size, resource bandwidth (between 24 PRBs and 272 PRBs in increments of 4 PRBs), PRB index start, number of resource symbols in a PRS slot. A PRS resource set can be located anywhere in the frequency grid by the PRB index start, which is an offset relative to the reference frequency point A.

[0475] The PRS resource set is sent by the gNB with a period of time slots.

[0476] The PRS resource repetition factor defines the number of times each DL-PRS resource is repeated for a single instance of the DL-PRS resource set. It can take values All DL PRS resources in a resource set have the same resource repetition factor.

[0477] In order to reduce the interference of weak PRS signals, strong PRS signals can be muted. The muting mode is specified by a bit string of {2, 4, 8, 16, 32} bits in each cell, where one bit indicates whether the PRS transmission in the corresponding time slot is muted.

[0478] A UE in RRC connected state only needs to measure DLPRS on the active bandwidth part (BWP) with the same parameter set as the active BWP. The UE can request the serving gNB to measure gaps, which can be used to measure DL PRS outside the active BWP and with a different parameter set.

[0479] For 15kHz SCS, the minimum DL PRS is about 5MHz and the maximum is about 50MHz. For 120kHz SCS, the minimum DL PRS bandwidth is about 34 mega Hertz (MHz) and the maximum bandwidth is about 400MHz.

[0480] 4.2UL PRS.

[0481] UL positioning RS (UL PRS) is based on sounding RS (SRS) and is called positioning SRS. The UL PRS sequence is 31 bits Zadoff-Chu, providing a good peak-to-average ratio. UL PRS can span {1, 2, 4, 8, 12} consecutive OFDM symbols in time, which can be located anywhere in the time slot. Similar to DL PRS, UL PRS has a comb-N pattern in frequency with comb sizes of {2, 4, 8}. Similar to UL PRS, DL PRS also has a comb offset that defines the relative frequency offset between consecutive OFDM symbols. The offset provides similar advantages to DL PRS, namely that only the first few symbols are considered for TOA measurement through coherent combining. Similar to DL PRS, UL PRS can be sent periodically with a certain period and time slot offset. However, the semi-static configuration is activated and deactivated through MAC-CE signaling. Aperiodic UL PRS is only sent when the gNB instructs the UE through downlink control information (DCI). ULPRS supports spatial relationships, where the spatial relationship can be a DL reference signal (SSB, CSI-RS or DL-PRS) or a previously transmitted SRS or UL-PRS. UL PRS can also have a spatial relationship with an adjacent TRP.

[0482] Another attribute of UL PRS is power transmission control, where the UE estimates the UL path loss of the serving and neighboring TRPs based on DL measurements and sets the UL PRS power accordingly.

[0483] The UL PRS resource set consists of one or more UL PRS resources and is defined by the resource set ID, resource type (non-periodic, semi-persistent, periodic), value α representing fractional power control, expected received power p0 at TRP, path loss reference RS and UL PRS resource list.

[0484] The UL resources are described by an ID, transmission comb, resource mapping (symbol position in the UL PRS time slot), frequency domain offset, bandwidth indication (as part of frequency hopping, for SRS case, frequency hopping is not used for frequency hopping indication), resource type (periodic, semi-static, non-periodic) and corresponding period, sequence ID for initializing pseudo-random group and sequence hopping, and spatial relationship information.

[0485] Similar to DL PRS, a UE may be configured with multiple UL PRS resource sets.

[0486] Fig.24 is a diagram of UL PRS resource configuration.

[0487] 5. Reference signal for sidelink positioning.

[0488] 5.1.S-SSB

[0489] Fig.25 is a diagram of S-SSB. The sidelink synchronization signal block (S-SSB) is a broadcast signal for synchronization purposes defined in TS 38.211, consisting of a sidelink primary synchronization signal (S-PSS), a sidelink secondary synchronization signal (S-SSS) and a physical sidelink broadcast channel (PSBCH). There are 672 unique physical layer sidelink synchronization identifiers, which are divided into two sets {0, 1...335} and {336...671}. The sidelink synchronization signal ID (SLSSID) indicates the source of the time reference (GNSS, gNB or another SL UE (SyncRef UE)), and therefore gives accuracy information of the time reference. Before starting to send the S-SSB, the SL UE must select its own time reference and announce it via the SLSSID.

[0490] In the frequency domain, S-SSB occupies 11 physical resource blocks (PRBs), that is, 132 subcarriers, of which S-PSS and S-SSS each occupy 127 subcarriers and are repeated twice during the S-SSB time slot. PSBCH occupies 132 subcarriers for a duration of eight symbols ( Figure 5 ). The first PSBCH symbol is used for automatic gain control (AGC) purposes. Each S-SSB transmission is repeated several times in each 16-subframe period. The frequency position of the S-SSB is fixed.

[0491] S-SSB can be mainly used by a receiver SL UE to acquire synchronization with a transmitter SL device, or by a target SL UE to measure the time difference of arrival (TDOA) between two SyncRef UEs synchronized to the same reference time. Therefore, the target SL UE can estimate the relative position to the SyncRef UE.

[0492] Observation 2: S-SSB can be used to estimate TDOA between anchor SL devices.

[0493] Observation 3: The accuracy of TDOA estimation improves when the S-SSB initiators have the same reference time (SLSSID).

[0494] Observation 4: Using S-SSB for positioning can achieve SL UE positioning in RRC_INACTIVE state.

[0495] Proposal 6: Consider supporting SL position determination based on S-SSB.

[0496] 5.2. Sidelink Positioning Signal (S-PRS).

[0497] One of the themes of this SI is:

[0498] - Study the sidelink reference signals for positioning purposes from the physical layer perspective, including signal design, resource allocation, measurement, association procedures, etc., and reuse existing reference signals, procedures, etc. from sidelink communications and from positioning as much as possible [RAN1]

[0499] In out-of-coverage (OOC) scenarios, the target SL UE must rely on the sidelink (PC5) reference signals received from other SL devices (SL UE, RSU) to determine the range or position. As mentioned above, the signal bandwidth plays a crucial role in the estimation accuracy. The bandwidth of the S-SSB may not be sufficient. In addition, the S-SSB period (160ms) may add additional latency to the position determination. Therefore, it is necessary for RAN1 to define a SL positioning reference signal (S-PRS), which shares some common features of DL and UL PRS, such as

[0500] -Flexible bandwidth size

[0501] - Comb-N distribution in frequency

[0502] - Repetition of frequency offsets in consecutive symbols

[0503] - Different time lengths and cycles of resource sets

[0504] -Aperiodic, semi-static and periodic transmission

[0505] The Zadoff-Chu (ZC) sequence for uplink PRS provides better PAPR characteristics (smaller power variation in time and frequency) than the Gold sequence for DL ​​PRS. We believe that such peak-to-average power ratio (PAPR) characteristics are ideal for SL UEs to avoid nonlinear signal distortion.

[0506] Proposal 7: RAN1 should consider UL PRS design as the starting point for S-PRS design.

[0507] SL UEs at the edge of network coverage may need to participate in SL positioning exchanges with other SLs in partial coverage. Therefore, the serving gNB should be able to control and configure S-PRS UE transmissions within its coverage to minimize interference and maximize capacity.

[0508] Proposal 8: When the SL UE is in coverage or in partial coverage, it is necessary to consider whether the S-PRS configuration is controlled by the gNB.

[0509] 6.SL positioning architecture.

[0510] TS 38.305 defines the functional specifications for UE positioning in NG-RAN. This document defines positioning methods, positioning architecture, signaling protocols and interfaces. Rel 16 and Rel 17 positioning solutions rely on the LTE positioning protocol (LPP) and location management function (LMF). Specifically, LMF is crucial for the orchestration of positioning methods and protocols.

[0511] “For positioning of the target UE, the LMF decides on the positioning method to be used based on factors that may include LCS client type, required QoS, UE positioning capabilities, gNB positioning capabilities, and ng-eNB positioning capabilities. The LMF then invokes these positioning methods in the UE, serving gNB, and / or serving ng-eNB. These positioning methods may produce a position estimate for UE-based positioning methods and / or positioning measurements for UE-assisted and network-based positioning methods. The LMF may combine all received results and determine a single position estimate for the target UE (hybrid positioning).”

[0512] When the SL UE participating in the positioning exchange is within the coverage of the gNB, the existing positioning protocol (LTE positioning protocol) should still be supported. The LMF through the Uu connection and SL relay should be able to coordinate and process measurements for positioning.

[0513] At the same time, the gNB can forward measurements from the SL UE to the LMF to estimate the location of the SL UE in partial coverage.

[0514] Proposal 9: In this study, RAN1 should consider extending LMF to support SL positioning of SL UEs in coverage or partial coverage as a working assumption.

[0515] Proposal 10: RAN1 should send LS to RAN2 and RAN3 to request extension of the existing LMF protocol for covered or partially covered SL UEs.

[0516] 7. Conclusion.

[0517] Proposal 1: SL positioning research should study the impact of BW size, non-ideal synchronization and NLOS propagation on SL positioning accuracy.

[0518] Observation 1: For sidelink Mode 2 operation, robust positioning methods (e.g., multi-RTT) are preferred.

[0519] Proposal 2: RAN1 should discuss SL UE support for positioning methods and measurements defined in Rel-16 and Rel 17.

[0520] Proposal 3: For position determination, SL UE should support aggregation of DL PRS resources with SL positioning resources.

[0521] Proposal 4: The SL positioning solution should support the necessary configuration and control of OOC SL positioning.

[0522] Proposal 5: Consider reusing or extending the IUC framework defined in Rel 17 for OOC SL positioning solutions.

[0523] Observation 2: S-SSB can be used to estimate TDOA between anchor SL devices.

[0524] Observation 3: The accuracy of TDOA estimation improves when the S-SSB initiators have the same reference time (SLSSID).

[0525] Observation 4: Using S-SSB for positioning can achieve SL UE positioning in RRC_INACTIVE state.

[0526] Proposal 6: Consider supporting SL position determination based on S-SSB.

[0527] Proposal 7: RAN1 should consider UL PRS design as the starting point for S-PRS design.

[0528] Proposal 8: When the SL UE is in coverage or in partial coverage, it is necessary to consider whether the S-PRS configuration is controlled by the gNB.

[0529] Proposal 9: In this study, RAN1 should consider extending LMF to support SL positioning of SL UEs in coverage or partial coverage as a working assumption.

[0530] Proposal 10: RAN1 should send LS to RAN2 and RAN3 to request extension of the existing LMF protocol for covered or partially covered SL UEs.

[0531] Fig.26 is a method implemented by a first UE according to an embodiment of the present invention. In box 2602, the first UE sends a first sidelink position reference signal (SL Pos-RS) to a second UE at a first time (t1). In box 2604, the first UE receives a second SL Pos-RS from the second UE at a fourth time (t4). In box 2606, the first UE receives a timing measurement report from the second UE, wherein the timing measurement report includes information about a second time (t2) when the second UE receives the first SL Pos-RS and about a third time (t3) when the second UE sends the second SL Pos-RS to the first UE. In box 2608, the first UE calculates the distance between the first UE and the second UE based on the first time, the fourth time and the timing measurement report.

[0532] Fig. 27 It is a method implemented by the first UE according to an embodiment of the present invention. In box 2702, the first UE sends a first sidelink positioning reference signal (SL Pos-RS) to the second UE at a first time (t1). In box 2704, the first UE receives a PSFCH sequence sent by the second UE on a physical sidelink feedback channel (PSFCH) at a fourth time (t4). In box 2706, the first UE receives a timing measurement report from the second UE, wherein the timing measurement report includes information about the difference between the second time (t2) when the second UE receives the first SL Pos-RS and the third time (t3) when the second UE sends the second SL Pos-RS to the first UE. In box 2708, the first UE calculates the distance between the first UE and the second UE based on the first time, the fourth time and the timing measurement report.

[0533] Fig.28It is a method implemented by a target UE according to an embodiment of the present invention. In box 2802, the target UE selects one or more anchor UEs for positioning. In box 2804, the target UE sends a positioning request to the selected one or more anchor UEs. In box 2806, the target UE receives a positive response from the one or more anchor UEs in response to the positioning request. In box 2808, the target UE sends a first sidelink position reference signal (SL Pos-RS) to the one or more anchor UEs, and the positive response is received from the one or more anchor UEs. In box 2810, the target UE receives a second SL Pos-RS from each of the one or more anchor UEs, and the positive response is received from the one or more anchor UEs. In box 2812, the target UE receives a timing measurement report from each of the one or more anchor UEs, and the positive response is received from the one or more anchor UEs. In box 2814, the target UE calculates the distance between the target UE and the one or more UEs based on the timing measurement report received from the one or more anchor UEs.

[0534] Fig.29 is a method implemented by a target UE according to an embodiment of the present invention. In box 2902, the target UE sends a positioning request to a first anchor UE and a second anchor UE. In box 2904, the target UE receives a positive response from the first anchor UE and the second anchor UE in response to the positioning request. In box 2906, the target UE sends a first sidelink position reference signal (SL Pos-RS) of the target UE to the first anchor UE and the second anchor UE. In box 2908, the target UE receives a second SL Pos-RS of the first anchor UE and a third SL Pos-RS of the second anchor UE in the same time slot. In box 2910, the target UE receives one or more timing measurement reports from the first anchor UE and / or the second anchor UE. In box 2912, the target UE calculates the distance between the target UE and at least one of the first anchor UE or the second anchor UE based on the received timing measurement report.

[0535] The following references may provide additional details:

[0536] [1] RP-213588, Study on expanded and improved NR positioning, RAN#94e, December 2021

[0537] [2] TR 38.845, Study on scenarios and requirements of in-coverage, partial coverage, and out-of-coverage NR positioning use cases (Release 17)

[0538] [3] TS22.261, Service requirements for the 5G system

[0539] [4] TS 22.186, Enhancement of 3GPP support for V2X scenarios; Stage 1 (Release 17)

[0540] [5] TS 22.104, Service requirements for cyber-physical control applications in vertical domains; Stage 1 (Release 18)

[0541] [6] 5GAA, A-200134, “Draft reply to LS to 3GPP RAN on requirements of in-coverage, partial coverage, and out-of-coverage positioning use cases”

[0542] [7] TS 38.855, Study on NR positioning support (Release 16)

[0543] [8] TS 38.211, Physical channels and modulation (Release 17)

[0544] Although the present invention provides several embodiments, it should be understood that the disclosed systems and methods may be embodied in other various specific forms without departing from the spirit or scope of the present invention. The present examples are considered to be illustrative rather than restrictive, and are not intended to be limited to the details given herein. For example, various elements or components may be combined or integrated in another system, or some features may be omitted or not implemented.

[0545] In addition, without departing from the scope of the present invention, the techniques, systems, subsystems and methods described and illustrated as discrete or separate in various embodiments may be combined or integrated with other systems, modules, techniques or methods. Other items shown or discussed as coupled or directly coupled or communicating with each other may also be indirectly coupled or communicated through an interface, device or intermediate component using electrical, mechanical or other means. Other examples of changes, substitutions, and alterations may be determined by those skilled in the art and may be exemplified without departing from the spirit and scope disclosed herein.

Claims

1. A method implemented by a first user equipment (UE), It is characterized in that include: At the first time (t 1 ) sending a first sidelink position reference signal (SL Pos-RS) to the second UE; At the fourth time (t 4 ) receiving a PSFCH sequence sent by the second UE on a physical sidelink feedback channel (PSFCH); receiving a timing measurement report from the second UE, wherein the timing measurement report includes a second time (t 2 ) and a third time (t 3 ) information; A distance between the first UE and the second UE is calculated based on the first time, the fourth time, and the timing measurement report.

2. The method according to claim 1, It is characterized in that The PSFCH sequence includes multiple PSFCHs in a single physical resource block (PRB) set.

3. The method according to claim 1 or 2, It is characterized in that A hybrid automatic repeat request acknowledgement (HARQ-ACK) is excluded from the single PRB set.

4. The method according to claim 1 or 2, It is characterized in that A hybrid automatic repeat request acknowledgement (HARQ-ACK) is included in the single PRB set and is used to calculate the distance.

5. The method according to claim 4, It is characterized in that A cyclic shift is applied to the HARQ-ACK to shift the HARQ-ACK from the PSFCH channel to a different PSFCH channel.

6. The method according to any one of claims 1 to 5, It is characterized in that A set of physical resource blocks (PRBs) not configured for the HARQ-ACK is used in the PSFCH sequence.

7. A method implemented by a first user equipment (UE), It is characterized in that include: At the first time (t 1 ) sending a first sidelink position reference signal (SL Pos-RS) to the second UE; At the fourth time (t 4 ) receiving a second SL Pos-RS from the second UE; receiving a timing measurement report from the second UE, wherein the timing measurement report includes a second time (t 2 ) and a third time (t 3 ) A distance between the first UE and the second UE is calculated based on the first time, the fourth time, and the timing measurement report.

8. The method according to claim 7, It is characterized in that The distance is calculated using the following formula: Among them, D 1,2 represents the distance, and c represents the speed of light.

9. The method according to claim 7 or 8, It is characterized in that The first UE includes a target UE, the second UE includes an anchor UE, and the timing measurement report includes a time value indicating a difference between the third time and the second time.

10. The method according to any one of claims 7 to 9, It is characterized in that The first UE sends one or more first SL Pos-RSs according to a first semi-static configuration, wherein the first semi-static configuration includes a period, a number of first SL Pos-RS transmissions, and parameters for generating the one or more first SL Pos-RSs; The first UE receives one or more second SL Pos-RSs according to a second semi-static configuration, wherein the second semi-static configuration includes a period, a number of second SL Pos-RS transmissions, and parameters for generating the one or more second SL Pos-RSs.

11. The method according to any one of claims 7 to 10, It is characterized in that The timing measurement report includes a value for each of the second time and the third time.

12. The method according to any one of claims 7 to 11, It is characterized in that The timing measurement report comprises a value representing a difference between the second time and the third time, the difference representing a fraction of a subframe or timeslot.

13. The method according to any one of claims 7 to 12, It is characterized in that The first time, the second time, the third time and the fourth time correspond to reference orthogonal frequency-division multiplexing (OFDM) symbols, respectively.

14. The method according to any one of claims 7 to 13, It is characterized in that The timing measurement report includes the number of orthogonal frequency-division multiplexing (OFDM) symbols and a relative timing offset corresponding to the second time and the third time.

15. The method according to any one of claims 7 to 14, It is characterized in that A difference between the second time and the third time is included in the second SL Pos-RS.

16. A method implemented by a target user equipment (UE), It is characterized in that include: Select one or more first anchor UEs for positioning; Sending a positioning request to the one or more first anchor UEs; receiving, in response to the positioning request, a positive acknowledgement from one or more second anchor UEs, the one or more second anchor UEs being at least a portion of the one or more anchor UEs; Sending a first sidelink position reference signal (SL Pos-RS) to the one or more second anchor UEs; receiving a timing measurement report from each of the one or more second anchor UEs; The distance between the target UE and the one or more UEs is calculated based on the timing measurement report received from each of the one or more anchor UEs.

17. The method according to claim 16, It is characterized in that The method further includes discovering one or more available candidate anchor UEs, and selecting the one or more first UEs from the one or more available candidate anchor UEs.

18. The method according to claim 16 or 17, It is characterized in that The one or more first anchor UEs are selected for positioning based on one or more of a synchronization source, a received signal strength, an anchor feature, a location area, or mobility of the one or more anchor UEs.

19. The method according to any one of claims 16 to 18, It is characterized in that Also includes: Before sending the first SL Pos-RS to the one or more second anchor UEs, receiving a second SL Pos-RS from the one or more second anchor UEs.

20. The method according to any one of claims 16 to 18, It is characterized in that Also includes: A second SL Pos-RS is received from the one or more second anchor UEs, wherein the timing measurement report is encoded in or multiplexed with the second SL Pos-RS.

21. A method implemented by a target user equipment (UE), It is characterized in that include: Sending a positioning request to the first anchor UE and the second anchor UE; receiving, in response to the positioning request, a positive acknowledgement from the first anchor UE and the second anchor UE; Sending a first sidelink position reference signal (SL Pos-RS) of the target UE to the first anchor UE and the second anchor UE; receiving a second SL Pos-RS of the first anchor UE and a third SL Pos-RS of the second anchor UE in a time slot; receiving a timing measurement report from at least one of the first anchor UE or the second anchor UE; A distance between the target UE and at least one of the first anchor UE or the second anchor UE is calculated based on the timing measurement report.

22. The method according to claim 21, It is characterized in that The second SL Pos-RS is received in a first portion of the time slot and the third SL Pos-RS is received in a second portion of the time slot, the first portion of the time slot being a first group of symbols and the second portion of the time slot being a second group of symbols separated in time.

23. The method according to claim 21 or 22, It is characterized in that The second SL Pos-RS is separated from the third SL Pos-RS by one or more guard symbols.

24. The method according to any one of claims 21 to 23, It is characterized in that The number of orthogonal frequency-division multiplexing (OFDM) symbols of each of the second SL Pos-RS and the third SL Pos-RS is four.

25. The method according to any one of claims 1 to 24, It is characterized in that The timing measurement report is based on the measured receiver-transmitter (Rx-Tx) time difference, or based on the version 16 or version 17 definition of the gNodeB (gNB) Rx-Tx time difference measurement or the UE Rx-Tx time difference in Uu.

26. The method according to any one of claims 21 to 25, It is characterized in that The comb-based SL Pos-RS transmissions are multiplexed from one or more UEs in a time slot in the sidelink resource pool.

27. The method according to claim 26, It is characterized in that The configuration of the SL Pos-RS includes a single (M, N) value for comb-based multiplexing in a time slot of two or more SL Pos-RSs from two or more UEs, where M is the number of OFDM symbols in the time slot scheduled for the SL-Pos-RSs and N is the comb size.

28. The method according to claim 27, It is characterized in that The comb tooth sizes include 2 and 4.

29. The method according to any one of claims 21 to 28, It is characterized in that The timing positioning measurement report includes measurements, and the measurements include line-of-sight (LOS) paths or all non-line-of-sight (NLOS) paths.

30. The method according to any one of claims 21 to 29, It is characterized in that The configuration of the SL PRS includes: SL PRS resource identifier (identifier, ID), SL PRS comb offset and associated SL-PRS comb size (N), SL PRS start symbol and the number of SL-PRS symbols (M), SL PRS frequency domain allocation.

31. A user equipment (UE), It is characterized in that include: one or more processors; a transmitter coupled to the one or more processors; A receiver coupled to the one or more processors, wherein the one or more processors, the transmitter and the receiver are configured to perform the method according to any one of claims 1 to 30.

32. A non-transitory computer readable medium, It is characterized in that A computer program product for use with a user equipment (UE), the computer program product comprising computer executable instructions stored in the non-transitory computer readable medium, wherein the computer executable instructions, when executed by one or more processors, cause the UE to perform a method according to any one of claims 1 to 30.

33. A target user equipment (UE), It is characterized in that include: A sending component, configured to send a positioning request directly to one or more anchor UEs via sidelink communication; A receiving component, configured to receive positioning data from the anchor UE via the sidelink communication; A calculation component is used to calculate a range or positioning measurement based on the positioning data.

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