New Radio (NR) Positioning Method for In-Coverage Sidelink Positioning

Abstract

Side link positioning can be achieved by a wireless transmit / receive unit (WTRU). The WTRU can be configured to transmit a first message that includes side link positioning information associated with a group of WTRUs. The side link positioning information can include an indication of a side link positioning method for determining the position of the WTRUs within the group of WTRUs. The WTRU can be configured to transmit a second message that includes a request for side link positioning reference signal (SL-PRS) resources for the group of WTRUs. The WTRU can be configured to receive an indication of the allocated SL-PRS resources for the group of WTRUs. The WTRU can be configured to send the indication of the allocated SL-PRS resources to the group of WTRUs.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims priority to U.S. Provisional Patent Application No. 63 / 334,809, filed on April 26, 2022; U.S. Provisional Patent Application No. 63 / 395,406, filed on August 5, 2022; U.S. Provisional Patent Application No. 63 / 421,669, filed on November 2, 2022; and U.S. Provisional Patent Application No. 63 / 445,340, filed on February 14, 2023. U.S. Provisional Patent Application No. 63 / 334,809 is hereby incorporated by reference in its entirety. U.S. Provisional Patent Application No. 63 / 395,406 is hereby incorporated by reference in its entirety. U.S. Provisional Patent Application No. 63 / 421,669 is hereby incorporated by reference in its entirety. U.S. Provisional Patent Application No. 63 / 445,340 is hereby incorporated by reference in its entirety.

Background Art

[0002] Side - link communication enables device - to - device (D2D) communication. Side - link communication can have various applications, such as vehicle - to - everything (V2X) applications. Side - link communication can be used in in - network coverage scenarios and out - of - network coverage scenarios. As telecommunications progress continues, users expect faster response times and lower latency times. To meet these expectations, progress in side - link communication is needed.

Summary of the Invention

[0003] Communications between one or more user equipment (UE) and a network are contemplated herein. The UE may also be referred to as a wireless transmit / receive unit (WTRU). The terms UE and WTRU may be used interchangeably herein. Methods and systems for reducing signaling overhead between network entities (e.g., servers, nodes, next generation node B - gNB, etc.) and a WTRU are described herein. For example, scheduling procedures for performing sidelink positioning by a group of WTRUs (e.g., target WTRUs and anchor WTRUs) to reduce signaling overhead between the gNB and the WTRUs within the group are described herein.

[0004] In various examples that become apparent in the context of the description of this specification, to achieve sidelink positioning, the WTRU may determine whether downlink control information (DCI) is for a sidelink-positioning reference signal (SL-PRS) based on an indication within the DCI. The WTRU may determine whether to transmit data and / or SL-PRS on scheduled sidelink resources. The WTRU may determine a positioning method based on a set of SL-PRSs scheduled by the network. The WTRU may determine whether to request SL-PRS resources for another WTRU. The WTRU may determine values of parameters for SL-PRS transmission / reception resources for a group. The WTRU may use one SL-PRS transmission to multiple anchor WTRUs in a round trip time (RTT) positioning method. The WTRU may determine whether to transmit SL-PRS using unicast or groupcast in the RTT method. The WTRU may determine which WTRU requests / selects sidelink resources for one or more members within a group. The WTRU may determine SL-PRS resources for the RTT positioning method. The WTRU may determine whether to transfer scheduled SL-PRS resources to another WTRU. The WTRU may determine SL-PRS transmission resources for other WTRUs. The WTRU may report positioning group synchronization offset information to the network. The WTRU may indicate a synchronization offset based on the resource allocation mode of two WTRUs. The WTRU may request periodic and / or aperiodic SL-PRS resources. The WTRU may trigger a change in the SL-PRS configuration (e.g., SL-PRS offset and / or periodicity). The WTRU may determine whether to measure a reference signal time difference (RSTD) between two radio access technologies (RATs).The WTRU may determine a reference node for RSTD measurement. The WTRU may request other WTRUs to mute during its measurement gap (MG) and / or positioning processing window (PPW) in user-to-user (Uu) communication. When the WTRU receives an MG / PPW configuration in Uu, it triggers resource reselection and / or preemption. When the WTRU receives an MG and / or PPW in the Uu of a peer WTRU, it triggers resource reselection and / or preemption.

[0005] In various additional examples that will become apparent in the context of the description of this specification, to achieve sidelink positioning, the WTRU may determine the time gap between the first transmission and the retransmission of the SL-PRS. The WTRU may determine which SL-PRS configuration to use. The WTRU may prioritize the resource pool used by the peer WTRU. The WTRU may determine which ID scrambles / generates the SL-PRS sequence. The WTRU may determine when to monitor the SL-PRS resource pool. The WTRU may determine whether the DCI is for SL-PRS or for data transmission based on a radio network temporary identifier (RNTI). The WTRU may determine whether the DCI is for SL-PRS or for data transmission based on a search space set. The WTRU may determine whether the DCI is for SL-PRS or for data based on the indicated code point within a bitfield. The WTRU may schedule group common DCI for SL-PRS. The WTRU may determine whether to forward the scheduled SL-PRS for the member WTRUs within the group. The WTRU may determine whether to transmit the scheduled SL-PRS based on an acknowledgement (ACK) from the member WTRU. The WTRU may transmit sidelink positioning group information to the network.

[0006] In various further examples that will become apparent in the context of the description herein, to achieve sidelink positioning, the WTRU may receive an SL-PRS configuration. The WTRU may determine the location of the physical sidelink control channel / physical sidelink shared channel (PSCCH / PSSCH) for SL-PRS multiplexing. The WTRU may embed sidelink control information (SCI) into the SL-PRS pattern. The WTRU may receive information for sidelink positioning from one node and indicate that information to another node. The WTRU may provide a request for sidelink positioning. The WTRU may indicate to the network an ID / index (identification information / index) associated with sidelink positioning.

[0007] In various other examples that will become apparent in the context of the description herein, to achieve sidelink positioning, the WTRU may determine whether to multiplex the SCI with the SL-PRS. The WTRU may determine the location of the SCI. The WTRU may determine the parameters for SL-PRS transmission. The WTRU may determine a resource pool for the SL-PRS. The WTRU may determine a resource location mode for sidelink positioning. The WTRU may receive scheduled resources for sidelink positioning. The WTRU may determine which WTRU to request resources for sidelink positioning. The WTRU may trigger a resource allocation and / or resource request for sidelink positioning. The WTRU may determine information for indicating and / or reporting SL-PRS resource usage. The WTRU may determine whether to indicate and / or report SL-PRS resource usage. The WTRU may determine a resource for indicating and / or reporting SL-PRS resource usage. The WTRU may determine information to include in an SL-PRS measurement report. The WTRU may determine information for indicating and / or reporting sidelink resource usage in the uplink. The WTRU may receive sidelink positioning resources for a group of WTRUs and forward them to other WTRUs. The WTRU may receive a configuration for sidelink positioning. The WTRU may transmit a configuration for sidelink positioning to other WTRUs. The WTRU may determine the SL-PRS reception resources for each WTRU within the group. The WTRU may determine its SL-PRS transmission resources. The WTRU may determine the SL-PRS measurement report resources from each WTRU within the group. The WTRU may be configured for periodic and / or semi-static resources for sidelink positioning. The behavior of the WTRU may be based on the status of feedback regarding SL-PRS resource usage from other WTRUs. The WTRU may indicate the priority of the sidelink positioning service. The WTRU may report its SL-PRS resources to the network. The WTRU may determine whether to perform SL-PRS resource reception. The WTRU may request an MG and / or a positioning processing window (PPW) for SL-PRS reception.The WTRU may indicate its SL-PRS reception resources to another WTRU. The WTRU may prioritize between SL-PRS reception and other types of sidelink transmission and / or reception.

[0008] An exemplary WTRU may be configured to transmit, via a transceiver, a first message that includes sidelink positioning information associated with a group of WTRUs. The sidelink positioning information may include an indication of a sidelink positioning method for determining the positions of the WTRUs within the group of WTRUs. The WTRU may transmit, via the transceiver, a second message that includes a request for sidelink positioning reference signal (SL-PRS) resources for the group of WTRUs. The WTRU may receive, via the transceiver, an indication of the allocated SL-PRS resources for the group of WTRUs. The WTRU may send, via the transceiver, the indication of the allocated SL-PRS resources to the group of WTRUs. The requested resources may be based on the sidelink positioning method, the number of WTRUs within the group of WTRUs, and / or the quality of service (QoS) associated with the sidelink positioning method. The sidelink positioning information within the first message may include a group identifier (ID) associated with the group of WTRUs. The request for SL-PRS resources within the second message may include the group ID. The sidelink positioning method may include at least one of round trip time (RTT) positioning, sidelink-time difference of arrival (SL-TDOA) positioning, and / or sidelink-angle of departure (SL-AoD) positioning. The WTRU may be one of the WTRUs within the group of WTRUs, and the request for SL-PRS resources may include a request for SL-PRS transmission resources for the WTRU and a request for SL-PRS transmission resources for other WTRUs within the group of WTRUs. The request for SL-PRS may include the number of SL-PRS transmission resources requested for the WTRU. The request for SL-PRS may include the number of SL-PRS transmission resources requested for the remaining WTRUs within the group of WTRUs. The second message may include a medium access control (MAC) control element (CE).The WTRU may be configured to perform sidelink discovery procedures to identify a group of WTRUs. The WTRU may be configured to send a first message and a second message to a node. The node may include at least one of a network node, another WTRU, a roadside unit (RSU), or any suitable combination thereof.

[0009] This specification further discloses at least one computer-readable storage medium storing executable instructions. For example, when executed by a WTRU's processor, the instructions may cause the at least one computer-readable storage medium to transmit a first message including sidelink positioning information associated with a group of WTRUs. The sidelink positioning information may include an indication of a sidelink positioning method for determining the positions of the WTRUs within the group of WTRUs. When executed, the instructions may further cause the processor to transmit a second message including a request for sidelink positioning reference signal (SL-PRS) resources for the group of WTRUs. When executed, the instructions may further cause the processor to receive an indication of the allocated SL-PRS resources for the group of WTRUs. When executed, the instructions may further cause the processor to send the indication of the allocated SL-PRS resources to the group of WTRUs. The requested resources may be based on the sidelink positioning method, the number of WTRUs within the group of WTRUs, and / or the quality of service (QoS) associated with the sidelink positioning method. The sidelink positioning information within the first message may include a group identifier (ID) associated with the group of WTRUs. The request for SL-PRS resources within the second message may include the group ID. The sidelink positioning method may include at least one of round trip time (RTT) positioning, sidelink time difference of arrival (SL-TDOA) positioning, and / or sidelink angle of departure (SL-AoD) positioning. The WTRU may be one of the WTRUs within the group of WTRUs, and the request for SL-PRS resources may include a request for SL-PRS transmission resources for the WTRU and a request for SL-PRS transmission resources for other WTRUs within the group of WTRUs. The request for SL-PRS may include the number of SL-PRS transmission resources requested for the WTRU. The request for SL-PRS may include the number of SL-PRS transmission resources requested for the remaining WTRUs within the group of WTRUs. The second message may include a medium access control (MAC) control element (CE).When executed, the instruction may further cause the processor to perform sidelink discovery procedures to identify a group of WTRUs. When executed, the instruction may further cause the processor to send a first message and a second message to a node. The node may include at least one of a network node, another WTRU, a roadside unit (RSU), or any suitable combination thereof.

[0010] Another example of a WTRU configured to perform sidelink positioning is that the WTRU may receive an indication of resources for performing sidelink positioning for a group of WTRUs. The indication may be based on the resources being able to transmit and receive sidelink positioning reference signals (SL-PRS) and / or perform RTT-based sidelink positioning. The indication may be based on the resources being able to transmit SL-PRS and / or perform SL-PRS transmission-based positioning, receive SL-PRS, and / or perform SL-PRS reception-based positioning. The WTRU may determine at least one anchor WTRU within the group of WTRUs. The WTRU may determine a group identifier for the group of WTRUs. The WTRU may send sidelink positioning group information to a network node. The network node may include a gNB. The WTRU may request resources for performing sidelink positioning for the group of WTRUs. The indication of resources may be received via downlink control information (DCI). Based on the resources being able to receive SL-PRS, the WTRU may send the indication of resources to at least one anchor WTRU. Based on the resources being able to report SL-PRS measurements, the WTRU may send the indication of resources to at least one anchor WTRU. Sending the indication of resources to at least one anchor WTRU may utilize a group identifier for the group of WTRUs. The WTRU may determine at least one anchor WTRU within the group of WTRUs. The WTRU may determine a group identifier for the group of WTRUs. The WTRU may send sidelink positioning group information to a network node. The network node may include a gNB.

[0011] Exemplary computer-readable storage media may store executable instructions. When executed by a processor, the executable instructions may configure the processor to facilitate sidelink positioning. When the executable instructions are executed, the processor may configure a WTRU to receive an indication of resources for performing sidelink positioning for a group of WTRUs. The WTRU may receive the indication based on the resources being capable of transmitting and receiving sidelink positioning reference signals (SL-PRSs). The WTRU may be configured to perform round-trip time (RTT)-based sidelink positioning based on the resources being capable of transmitting SL-PRSs. The WTRU may be configured to perform SL-PRS transmission-based positioning based on the resources being capable of receiving SL-PRSs. The WTRU may be configured to perform SL-PRS reception-based positioning. When the executable instructions are executed, the processor may configure the WTRU to determine at least one anchor WTRU within the group of WTRUs. When the executable instructions are executed, the processor may configure the WTRU to determine a group identifier for the group of WTRUs. When the executable instructions are executed, the processor may configure the WTRU to send sidelink positioning group information to a network node. The network node may include a gNB. When the executable instructions are executed, the processor may configure the WTRU to request resources for performing sidelink positioning for the group of WTRUs. Downlink control information (DCI) transmission may receive an indication of resources. Based on the resources being capable of receiving SL-PRSs, when the executable instructions are executed, the processor may configure the WTRU to send the indication of resources to at least one anchor WTRU. Based on the resources being capable of reporting SL-PRS measurements, when the executable instructions are executed, the processor may configure the WTRU to send the indication of resources to at least one anchor WTRU. Sending the indication of resources to at least one anchor WTRU may utilize a group identifier for the group of WTRUs.

[0012] In an example, each WTRU of a group of WTRUs may be configured with its respective orthogonal cover code (OCC). Each OCC may be based on the respective identifier (ID) of each WTRU within the group of WTRUs. Each OCC may receive a respective sidelink positioning reference signal (SL-PRS) configuration for each resource of a plurality of resources. Each respective SL-PRS configuration may include at least one of a bandwidth associated with each resource, a duration associated with each resource, a number of repetitions associated with each resource, a size of each resource, a multiplexing rule associated with each resource, and / or a respective SL-PRS measurement report configuration for each resource of the plurality of resources.

[0013] Each SL-PRS measurement report configuration may include at least one of a bandwidth associated with each resource, a duration associated with each resource, a number of repetitions associated with each resource, a size of each resource, and / or a multiplexing rule associated with each resource.

[0014] Each SL-PRS measurement report configuration may send an indication of each respective SL-PRS configuration and / or each respective SL-PRS measurement report configuration to each WTRU of a group of WTRUs that utilizes a group ID identifying the group of WTRUs. Each SL-PRS measurement report configuration may receive an indication of a scheduled resource among a plurality of resources for performing sidelink positioning for a group of WTRUs and / or may determine SL-PRS resources and / or SL-PRS measurement report resources for each anchor WTRU within the group of WTRUs. The determination of the SL-PRS resources and / or SL-PRS measurement report resources for each anchor WTRU may be based on at least one of an ID for each anchor WTRU, the number of WTRUs within the group of WTRUs, an OCC for each WTRU within the group of WTRUs, a set of sidelink resources scheduled for the group, and / or a multiplexing rule associated with each resource among the plurality of resources. To perform SL-PRS measurements and / or derive its positioning, a WTRU may calculate a round-trip time (RTT) between each WTRU of the group of WTRUs and each anchor WTRU of the group of WTRUs based on the measured and reported transmission and reception times therebetween. The WTRU may determine a relative positioning of each WTRU of the group of WTRUs based on the calculated RTT. The WTRU may send an indication of the relative positioning to each WTRU of the group of WTRUs.

[0015] Each SL-PRS measurement report configuration may include at least one of the bandwidth associated with each respective resource, the duration associated with each respective resource, the number of repetitions associated with each respective resource, the size of each respective resource, and / or the multiplexing rule associated with each respective resource. Each SL-PRS measurement report configuration may send an indication of each respective SL-PRS configuration and / or each respective SL-PRS measurement report configuration to each WTRU of a group of WTRUs using a group ID that identifies the group of WTRUs. Each SL-PRS measurement report configuration may receive an indication of a scheduled resource among a plurality of resources for performing sidelink positioning for a group of WTRUs and / or determine SL-PRS resources and / or SL-PRS measurement report resources for each anchor WTRU within the group of WTRUs. The determination of the SL-PRS resources and / or SL-PRS measurement report resources for each anchor WTRU may be based on at least one of the ID for each anchor WTRU, the number of WTRUs within the group of WTRUs, the OCC for each WTRU within the group of WTRUs, the set of sidelink resources scheduled for the group, and / or the multiplexing rule associated with each resource among the plurality of resources.

[0016] A may include a transceiver and a processor. The processor may be configured to transmit, via the transceiver, a first message including sidelink positioning information associated with a group of WTRUs. The sidelink positioning information may include an indication of a sidelink positioning method for determining the positions of the WTRUs within the group of WTRUs. The processor may be configured to transmit, via the transceiver, a second message including a request for sidelink positioning reference signal (SL-PRS) resources for the group of WTRUs. The processor may be configured to receive, via the transceiver, an indication of the assigned SL-PRS resources for the group of WTRUs. The processor may be configured to send, via the transceiver, the indication of the assigned SL-PRS resources to the group of WTRUs.

[0017] The resources requested by the WTRU may be at least partially based on a sidelink positioning method, the number of WTRUs within the group of WTRUs, and / or the quality of service (QoS) associated with the sidelink positioning method.

[0018] The sidelink positioning information within the first message may include a group identifier (ID) associated with the group of WTRUs. The request for SL-PRS resources within the second message may include the group ID. The sidelink positioning method may include at least one of round trip time (RTT) positioning, sidelink time difference of arrival (SL-TDOA) positioning, and / or sidelink angle of departure (SL-AoD) positioning.

[0019] The request for SL-PRS resources may include a request for SL-PRS transmission resources for the WTRU. The request for SL-PRS resources may include a request for SL-PRS transmission resources for other WTRUs within the group of WTRUs. The request for SL-PRS may include the number of SL-PRS transmission resources requested for the WTRU and / or the number of SL-PRS transmission resources requested for other WTRUs within the group of WTRUs.

[0020] The second message may include a media access control (MAC) control element (CE).

[0021] The processor is further configured to perform sidelink discovery procedures to identify a group of WTRUs.

[0022] The processor may be configured to transmit the first message and the second message to a node. The node may include at least one of a network node, another WTRU, and / or a roadside unit (RSU).

[0023] At least one computer-readable storage medium may store executable instructions. When executed by a processor, the executable instructions may configure the processor to transmit a first message that includes sidelink positioning information associated with a group of WTRUs. The sidelink positioning information may include an indication of a sidelink positioning method for determining the position of WTRUs within the group of WTRUs. The processor may transmit a second message that includes a request for a sidelink positioning reference signal (SL-PRS) for the group of WTRUs. The processor may receive an indication of an assigned SL-PRS resource for the group of WTRUs. The processor may send the indication of the assigned SL-PRS resource to the group of WTRUs. The requested resources may be at least partially based on the sidelink positioning method, the number of WTRUs within the group of WTRUs, and / or the quality of service (QoS) associated with the sidelink positioning method.

Brief Description of the Drawings

[0024] A more detailed understanding can be provided from the following detailed description in conjunction with the accompanying drawings by way of illustration. The figures of such drawings, like the detailed description, are examples. Accordingly, the figures and the detailed description should not be considered limiting, and other equally effective embodiments are possible and likely. Like reference numerals (「ref.」 or 「refs.」) in the figures indicate like elements.

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[0025] FIG. 1A illustrates an exemplary communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multi-access system that provides content such as voice, data, video, messaging, broadcast, etc. to a plurality of wireless users. The communication system 100 may enable a plurality of wireless users to access such content through sharing of system resources including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), etc.

[0026] As shown in Figure 1A, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104 / 113, a CN 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112. However, it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and / or “STA,” may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed subscriber units or mobile subscriber units, subscriber-based units, pagers, cellular telephones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., for remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), home appliances, devices operating in commercial wireless networks and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0027] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks such as CN106 / 115, the Internet 110, and / or other network 112. By way of example, base stations 114a, 114b may be a base transceiver station (BTS), Node B, eNode B, home Node B, home eNode B, gNB, NR Node B, site controller, access point (AP), wireless router, etc. Although base stations 114a, 114b are each depicted as a single element, it will be understood that base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0028] Base station 114a may be part of RAN 104 / 113 and may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals at one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. The cell may provide coverage of wireless services to a specific geographic area that may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0029] Base stations 114a, 114b may communicate with one or more of WTRUs 102a, 102b, 102c, 102d via air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interface 116 may be established using any suitable radio access technology (RAT).

[0030] More specifically, as described above, the communication system 100 may be a multiple access system, but may adopt one or more channel access methods such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base stations 114a within RAN104 / 113, and the WTRUs 102a, 102b, 102c may implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use wideband CDMA (WCDMA) to establish the air interfaces 115 / 116 / 117. WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink Packet Access (HSDPA) and / or High-Speed UL Packet Access (HSUPA).

[0031] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may use Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro) to establish the air interface 116.

[0032] In one embodiment, the base station 114a, and the WTRUs 102a, 102b, 102c may implement radio technologies such as NR radio access, which may use New Radio (NR) technology to establish the air interface 116.

[0033] In one embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. Accordingly, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by transmissions sent to / from multiple types of radio access technologies and / or multiple types of base stations (e.g., eNBs and gNBs).

[0034] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c may implement wireless technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), IS-95, IS-856, Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0035] The base station 114b in FIG. 1A can be, for example, a wireless router, a home node B, a home e-node B, or an access point, and can utilize any suitable RAT to facilitate wireless connection in a local area such as an office, a home, a vehicle, a campus, an industrial facility, an aerial corridor (for example, for use by a drone), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d can utilize a cellular-based RAT (for example, WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. As shown in FIG. 1A, the base station 114b can have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0036] RAN 104 / 113 may communicate with CN 106 / 115, which may be any type of network configured to provide voice, data, applications, and / or voice over internet protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, 102d. The data may have various quality of service (QoS) requirements such as, for example, different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calls, internet connectivity, video delivery, etc., and / or may implement high-level security functions such as user authentication. Although not shown in Figure 1A, it will be understood that RAN 104 / 113 and / or CN 106 / 115 may communicate directly or indirectly with other RANs that employ the same or a different radio access technology (RAT) as RAN 104 / 113. For example, in addition to being connected to RAN 104 / 113 which may utilize New Radio (NR) radio technology, CN 106 / 115 may also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0037] CN106 / 115 may also serve as a gateway for WTRU102a, 102b, 102c, 102d to access the PSTN108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides a plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the internet protocol (IP) of the TCP / IP internet protocol suite. The network 112 may include a wired communication network and / or a wireless communication network that is owned and / or operated by another service provider. For example, the network 112 may include another CN connected to one or more RANs that may employ the same RAT or a different RAT than the RAN 104 / 113.

[0038] Some or all of the WTRU102a, 102b, 102c, 102d in the communication system 100 may include multimode capabilities (e.g., the WTRU102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, the WTRU102c shown in Figure 1A may be configured to communicate with a base station 114a that may employ a cellular-based wireless technology and a base station 114b that may employ IEEE802 wireless technology.

[0039] Figure 1B is a system diagram illustrating an exemplary WTRU 102. As shown in Figure 1B, the WTRU 102 can include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripheral devices 138. It will be understood that the WTRU 102 can include any partial combination of the foregoing elements while remaining consistent with one embodiment.

[0040] The processor 118 can be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 can perform signal coding, data processing, power control, input / output processing, and / or any other function that enables the WTRU 102 to operate in a wireless environment. The processor 118 can be coupled to the transceiver 120 which can be coupled to the transmit / receive element 122. Although Figure 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 can be integrated together in an electronic package or chip.

[0041] The transmit / receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR signals, UV signals, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0042] Although the transmit / receive element 122 is depicted in FIG. 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via the air interface 116.

[0043] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs such as, for example, NR and IEEE 802.11.

[0044] The processor 118 of the WTRU 102 may be coupled to the speaker / microphone 124, keypad 126, and / or the display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and may receive user input data therefrom. The processor 118 may also output user data to the speaker / microphone 124, keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any suitable type of memory, such as the non-removable memory 130 and / or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0045] The processor 118 may receive power from the power supply 134 and may be configured to distribute power to and / or control the power of other components within the WTRU 102. The power supply 134 may be any suitable device for supplying power to the WTRU 102. For example, the power supply 134 may include one or more dry cells (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), a solar cell, a fuel cell, etc.

[0046] The processor 118 can also be coupled to a GPS chipset 136 that can be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or instead of, information from the GPS chipset 136, the WTRU 102 can receive location information from a base station (e.g., base stations 114a, 114b) via the air interface 116 and / or can determine its location based on the timing of signals received from two or more neighboring base stations. It will be understood that the WTRU 102 can obtain location information by any suitable location determination method while remaining consistent with one embodiment.

[0047] The processor 118 can be further coupled to other peripheral devices 138 that can include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connections. For example, the peripheral devices 138 can include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. The peripheral devices 138 can include one or more sensors, where the sensors can be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0048] WTRU102 may include a full-duplex radio in which some or all of the transmission and reception of signals associated with certain subframes (e.g., for both UL (e.g., for transmission) and downlink (e.g., for reception)) can be parallel and / or simultaneous. The full-duplex radio may include an interference management unit 139 for reducing and / or substantially eliminating self-interference either through hardware (e.g., choke) or through signal processing via a processor (e.g., via a separate processor (not shown) or via processor 118). In one embodiment, the WRTU102 may include a half-duplex radio for the transmission and reception of some or all of the signals (e.g., associated with a particular subframe for either UL (e.g., for transmission) or downlink (e.g., for reception)).

[0049] Figure 1C is a system diagram illustrating RAN104 and CN106 according to one embodiment. As described above, RAN104 may employ E-UTRA radio technology to communicate with WTRU102a, 102b, 102c via air interface 116. RAN104 may also communicate with CN106.

[0050] RAN104 may include eNodeBs 160a, 160b, 160c, although it will be understood that RAN104 may include any number of eNodeBs while remaining consistent with one embodiment. Each of eNodeBs 160a, 160b, 160c may include one or more transceivers for communicating with WTRU102a, 102b, 102c via air interface 116. In one embodiment, eNodeBs 160a, 160b, 160c may implement MIMO technology. Thus, eNodeB 160a may transmit wireless signals to and / or receive wireless signals from WTRU102a, for example, using multiple antennas.

[0051] Each of the eNodeBs 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decision-making, handover decision-making, user scheduling in the UL and / or DL, etc. As shown in FIG. 1C, the eNodeBs 160a, 160b, and 160c can communicate with each other via the X2 interface.

[0052] The CN 106 shown in FIG. 1C can include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the foregoing elements is depicted as part of the CN 106, it will be understood that any of these elements can be owned and / or operated by an entity other than the CN operator.

[0053] The MME 162 can be connected to each of the eNodeBs 162a, 162b, and 162c in the RAN 104 via the S1 interface and can function as a control node. For example, the MME 162 can be involved in authenticating the users of the WTRUs 102a, 102b, and 102c, activating / deactivating bearers, selecting a specific serving gateway during the initial attach of the WTRUs 102a, 102b, and 102c, etc. The MME 162 can provide control plane functions for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies such as GSM and / or WCDMA.

[0054] SGW 164 can be connected to each of the eNodeBs 160a, 160b, and 160c in RAN 104 via the S1 interface. SGW 164 can generally route and transfer user data packets to / from WTRUs 102a, 102b, and 102c. SGW 164 can perform other functions such as anchoring the user plane during handover between eNodeBs, triggering paging when DL data is available to WTRUs 102a, 102b, and 102c, and managing and storing the contexts of WTRUs 102a, 102b, and 102c.

[0055] SGW 164 can be connected to PGW 166, which can provide access to a packet switched network such as the Internet 110 to WTRUs 102a, 102b, and 102c in order to facilitate communication between WTRUs 102a, 102b, and 102c and IP-enabled devices.

[0056] CN 106 can facilitate communication with other networks. For example, CN 106 can provide access to a circuit switched network such as PSTN 108 to WTRUs 102a, 102b, and 102c in order to facilitate communication between WTRUs 102a, 102b, and 102c and conventional landline communication devices. For example, CN 106 can include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that functions as an interface between CN 106 and PSTN 108. In addition, CN 106 can provide access to other networks 112 to WTRUs 102a, 102b, and 102c, and these other networks can include other wired and / or wireless networks owned and / or operated by other service providers.

[0057] The WTRU is described as a wireless terminal in FIGS. 1A - 1D, but in certain representative embodiments, it is contemplated that such a terminal can use (e.g., temporarily or permanently) a wired communication interface with the communication network.

[0058] In a representative embodiment, the other network 112 can be a WLAN.

[0059] A WLAN in infrastructure basic service set (BSS) mode can have an access point (AP) of the BSS and one or more stations (STAs) associated with the AP. The AP can have access to or an interface to another type of wired / wireless network that carries traffic within and / or outside the distribution system (DS) or BSS. Traffic to an STA originating outside the BSS can reach and be delivered to the STA through the AP. Traffic originating from an STA and going to a destination outside the BSS can be sent to the AP so as to be delivered to their respective destinations. Traffic between STAs within the BSS can be sent through the AP, for example. The source STA can send traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic can be sent between the source STA and the destination STA (e.g., directly between them) using direct link setup (DLS). In a particular representative embodiment, the DLS can use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (e.g., all of the STAs) can communicate directly with each other. The IBSS mode of communication can be referred to herein as the "ad hoc" communication mode.

[0060] When using the 802.11ac infrastructure operation mode or a similar operation mode, the AP may transmit beacons on a fixed channel such as the primary channel. The primary channel can be of a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In certain representative embodiments, for example, in an 802.11 system, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) can be implemented. In the case of CSMA / CA, STAs including the AP (e.g., all STAs) can sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA can back off. Only one STA (e.g., only one station) can transmit at any given time in a given BSS.

[0061] A High Throughput (HT) STA can use a 40 MHz wide channel for communication, and this 40 MHz wide channel can be formed, for example, through a combination of a primary 20 MHz channel and an adjacent or non - adjacent 20 MHz channel.

[0062] A Very High Throughput (VHT) STA can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. A 40 MHz and / or 80 MHz channel can be formed by combining a plurality of adjacent 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels or by combining two non - adjacent 80 MHz channels, which can be referred to as an 80 + 80 configuration. In the case of the 80 + 80 configuration, after channel encoding, the data can pass through a segment parser that can divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time - domain processing can be performed separately for each stream. The streams can be mapped to two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80 + 80 configuration can be reversed, and the combined data can be sent to the media access control.

[0063] The sub-1 GHz operating mode is supported by 802.11af and 802.11ah. The channel operating bandwidth and carrier frequency are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV White Space (TVWS) spectrum, and 802.11ah supports bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using the non-TVWS spectrum. According to an exemplary embodiment, 802.11ah may support meter type control / machine type communication such as MTC devices within a macro communication range area. The MTC device may have limited capabilities, including certain capabilities, for example, support for a certain and / or limited bandwidth (e.g., supporting only these). The MTC device may include a battery having a battery life above a threshold (e.g., to maintain a very long battery life).

[0064] A WLAN system that supports multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah includes channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or restricted by an STA from among all STAs operating in a BSS that supports a minimum bandwidth operation mode. In an example of 802.11ah, the primary channel is 1 MHz wide for an STA (e.g., an MTC type device) that supports the 1 MHz mode (e.g., supports only this) even when the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operation modes. Carrier sensing and / or Network Allocation Vector (NAV) setting may depend on the status of the primary channel. For example, due to an STA transmitting to an AP (supporting only the 1 MHz operation mode), if the primary channel is busy, the entire available frequency band may be considered busy even if most of the frequency band remains idle and available.

[0065] In the United States, the available frequency band that can be used by 802.11ah is 902 MHz to 928 MHz. In South Korea, the available frequency band is 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is 916.5 MHz to 927.5 MHz. The total available bandwidth for 802.11ah is 6 MHz to 26 MHz depending on the country code.

[0066] FIG. 1D is a system diagram illustrating RAN 113 and CN 115 according to one embodiment. As described above, RAN 113 may employ NR radio technology to communicate with WTRUs 102a, 102b, 102c via air interface 116. RAN 113 may also communicate with CN 115.

[0067] RAN 113 may include gNBs 180a, 180b, and 180c, although it will be understood that RAN 113 may include any number of gNBs while remaining consistent with one embodiment. Each of gNBs 180a, 180b, and 180c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, and 180c. Thus, gNB 180a may transmit and / or receive radio signals to / from WTRU 102a using, for example, multiple antennas. In one embodiment, gNBs 180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In one embodiment, gNBs 180a, 180b, and 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0068] WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using transmissions associated with scalable numerology. For example, the OFDM symbol interval and / or the OFDM sub-carrier interval may vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using sub-frames or transmission time intervals (TTIs) of various or scalable lengths (e.g., including various numbers of OFDM symbols and / or having absolute times of various lengths).

[0069] gNBs 180a, 180b, and 180c may be configured to communicate with WTRUs 102a, 102b, and 102c in a stand-alone configuration and / or a non-stand-alone configuration. In a stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNodeBs 160a, 160b, 160c, etc.). In a stand-alone configuration, WTRUs 102a, 102b, and 102c may utilize one or more of gNBs 180a, 180b, and 180c as a mobility anchor point. In a stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using signals in an unlicensed band. In a non-stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with and connect to gNBs 180a, 180b, and 180c while also communicating with and connecting to another RAN such as eNodeBs 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c may implement a DC principle for communicating with one or more gNBs 180a, 180b, and 180c and one or more eNodeBs 160a, 160b, and 160c substantially simultaneously. In a non-stand-alone configuration, eNodeBs 160a, 160b, and 160c may function as a mobility anchor for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c may provide additional coverage and / or throughput for servicing WTRUs 102a, 102b, and 102c.

[0070] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decision-making, handover decision-making, user scheduling in UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to user plane functions (UPFs) 184a, 184b, routing of control plane information to access and mobility management functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D, gNBs 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0071] As shown in FIG. 1D, CN 115 can include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and optionally data networks (DNs) 185a, 185b. Although each of the foregoing elements is depicted as part of CN 115, it will be understood that any of these elements can be owned and / or operated by entities other than the CN operator.

[0072] AMF 182a and 182b can be connected to one or more of gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can function as control nodes. For example, AMF 182a and 182b can be involved in user authentication of WTRUs 102a, 102b, and 102c, support for network slicing (e.g., handling different PDU sessions with different requirements), selection of specific SMFs 183a and 183b, management of the registration area, termination of NAS signaling, mobility management, etc. Network slicing can be used by AMF 182a and 182b to customize the CN support for WTRUs 102a, 102b, and 102c based on the type of service being utilized by WTRUs 102a, 102b, and 102c. For example, different network slices can be established for different use cases such as services that rely on ultra-reliable low latency (URLLC) access, services that rely on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, etc. AMF 162 can provide control plane functions for switching between RAN 113 and other RANs (not shown) that employ other radio technologies such as non-3GPP access technologies like LTE, LTE-A, LTE-A Pro, and / or WiFi.

[0073] SMF183a and 183b can be connected to AMF182a and 182b in CN115 via the N11 interface. SMF183a and 183b can also be connected to UPF184a and 184b in CN115 via the N4 interface. SMF183a and 183b can select and control UPF184a and 184b, and configure the routing of traffic passing through UPF184a and 184b. SMF183a and 183b can perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. The PDU session type can be IP-based, non-IP-based, Ethernet-based, etc.

[0074] UPF184a and 184b can be connected to one or more of gNB180a, 180b, and 180c in RAN113 via the N3 interface, thereby providing WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-corresponding devices. UPF184 and 184b can perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-home PDU sessions, processing user plane QoS, buffering downlink packets, and providing mobility anchoring.

[0075] CN115 can facilitate communication with other networks. For example, CN115 can include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that functions as an interface between CN115 and the PSTN 108. Additionally, CN115 can provide the WTRU 102a, 102b, 102c with access to other networks 112 that may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRU 102a, 102b, 102c can be connected to the local data network (DN) 185a, 185b through the UPF 184a, 184b via an N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0076] In view of FIGS. 1A - 1D, and the corresponding descriptions of FIGS. 1A - 1D, one or more of the functions described herein with respect to one or more of the WTRU 102a - d, base stations 114a - b, eNodeB 160a - c, MME 162, SGW 164, PGW 166, gNB 180a - c, AMF 182a - b, UPF 184a - b, SMF 183a - b, DN 185a - b, and / or any other device described herein can be implemented by one or more emulation devices (not shown). An emulation device can be one or more devices configured to emulate one or more or all of the functions described herein. For example, an emulation device can be used to test other devices and / or to simulate network and / or WTRU functionality.

[0077] An emulation device can be designed to implement one or more tests of other devices in a laboratory environment and / or an operator network environment. For example, one or more emulation devices can perform one or more or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more emulation devices can perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. An emulation device can be directly coupled to another device for testing purposes and / or can perform tests using terrestrial wireless communication.

[0078] One or more emulation devices can perform one or more functions, including all, while not being implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device can be utilized in a test scenario in a test laboratory and / or in a non-deployed (e.g., for testing) wired and / or wireless communication network to implement tests of one or more components. One or more emulation devices can be test equipment. Direct RF coupling and / or wireless communication via an RF circuit (which can include one or more antennas) can be used by an emulation device to transmit and / or receive data.

[0079] Wireless communication between one or more user equipment (UE) and a network is contemplated herein. A WTRU can also be referred to as a wireless transmit / receive unit (WTRU). The terms UE and WTRU are used interchangeably herein.

[0080] Side link communication may support communication between different vehicles. Side link communication (e.g., transmission, reception, etc.) may be provided with resources in various ways. For example, resources for side link transmission / reception may be structured as a resource pool. The resource pool may include a set of continuous frequency resources that repeat temporally according to a bitmap pattern. The WTRU may be configured via one or more resource pools. In the case of a WTRU within coverage (e.g., a WTRU within network coverage), the resource pool may be configured via a system information block (SIB), radio resource control (RRC), etc., and / or any suitable combination thereof. In the case of a WTRU outside coverage (e.g., a WTRU not covered by the network), the resource pool may be pre-configured on the WTRU.

[0081] Each side link transmission may spread within a slot including a physical side link shared channel (PSSCH), a physical side link control channel (PSCCH), and / or any suitable combination thereof. The PSSCH and PSCCH may utilize frequency division multiplexing (FDM), time division multiplexing (TDM), and / or any suitable combination thereof.

[0082] Side link control information (SCI) may be split into two parts. These two parts may be known as a first stage SCI and a second stage SCI. The first stage SCI may indicate resources used for side link transmission, the quality of service (QoS) of the transmission (e.g., priority), a demodulation reference signal (DMRS), a phase tracking reference signal (PTRS) used for side link transmission, and a second SCI format, and / or any suitable combination thereof. The second stage SCI may indicate the remaining control information. The SCI may be used to reserve resources for future transmissions within the resource pool.

[0083] The sidelink resources can be scheduled by a network, referred to herein as mode 1, and / or autonomously selected by a WTRU, referred to herein as mode 2. When the WTRU operates in mode 2, the WTRU may perform sensing by decoding SCI from other WTRUs before selecting sidelink resources to avoid selecting resources reserved by other WTRUs.

[0084] The sidelink channel state information reference signal (SL-CSI-RS) can be supported for unicast to support a transmitting WTRU (Tx WTRU) in determining transmit (Tx) parameters (e.g., power and rank). The Tx WTRU may indicate the presence of the SL-CSI-RS by using the SCI. Channel state information reference signal (CSI-RS) transmission may trigger channel state information (CSI) reporting. The PC5-RRC may configure the CSI reporting delay. Each report may be associated with one SL-CSI-RS transmission.

[0085] Positioning techniques (e.g., determining the location / position of a WTRU) can be new radio (NR) universal mobile telephone system (UMTS), air interface location, specified download (DL) based, uplink (UL) based, DL+UL based, timing and / or angle based, round trip time (RTT) based, and / or any suitable combination thereof. A geographical coordinate system (GCS), local coordinate system, etc., and / or any suitable combination thereof can represent the absolute position of the WTRU. The relative position of a WTRU (e.g., a target WTRU) can be represented with respect to distance, an angle from another WTRU (e.g., an anchor WTRU), a reference point with a known location, etc., and / or any suitable combination thereof.

[0086] In DL-based positioning, a downlink positioning reference signal (DL-PRS) can be sent from multiple transmission / reception points (TRPs) to a WTRU. Also, the WTRU can observe and measure the downlink signals from the TRPs. In an example referred to herein as the WTRU-B method, the WTRU can calculate its position. In another example referred to herein as the WTRU-A method, the WTRU can return downlink measurement values to the network. In another example referred to herein as the angle-based method, the WTRU can report the angle of arrival (AoA) and the reference signal receive power (RSRP) of the downlink signals from the TRPs. In another example referred to herein as the timing-based method, the WTRU can report the reference signal time difference (RSTD). The above methods may rely on transmission timing synchronization between TRPs. The positioning calculation error may be the result of synchronization error and multipath.

[0087] In UL-based positioning (e.g., UL-based), the WTRU can send at least one uplink positioning reference signal (UL-PRS) for positioning configured by the RRC to the TRP. Then, the network can calculate the position of the WTRU based on the cooperation of all TRPs that receive the UL-PRS from the WTRU.

[0088] In UL and DL-based methods (e.g., DL+UL-based), the WTRU can measure the receive-transmit (Rx-Tx) time difference between the received DL-PRS and the transmitted UL-PRS. The Rx-Tx time difference and the RSRP can be reported to the network. Then, the network can TRP to calculate the position of the WTRU.

[0089] Other exemplary SL positioning methods may include timing / angle positioning and round trip time (RTT) positioning. Timing / angle positioning may refer to any positioning method that uses a reference signal such as an SL-PRS. The WTRU may receive a plurality of reference signals from the WTRU and may measure RSTD, RSRP, and / or AoA. Examples of angle / timing positioning may include angle of departure (SL-AoD) or sidelink time difference of arrival (SL-TDOA) positioning. In another example, the WTRU may transmit the SL-PRS to the WTRU and receiver performance measurements (e.g., RSTD, AoA, RSRP) for the determination of the location of the WTRU that transmitted the SL-PRS.

[0090] RTT positioning may refer to any positioning method that requires two WTRUs to transmit SL-PRSs to each other. In an example, the anchor WTRU may transmit the SL-PRS to the target WTRU. When the target WTRU receives the SL-PRS from the anchor WTRU, the target WTRU may transmit the SL-PRS to the anchor WTRU. The target WTRU may measure the WTRU Tx-Rx time difference, which is the difference between the transmission time of the SL-PRS from the target WTRU and the reception time of the SL-PRS transmitted from the anchor WTRU. The target WTRU may report the WTRU Tx-Rx time difference to the anchor WTRU.

[0091] Side link positioning may be applicable to a WTRU that is covered by the network, partially covered by the network, out of coverage, and / or any suitable combination thereof. The metrics used to represent the side link position may include absolute positioning, relative positioning, and / or any suitable combination thereof. By way of example, side link positioning may be SL-PRS transmission based, SL-PRS reception based, round trip time (RTT) based side link positioning, and / or any suitable combination thereof. With regard to resource allocation for side link positioning, the network may perform resource allocation for side link resources for side link positioning, and network-scheduled resources may be utilized. Supporting the network scheduling resource allocation mode may enable the network to fully control side link resources.

[0092] With regard to resource allocation for side link positioning, using existing dynamic scheduling procedures may require each individual WTRU to separately request side link resources for SL-PRS transmission and / or side link measurement reporting. Thus, existing dynamic scheduling procedures may require excessive signaling overhead, particularly for large positioning groups and / or low latency positioning requirements. Further, existing dynamic scheduling procedures may require that the anchor WTRU be in the CONNECTED state during the side link procedure.

[0093] Also described herein are scheduling procedures for groups of WTRUs, such as a target WTRU and at least one anchor WTRU. Under these procedures, a group of WTRUs may perform side link positioning to reduce signaling overhead between the gNB and the WTRUs within the group.

[0094] A method and system for improving existing scheduling procedures for a group of WTRUs (e.g., target WTRU and / or anchor WTRU) to perform sidelink positioning in order to reduce signaling overhead between network entities (e.g., gNB, network node, server WTRU, WTRU having LMF capabilities, WTRU having the ability to process measurements and determine location information of other WTRUs, WTRU having the ability to configure SL-PRS for other WTRUs and / or servers, etc.) and / or between WTRUs within a group are described herein. An example of a server WTRU can be a WTRU that provides an SL-PRS configuration to other WTRUs and / or receives measurement reports from WTRUs and determines location information of other WTRUs based on the measurement reports. As described herein, positioning can be used for ranging without any limitation. Positioning can be referred to as a method / manner for estimating the geographical location of a WTRU. Ranging can be referred to as a method / manner for estimating the distance between WTRUs. The terms "positioning of a WTRU" and / or "location information of a WTRU" can be used interchangeably with "distance between WTRUs". Positioning of a WTRU and sidelink positioning can be applicable to ranging. Positioning of a WTRU can include an absolute position that can include coordinates and / or a zone ID. Positioning of a WTRU can include a relative position that can include a range, distance, propagation time, RTT to another entity and / or node (e.g., another WTRU, roadside unit (RSU), positioning reference unit (PRU), gNB, and / or any suitable combination thereof).

[0095] As described herein, a WTRU can indicate any type of device such as an anchor WTRU, target WTRU, assistant WTRU, server WTRU, PRU, and / or RSU. In an example, a WTRU can be scheduled using one or more resources, and the one or more resources can be used interchangeably with the WTRU. A WTRU can select one or more resources.

[0096] Any solution applicable for the WTRU to select one or more resources may be used for the WTRU to request one or more resources from another node. Additionally or alternatively, any solution applicable for the WTRU to request one or more resources may be used for the WTRU to request one or more resources. For example, any trigger condition for the WTRU to select one or more resources may be used for the WTRU to request one or more resources from another node. Any trigger condition for the WTRU to request one or more resources from another node may be used for the WTRU to select one or more resources by itself.

[0097] As used herein, the term scheduled may be used when a resource may be determined by another entity (e.g., other than the WTRU itself). As used herein, the term selected may be used when a resource may be determined by the WTRU itself. However, any applicable solution described for the case where the WTRU is scheduled using a resource may be used compatibly with the case where the WTRU makes its own resource selection.

[0098] The SL-PRS resources for the reception of one WTRU (e.g., the target WTRU) may be used compatibly with the SL-PRS for the transmission of other WTRUs (e.g., the anchor WTRU).

[0099] One resource may be used compatibly with one set of resources. For example, one resource for SL-PRS transmission / reception may be used compatibly with one set of resources for SL-PRS transmission / reception. A WTRU that does not perform SL-PRS reception in one SL-PRS resource may be equivalent to a WTRU that pays attention to obtaining SL-PRS measurement results from the resource.

[0100] As used herein, the terms indicating, reporting, and / or transmitting a message to another WTRU may be used interchangeably with the terms indicating, reporting, and / or transmitting a message to another entity or node (e.g., gNB, and / or RSU, etc.). As used herein, a WTRU receiving a message from another WTRU may be used interchangeably with a WTRU receiving a message from any other node (e.g., gNB, and / or RSU, etc.). The SL-PRS reception time and / or duration may include the SL-PRS signal reception and / or the SL-PRS processing time after receiving the SL-PRS signal.

[0101] As used herein, the term SCI may be used interchangeably with the terms first-stage SCI, second-stage SCI, and / or both first-stage SCI and second-stage SCI. As used herein, the term SCI may be used interchangeably with the term PSCCH.

[0102] As used herein, a group of WTRUs may refer to one or more WTRUs. A positioning group may refer to a group of two or more WTRUs. The SL-PRS reception resources of one WTRU (e.g., the target WTRU) may be used interchangeably with the SL-PRS transmission of another WTRU (e.g., the anchor WTRU). The SL-PRS Tx-based positioning method and / or the SL-Rx-based positioning method may be used interchangeably with the SL-TDOA positioning method. The SL-TDOA method may be used to describe a timing-based positioning method where the target WTRU may be a transmitter of only SL-PRS (e.g., UL-like SL-TDOA) and / or a receiver of only SL-PRS (e.g., DL-like SL-TDOA).

[0103] The WTRU may use, as the SL-PRS, the DMRS of the PSSCH and / or PSCCH, the sidelink synchronization signal (SLSS), the sidelink primary synchronization signal (S-PSS), the sidelink secondary synchronization signal (S-SSS), the phase tracking reference signal (PTRS), the sidelink channel state information reference signal (SL-CSI-RS), the physical sidelink feedback channel (PSFCH), the reference signal (RS) designed for positioning purposes, etc., and / or any suitable combination thereof.

[0104] The WTRU may be configured and / or pre-configured. As used herein, the WTRU being pre-represented and / or (pre-)configured may refer to the WTRU being pre-configured, the WTRU receiving a configuration from another entity such as a node, gNB, another WTRU, etc., and / or any suitable combination thereof. By way of example, a resource pool for sidelink positioning may configure / pre-configure the WTRU.

[0105] One or any combination of the following resource pools for SL-PRS transmission / reception may configure / pre-configure a WTRU: one or more dedicated resource pools for SL-PRS transmission / reception, one or more shared resource pools having data for SL-PRS transmission / reception, one or more network-scheduled resource pools dedicated to SL-PRS transmission / reception, one or more network-scheduled resource pools for SL-PRS transmission shared with sidelink data communication, one or more WTRU autonomous selection resource pools dedicated to SL-PRS transmission / reception, one or more WTRU autonomous selection resource pools for SL-PRS transmission shared with sidelink data communication, one or more WTRU autonomous selection resource pools for sidelink communication to facilitate sidelink positioning, one or more network-scheduled resource pools for sidelink communication to facilitate sidelink positioning, one or more resource pools for sidelink communication having SL-PRS in transmission with data communication, and / or any suitable combination thereof.

[0106] The WTRU may configure itself for SL-PRS positioning and / or location determination. The WTRU may receive a configuration from another entity (e.g., another WTRU, a network node such as a gNB, etc.). The SL-PRS configuration may include any of the following, individually or in any suitable combination. A resource pool for SL-PRS transmission, reception, and / or sidelink measurement reporting, an SL-PRS resource ID, an SL-PRS sequence ID, or other ID used to generate an SL-PRS sequence, the time-frequency of the SL-PRS resource, the SL-PRS resource element offset, the SL-PRS resource slot offset, the SL-PRS symbol offset, SL-PRS QCL information, an SL-PRS resource set ID, a list of SL-PRS resources in the resource set, Mutating parameters such as the number of SL-PRS symbols, mutating patterns for SL-PRS, repetition coefficients, mutating options, SL-PRS resource power, periodicity of SL-PRS transmission, The number of periods for SL-PRS transmission, spatial direction information of SL-PRS transmission (e.g., beam information, transmission angle), spatial direction information of SL-RS reception (e.g., beam ID used to receive SL-RS, angle of arrival), frequency layer ID, WTRU ID and / or SL-PRS ID.

[0107] The WTRU may determine whether to multiplex side link control information (SCI) with a side link positioning reference signal (SL-RPS) in one transmission. In an example, the WTRU may determine whether to multiplex SCI with SL-PRS in one transmission (e.g., a transmission having SCI and SL-PRS within the same slot, where the SCI may occur within the first few symbols of the transmission).

[0108] The WTRU may determine whether to multiplex SCI with SL-PRS based on the resource pool used for SL-PRS transmission. For example, the WTRU may determine to multiplex SCI with SL-PRS in one transmission if the WTRU uses a shared resource pool for side link data communication. Otherwise, if the WTRU uses a dedicated resource pool for SL-PRS transmission, the WTRU may not multiplex SCI with SL-PRS in one transmission.

[0109] The WTRU may determine whether to multiplex SCI with SL-PRS based on the scheduling mode of the SL-PRS resources. For example, the WTRU may determine to multiplex SCI with SL-PRS in one transmission if the WTRU performs autonomous resource allocation for SL-PRS. Otherwise, if the SL-PRS is scheduled by the network, the WTRU may not need to multiplex SCI with SL-PRS.

[0110] A WTRU may determine whether to multiplex sidelink control information (SCI) with a sidelink positioning reference signal (SL-RPS) in one transmission based on whether another WTRU indicates a resource. For example, the WTRU may determine whether to multiplex SCI in one SL-PRS transmission based on whether the WTRU itself selects the SL-PRS and / or whether another WTRU selects the SL-PRS. The WTRU may determine to multiplex SCI in an SL-PRS transmission if the WTRU autonomously selects the SL-PRS resource. Otherwise, if another WTRU indicates a resource, the WTRU may not multiplex SCI in the SL-PRS transmission.

[0111] A WTRU may determine whether to multiplex sidelink control information (SCI) with a sidelink positioning reference signal (SL-RPS) in one transmission based on the time / frequency location of the SL-PRS resource. For example, the WTRU may determine to multiplex SCI in an SL-PRS transmission if the SL-PRS resource is within the first few symbols of a slot. Otherwise, the WTRU may not multiplex SCI in the SL-PRS transmission if the SL-PRS is within the last few symbols of a slot. Such an SL-PRS resource may be indicated by another WTRU.

[0112] A WTRU may determine whether to multiplex sidelink control information (SCI) with a sidelink positioning reference signal (SL-RPS) in one transmission. The WTRU may make this determination based on whether the SL-PRS resource is the first and / or repeated SL-PRS resource in the same and / or different slots. For example, the WTRU may multiplex SCI for the first SL-PRS transmission. Otherwise, for repeated SL-PRS transmissions in the same or future slots, the WTRU may not multiplex SCI. The SCI associated with the first SL-PRS transmission may indicate information associated with the repeated SL-PRS.

[0113] In an example, the WTRU may determine not to multiplex the SCI with the SL-PRS in one transmission in a network-scheduled resource pool dedicated for SL-PRS transmission. The WTRU may determine to multiplex the SCI with the SL-PRS in one transmission in a WTRU autonomous selection resource pool shared with sidelink data communication.

[0114] Figure 2 depicts an example of an RTT-based sidelink positioning method where a WTRU (e.g., an anchor WTRU) may be indicated by another WTRU (e.g., a target WTRU) to transmit the SL-PRS in one SL-PRS resource. The anchor WTRU may determine whether to multiplex the SCI with the SL-PRS based on whether the indicated resource is within the first few symbols of the slot or within the last few symbols of the slot. For example, as depicted in case 1 of Figure 2, if the indicated SL-PRS 202 is within the first few symbols of slot 204, the WTRU may multiplex the SCI 206 with the SL-PRS 202. Otherwise, if the indicated SL-PRS 208 is within the last few symbols of slot 210, the WTRU may not multiplex the SCI with the SL-PRS 208 as depicted in case 2 of Figure 2.

[0115] In an example, the WTRU may determine whether to multiplex the SCI with the SL-PRS based on whether there is any previous SL-PRS transmission within the same slot from a peer WTRU (e.g., for an RTT-based positioning method). Specifically, if one or more previous SL-PRSs from the peer WTRU are present within the slot, the WTRU may not multiplex the SCI in the SL-PRS transmission. Otherwise, if no previous SL-PRS transmission from the peer WTRU is present within the slot, the WTRU may multiplex the SCI in the SL-PRS transmission.

[0116] In an example, the WTRU may determine whether to multiplex the SCI with the SL-PRS based on whether there is any previous SL-PRS transmission within the same slot from a peer WTRU (e.g., for an RTT-based positioning method). For example, if one or more previous SL-PRSs from a peer WTRU are present within the slot, the WTRU may not multiplex the SCI in the SL-PRS transmission. Otherwise, if no previous SL-PRS transmission from a peer WTRU is present within the slot, the WTRU may multiplex the SCI in the SL-PRS transmission.

[0117] The WTRU may determine the time gap between the first transmission and the retransmission of the SL-PRS. The WTRU may select the resources for the first transmission and the retransmission of the SL-PRS. The minimum time gap between any two transmissions of the SL-PRS may be preconfigured. Then, the WTRU may select the resources for the SL-PRS transmission to satisfy the preconfigured minimum gap. For example, the WTRU may be preconfigured with multiple SL-PRS resources in the time domain within a slot. Then, the WTRU may select the SL-PRS resources such that two resources do not occupy the same slot. This approach may reduce the half-duplex problem and, when the WTRU prioritizes other sidelink transmissions and / or receptions in the same slot, the WTRU may not miss two SL-PRS receptions.

[0118] Figure 3 depicts an example of SCI multiplexing with SL-PRS in shared and dedicated resource pools. A WTRU may determine the location of side link control information (SCI) in a transmission. For example, the WTRU may determine to multiplex an SCI (e.g., a first stage SCI) with SL-PRS in one transmission. The WTRU may then determine the location of the SCI (e.g., the first stage SCI) in the transmission based on one or any combination of the following. The WTRU may determine the location of the SCI based on the resource pool used for transmission of the SL-PRS. At 302, the WTRU may place the SCI 304 associated with the SL-PRS at the same subchannel location as the SCI of other side link data 306 communication in the resource pool shared with side link communication. At 308, the WTRU may TDM an SCI (e.g., the first SCI) with the SL-PRS in a resource pool dedicated to the SL-PRS. The SCI 310 may occupy only the first symbol 312 of one of the transmissions.

[0119] The WTRU may determine the location of the SCI in the transmission based on the scheduling mode for the SL-PRS. For example, the WTRU may place the SCI associated with the SL-PRS at the same subchannel location as the SCI of other side link communication if the TRU autonomously selects the SL-PRS. Otherwise, if the network schedules the SL-PRS, the WTRU may place an SCI (e.g., the first SCI) that is time division multiplexed (TDMed) with the SL-PRS. In this case, the SCI may occupy only the first symbol of one of the transmissions.

[0120] For each SL-PRS transmission, the WTRU may transmit an associated PSCCH and / or PSSCH to indicate SL-PRS information (e.g., SL-PRS pattern, QoS associated with the SL-PRS). The WTRU may determine the location (e.g., time-frequency resource) of the PSCCH and / or PSSCH to indicate the associated SL-PRS information. For example, the WTRU may determine the time-frequency resource for transmitting the PSCCH and / or the time-frequency resource for transmitting the PSSCH to indicate the associated SL-PRS information. The WTRU may transmit the PSCCH and / or PSSCH associated with the SL-PRS.

[0121] The WTRU may determine the location of the PSCCH and / or PSSCH based on one or any combination of the following information for the SL-PRS, i.e., the SL-PRS pattern (e.g., comb value, number of symbols used, and / or RE offset pattern in each symbol, etc.). The WTRU may be (pre)-configured to multiplex multiple SL-PRS patterns in time and / or frequency resources, and each pattern may have one associated PSCCH and / or PSSCH. The WTRU may then determine where to place the PSCCH and / or PSSCH based on the pattern of the SL-PRS and / or the time-frequency location of the SL-PRS. The WTRU may have one PSCCH and / or PSSCH resource to indicate one or more SL-PRS patterns. In that case, each SL-PRS pattern may be within the range of time and frequency resources. The WTRU may then indicate which SL-PRS pattern the WTRU is transmitting in the SCI transmitted in the associated PSCCH and / or PSSCH.

[0122] The WTRU may (pre-)configure one PSCCH and / or PSSCH to indicate an SL-PRS pattern of up to M symbols. The WTRU may then indicate any SL-PRS transmission having a duration of 1 to M symbols. This may help the WTRU to indicate more SL-PRS patterns for one (pre-)configured PSCCH / PSSCH opportunity.

[0123] Figure 4 depicts an exemplary diagram of pattern-based PSCCH and / or PSSCH and SL-PRS multiplexing. The WTRU may be (pre-)configured with three SL-PRS patterns within a slot, and each SL-PRS pattern may have one associated PSCCH 402a-c and / or PSSCH 404a-c. The WTRU may then determine the location of the PSCCH 402a-c and / or PSSCH 404a-c based on the selected SL-PRS pattern. If the WTRU transmits in the first pattern 406a, the WTRU may transmit the PSCCH 402a and / or PSSCH 404a in the first region (e.g., the first subchannel). If the WTRU uses the second pattern 406b, the WTRU may transmit in the second region (e.g., the second subchannel). If the WTRU selects the third pattern 406c, the WTRU may transmit the PSCCH 402c and / or PSSCH 404c in the third region (e.g., the third subchannel). The WTRU may reserve a period for the ACG and transition time 408 between the PSCCH 402a-c and / or PSSCH 404a-c and the SL-PRS 410. The transition time may be (pre-)configured within a resource pool, which may be a function of the SCS of the resource pool.

[0124] Figure 5 depicts an exemplary diagram of time-frequency based PSCCH / PSSCH and SL-PRS multiplexing. In the example shown in Figure 5, the WTRU may be configured (a priori) with three time locations of SL-PRS 510 within a slot, and each SL-PRS location may have one associated PSCCH 502a-c and / or PSSCH 504a-c. The WTRU may then determine the locations of PSCCH 502a-c and / or PSSCH 504a-c based on the selected location of SL-PRS 510. If the WTRU transmits in the first symbol 506a, the WTRU may need to transmit PSCCH 502a and / or PSSCH 504a in the first PSCCH / PSSCH region (e.g., the first subchannel). If the WTRU uses the second symbol 506b, the WTRU may transmit PSCCH 502b and / or PSSCH 504b in the second region (e.g., the second subchannel). If the WTRU selects the third symbol 506c, the WTRU may transmit PSCCH 502c and / or 504c PSSCH in the third region (e.g., the third subchannel). The WTRU may reserve a period for the ACG and transition time 508 between PSCCH 502a-c and / or 504a-c PSSCH and SL-PRS 510. The transition time may be configured (a priori) within a resource pool, which may be a function of the SCS of the resource pool. The WTRU may place an ACG slot between the SL-PRS patterns of different WTRUs.

[0125] Figure 6 depicts an exemplary diagram of PSCCH / PSSCH with associated SL-PRS. In the example shown in Figure 6, the WTRU may be (pre-)configured with three time locations of SL-PRS 610 within a slot, and each SL-PRS location may have one associated PSCCH 602a-c and / or PSSCH 604a-c. The WTRU may then determine the location of PSCCH 602a-c and / or PSSCH 504a-c based on the selected location of SL-PRS 610. If the WTRU transmits in the first symbol 606a, the WTRU may need to transmit PSCCH 602a and / or PSSCH 604a in the first PSCCH / PSSCH region (e.g., the first subchannel). If the WTRU uses the second symbol 606b, the WTRU may transmit PSCCH 602b and / or PSSCH 604b in the second region (e.g., the second subchannel). If the WTRU selects the third symbol 606c, the WTRU may transmit PSCCH 602c and / or 604c PSSCH in the third region (e.g., the third subchannel). The WTRU may reserve a period for the ACG and transition time between PSCCH 602a-c and / or 604a-c PSSCH and SL-PRS 610. The transition time may be (pre-)configured within a resource pool, which may be a function of the SCS of the resource pool. The WTRU may place an ACG 612 slot between the SL-PRS patterns of different WTRUs.

[0126] In the example, the WTRU may be (pre-)configured with multiple cyclic shifts to transmit one SL-PRS pattern, and each cyclic shift may have an associated PSCCH and / or PSSCH location. The WTRU may determine the location of PSCCH and / or PSSCH based on the cyclic shift selected by the WTRU to transmit the associated SL-PRS.

[0127] As depicted in FIG. 7, the WTRU may embed the SCI in the SL-PRS pattern. The WTRU may embed its SCI 710 in the pattern. The WTRU may configure (in advance) the region (e.g., time-frequency) for the SCI 710. Then, the WTRU may use the REs associated with the SL-PRS pattern in the pre-configured SCI region to carry the SCI 710 information. Then, the WTRU may use the remainder to transmit the SL-PRS. In one example shown in FIG. 5, the WTRU may use the first three symbols to carry the SCI for the SL-PRS pattern.

[0128] The WTRU may determine the parameters for SL-PRS transmission. The WTRU may determine one or any combination of the following parameters for SL-PRS transmission, namely, the number of subchannels used for each SL-PRS resource, the number of symbols and / or slots used for each SL-PRS transmission resource, the comb value, and / or the number of repetitions. The WTRU may determine one or any combination of these parameters based on the pre-configured transmission power parameters for SL-PRS transmission. In an example, the WTRU may perform SL-PRS with the maximum allowable bandwidth if the WTRU is permitted to transmit at full power (e.g., open loop power control (OLPC) is not pre-configured in the resource pool in advance). Additionally or alternatively, the WTRU may perform SL-PRS with a smaller bandwidth if the WTRU is not permitted to transmit at full power (e.g., OLPC is configured in the resource pool in advance). In an example, the WTRU may use Comb-1 if OLPC is not configured in the resource pool (e.g., the WTRU transmits SL-PRS in all REs of the SL-PRS bandwidth). Otherwise, the WTRU may use Comb-N (e.g., N>1) if OLPC is configured in the resource pool.

[0129] Regarding the maximum number of subchannels allowed in a resource pool, the WTRU may be (pre-)configured with the maximum number of subchannels to use for SL-PRS transmission. The WTRU may then perform SL-PRS transmission within the maximum allowable bandwidth.

[0130] The WTRU may determine which resource pool transmits SL-PRS for sidelink positioning. The WTRU may determine which resource pool (e.g., which type of resource pool) is for SL-PRS sidelink communication based on the QoS of the positioning service (e.g., latency, accuracy requirements). The WTRU may use a sidelink resource pool that requires SL-PRS in the sidelink data for a sidelink positioning service with low latency and / or low accuracy requirements. The WTRU may use a dedicated resource pool for SL-PRS for a sidelink positioning service with high accuracy and / or strict latency requirements.

[0131] The WTRU may determine which SL-PRS configuration to use. For example, the WTRU may be (pre-)configured or may receive multiple SL-PRS configurations. The WTRU may receive an SL-PRS configuration from another WTRU, gNB (e.g., via RRC, SIB, and / or Location Management Function (LMF), etc.), from a (pre-)configuration, and / or from any suitable combination thereof.

[0132] The WTRU may determine which SL-PRS configuration to use based on a (pre-)configured priority associated with each configuration, or a predefined priority / priority order associated with each configuration. For example, the WTRU may prioritize the SL-PRS configuration indicated by a peer WTRU. The WTRU may then prioritize the SL-PRS configuration from the SIB, followed by the (pre-)configured SL-PRS configuration. The WTRU may prioritize the SL-PRS configuration sent from the network via RRC. The WTRU may then prioritize the SL-PRS configuration provided by another WTRU, followed by the SL-PRS configuration from the SIB, then the (pre-)configured SL-PRS configuration. The WTRU may request that another WTRU (e.g., an anchor WTRU) provide the SL-PRS configuration instead of reading the SIB. The WTRU may then prioritize using the SL-PRS received from the peer WTRU.

[0133] The WTRU may determine which SL-PRS configuration to use based on the coverage status (e.g., whether the WTRU is inside or outside coverage). For example, if the WTRU is outside coverage, the WTRU may prioritize the SL-PRS configuration received from a peer WTRU. If the peer WTRU does not provide an SL-PRS configuration, the WTRU may use the (pre-)configured SL-PRS configuration. If the WTRU is inside coverage, the WTRU may prioritize any SL-PRS configuration provided by the network. The WTRU may then prioritize the SL-PRS configuration from another WTRU. If no such SL-PRS configuration is available, the WTRU may use the (pre-)configured SL-PRS configuration.

[0134] The WTRU may prioritize resource pools used by peer WTRUs. The WTRU may be (pre-)configured with multiple resource pools for SL-PRS transmission. The WTRU may determine which resource pool to select based on the priority and / or precedence of each resource pool. In an example, the WTRU may be (pre-)configured with two resource pools, and one resource pool is prioritized for use. The WTRU may use the prioritized resource pool for SL-PRS transmission. In an example, the WTRU may be (pre-)configured with two types of resource pools for SL-PRS, namely, a dedicated resource pool and a shared resource pool. The WTRU may prioritize the dedicated resource pool over the shared resource pool.

[0135] The WTRU may prioritize resource pools based on resource pools used by peer WTRUs. For example, the WTRU may prioritize the resource pool used by a peer WTRU for SL-PRS for its SL-PRS transmission.

[0136] The WTRU may determine which ID(s) may generate / scramble the SL-PRS sequence. The WTRU may determine that N_ID may generate / scramble the SL-PRS sequence. The WTRU may use one or any combination of the following IDs, namely, group ID, link ID, destination ID, source ID, generated ID (e.g., from a higher layer), etc., and / or any suitable combination thereof to generate / scramble the SL-PRS sequence. The WTRU may indicate the ID(s) to other WTRUs (e.g., peer WTRUs or group members) for generating / scrambling the SL-PRS sequence.

[0137] The WTRU may determine when to monitor an SL-PRS resource pool. The WTRU may trigger the monitoring of the SL-PRS (e.g., monitor a dedicated resource pool for the SL-PRS) based on whether a positioning group and / or a positioning session is established. The WTRU may start monitoring the SL-PRS (e.g., start monitoring a dedicated resource pool for the SL-PRS) when a positioning session and / or a positioning group is established. The WTRU may stop monitoring the SL-PRS (e.g., stop monitoring a dedicated resource pool for the SL-PRS) when the positioning session ends and / or an RLF is detected and / or indicated by another node.

[0138] The WTRU may receive SL-PRS scheduling information from another node. For example, in the case of an SL-PRS reception-based method, the WTRU may receive information regarding the SL-PRS resources for the group. The WTRU may then trigger the monitoring of a dedicated SL-PRS resource pool based on the reception of the SL-PRS scheduling information.

[0139] The WTRU may determine to transmit multiple SL-PRSs within one slot, where each SL-PRS may consist of M symbols. The WTRU may then perform SL-PRS repetitions within one slot, and the WTRU may transmit multiple SL-PRSs each consisting of M symbols. The WTRU may then determine the number of repetitions to transmit within the slot based on the number of (pre-)configured symbols for the SL-PRS within one slot and the duration of each SL-PRS (i.e., the value of M). The WTRU may transmit the SL-PRS until all of the (pre-)configured symbols for the SL-PRS are filled. In one example, the WTRU may perform one SL-PRS consisting of 3 symbols within a slot of 9 symbols configured for the SL-PRS. The WTRU may then repeat the SL-PRS 3 times to fill the (pre-)configured slot for the SL-PRS.

[0140] The WTRU may perform multiple transmissions of one SL-PRS within a slot. The WTRU may indicate and / or reserve all transmissions of the SL-PRS within the slot using one PSCCH and / or PSSCH. The WTRU may indicate the number of repetitions and the SL-PRS pattern associated with the SL-PRS transmission. This approach may be motivated to reduce the number of PSCCH / PSSCH transmitted within one slot to indicate multiple repetitions of the SL-PRS.

[0141] The WTRU may be configured / pre-configured for sidelink positioning. The WTRU may receive the sidelink positioning configuration from the network via broadcast (e.g., via SIB) or via unicast (e.g., by an access stratum (AS) message (e.g., RRC) or a non-access stratum (NAS) message (e.g., location positioning protocol (LPP))). The WTRU may receive one or any combination of the following configurations for sidelink positioning, namely, a resource pool for sidelink communication to facilitate sidelink positioning, a resource pool for SL-PRS transmission / reception, a positioning method, or any suitable combination thereof. For example, the WTRU may be (pre)-configured via one resource pool for both SL-PRS communication and sidelink communication to facilitate sidelink positioning (e.g., to indicate and / or reserve sidelink transmissions for other sidelink transmissions, SL-PRS measurement reports, and / or SL-PRS resource usage reports).

[0142] In an example, the WTRU may be pre-configured with two resource pools, one resource pool may be used for sidelink communication to facilitate SL-PRS transmission and / or reception, and another resource pool may be used for SL-PRS transmission and / or reception. When the WTRU is configured with two resource pools for sidelink positioning, the WTRU may use the sidelink communication resource pool.

[0143] The WTRU may determine whether the network (e.g., gNB, Location Management Function (LMF), etc.) supports sidelink positioning. The WTRU (e.g., the target WTRU) may determine whether the network supports sidelink positioning based on the sidelink positioning SIB and / or the availability of the resource pool for SL-PRS transmission / reception in the SIB. If the network does not support sidelink positioning, the WTRU may use the pre-configured resource pool for sidelink positioning. Additionally or alternatively, the WTRU may use the resource pool configured in the unicast / broadcast message (e.g., SIB, RRC, and / or LPP) if the network supports sidelink positioning.

[0144] The WTRU may determine the resource location mode for sidelink positioning. For example, the WTRU (e.g., the target WTRU) may determine the resource allocation mode for sidelink positioning. The WTRU may determine whether to request resources from another node (e.g., the network or another WTRU) and / or whether to perform autonomous resource allocation for sidelink positioning. The WTRU may determine the resource allocation mode for one or any combination of the following, namely, sidelink positioning, SL-PRS transmission, SL-PRS reception, SL-PRS resource usage reporting and / or indication, and / or other resources for SL-PRS measurement reporting, i.e., the sidelink resources for indicating and / or requesting.

[0145] The resource allocation mode for each type of resource for sidelink positioning may be based on one or any combination of factors. For example, the resource allocation mode for each type of resource for sidelink positioning may be determined based on an indication from the network. The WTRU may request the network to provide a service for sidelink positioning (e.g., via LPP and / or RRC). The network may then determine the resource allocation mode for one or more types of resources for sidelink positioning. The network may request the WTRU to implement an autonomous resource allocation mode for SL-PRS transmission and / or reception. The network may request the WTRU to implement a network scheduling mode for SL-PRS measurement reporting. The resource allocation mode for each type of resource for sidelink positioning may be based on the coverage status of each WTRU within a sidelink positioning group. For example, a WTRU (e.g., a target WTRU) may implement a network-scheduled mode if the WTRU is within network coverage. Otherwise, if the WTRU is outside coverage, the WTRU may implement autonomous resource allocation.

[0146] A WTRU (e.g., an anchor WTRU) may perform network-scheduled resource allocation when the WTRU is within network coverage. Otherwise, if the WTRU is outside network coverage, the WTRU may receive scheduling information from another WTRU (e.g., a target WTRU) if the network supports and / or permits the transfer of scheduling resources for sidelink positioning. The resource allocation mode for each type of resource for sidelink positioning may be based on whether the network supports and / or permits the transfer of scheduling resources for sidelink positioning. For example, in an out-of-coverage scenario, the WTRU may perform autonomous resource allocation if the network does not support and / or permit the transfer of scheduling resources for sidelink positioning. Otherwise, if the network supports and / or permits the transfer of scheduling resources for sidelink positioning, the WTRU may receive scheduling from another WTRU.

[0147] The resource allocation mode for each type of resource for sidelink positioning may be based on the RRC status of the WTRU. For example, the WTRU may perform autonomous resource allocation or receive scheduling from another WTRU if the WTRU is in the RRC inactive state and / or the Ile state. Otherwise, if the WTRU is in the RRC connected state, the WTRU may perform network-scheduled resource allocation for sidelink positioning.

[0148] The resource allocation mode for each type of resource for sidelink positioning can be determined based on the role of the WTRU in sidelink positioning. For example, the WTRU can determine the resource allocation mode based on whether the WTRU is a target WTRU or an anchor WTRU. In a coverage scenario, the WTRU can implement a network scheduling mode if the WTRU is a target WTRU. Otherwise, if the WTRU is an anchor WTRU, the WTRU can receive scheduling from another WTRU (e.g., from the target WTRU).

[0149] The WTRU can determine the resources for sidelink positioning. For example, the WTRU can determine the resources for sidelink positioning (e.g., sidelink resources, uplink resources). The resources can be one or any combination of factors that indicate and / or request other resources for sidelink positioning and include sidelink resources. The indicated and / or reserved resources can be one or any combination of the following resources, namely, SL-PRS transmission, SL-PRS reception, SL-PRS resource usage reporting / indication, SL-PRS measurement reporting, uplink resources for indicating and / or reporting the use of scheduled sidelink resources for sidelink positioning, and / or any suitable combination thereof.

[0150] The resources can be sidelink resources for SL-PRS transmission, SL-PRS reception, which are used to report SL-PRS positioning measurements and / or to indicate and / or report the use of scheduled sidelink resources (e.g., SL-PRS transmission, SL-PRS reception, and / or SL-PRS measurement reporting resources) for sidelink positioning.

[0151] A WTRU may receive scheduled resources for sidelink positioning. For example, a WTRU (e.g., a target WTRU) may receive one or any combination of the following scheduled resources (e.g., sidelink resources and uplink resources) that may be from a network (e.g., a gNB, an LMF) or from another WTRU (e.g., an anchor WTRU) for sidelink positioning.

[0152] Sidelink transmission resources for indicating and / or reserving other resources for sidelink positioning may include resources for SL-PRS transmission, SL-PRS reception, SL-PRS resource usage reporting and / or indication, and / or SL-PRS measurement reporting. Messages transmitted on this type of resource may be referred to herein as sidelink positioning requests and / or request messages. A WTRU may use one or any combination of AS messages (e.g., SCI, MAC control element (MAC CE), and / or PC5-RRC messages) or NAS messages (e.g., LTE positioning protocol (LPP) messages) to indicate / reserve resources for sidelink resources.

[0153] The WTRU may schedule a sidelink transmission resource to indicate an SL-PRS transmission resource. The sidelink transmission resource may occur in the same slot as the associated SL-PRS transmission resource. The WTRU may further use the scheduled sidelink resource to indicate an SL-PRS reception resource and / or an associated SL-PRS measurement report resource. For example, if the scheduled sidelink transmission and its associated SL-PRS transmission occupy the same slot, the WTRU may use the SCI to indicate the SL-PRS transmission. Additionally or alternatively, the WTRU may use the SCI, MAC CE, RRC, and / or NAS (e.g., LPP) to indicate an associated SL-PRS reception resource and / or an associated SL-PRS measurement report that may occur in a different slot compared to the scheduled sidelink SL-PRS transmission resource.

[0154] The WTRU may schedule one sidelink transmission resource to indicate an SL-PRS transmission in another slot and / or resource. The WTRU may use any combination of SCI, MAC CE, PC5-RRC, and / or NAS (e.g., LPP) to indicate a sidelink positioning resource (e.g., SL-PRS transmission, SL-PRS reception, and / or SL-PRS measurement report resource).

[0155] The WTRU (e.g., the target WTRU) may receive one or more SL-PRS resources from a network (e.g., a gNB or LMF) for SL-PRS transmission. In an example, the WTRU (e.g., the anchor WTRU) may receive one or more SL-PRS resources from another WTRU (e.g., the target WTRU) for SL-PRS transmission. The target WTRU may receive SL-PRS resources from a network (e.g., a gNB or LMF). Additionally or alternatively, the target WTRU may perform autonomous resource selection for the SL-PRS resources and / or indicate and / or forward them to the anchor WTRU.

[0156] A WTRU (e.g., a target WTRU) may be indicated by a network with sidelink resources for SL-PRS reception. The network may also schedule the same sidelink resources for an anchor WTRU to perform SL-PRS transmission.

[0157] A WTRU (e.g., a target WTRU) may be indicated and / or scheduled by a network (e.g., a gNB, an LMF) with sidelink resources for SL-PRS reception. The WTRU may then transfer and / or indicate the scheduled SL-PRS reception resources to an anchor WTRU to perform SL-PRS transmission. The anchor WTRU may then perform SL-PRS transmission with the indicated / transferred SL-PRS resources, and then the target WTRU may perform SL-PRS reception with the SL-PRS resources.

[0158] In an example, a WTRU (e.g., an anchor WTRU) may indicate sidelink resources for SL-PRS reception to another WTRU (e.g., a target WTRU). The network may schedule SL-PRS resources from the anchor WTRU. The anchor WTRU may autonomously select SL-PRS resources.

[0159] A WTRU may have sidelink resources scheduled prior to SL-PRS transmission and / or reception resources. The scheduled sidelink resources may indicate whether the WTRU performs SL-PRS transmission and / or reception with the scheduled SL-PRS resources.

[0160] The target WTRU may indicate and / or be scheduled for two sidelink resources. The first resource may be used for SL-PRS reception (e.g., a sidelink resource for an anchor WTRU to perform SL-PRS transmission). The second sidelink resource may be used for the anchor WTRU to indicate whether the anchor WTRU will perform SL-PRS transmission. The second resource may occur before the first resource. The anchor WTRU may then use the second resource to indicate whether the anchor WTRU will perform SL-PRS transmission.

[0161] The target WTRU may indicate and / or be scheduled for two sidelink resources. The first resource may be used for SL-PRS transmission. The second resource may be used for the anchor WTRU to indicate whether the anchor WTRU will perform SL-PRS reception (e.g., whether the WTRU will perform SL-PRS measurement on the indicated resource). The second resource may occur before the SL-PRS transmission resource. The anchor WTRU may then use the second resource to indicate whether the WTRU will perform SL-PRS reception.

[0162] The WTRU may schedule sidelink resources after the SL-PRS transmission and / or reception resources. The scheduled sidelink resources may indicate whether the WTRU will perform SL-PRS transmission and / or reception on the scheduled SL-PRS resources.

[0163] The target WTRU may indicate and / or be scheduled for two sidelink resources. The first resource may be used for SL-PRS reception (e.g., a sidelink resource for an anchor WTRU to perform SL-PRS transmission). The second sidelink resource may be used for the anchor WTRU to indicate whether the anchor performs SL-PRS transmission. The second resource may occur after the first resource. Then, the WTRU may determine whether to perform SL-PRS transmission on the first resource. The WTRU may use the second resource to indicate whether the WTRU performs SL-PRS transmission on the first resource. For example, if the WTRU performs SL-PRS transmission on the first resource, the WTRU may indicate that it has transmitted SL-PRS on the first resource. Otherwise, if the WTRU lowers the priority of SL-PRS transmission on the first resource, the WTRU may indicate that it has not transmitted SL-PRS on the first resource.

[0164] The target WTRU may indicate and / or be scheduled for two sidelink resources. The first resource may be used for SL-PRS transmission, and the second resource may be used for the anchor WTRU to indicate whether the anchor WTRU performs SL-PRS reception (e.g., whether the WTRU performs SL-PRS measurement at the indicated resource). The second resource may occur after the SL-PRS transmission resource. The anchor WTRU may then use the second resource to indicate whether the WTRU performs SL-PRS reception. For example, if the WTRU performs SL-PRS reception and / or measurement on the first SL-PRS resource, the WTRU may indicate that it has performed SL-PRS reception on the second resource. Otherwise, if the WTRU lowers the priority of SL-PRS reception on the first resource, the WTRU may indicate that it has not performed SL-PRS reception on the second sidelink resource.

[0165] A WTRU (e.g., a target WTRU) may have two sidelink resources scheduled and / or indicated, where one resource may be used for the WTRU's own SL-PRS transmission and another sidelink resource may be used for SL-PRS measurement reporting. The anchor WTRU may perform such reporting using the sidelink resource used for SL-PRS measurement reporting. Positioning based on SL-PRS transmission may adopt this method. In the positioning method based on SL-PRS transmission, the target WTRU may perform SL-PRS transmission and / or receive measurement reports from the anchor WTRU.

[0166] A WTRU (e.g., a target WTRU) may be indicated and / or scheduled (e.g., by an anchor WTRU) for two sidelink resources. The target WTRU may use a first resource to perform SL-PRS reception. The target WTRU may use a second resource to perform SL-PRS measurement reporting. This approach may be used because the Network-Initiated Location Request (NI-LR) sidelink positioning method may adopt this approach. In NI-LR, the network may indicate and / or request the anchor WTRU to identify the location of the target WTRU.

[0167] A WTRU (e.g., a target WTRU) may be indicated / scheduled (e.g., from a gNB, LMF) for three sidelink resources, where the first two resources may be used for SL-PRS transmission and SL-PRS reception, and the third resource may be used for receiving SL-PRS measurement reports (e.g., Tx-Rx difference reports from an anchor WTRU). This approach may be used in the round-trip time (RTT) sidelink positioning method where the target WTRU may perform SL-PRS transmission, reception, and SL-PRS measurement report reception.

[0168] A WTRU (e.g., a target WTRU) may be indicated and / or scheduled for three sidelink resources (e.g., from a gNB and / or LMF), where the first two resources may be used for SL-PRS transmission and SL-PRS reception, and the third resource may be used for transmission of an SL-PRS measurement report (e.g., a Tx-Rx difference report from the target WTRU). Round-trip time (RTT) sidelink positioning may employ this method. In RTT, the target WTRU may perform SL-PRS transmission, reception, and / or SL-PRS measurement report transmission. The target WTRU may send an SL-PRS measurement report (e.g., a Tx-Rx difference from the target WTRU, which is the time difference between transmission of SL-PRS from the target WTRU and reception of SL-PRS from an anchor WTRU) to one of the anchor WTRUs. The target WTRU may receive an indication and / or configuration from a network and / or an anchor WTRU that instructs where the target WTRU may send its report. Additionally or alternatively, the target WTRU may send the SL-PRS measurement report to a network (e.g., an LMF and / or a gNB).

[0169] The uplink resources used to indicate and / or report the use of scheduled sidelink resources for sidelink positioning may be any combination of the following factors. The WTRU may schedule one uplink resource after one or more scheduled SL-PRS transmissions, SL-PRS receptions, and / or SL-PRS measurement reporting resources to indicate and / or report the use of the scheduled sidelink resources. The WTRU may indicate whether it uses the scheduled sidelink resources for sidelink positioning. For example, the WTRU may indicate whether the scheduled sidelink resources for SL-PRS transmission, reception, and / or SL-PRS measurement reporting are used. The WTRU may indicate and / or report whether it properly receives an SL-PRS measurement report from another WTRU (e.g., an anchor WTRU) using the scheduled sidelink resources. The WTRU may indicate and / or report whether it requires more sidelink resources for sidelink positioning.

[0170] Uplink resources for sidelink positioning reports (e.g., sidelink positioning and / or Uu positioning reports). For example, the WTRU may schedule uplink resources to perform a sidelink positioning report. The sidelink positioning report may be a sidelink positioning measurement report and / or the relative position of the WTRU (e.g., a target WTRU) with respect to another WTRU (e.g., an anchor WTRU).

[0171] Figure 8 depicts an exemplary diagram of potential scheduled and / or selected resources for sidelink positioning. As shown in Figure 8, the sidelink resources may indicate and / or reserve other resources for sidelink communication (e.g., resources for SL-PRS transmission, SL-PRS reception, SL-PRS resource usage reporting / indication, and / or SL-PRS measurement reporting), and occupy different slots from the SL-PRS transmission resources. In this example, a WTRU (e.g., a target WTRU) may be scheduled one or any combination of six types of resources for sidelink positioning. The first type of resource 802 (e.g., the resource with index 1) may implicitly and / or explicitly indicate one or any combination of the remaining types of resources. The second type of resources 804a - b (e.g., the resources with index 2) may indicate SL-PRS resource usage (e.g., by an anchor WTRU). The second type of resources 804a - b may occur before (804a) or after (804b) SL-PRS transmission and / or reception. The third and fourth types of resources 806 and 808 (e.g., the resources with index 3 or 4) may be used, respectively, for SL-PRS transmission and reception (e.g., by a target WTRU). The fifth type of resource 810 (e.g., the resource with index 5) may report SL-PRS measurements (e.g., by an anchor WTRU). Finally, the sixth type of resource 812 (e.g., the resource with index 6) may be a UL resource and may indicate sidelink resource usage for sidelink positioning (e.g., by a target WTRU).

[0172] Figure 9 depicts an example of potential scheduled / selected resources for sidelink positioning where the SL-PRS transmission resource 906 is within the same slot as its indication 902. Sidelink resources shown for and / or used to reserve other resources for sidelink communication may transmit in the same slot and / or resource as the SL-PRS transmission. In this example, a second type of resource 904a - b (e.g., resource with index 2) may indicate (e.g., by the anchor WTRU) SL-PRS resource usage (e.g., whether the WTRU performs SL-PRS transmission and / or reception of resources having index 3 or 4 at 906 and 908 respectively). The second type of resource 904a - b may occur before (904a) or after (904b) the SL-PRS reception resource 908. Similar to the example shown in Figure 8, a fifth type of resource 910 may report SL-PRS measurements. A sixth type of resource 912 may indicate sidelink resource usage for sidelink positioning.

[0173] A WTRU (e.g., a target WTRU) may determine a positioning method for a positioning group. For example, the WTRU may determine one or any combination of sidelink positioning methods including an SL-PRS transmission-based method, an SL-PRS reception-based method, and / or a sidelink RTT-based method.

[0174] Based on the determined positioning method, the WTRU (e.g., a target WTRU) may further request another WTRU (e.g., an anchor WTRU) to perform an SL-PRS transmission. For example, the WTRU may determine to perform a sidelink positioning method based on SL-PRS reception. The WTRU may then request the anchor WTRU to perform an SL-PRS transmission.

[0175] Based on the determined positioning method, the WTRU (e.g., the target WTRU) may further determine to request another WTRU (e.g., the anchor WTRU) to perform SL-PRS reception. For example, the WTRU may determine to implement a side link positioning method based on SL-PRS transmission. Then, the WTRU may request the anchor WTRU to perform SL-PRS reception.

[0176] Based on the determined positioning method, the WTRU (e.g., the target WTRU) may further determine to request another WTRU (e.g., the anchor WTRU) to perform both SL-PRS transmission and / or reception. The WTRU may determine to implement a positioning method based on SL RTT. The WTRU may then request the anchor WTRU to perform both SL-PRS transmission and / or reception. Based on the determined positioning method, the WTRU (e.g., the target WTRU) may further determine to request another WTRU (e.g., the anchor WTRU) to perform SL-PRS measurement reporting.

[0177] The WTRU may request the anchor WTRU to report different measurement parameters based on the selected sidelink positioning method. For the SL-PRS transmission-based method, the WTRU may request the anchor WTRU to report the reference signal time difference (RSTD), time of arrival (ToA), angle of arrival (AoA), phase of arrival (PoA), difference phase of arrival (DPoA), and / or SL-RSRP of the SL-PRS transmitted from the target WTRU. For the SL-PRS reception-based sidelink positioning method, the WTRU may request the anchor WTRU to report the time of departure (ToD), angle of departure (AoD), phase of departure (PoD), and / or difference phase of departure (DPoD) of the SL-PRS. For the RTT-based sidelink positioning method, the WTRU may request the anchor WTRU to report the Tx-Rx difference, SL-RSRP, ToD, AoD, ToA, ToD, PoA, PoD, DPoA, RSTD, and / or DPoD.

[0178] The WTRU may determine a positioning method for a sidelink positioning group based on one or any combination of the following factors, including scheduled sidelink resources (e.g., SL-PRS resources and / or SL-PRS measurement reporting resources) from the network (e.g., gNB and / or LMF). The WTRU may receive the scheduled sidelink resources from AS and / or NAS messages. The AS and / or NAS messages may include one or any combination of DCI, DL MAC CE, RRC, and / or LPP messages.

[0179] If the scheduled resource has both an SL-PRS transmission resource and an SL-PRS reception resource, the WTRU may perform RTT-based sidelink positioning. If the scheduled resource has an SL-PRS transmission resource, the WTRU may perform an SL-PRS transmission-based method. If the scheduled resource has an SL-PRS reception resource, the WTRU may perform an SL-PRS reception-based method.

[0180] The WTRU may determine the positioning method based on a set of SL-PRSs scheduled by the network. The WTRU (e.g., a target WTRU) may determine the positioning method for a group. The WTRU may indicate the determined positioning method to the WTRUs within the group. The WTRU may determine which positioning method to use for a sidelink positioning group based on one or any suitable combination of the following factors, namely, the set of scheduled SL-PRS resources scheduled by the network (e.g., the number of SL-PRS resources), the number of anchor WTRUs transmitting SL-PRS, and / or the characteristics of the scheduled SL-PRS resources. The number of anchor WTRUs transmitting SL-PRS, and / or the characteristics of the scheduled SL-PRS resources may include the time gap between the first SL-PRS resource and the last SL-PRS resource, and / or the time gap between two resources.

[0181] The WTRU may determine to perform SL-PRS SL-TDOA if the number of resources is less than twice the number of anchor WTRUs. The WTRU may determine to perform the RTT method if the number of SL-PRS resources is greater than twice the number of anchor WTRUs.

[0182] The WTRU may determine to implement an SL-TDOA positioning method, such as UL, if the time gap between the first SL-PRS resource and the last SL-PRS resource is smaller than a threshold. The WTRU may determine to implement an RTT method if the time gap between pairs of SL-PRS resources is smaller than a threshold.

[0183] FIG. 10 depicts an exemplary diagram of downlink control information (DCI) for scheduling resources for sidelink positioning. As shown in FIG. 10, in one resource scheduling message (e.g., DCI1000), the WTRU may be indicated one or any combination of bits in a bitfield for decoding one type of resource. The combination of bitfields may include sidelink resources 1002 for sidelink positioning, sidelink resources 1004 for SL-PRS transmission, sidelink resources 1006 for SL-PRS reception, sidelink resources 1008 for SL-PRS measurement reporting, and / or uplink resources for reporting the use of scheduled SL-PRS resources in the uplink, and / or sidelink resources for reservation.

[0184] The WTRU may be (pre-)configured with one value and / or code point within each bitfield to indicate that a type of resource is unavailable in a scheduled message. The WTRU may then determine whether there is a scheduled resource within each bitfield and / or any combination of bitfields for each type of resource in the scheduled message. In an example, in the scheduled message, the WTRU may determine that there are both SL-PRS transmission resources and SL-PRS reception resources. The WTRU may then determine to perform an RTT-based sidelink positioning method. In an example, in the scheduled message, the WTRU may determine that there is an SL-PRS transmission (e.g., there is no SL-PRS reception resource). The WTRU may then determine to perform an SL-PRS transmission-based sidelink positioning method. In an example, in the scheduled message, the WTRU may determine that there is an SL-PRS reception (e.g., there is no SL-PRS transmission resource). The WTRU may then determine to perform an SL-PRS reception-based sidelink positioning method.

[0185] The WTRU (e.g., the target WTRU) may be (pre-)configured with a plurality of resource scheduling formats (e.g., a plurality of DCI formats). Each format may include one or more types of resources for sidelink positioning. One type of resource for sidelink positioning may be a resource for sidelink positioning, a sidelink resource for SL-PRS transmission, a sidelink resource for SL-PRS reception, a sidelink resource for SL-PRS measurement reporting, and / or a sidelink resource for indicating / reserving the use of a scheduled SL-PRS resource in the uplink.

[0186] Next, the WTRU may decode (e.g., via RRC) one DCI format for one or more types of resources for sidelink positioning. The WTRU may decode one DCI format for an SL-PRS transmission-based method, and the WTRU may decode a DCI format that schedules sidelink resources for SL-PRS transmission and sidelink resources for SL-PRS measurement reporting. The WTRU may decode one DCI format for an SL-PRS reception-based method. The WTRU may decode a DCI format that schedules sidelink resources for SL-PRS reception. The WTRU may decode one DCI format for an SL-PRS transmission-based method. The WTRU may decode a DCI format that schedules sidelink resources for SL-PRS transmission and / or sidelink resources for SL-PRS measurement reporting.

[0187] The WTRU may be (pre-)configured with different scrambling codes (e.g., wireless network temporary identifier - RNTI) for different types of resource allocations for sidelink positioning. The WTRU may determine which type of resource allocation to perform for sidelink positioning based on the decoded scrambling code. For example, the WTRU may be (pre-)configured with three scrambling codes (e.g., via RRC) along with one scrambling code used for DCI that schedules SL-PRS transmission, SL-PRS reception, and / or SL-PRS measurement reporting. Another scrambling code may be used for SL-PRS reception. Another scrambling code may be used for SL-PRS transmission.

[0188] The WTRU may be pre-configured with two scrambling codes (e.g., via RRC). One scrambling code may be used for dynamic SL-PRS transmission, SL-PRS reception, and / or SL-PRS measurement reporting. Another scrambling code may be used for semi-static SL-PRS transmission, SL-PRS reception, and / or SL-PRS measurement reporting.

[0189] The WTRU may be pre-configured with one or more resource scheduling formats (e.g., DCI format). Each format may include one or more types of resources for sidelink positioning. The WTRU may then determine the resource scheduling format based on a format indicator in the message. The message may implicitly indicate the sidelink positioning method to be used. For example, the WTRU may be configured with three resource scheduling formats. Each format may be associated with one sidelink positioning method including SL-PRS transmission-based, SL-PRS reception-based, and / or sidelink RTT-based.

[0190] The WTRU may determine whether the DCI is for SL-PRS or for data transmission based on the RNTI. For example, the WTRU may be pre-configured with different scrambling codes (e.g., RNTI) for different types of DCI. One type of DCI may be used to schedule SL-PRS transmission and / or reception, and another type of DCI may be used to schedule normal data transmission. The WTRU may then determine whether to use the DCI for SL-PRS scheduling and / or normal data scheduling based on the associated RNTI.

[0191] The WTRU may determine whether the DCI is for SL-PRS and / or data transmission based on a search space set. For example, the WTRU may be (pre-)configured with different search space sets for different types of DCI. One search space set may be used for DCI that schedules SL-PRS transmission / reception, and another search space set may be used for DCI that schedules normal sidelink data transmission.

[0192] The WTRU may determine whether the DCI is for SL-PRS and / or data based on the indicated code point within a bit field. For example, the WTRU may be configured with one bit field in the DCI. One code point may be used for SL-PRS scheduling, and another code point may be used for normal data scheduling. The WTRU may then determine whether the DCI is used for SL-PRS transmission / reception or sidelink data based on the code point indicated in the DCI.

[0193] The WTRU may determine the DCI for SL-PRS based on an indication in the DCI. The WTRU may be configured with a 1-bit indicator in the DCI. The bit indicator may explicitly indicate whether the DCI is used to schedule SL-PRS. The WTRU may use the SL-PRS transmission scheduled in the DCI. The DCI may indicate that the resources are used for SL-PRS. Otherwise, the WTRU may not use the resources for SL-PRS.

[0194] The WTRU may determine whether the DCI is for SL-PRS based on the indication in the DCI. The WTRU may be configured with a 1-bit indicator in the DCI, and the bit indicator may explicitly indicate whether the DCI is used to schedule SL-PRS. The WTRU may use the SL-PRS transmission scheduled in the DCI. The DCI may indicate that the resource is used for SL-PRS. Otherwise, the WTRU may not use the resource for SL-PRS.

[0195] The WTRU may determine whether to transmit data and / or SL-PRS on the scheduled sidelink resource. The sidelink resource (e.g., within a shared resource pool between SL-PRS and data) may be scheduled for the WTRU. The WTRU may perform resource selection to select the sidelink resource. The WTRU may determine whether to transmit SL-PRS and / or sidelink data on the scheduled / selected resource based on one or any combination of factors including the priority associated with SL-PRS, the priority of the data, and the relative priority between SL-PRS and sidelink data.

[0196] The WTRU may determine whether to transmit SL-PRS and / or sidelink data on the scheduled / selected resources based on the characteristics of the scheduled sidelink resources (e.g., number of retransmissions and / or repetitions, bandwidth of the resource, time gap between the first and last resources, time gap between two consecutive resources, etc.). For example, the WTRU may determine whether to place SL-PRS on the sidelink resources based on the characteristics of the scheduled / selected sidelink resources. The WTRU may transmit SL-PRS having a bandwidth greater than a (pre-)configured threshold and / or a number of repetitions greater than a (pre-)configured threshold. If a (pre-)configured condition is met, the WTRU may prioritize transmitting SL-PRS. Otherwise, if the (pre-)configured condition is not met, the WTRU may not transmit SL-PRS. The WTRU may then transmit sidelink data. If a (pre-)configured condition is met, the WTRU may determine whether to transmit SL-PRS and / or sidelink data based on the relative priorities between SL-PRS. The WTRU may transmit the one with the higher priority.

[0197] The WTRU may determine whether to transmit SL-PRS and / or sidelink data on the scheduled / selected resources based on the destination associated with the data in the buffer. For example, when the WTRU places SL-PRS on a sidelink resource, the WTRU may place the sidelink data on the sidelink resource and transmit the SL-PRS together with the data. The WTRU may be (pre-)configured with a set of destination IDs for multiplexing with the SL-PRS. In the case of unicast SL-PRS, the WTRU may transmit the data together with the SL-PRS if both the data and / or the SL-PRS target the same WTRU. The WTRU may transmit the data together with the SL-PRS if the receiver of the SL-PRS receives the sidelink data. In the case of groupcast SL-PRS, the WTRU may transmit the data together with the SL-PRS if the receiver of the sidelink data receives the SL-PRS.

[0198] The WTRU may determine whether to transmit SL-PRS and / or sidelink data on the scheduled / selected resources based on the destination associated with the SL-PRS. For example, when the WTRU determines to place sidelink data on a sidelink resource, the WTRU may determine to opportunistically place the SL-PRS on the sidelink resource to transmit the SL-PRS along with the data. For each destination ID associated with the sidelink data, the WTRU may be (pre-)configured with a set of destination IDs associated with the SL-PRS for multiplexing with the sidelink data. For unicast sidelink data, the WTRU may transmit the data along with the SL-PRS if both the data and the SL-PRS target the same WTRU. In another approach, the WTRU may transmit the data along with the SL-PRS if the receiver of the sidelink data receives the SL-PRS. For groupcast sidelink data, the WTRU may transmit the data along with the SL-PRS if the receiver of the SL-PRS receives the sidelink data. For broadcast sidelink data, the WTRU may transmit the SL-PRS along with the sidelink data if both the sidelink data and / or the SL-PRS have the same destination ID (e.g., the same broadcast service).

[0199] The WTRU may determine whether to transmit SL-PRS and / or sidelink data on the scheduled / selected resources based on the cast type associated with the SL-PRS and / or sidelink data. In an example, if the WTRU determines to transmit SL-PRS on sidelink resources, the WTRU may determine to multiplex sidelink data on the resources based on the cast type associated with the SL-PRS and / or the cast type associated with the sidelink data. If the WTRU determines to transmit SL-PRS using broadcast, the WTRU may transmit sidelink data if the sidelink data is to be broadcast. The WTRU may transmit broadcast sidelink data if they belong to the same service. If the WTRU determines to transmit SL-PRS using groupcast, the WTRU may transmit sidelink data if the sidelink data targets the same group. If the WTRU determines to transmit sidelink data on sidelink resources, the WTRU may determine to multiplex SL-PRS on the resources based on the cast type associated with the SL-PRS and / or the cast type associated with the sidelink data. If the WTRU determines to transmit sidelink data using unicast, the WTRU may transmit SL-PRS if both the SL-PRS and / or the data target the same receiver.

[0200] The WTRU may determine whether to transmit SL-PRS and / or sidelink data on the scheduled / selected resources based on (pre-)configured restrictions. For example, the WTRU may be (pre-)configured to multiplex SL-PRS with sidelink data in one transmission in a resource pool. In one (pre-)configuration, the WTRU may not permit SL-PRS to be multiplexed with sidelink data. In another (pre-)configuration, SL-PRS may be multiplexed with sidelink data.

[0201] The WTRU may first determine whether to place data or SL-PRS on a resource based on the priority associated with the data and / or the priority associated with the SL-PRS. For example, the WTRU may place the one with the higher priority first. If the SL-PRS and / or the data have the same priority, the WTRU may prioritize one of the (pre)-configured priorities (e.g., either the data or the SL-PRS).

[0202] WTRU scheduling may be based on group common DCI for SL-PRS. For example, the WTRU may be (pre)-configured to monitor group common DCI (e.g., DCI for the group of WTRUs) and / or scheduling for SL-PRS transmission and / or reception for the group of WTRUs. The WTRU may then receive DCI that schedules a group of SL-PRS resources for the group of WTRUs.

[0203] The WTRU may determine the receiver and / or transmitter of each scheduled SL-PRS resource based on the role of the WTRU within the group (e.g., whether the WTRU is a target WTRU or an anchor WTRU), based on the positioning method (e.g., whether the positioning method can be SL-PRS transmission-based, SL-PRS reception-based, and / or RTT-based), based on the sequence of SL-PRS transmission and / or reception, based on the member ID of the WTRU within the group (e.g., the WTRU may determine which of the resources indicated by the DCI can be scheduled for the WTRU based on its member ID), and / or based on any suitable combination thereof. For example, the WTRU (e.g., the target WTRU) may be configured with an SL-PRS reception-based positioning method for a group of 5 WTRUs. The WTRU as the target WTRU may receive SL-PRS from the other 4 anchor WTRUs. The group may be scheduled 4 resources for SL-PRS, and each anchor WTRU may select one resource based on a function of its member ID.

[0204] The WTRU may determine whether to forward the scheduled SL-PRS for member WTRUs within the group. For example, the WTRU (e.g., the target WTRU) may receive SL-PRS scheduling for its SL-PRS transmission from the network (e.g., the gNB and / or the LMF). The WTRU may then determine whether to forward the scheduled SL-PRS transmission for WTRUs within the group (e.g., peer WTRUs or member WTRUs within the sidelink positioning group). The determination of whether to forward the scheduled SL-PRS may be based on the coverage status of the peer WTRU and / or member WTRUs. For example, if the peer WTRU or one or more member WTRUs are outside network coverage, the WTRU may forward the scheduled SL-PRS to the peer WTRU of the member WTRU.

[0205] The determination of whether to forward the scheduled SL-PRS may be based on the RRC state of the peer WTRU and / or member WTRUs. For example, if the peer WTRU or at least one member WTRU is not in the RRC connected (RRC_CONNECTED) state, the WTRU may forward the scheduled SL-PRS to the peer WTRU and / or member WTRUs. Otherwise, the WTRU may not forward the scheduled SL-PRS to the peer WTRU and / or member WTRUs.

[0206] The WTRU may determine to transmit the scheduled SL-PRS based on a positive acknowledgment (ACK) from the member WTRU. For example, the WTRU may be scheduled (e.g., by the gNB or LMF) for one or more SL-PRSs or may select them itself. The WTRU may send information regarding the scheduled and / or selected SL-PRS resources. The WTRU may expect a positive acknowledgment from the peer WTRU and / or the member WTRU. If the WTRU does not receive a positive acknowledgment from the peer WTRU and / or the member WTRU within the group, the WTRU may discard and / or release one or more SL-PRS resources. This approach may help prevent the WTRU from transmitting the SL-PRS when there is no WTRU receiving the SL-PRS.

[0207] The WTRU may determine which WTRU requests resources for sidelink positioning. In one approach, the WTRU (e.g., the target WTRU) may establish a group of WTRUs for sidelink positioning. The WTRU may then determine which WTRU within the group of WTRUs requests resources (e.g., sidelink and / or uplink) for sidelink positioning. The WTRU may then indicate (e.g., using the group ID) to the other WTRUs within the group which WTRU within the group is making the resource request (e.g., by using group PC5-RRC and / or LPP). In one approach, the target WTRU may request resources (e.g., for mobile originating location request (MO-LR) positioning services) for sidelink positioning. In an example, the anchor WTRU connected to the network may request resources (e.g., for network induced location request (NI-LR) positioning services) for sidelink positioning.

[0208] A WTRU may trigger resource allocation and / or resource requests for sidelink positioning. For example, a WTRU (e.g., a target WTRU) may trigger resource allocation and / or resource requests for sidelink positioning, which may include one or more of the following resources: sidelink resources for indicating and / or reserving other resources for sidelink positioning (e.g., sidelink resources for indicating and / or reserving resources for SL-PRS transmission, SL-PRS reception, and / or SL-PRS measurement reporting), sidelink resources for SL-PRS transmission, sidelink resources for SL-PRS reception, sidelink resources for reporting SL-PRS resource usage, sidelink resources for SL-PRS measurement reporting, uplink resources used to indicate and / or report the usage of scheduled SL-PRS resources, and / or uplink resources for sidelink positioning reports (e.g., sidelink positioning and / or Uu positioning reports).

[0209] To request resources for sidelink positioning (e.g., sidelink resources or uplink resources), a WTRU may use one or any combination of AS messages (e.g., a scheduling request (SR), an uplink media access control control element (UL MAC CE), RRC, and / or NAS messages (e.g., LPP)) for transmission in the uplink direction. A WTRU may use information related to group sidelink positioning (e.g., a group ID, a sidelink positioning service ID, and / or an L2 destination index, etc.) to request resources for sidelink positioning. A WTRU may trigger resource allocation and / or resource requests for sidelink positioning based on one or any combination of the events described herein and / or one or any combination of the following events.

[0210] A WTRU may initiate a sidelink positioning service. For example, the WTRU may initiate a sidelink positioning service (for a MO-LR service, for example). The WTRU may trigger resource allocation and / or resource requests for sidelink positioning.

[0211] A WTRU may receive an indication and / or a request from the network to potentially perform sidelink positioning. For example, the WTRU may receive a request and / or an indication from the network (from the LMF via an LPP message, for example) to potentially initiate sidelink positioning. The WTRU may trigger resource allocation and / or resource requests for sidelink positioning.

[0212] A WTRU (e.g., a target WTRU) may receive an indication and / or a request from another WTRU (e.g., an anchor WTRU) to perform sidelink positioning. For example, the anchor WTRU may initiate a sidelink positioning service to identify the location of the relative positioning of the target WTRU. The anchor WTRU may perform sidelink positioning by transmitting SL-PRS and / or may request the target WTRU to transmit and / or receive SL-PRS. The target WTRU may then receive an indication and / or a request from the anchor WTRU to perform sidelink positioning by transmitting and / or receiving SL-PRS and / or by performing SL-PRS measurement reports. The target WTRU may then trigger resource allocation and / or resource requests for sidelink positioning.

[0213] A WTRU (e.g., an anchor WTRU) receives implicit and / or explicit requests from another WTRU (e.g., a target WTRU) to perform sidelink transmission and / or reception for sidelink positioning (e.g., SL-PRS transmission, SL-PRS reception, SL-PRS measurement reporting, and / or SL-PRS resource usage reporting). In the case of a sidelink RTT-based positioning method, the target WTRU may perform SL-PRS transmission. Then, upon receiving the SL-PRS transmission from the target WTRU, the anchor WTRU may trigger a resource allocation and / or resource request for SL-PRS transmission and / or SL-PRS measurement reporting. A WTRU (e.g., an anchor WTRU) may receive SL-PRS from another WTRU (e.g., a target WTRU). Having SL-PRS measurement results, the WTRU may then trigger a resource allocation and / or resource request for SL-PRS measurement reporting. One WTRU (e.g., a target WTRU) may receive an SL-PRS resource usage report from another WTRU (e.g., an anchor WTRU), which may indicate that the WTRU does not perform SL-PRS reception and / or transmission on the scheduled and / or indicated sidelink resources. The target WTRU may then trigger a resource allocation and / or resource request for SL-PRS transmission and / or reception, which may be used to increase the number of SL-PRS resources for sidelink positioning reporting.

[0214] A WTRU (e.g., a target WTRU) may determine that existing sidelink resources are insufficient for positioning services. For example, if the WTRU (e.g., the target WTRU) does not receive an expected SL-PRS resource usage report, SL-PRS reception, and / or SL-PRS measurement report, it may trigger resource allocation for sidelink positioning and / or request additional resources. For example, if the WTRU or a peer WTRU (e.g., an anchor WTRU) downgrades the priority of SL-PRS transmission, SL-PRS reception, SL-PRS resource usage report, and / or SL-PRS measurement report, the WTRU (e.g., the target WTRU) may trigger resource allocation for sidelink positioning and / or request additional resources.

[0215] The WTRU (e.g., the target WTRU) receives from another WTRU an SL-PRS resource usage report and / or an SL-PRS measurement report that implicitly and / or explicitly indicates that the scheduled resources may not be used and / or are insufficient.

[0216] The WTRU (e.g., the target WTRU) receives from another WTRU (e.g., an anchor WTRU) an SL-PRS measurement report that implicitly and / or explicitly indicates that the scheduled resources may be insufficient for SL-PRS measurement.

[0217] The WTRU may have available SL-PRS positioning measurement results. For example, the WTRU (e.g., an anchor WTRU) may request (e.g., by a target WTRU) to perform an SL-PRS measurement report. Then, if the WTRU has available SL-PRS measurement results, the WTRU may trigger a request and / or resource allocation for an SL-PRS measurement report (e.g., from the network). For example, the WTRU (e.g., a target WTRU) may be (pre-)configured to perform SL-PRS measurements of at least N SL-PRS resources to generate an SL-PRS measurement report. When the WTRU successfully measures the N SL-PRS resources, the WTRU may generate SL-PRS measurement results. Then, the WTRU may trigger a resource request and / or resource allocation for the transmission of the SL-PRS measurement report.

[0218] The WTRU may receive information for sidelink positioning from one node and indicate that information to another node. For example, the WTRU may receive information for sidelink positioning implicitly and / or explicitly from one node (e.g., a network node, LMF (Location Management Function), gNB, another WTRU, etc.). For example, the WTRU may receive information regarding sidelink positioning from the LMF via an LPP message. For example, the WTRU may receive information regarding sidelink positioning from another node via its SL-PRS transmission. Then, the WTRU may indicate one or any combination of the information received from the node to another node (e.g., a network node, LMF, gNB, and / or another WTRU, etc.). Information that the WTRU may receive from one node and / or indicate to another node may include information for sidelink positioning. The information may include one or any combination of the following.

[0219] QoS associated with sidelink positioning (e.g., accuracy, latency, reliability, and / or availability of the sidelink positioning service).

[0220] The SL-PRS transmission and / or reception configuration may include one or any combination of the number of subchannels used for each SL-PRS resource, the number of symbols and / or slots used for each SL-PRS transmission resource, the COM value, the number of repetitions, the periodicity of SL-PRS transmission and / or reception, and / or the number of anchor WTRUs transmitting / receiving SL-PRS. The SL-PRS measurement report configuration may include one or any combination of a delayed SL-PRS measurement report and / or the periodicity of the SL-PRS measurement report.

[0221] In an example, sidelink positioning may be initiated based on at least one or a combination of the following. The anchor WTRU may send a request to the network (e.g., gNB, LMF, etc.) to obtain the relative and / or absolute position of the target WTRU. When the anchor WTRU sends a request to the LMF, the request may be sent via an LPP message. In an example, the anchor WTRU may include the ID of the target WTRU in the request to the network (e.g., LMF, gNB, etc.).

[0222] The target WTRU may send a request to the network to obtain its relative and / or absolute position. When the target WTRU sends a request to the LMF, the request may be sent via an LPP message. In an example, the target WTRU may include the ID of the anchor WTRU whose relative position can be determined in the request.

[0223] The target WTRU may send a request to one or more anchor WTRUs to determine its relative and / or absolute position. When the target WTRU sends a request to an anchor WTRU, the request may be sent via an LPP message (e.g., SL-LPP) or an AS layer message (e.g., PC5-RRC and / or MAC CE). Such a request may be sent over the sidelink via unicast, groupcast, and / or broadcast transmission. In an example associated with groupcast transmission and / or broadcast transmission, the target WTRU may include the ID of the anchor WTRU whose relative position can be determined in the request.

[0224] The LMF and / or gNB may send a request to the anchor WTRU to determine the relative and / or absolute position of the target WTRU. The request may be sent by the WTRU via an LPP message. In one example, the anchor WTRU receives the ID of the target WTRU.

[0225] The LMF and / or gNB may send a request to the target WTRU to report its relative and / or absolute position. In one example, the LMF and / or gNB includes the ID of the anchor WTRU whose relative position can be determined in the request.

[0226] The WTRU and / or a location service (LCS) client and / or application within the network may send a request to determine the relative and / or absolute position of the target WTRU. Such a request may be sent as an LCS (e.g., MO-LR and / or mobile terminal location request (MT-LR)), LPP, and / or AS layer (e.g., RRC, PC5, and / or RRC) message to the gNB, LMF, or anchor WTRU.

[0227] The WTRU may determine information for indicating and / or reporting SL-PRS resource usage. For example, the WTRU (e.g., the anchor WTRU) may receive an instruction and / or request (e.g., from the target WTRU) to perform SL-PRS transmission and / or SL-PRS reception. The WTRU may then determine to feedback to the requesting WTRU regarding SL-PRS resource usage. The WTRU may indicate information related to group sidelink positioning (e.g., the requesting WTRU ID, the sidelink positioning group ID, the sidelink positioning service ID, etc.) for feedback of a request for sidelink positioning.

[0228] The WTRU may use one or any combination of the following information, i.e., one or any combination of PSFCH, SCI, MAC CE, PC5-RRC, and / or NAS (e.g., LPP), to implicitly and / or explicitly feedback that the WTRU has successfully decoded a sidelink positioning request message. For example, the target may receive sidelink communication indicating and / or reserving SL-PRS resources for the anchor WTRU to perform SL-PRS transmission and / or reception. The anchor WTRU may feedback SL-PRS resource usage based on the reception of such sidelink communication. The WTRU may feedback ACK / NACK based on the decoding status of the sidelink communication. For example, if the WTRU successfully receives sidelink communication, the WTRU may feedback ACK. Otherwise, the WTRU may feedback NACK.

[0229] The WTRU may perform SL-PRS transmission and / or reception. In this case, the WTRU may feedback to the requesting WTRU prior to the SL-PRS transmission and / or reception resources. For example, the WTRU (e.g., the anchor WTRU) may receive an implicit and / or explicit request from another WTRU (e.g., the target WTRU) to perform SL-PRS transmission and / or reception. The WTRU may then feedback to the target WTRU that it may perform SL-PRS transmission and / or reception. The feedback resource may be sent after the request message and / or before the SL-PRS transmission and / or reception resources.

[0230] The WTRU may not perform SL-PRS transmission and / or reception. In this case, the WTRU may feedback to the requesting WTRU before the SL-PRS transmission and / or reception resources. For example, the WTRU (e.g., the anchor WTRU) may receive an implicit and / or explicit request to perform SL-PRS transmission and / or reception from another WTRU (e.g., the target WTRU). Then, the WTRU may feedback to the target WTRU that the WTRU may not perform SL-PRS transmission and / or reception. The feedback resource may be sent after the request message and / or before the SL-PRS transmission and / or reception resources. The WTRU may lower the priority of the SL-PRS transmission and / or reception resources and / or may feedback such information due to a WTRU that fails to decode the request message.

[0231] The WTRU may perform SL-PRS transmission and / or reception. In this case, the WTRU may feedback to the requesting WTRU after the SL-PRS transmission and / or reception resources. For example, the WTRU (e.g., the anchor WTRU) may receive an implicit and / or explicit request to perform SL-PRS transmission and / or reception from another WTRU (e.g., the target WTRU). Then, the WTRU may perform SL-PRS transmission and / or reception in the SL-PRS transmission and / or reception resources. The SL-PRS transmission and / or reception may be indicated in the request message. The WTRU may then feedback to the requesting WTRU that the WTRU has performed SL-PRS transmission and / or reception. The feedback message may occur after the SL-PRS transmission and / or reception resources.

[0232] The WTRU may lower the priority of one or more SL-PRS transmissions and / or receptions. In this case, the WTRU may feedback to the requesting WTRU after the SL-PRS transmission and / or reception resources. For example, a WTRU (e.g., an anchor WTRU) may receive an implicit and / or explicit request from another WTRU (e.g., a target WTRU) to perform SL-PRS transmission and / or reception.

[0233] The WTRU may then lower the priority of SL-PRS transmission and / or reception in the SL-PRS transmission and / or reception resources. The SL-PRS transmission and / or reception may be indicated in a request message. The WTRU may then feedback to the requesting WTRU that the WTRU has lowered the priority of SL-PRS transmission and / or reception. The feedback message may occur after the SL-PRS transmission and / or reception resources.

[0234] The WTRU may require more resources for SL-PRS transmission and / or reception. In an example, a WTRU (e.g., an anchor WTRU) may receive an implicit and / or explicit request from another WTRU (e.g., a target WTRU) to perform SL-PRS transmission / reception. In an example, the WTRU may lower the priority of SL-PRS transmission / reception. In another example, the WTRU may not receive sufficient SL-PRS resources to perform SL-PRS transmission and / or reception. The WTRU may then feedback to the requesting WTRU (e.g., the target WTRU) to indicate that the WTRU may require more resources for SL-PRS transmission and / or reception.

[0235] The WTRU may determine whether to report and / or indicate SL-PRS resource usage. For example, a WTRU (e.g., an anchor WTRU) may receive an instruction and / or request (e.g., from a target WTRU) to perform SL-PRS transmission and / or SL-PRS reception.

[0236] Next, the WTRU may determine whether to report and / or indicate SL-PRS resource usage based on one or any combination of the decoding statuses of the sidelink positioning request messages, i.e., the decoding status of the sidelink positioning request messages.

[0237] In an example, the WTRU may determine not to report and / or indicate SL-PRS resource usage if the WTRU successfully decodes the request message. Otherwise, if the WTRU fails to decode the request message, the WTRU may indicate and / or report SL-PRS resource usage to notify that the WTRU has failed to decode the request message. In an example, the WTRU may determine to indicate and / or report SL-PRS resource usage to indicate that the WTRU has successfully decoded the request message. Otherwise, if the WTRU fails to decode the request message, the WTRU may not perform an SL-PRS resource usage report.

[0238] In an example, the WTRU may perform an SL-PRS resource usage report regardless of whether the WTRU successfully decodes the request message. For example, the WTRU may indicate whether the WTRU has successfully or failed to decode the request message. In an example, the WTRU may determine not to indicate and / or report an SL-PRS resource usage report regardless of whether the WTRU fails or succeeds in decoding the request message.

[0239] The WTRU may determine whether to perform SL-PRS transmission and / or reception. For example, if the WTRU determines to perform SL-PRS transmission and / or reception, the WTRU may determine not to report and / or indicate SL-PRS resource usage. Otherwise, if the WTRU determines not to perform SL-PRS transmission and / or reception, the WTRU may indicate and / or report that the WTRU may not perform SL-PRS transmission and / or reception.

[0240] In an example, if the WTRU determines to perform SL-PRS transmission / reception, the WTRU may determine to indicate and / or report SL-PRS resource usage to indicate that the WTRU may perform SL-PRS transmission / reception. Otherwise, if the WTRU determines not to perform SL-PRS transmission / reception, the WTRU may not perform an SL-PRS resource usage report.

[0241] In an example, the WTRU may perform an SL-PRS resource usage report regardless of whether the WTRU performs SL-PRS transmission and / or reception. For example, if the WTRU determines to perform SL-PRS transmission and / or reception, the WTRU may report SL-PRS resource usage to indicate to the requesting WTRU that the WTRU may perform SL-PRS transmission and / or reception. Otherwise, if the WTRU determines not to perform SL-PRS transmission and / or reception, the WTRU may report SL-PRS resource usage to indicate to the requesting WTRU that the WTRU may not perform SL-PRS transmission and / or reception. In an example, the WTRU may determine not to indicate and / or report an SL-PRS resource usage report regardless of whether the WTRU performs SL-PRS transmission and / or reception.

[0242] The WTRU may determine whether to report and / or indicate SL-PRS resource usage based on whether the WTRU has performed SL-PRS transmission and / or reception. In an example, if the WTRU has performed SL-PRS transmission and / or reception, the WTRU may determine not to report and / or indicate SL-PRS resource usage. Otherwise, if the WTRU has not performed SL-PRS transmission and / or reception, the WTRU may indicate and / or report that the WTRU has not performed SL-PRS transmission / reception.

[0243] In an example, the WTRU may determine to indicate and / or report SL-PRS resource usage when the WTRU performs SL-PRS transmission and / or reception. Otherwise, if the WTRU is not performing SL-PRS transmission and / or reception, the WTRU may not perform an SL-PRS resource usage report.

[0244] In an example, the WTRU may perform an SL-PRS resource usage report regardless of whether the WTRU performs SL-PRS transmission and / or reception. For example, if the WTRU performs SL-PRS transmission and / or reception, the WTRU may report SL-PRS resource usage to indicate to the requesting WTRU that the WTRU has performed SL-PRS transmission and / or reception. Otherwise, if the WTRU is not performing SL-PRS transmission and / or reception, the WTRU may report SL-PRS resource usage to indicate to the requesting WTRU that the WTRU is not performing SL-PRS transmission / reception.

[0245] In an example, the WTRU may determine not to indicate and / or report SL-PRS resource usage regardless of whether the WTRU performs SL-PRS transmission / reception.

[0246] Next, the WTRU may determine whether to report and / or indicate SL-PRS resource usage regarding whether the WTRU has downgraded the priority of one or more SL-PRS transmissions and / or receptions.

[0247] In an example, the WTRU may determine not to indicate and / or report SL-PRS resource usage if the WTRU has downgraded the priority of one or more SL-PRS transmissions and / or receptions. Otherwise, if the WTRU has not downgraded the priority of one or more SL-PRS transmissions and / or receptions, the WTRU may indicate and / or report that the WTRU has not downgraded the priority of one or more SL-PRS transmissions and / or receptions.

[0248] In an example, the WTRU may determine to indicate and / or report SL-PRS resource usage when the WTRU lowers the priority of one or more SL-PRS transmissions and / or receptions. Otherwise, if the WTRU has not lowered the priority of one or more SL-PRS transmissions / receptions, the WTRU may not perform an SL-PRS resource usage report.

[0249] In an example, the WTRU may perform an SL-PRS resource usage report regardless of whether the WTRU has lowered the priority of one or more SL-PRS transmissions and / or receptions. For example, if the WTRU has lowered the priority of one or more SL-PRS transmissions and / or receptions, the WTRU may report SL-PRS resource usage to indicate to the requesting WTRU that the WTRU has lowered the priority of one or more SL-PRS transmissions and / or receptions. Otherwise, if the WTRU has not lowered the priority of one or more SL-PRS transmissions and / or receptions, the WTRU may report SL-PRS resource usage to indicate to the requesting WTRU that the WTRU has not lowered the priority of one or more SL-PRS transmissions and / or receptions.

[0250] In an example, the WTRU may determine not to indicate and / or report SL-PRS resource usage regardless of whether the WTRU has lowered the priority of one or more SL-PRS transmissions / receptions.

[0251] The WTRU may then determine whether to report and / or indicate SL-PRS resource usage based on whether the WTRU needs more resources for SL-PRS transmission and / or reception.

[0252] In an example, the WTRU may determine not to report and / or indicate SL-PRS resource usage if the WTRU does not need more SL-PRS transmission and / or reception resources. Otherwise, if the WTRU needs more SL-PRS transmission / reception resources, the WTRU may indicate and / or report that it needs more SL-PRS transmission and / or reception resources.

[0253] In an example, the WTRU may not perform an SL-PRS resource usage report if the WTRU requires more SL-PRS transmission and / or reception resources. Otherwise, if the WTRU does not require more SL-PRS transmission and / or reception resources, the WTRU may perform an SL-PRS resource usage report to indicate to other WTRUs that the WTRU does not require more SL-PRS transmission and / or reception resources.

[0254] The WTRU may determine a resource for indicating and / or reporting SL-PRS resource usage. For example, the WTRU may determine a resource for feeding back the usage of SL-PRS transmission / reception resources. For example, the feedback resource may be determined based on one or any combination of the following, including an indication from the requesting WTRU. For example, the requesting WTRU (e.g., the target WTRU) may indicate and / or reserve a resource for the receiving WTRU to feed back SL-PRS transmission and / or reception resource usage. The feedback resource may be indicated in a transmission that indicates and / or reserves SL-PRS transmission and / or reception resources.

[0255] The feedback resource may be determined based on a resource that indicates and / or reserves SL-PRS transmission / reception resources.

[0256] In an example, the WTRU may be (pre)configured (e.g., in a resource pool) with a mapping between a resource indicating and / or reserving SL-PRS transmission and / or reception and an associated feedback message. The WTRU may then determine to feedback a request message on the associated feedback resource. This approach may be used for scenarios where the WTRU uses the PSFCH to feedback SL-PRS transmission and / or reception resource usage.

[0257] In an example, a WTRU (e.g., an anchor WTRU) may trigger resource allocation and / or request sidelink resources (e.g., request to a gNB and / or LMF) to feedback a request. When the WTRU requests sidelink resources from the network, the WTRU may implicitly indicate the delay requirement (e.g., PDB) of the feedback message to assist the network in properly scheduling the feedback resources. For example, the WTRU may implicitly indicate the priority of the feedback. Additionally or alternatively, when the WTRU performs resource allocation, the WTRU may determine a resource allocation window for the feedback message based on the delay requirement of the feedback message.

[0258] The delay requirement of the feedback may be determined based on one or any combination of the following, i.e., whether the WTRU is (pre-)configured. For example, the WTRU may be (pre-)configured with a fixed delay requirement for the time gap between the resources reserved for and / or indicating SL-PRS transmission / reception and the feedback resources.

[0259] The delay of the feedback may be indicated from another WTRU. For example, a WTRU (e.g., an anchor WTRU) may receive the delay requirement for the feedback message from another WTRU (e.g., a target WTRU). The target WTRU may use PC5-RRC to convey the delay requirement to the feedback message.

[0260] The delay of the feedback can be indicated by a time gap between the resource indicating and / or reserving the SL-PRS resource and the SL-PRS transmission and / or reception resource. For example, the WTRU may determine the maximum delay of the feedback message based on the time gap between the resource indicating and / or reserving the SL-PRS resource and the actual SL-PRS resource. For example, the WTRU may transmit the feedback during the gap between the two resources considering WTRU processing (e.g., the WTRU may not be permitted to transmit the feedback in the N slots before the SL-PRS resource, where N may be based on the WTRU processing capability). Transmitting the feedback may enable the requesting WTRU to identify potential SL-PRS transmitting and / or receiving WTRUs.

[0261] The feedback resource may be determined based on the SL-PRS transmission / reception resource. For example, the WTRU may be (pre)-configured with an implicit mapping between the SL-PRS transmission and / or reception resource and the feedback resource to indicate and / or report SL-PRS resource usage (e.g., in a resource pool). The WTRU may then transmit the feedback based on the SL-PRS transmission and / or reception resource and the implicit mapping rule between the SL-PRS and / or feedback resources.

[0262] In an example, the WTRU may determine the feedback resource based on the SL-PRS transmission and / or reception resource and the delay requirement of the feedback. The WTRU may then feedback in the resource to meet the delay requirement.

[0263] The delay requirement of the feedback may be determined based on one or any combination of the following, including whether it is (pre)-configured with the WTRU. For example, the WTRU may be (pre)-configured with a fixed delay requirement for the time gap between the SL-PRS resource and the feedback resource (e.g., for each sidelink positioning service).

[0264] The feedback delay requirement may be indicated from another WTRU. For example, a WTRU (e.g., an anchor WTRU) may receive a delay requirement from another WTRU (e.g., a target WTRU) for feedback indicating SL-PRS resource usage. For example, the target WTRU may use PC5-RRC to convey the delay requirement of the feedback message. The delay requirement may then be determined as the time gap between the SL-PRS resource and the feedback resource.

[0265] The feedback delay requirement may be indicated by the time gap between the SL-PRS resource and the measurement report resource. For example, the WTRU may determine the maximum delay of the feedback message based on the time gap between the SL-PRS resource and the SL-PRS measurement report resource. For example, the WTRU may be allowed to transmit feedback in the gap between the two resources taking into account WTRU processing (e.g., the WTRU may not be permitted to transmit feedback in the N slots preceding the SL-PRS measurement report resource, where N may be based on the WTRU processing capability).

[0266] The feedback resource may be determined by the SL-PRS measurement report resource. For example, the WTRU may be (pre)-configured with an implicit mapping between the SL-PRS transmission and / or reception resource and the feedback resource to indicate and / or report SL-PRS resource usage (e.g., in a resource pool). The WTRU may then transmit feedback to indicate and / or report SL-PRS resource usage based on the SL-PRS transmission and / or reception resource and the implicit mapping rule between the SL-PRS and the feedback resource.

[0267] The feedback resource can be determined by a channel and / or message used to feedback SL-PRS transmission / reception resource usage. The WTRU can be configured (a priori) with two or more types of channels and / or messages to feedback SL-PRS transmission and / or reception resource usage. The WTRU can then determine a resource for feedbacking SL-PRS resource usage based on the type of channel / message used to feedback SL-PRS resource usage.

[0268] In an example, the WTRU can use a pre-configured implicit mapping-based approach to feedback SL-PRS resource usage for a first type of feedback channel (e.g., PSFCH feedback channel). For example, the WTRU can be pre-configured with a mapping between a resource indicating the SL-PRS resource and the PSFCH resource, or a mapping between the SL-PRS resource and the PSFCH feedback, to report and / or indicate SL-PRS resource usage. The WTRU can then determine a resource for feedbacking SL-PRS resource usage based on the resource indicating the SL-PRS resource or the SL-PRS resource and the pre-configured mapping rule.

[0269] In an example, the WTRU may use a window-based approach to feedback SL-PRS resource usage for a second type of feedback channel (e.g., feedback using one or any combination of SCI, MAC CE, PC5-RRC, and / or LPP). For example, the WTRU may first determine the delay requirement for feedback transmission. Next, the WTRU may request sidelink resources and / or perform resource allocation for feedback transmission within a time window. The time window may be within the delay requirement for feedback to indicate and / or report SL-PRS resource usage. Next, the WTRU may perform feedback transmission on the scheduled and / or selected feedback resources.

[0270] FIG. 11 depicts an exemplary diagram providing feedback of SL-PRS resource usage prior to the SL-PRS resource. In the example, as shown in FIG. 11, the target WTRU may perform a sidelink transmission 1102 in a sidelink communication resource pool 1104 to indicate and / or reserve an SL-PRS resource 1106 within an SL-PRS resource pool 1108. The anchor WTRU may have two options for feedback of SL-PRS resource usage. In option 1 at 1110, the WTRU may use an implicit mapping between the sidelink transmission and the feedback resources. In option 2 at 1112, the WTRU may transmit feedback on one of the resources within a window between the sidelink communication indicating and / or reserving the SL-PRS resource and the SL-PRS resource.

[0271] Figure 12 depicts an exemplary diagram that feeds back SL-PRS resource usage after the SL-PRS resource. In the example depicted in Figure 12, the target WTRU may perform sidelink transmission 1202. The anchor WTRU may have two options for feeding back SL-PRS resource usage. In Option 1 at 1204, the WTRU may use an implicit mapping between the sidelink transmission and the feedback resource. In Option 2 at 1206, the WTRU may transmit feedback on one of the resources within the window after the SL-PRS resource 1208.

[0272] The WTRU may determine the information to include in the SL-PRS measurement report. For example, the WTRU may include one or any combination of the following information in the SL-PRS measurement report: Information related to group sidelink positioning (e.g., anchor WTRU ID, target WTRU ID, group ID, and / or sidelink positioning service ID, etc.).

[0273] Information related to the SL-PRS resource can be used for measurement (e.g., SL-PRS transmission resource and / or SL-PRS reception resource). The WTRU may indicate the resource index used by the WTRU for performing the measurement and / or the measurement report. The WTRU may indicate the number of resources used by the WTRU for SL-PRS measurement. The WTRU may indicate the SL-PRS window used by the WTRU for SL-PRS measurement.

[0274] SL-PRS positioning measurement parameters that can be determined based on the sidelink positioning method. The WTRU may report the RSTD, ToA, AoA, PoA, DPoA, and / or SL-RSRP of the SL-PRS transmitted from the target WTRU for the SL-PRS transmission-based method. For example, the WTRU may report the ToD, AoD, PoD, DPoD, and / or SL-PRS for the sidelink positioning method based on SL-PRS reception. For example, the WTRU may report the Tx-Rx difference, RSTD, SL-RSRP, ToD, AoD, ToA, ToD, PoA, PoD, DPoA, and / or DPoD for the RTT-based sidelink positioning method.

[0275] The WTRU may include the accuracy of the SL-PRS measurement in its SL-PRS measurement report. For example, the WTRU may indicate the error limit of the SL-PSR measurement (e.g., maximum error and / or deviation of the error, etc.).

[0276] The WTRU may include the need for additional SL-PRS resources in its SL-PRS measurement report. For example, the WTRU may implicitly and / or explicitly indicate whether the WTRU needs additional SL-PRS resources to perform the SL-PRS measurement. The WTRU may determine whether to request more resources for the SL-PRS measurement based on the accuracy and / or availability of the SL-PRS measurement. For example, if the accuracy of the current SL-PRS measurement is less than the threshold and / or the WTRU does not have available SL-PRS measurements, the WTRU may implicitly and / or explicitly request more SL-PRS resources for the measurement.

[0277] The WTRU may include sidelink positioning assistance information in its SL-PRS measurement report. For example, the WTRU (e.g., the anchor WTRU) may indicate assistance information to help the WTRU reported in the sidelink positioning. The assistance information may include the location of the WTRU (e.g., the zone ID of the WTRU and / or the absolute position of the WTRU), the movement characteristics of the WTRU (e.g., direction of travel and / or speed, etc.), and / or the antenna configuration of the WTRU.

[0278] The WTRU may drop the scheduled resources for SL-PRS resource usage reporting. For example, the WTRU (e.g., the anchor WTRU) may request the network to schedule sidelink resources to indicate and / or report the SL-PRS resource usage report. The WTRU may determine not to perform the transmission of the SL-PRS resource usage report if the scheduled resources do not meet the reporting latency requirement.

[0279] The WTRU may determine information to indicate and / or report sidelink resource usage in uplink transmission. For example, the WTRU may report sidelink resource usage for sidelink positioning to the network. The WTRU may include one or any combination of the following information to the network: The WTRU has or has not received feedback to indicate SL-PRS resource usage from one or more WTRUs and / or resources. For example, the WTRU (e.g., the target WTRU) may be the scheduled sidelink resource for a group of WTRUs (e.g., the group of anchor WTRUs). The WTRU may perform sidelink transmission to indicate and / or reserve resources for sidelink positioning. The WTRU may expect to receive feedback from all WTRUs within the group. Then, the WTRU may decode the feedback from the WTRUs within the group indicating the SL-PRS resource usage. Then, the WTRU may report the set of WTRUs to the network.

[0280] The feedback that a WTRU can report to the network can have one or any combination of the following information: a set of WTRUs with ACK feedback, a set of WTRUs with NACK feedback, a set of WTRUs with DTX, a set of WTRUs that can perform SL-PRS transmission and / or reception, a set of WTRUs that may not perform SL-PRS transmission and / or reception, a set of WTRUs that have performed SL-PRS transmission and / or reception, a set of WTRUs with SL-PRS transmission and / or reception with reduced priority.

[0281] The WTRU may include information for indicating and / or reporting in the uplink side link resource usage whether the WTRU has received SL-PRS from one or more WTRUs / resources. For example, the WTRU (e.g., the target WTRU) may have a set of SL-PRS reception resources from one or more anchor WTRUs scheduled. The WTRU may then perform SL-PRS reception on the scheduled set of SL-PRS resources. The WTRU may then report a set of WTRUs that transmit SL-PRS and / or a set of SL-PRS resources with SL-PRS measurement results. The WTRU may report a set of WTRUs that do not transmit SL-PRS and / or a set of SL-PRS resources without SL-PRS measurement results.

[0282] The WTRU may include information for indicating and / or reporting in the uplink side link resource usage whether the WTRU has received and / or for SL-PRS measurement reports from one or more WTRUs / resources. The WTRU may indicate to the network a set of WTRUs that report SL-PRS measurement results. The WTRU may indicate to the network a set of WTRUs that do not report SL-PRS measurement results.

[0283] The WTRU may include information for indicating and / or reporting whether the WTRU can perform SL-PRS transmission and / or reception in one or more SL-PRS resources in the uplink side link resource usage. For example, the WTRU may have a set of SL-PRS transmission and / or reception resources scheduled by the network. The WTRU may then report the set of SL-PRS resources to the network, and the WTRU can perform SL-PRS transmission and / or reception. The WTRU may report the set of SL-PRS resources, and the WTRU may not perform SL-PRS transmission and / or reception. In this case, the uplink resource may occur before the SL-PRS transmission and / or reception resources.

[0284] The WTRU may include information for indicating and / or reporting whether the WTRU has performed SL-PRS transmission and / or reception in one or more SL-PRS resources in the uplink side link resource usage. For example, the WTRU may have a set of SL-PRS transmission / reception resources scheduled by the network. After performing SL-PRS transmission and / or reception in 0 or more scheduled SL-PRS resources, the WTRU may then report the set of SL-PRS resources to the network, and the WTRU is performing SL-PRS transmission and / or reception. The WTRU may then report the set of SL-PRS resources to the network, and the WTRU is not performing SL-PRS transmission and / or reception. In this case, the uplink resource may occur after the SL-PRS transmission and / or reception resources.

[0285] The WTRU may include information for indicating and / or reporting whether the WTRU may need additional sidelink resources for sidelink positioning, as indicated by sidelink resource usage in the uplink. The WTRU may implicitly and / or explicitly indicate to the network that the WTRU may or may not need more sidelink resources for sidelink positioning. The WTRU may indicate ACK / NACK to the network as to whether the WTRU needs more sidelink resources for sidelink positioning. These required sidelink resources may be associated with one sidelink positioning cycle. If the WTRU does not need more resources for sidelink positioning, the WTRU may report an ACK. Otherwise, the WTRU may report a NACK if the WTRU needs more resources for sidelink positioning.

[0286] The WTRU may determine whether the WTRU needs more resources for sidelink positioning based on one or any combination of the following: The WTRU has received at least N ACK feedbacks from other WTRUs for transmitting and / or receiving SL-PRS. For example, the WTRU may report an ACK. The WTRU may use an ACK to indicate to the network that the WTRU needs more resources for sidelink positioning if the WTRU has received at least N ACK feedbacks from other WTRUs for transmitting and / or receiving SL-PRS. Otherwise, the WTRU may report a NACK if the WTRU has received less than N ACK feedbacks from other WTRUs for transmitting and / or receiving SL-PRS. The value of N may be fixed and pre-configured based on positioning accuracy requirements and / or the total number of WTRUs in the sidelink positioning group.

[0287] The WTRU may determine whether it needs more resources for sidelink positioning based on whether the WTRU has performed / received SL-PRS transmission / reception from at least N WTRUs / resources. For example, the WTRU may report an ACK to the network if it has received SL-PRS transmission and / or reception from at least N WTRUs and / or N resources. Otherwise, if the WTRU has received SL-PRS transmission and / or reception from fewer than N WTRUs and / or resources, the WTRU may report a NACK. The value of N may be (pre-)configured based on positioning accuracy requirements, the total number of WTRUs within the sidelink positioning group, and / or the total number of scheduled SL-PRS transmission and / or reception resources.

[0288] The WTRU may determine whether it needs more resources for sidelink positioning based on whether the WTRU has received an ACK feedback to indicate and / or report SL-PRS resource usage from at least N WTRUs. For example, the WTRU may report an ACK to the network if it has received at least N ACK feedbacks from other WTRUs that indicate and / or report SL-PRS resource usage. Otherwise, the WTRU may report a NACK. The value of N may be (pre-)configured based on positioning accuracy requirements and / or the total number of WTRUs within the sidelink positioning group.

[0289] The WTRU may determine whether more resources for sidelink positioning are needed based on whether the WTRU has received SL-PRS measurement reports from at least N WTRUs (e.g., having valid / available measurement results). For example, the WTRU may report an ACK to the network if the WTRU has received SL-PRS measurement reports from at least N WTRUs (e.g., having valid / available measurement results). Otherwise, the WTRU may report a NACK to the network if the WTRU has received SL-PRS measurement reports from less than N WTRUs. The value of N may be fixed and pre-configured based on positioning accuracy requirements and / or the total number of WTRUs within the sidelink positioning group.

[0290] A WTRU (e.g., a target WTRU) may perform SL-PRS measurements to the network. The WTRU may report its SL-PRS measurements and / or forward the SL-PRS measurements of other WTRUs to the network. The WTRU may use one or any combination of MAC CE, RRC, and / or NAS (e.g., LPP) to report sidelink positioning to the network. In an example, the WTRU may send all SL-PRS measurement reports (e.g., including its SL-PRS measurements) from one or more WTRUs within the sidelink positioning group to the network. In another approach, the WTRU may filter which SL-PRS measurement reports, resources, and / or WTRUs from multiple WTRUs (e.g., including itself) to the network based on one or any combination of the maximum number and / or minimum number of WTRUs / reports to forward to the network. For example, a WTRU (e.g., a target WTRU) may pre-configure the maximum number and / or minimum number of reports and / or WTRU measurement reports in a message for reporting to the network. The WTRU may then select the number of reports to the network and / or WTRU measurement reports based on the pre-configured values.

[0291] The WTRU may filter any SL-PRS measurement reports, resources, and / or WTRUs from multiple WTRUs based on the availability of one or more parameters in the SL-PRS measurement report. For example, the WTRU may transfer the measurement report and / or the measurement report of the WTRU if the measurement report includes one or any combination of the following parameters that include the location of the reporting WTRU (e.g., the anchor WTRU). For example, the WTRU may not report the SL-PRS measurement report of one anchor WTRU if the location information of the anchor WTRU is not available in the report.

[0292] The measurement report may include one or more SL-PRS measurement parameters from one or more WTRUs, such as RSTD, Tx-Rx, SL-RSRP, per-path SL reference signal power (SL-RSRPP), ToD, AoD, ToA, ToD, PoA, PoD, DPoA, and / or DPoD for RTT-based sidelink positioning methods. For example, in the case of the RTT method, the WTRU may not transfer the SL-PRS measurement report (e.g., Tx-Rx) of one anchor WTRU if the Tx-Rx between the SL-PRS transmission and / or reception measured from the target WTRU is not available.

[0293] The WTRU may filter any SL-PRS measurement reports, resources, and / or WTRUs from multiple WTRUs based on whether one or more parameters in each SL-PRS measurement report are within a range. For example, the WTRU may transfer the SL-PRS measurement report of one WTRU if one or more measurement parameters are within the range. The parameters within the range may be (pre-)configured. The measurement parameters may be one or more of RSTD, Tx-Rx, SL-RSRP, ToD, AoD, ToA, ToD, PoA, PoD, DPoA, and / or DPoD.

[0294] A WTRU may determine whether to request SL-PRS resources for another WTRU. In an example, each WTRU within a positioning group may request SL-PRS resources for itself. In an example, one WTRU may request SL-PRS resources for multiple WTRUs. A WTRU (e.g., a target WTRU) may determine whether to request and / or select SL-PRS resources for another WTRU based on one or any suitable combination of the following, including a positioning method. For example, the target WTRU may request SL-PRS resources for the WTRUs within the group if the group uses the SL-TDOA positioning method. Additionally and alternatively, if the group uses the RTT method, each WTRU may independently select its transmission resources. For example, when utilizing an angle-based positioning method, the WTRU may determine not to request SL-PRS resources for other WTRUs.

[0295] A WTRU may determine whether to request and / or select SL-PRS resources for another WTRU based on the coverage status of each WTRU within the group. For example, a WTRU (e.g., a target WTRU) may request SL-PRS resources for another WTRU if the other WTRU is out of coverage.

[0296] A WTRU may determine whether to request and / or select SL-PRS resources for another WTRU based on the RRC state of each WTRU. For example, a WTRU (e.g., a target WTRU) may request SL-PRS resources for another WTRU if the other WTRU is in the RRC idle and / or RRC inactive state.

[0297] In an example, for the SL-TDOA positioning method, the WTRU may request SL-PRS for all WTRUs within the positioning group. In an example, the WTRU may request SL-PRS resources for an out-of-coverage WTRU. In an example, the WTRU may request SL-PRS resources for a WTRU within RRC-inactive and RRC-idle WTRUs.

[0298] The WTRU may determine the value of parameters for SL-PRS transmission / reception resources for a group. The WTRU may determine the value of one or any suitable combination of the following parameters for SL-PRS transmission and / or reception resources for a group, namely, the number of SL-PRS transmission and / or reception resources, the minimum, maximum, and / or exact time gap between two SL-PRS resources, the earliest and / or latest SL-PRS resources, and / or the SL-PRS measurement and processing window.

[0299] After determining one or more of the above parameters, the WTRU may indicate one or more of these parameters to a network (e.g., LMF and / or gNB), which may help the network schedule SL-PRS resources. One or any combination of these parameters for SL-PRS transmission and / or reception may be resources for a group.

[0300] One or any combination of the above parameters may be determined by one or any suitable combination of the following, including a positioning method. In an example, for the SL-TDOA method such as DL, the WTRU may determine that the maximum time gap between the first SL-PRS resource and the last SL-PRS resource is less than a threshold. The network (e.g., LMF) may indicate the time gap and / or the threshold. In an example, for the RTT method, the WTRU may determine the maximum time gap between SL-PRS and / or SL-PRS Rx. The network (e.g., LMF) may indicate the maximum time gap.

[0301] The QoS of the positioning service may also determine the above parameters. For example, the WTRU may determine the number and / or the latest SL-PRS resources based on the delay requirement of the positioning service.

[0302] The WTRU processing capabilities and / or WTRU type may also determine the above parameters. For example, the WTRU may send its capabilities for transmitting and / or receiving a first SL-PRS to the network. The network may then schedule the first SL-PRS that the WTRU will transmit and / or receive accordingly.

[0303] The WTRU may use one SL-PRS transmission to multiple anchor WTRUs in the RTT method. The WTRU (e.g., the target WTRU) may perform the SL-PRS for the RTT method using unicast (e.g., the SL-PRS targets only one WTRU). In another approach, the WTRU may perform the SL-PRS for the RTT method using groupcast (e.g., the SL-PRS targets one group of WTRUs). The WTRU may transmit a group ID in a transmission (e.g., SCI) associated with the SL-PRS to indicate group information. Each receiving WTRU within the group may then transmit the SL-PRS as a reply for the transmitter.

[0304] SL-PRS transmission may be achieved via unicast, groupcast, and / or broadcast. In one example, the WTRU may determine to transmit the SL-PRS via unicast based on a positioning method. In the case of an RTT-based positioning method, unicast-based SL-PRS transmission may be applicable. The target WTRU and / or the anchor WTRU may transmit and / or receive the SL-PRS to / from each other.

[0305] In an example, in the case of a TDOA-based positioning method, SL-PRS transmission via groupcast can be applied. The Tx WTRU may transmit SL-PRS to a group of WTRUs. The Tx WTRU may send a message to the group of WTRUs notifying of the PRS configuration used for groupcast transmission (e.g., SL PRS resource ID, group ID, SL PRS ID, index and / or method used to generate the SL-PRS sequence, where the sequence consists of complex symbols and / or real symbols and they are mapped to resource elements).

[0306] In an example, in the case of TDOA-based positioning targeting, broadcast SL-PRS transmission can be applied for two or more Rx WTRUs. The Tx WTRU may transmit SL-PRS to a potentially unknown number of Rx WTRUs. The Rx WTRU may make measurements (e.g., RSTD) on the received SL-PRS, and the Rx WTRU may be configured to receive SL-PRS and / or PRS from a reference WTRU and / or TRP. The Rx WTRU may make measurements on ToA for the SL-PRS and / or PRS received from the reference WTRU / TRP and the target WTRU / TRP, and may determine RSTD based on ToA. The Rx WTRU may receive a broadcast ID from the network and / or peer WTRUs based on the generated PRS sequence. The peer WTRU may be an anchor WTRU / Tx WTRU / positioning reference unit (PRU) and / or a WTRU having LMF capabilities.

[0307] In an example, a WTRU (e.g., a target WTRU) may participate in the positioning procedure of a sidelink positioning group for an RTT-based positioning method. The positioning group may include one target WTRU and / or one or more anchor WTRUs. The WTRU (e.g., the target WTRU) may send SL-PRS to one or more anchor WTRUs using groupcast-based SL-PRS. Specifically, the WTRU may send one SL-PRS targeting one or more anchor WTRUs. As an example, the WTRU may use a group ID to indicate the destination of its SL-PRS. All anchor WTRUs within the group may be the destination of that SL-PRS transmission. For the transmission of SL-PRS from each anchor WTRU to the target WTRU, each anchor WTRU may send the associated SL-PRS to the target WTRU using unicast-based transmission. Specifically, each anchor WTRU may use the target WTRU ID as the destination of its SL-PRS transmission. In an example, each anchor WTRU may send the associated SL-PRS using groupcast-based transmission. Specifically, each anchor UE may use the group ID to send the SL-PRS to the target WTRU.

[0308] In an example, a WTRU (e.g., an anchor WTRU) may participate in the positioning procedure of a sidelink positioning group for an RTT-based positioning method. The positioning group may include one or more anchor WTRUs and / or a plurality of target WTRUs. The WTRU (e.g., an anchor WTRU) may use groupcast-based transmission to transmit SL-PRS to a plurality of target WTRUs within the group and potentially other anchor WTRUs. For example, the WTRU (e.g., an anchor WTRU) may use a group ID to indicate the destination of its SL-PRS, which may target all target WTRUs within the group and / or potentially other anchor WTRUs. For the transmission of SL-PRS from each target WTRU to the anchor WTRU, each target WTRU may use unicast-based transmission to transmit the SL-PRS to the anchor WTRU. Specifically, each target WTRU may use the anchor WTRU ID as the destination of its SL-PRS transmission. In the example, each target WTRU may use groupcast-based transmission to transmit the associated SL-PRS to the anchor WTRU. Specifically, each target WTRU may use the group ID to transmit the SL-PRS to the anchor WTRU.

[0309] The WTRU may determine whether to use unicast or groupcast to transmit the SL-PRS for the RTT method. The WTRU may make this determination based on one or any combination of the following, including the QoS requirements (e.g., latency) of the positioning service. For example, the WTRU (e.g., a target WTRU) may use groupcast for a low-latency positioning service to transmit the SL-PRS. Additionally or alternatively, for a less stringent positioning service, the WTRU may use the unicast type to transmit the SL-PRS to the group.

[0310] Positioning result / output (e.g., whether the result / output is relative positioning or absolute positioning). For example, in the case of absolute positioning output, the WTRU may transmit the SL-PRS using a groupcast message. In the case of relative positioning output, the WTRU may transmit the SL-PRS using a unicast message.

[0311] The WTRU may determine whether to use unicast and / or groupcast for the RTT method to transmit the SL-PRS based on the type of device. For example, a roadside unit (RSU) may transmit the SL-PRS using groupcast when a positioning group is set. Additionally or alternatively, the RSU may transmit the SL-PRS using broadcast when the WTRU is not involved in a positioning group and / or when the SL-PRS is not group-intended.

[0312] The WTRU may determine whether to use unicast and / or groupcast for the RTT method to transmit the SL-PRS based on network indication. The WTRU may determine to transmit the SL-PRS via unicast, groupcast, and / or broadcast based on an indication and / or configuration from the network.

[0313] The WTRU may determine whether to use unicast and / or groupcast for the RTT method to transmit the SL-PRS based on the number of resources for transmitting the SL-PRS. The WTRU may select the number of resources for transmitting the SL-PRS. The network (e.g., gNB or LMF) may schedule the number of resources for transmitting the SL-PRS. For example, if the number of resources for transmitting the SL-PRS is less than a (pre-)configured threshold, the WTRU may use groupcast-based transmission to transmit the SL-PRS. Otherwise, the WTRU may use unicast-based SL-PRS transmission. The (pre-)configured threshold may be a function of the WTRUs within the group.

[0314] A WTRU may determine which WTRU requests / selects sidelink resources for one or more members within a group. A WTRU (e.g., a target WTRU) may determine which WTRU (including itself) requests and / or selects sidelink resources for one or more WTRUs within a group based on one or any combination of the following, including whether the WTRU has initiated a positioning session. In an example, a target WTRU may request and / or select sidelink resources for the group if the WTRU triggers a sidelink positioning session and / or procedure to identify its own location. In an example, if an anchor WTRU triggers a sidelink positioning session and / or procedure to identify the location of one or more target WTRUs, the anchor WTRU may request and / or select sidelink resources for the group. The anchor WTRU may receive a request from the LMF to trigger the location identification of the target WTRU. In this scenario, the anchor WTRU may request and / or select sidelink resources for other WTRUs (e.g., one or more target WTRUs).

[0315] A WTRU (e.g., a target WTRU) may determine which WTRU (including itself) requests and / or selects sidelink resources for one or more WTRUs within a group based on the coverage status of the WTRU. One WTRU may request sidelink resources for the group if that WTRU is within coverage.

[0316] A WTRU (e.g., a target WTRU) may determine which WTRU (including itself) requests and / or selects sidelink resources for one or more WTRUs within a group based on the WTRU type. An RSU may request and / or select sidelink resources for another WTRU (e.g., a target WTRU).

[0317] For RTT positioning methods, the WTRU may determine SL-PRS resources. In the case of RTT positioning methods, one WTRU (e.g., an anchor WTRU) may receive SL-PRS Tx from another WTRU (e.g., a target WTRU). The WTRU may determine which resources will send back SL-PRS based on a (pre-)configured mapping between a first SL-PRS transmission resource and a second SL-PRS transmission resource. For example, the WTRU may (pre-)configure a mapping between a first SL-PRS and a second SL-PRS within a resource pool. The WTRU may then determine the resources for the second SL-PRS based on the resources for the first SL-PRS.

[0318] The WTRU may also determine which resources to send back for SL-PRS based on an indication from another WTRU (e.g., a target WTRU).

[0319] The WTRU may also determine which resources to send back for SL-PRS based on resources scheduled by the network based on a request from the WTRU. For example, the WTRU may request the network to schedule SL-PRS resources. The WTRU may implicitly and / or explicitly indicate the purpose of the requested resources (e.g., for transmitting a second SL-PRS in an RTT positioning method). The WTRU may then further indicate information about the requested SL-PRS resources such as bandwidth, SL-PRS pattern, delay, and / or number of repetitions and / or retransmissions. Such parameters may be determined based on the SL-PRS configuration of the first SL-PRS transmission. For example, the WTRU may (pre-)configure a maximum gap between two resources. The WTRU may then indicate the delay of the second SL-PRS resource based on the timing of the first SL-PRS resource.

[0320] A WTRU may request resources for sidelink positioning. For example, in one set of solutions, a WTRU (e.g., a target WTRU) may request sidelink positioning for itself and / or for a group of sidelink positioning. The WTRU may first establish group communication for sidelink communication, and the group communication may include itself (e.g., the target WTRU) and other WTRUs (e.g., anchor WTRUs). The WTRU may (pre-)configure and / or allocate one or more IDs and / or indexes (e.g., group ID, L2 ID, and / or L2 destination index) for communicating between WTRUs within the group for sidelink positioning and / or for communicating with the network (e.g., via UCI, MAC CE, RRC, and / or LPP). The WTRU may use one or a combination of AS messages (e.g., one or any combination of UCI, MAC CE, and / or RRC) and / or NAS messages (e.g., LPP) to request resources for sidelink positioning. The WTRU may use information related to group sidelink positioning (e.g., group ID, L2 ID, and / or L2 destination index) to request resources for sidelink positioning. The WTRU may be (pre-)configured with one or more group IDs. Each group ID may be associated with one group that the WTRU participates in for sidelink positioning.

[0321] The WTRU may implicitly and / or explicitly include one or any combination of the following information to request resources for sidelink positioning: sidelink positioning method, total number of resources for SL-PRS transmission and / or reception, total number of resources for SL-PRS transmission and / or reception per SL-PRS period, total number of resources for SL-PRS measurement reporting, number of SL-PRS transmission and / or reception periods, duration of SL-PRS transmission and / or reception, duration of SL-PRS measurement reporting, periodicity of SL-PRS transmission and / or reception, periodicity of SL-PRS measurement reporting, number of WTRUs in the sidelink positioning group, amount of data for SL-PRS measurement reporting in sidelink and / or uplink, QoS of sidelink positioning (e.g., priority, delay, and / or reliability).

[0322] The WTRU may send sidelink positioning group information to the network. The information may assist the network in resource scheduling. The information may include a set of sidelink positioning members including itself, the coverage status of one or more WTRUs in the group, positioning method, etc., and / or any combination thereof.

[0323] A WTRU may indicate to the network an ID and / or index associated with sidelink positioning. For example, the WTRU may indicate to the network an ID and / or index (e.g., a destination ID) associated with sidelink positioning. The WTRU may send a message (e.g., an RRC message, and / or a sidelink WTRU information message, etc.) to the network to indicate that an ID has been allocated to the WTRU for sidelink positioning. The WTRU may then communicate with the network using such an ID for sidelink positioning. Specifically, the WTRU may then use the ID to send UCI, MAC CE, RRC, LPP, and / or NAS messages to the network. The WTRU may then determine whether any transmission from the network (e.g., DCI, MAC CE, RRC, LPP, and / or NAS) can be used for sidelink positioning based on the ID associated with and / or embedded in the message.

[0324] The WTRU may send a UCI (e.g., an SR) to request resources for sidelink positioning. The WTRU (e.g., a target WTRU) may first trigger a UCI (e.g., an SR) to request resources for sidelink positioning. In an example, the WTRU may be (pre-)configured with a dedicated UCI resource (e.g., a dedicated SR) for requesting resources for sidelink positioning. In this case, the WTRU may trigger a UCI (e.g., an SR) transmission for a resource request for sidelink positioning, and the WTRU may not need to trigger a MAC CE (e.g., an SL-BSR). In another approach, the WTRU may be (pre-)configured with a UCI (e.g., an SR) for requesting resources for both sidelink positioning and / or other sidelink resources. In this case, the WTRU may trigger transmissions of both the UCI (e.g., an SR) and / or a MAC CE (e.g., an SL-BSR).

[0325] The WTRU may send a MAC CE (e.g., a sidelink buffer status report (SL-BSR)) to request resources for sidelink positioning. The WTRU (e.g., a target WTRU) may trigger a MAC CE (e.g., an SL-BSR) to request resources for sidelink positioning. In an example, the WTRU may use a dedicated MAC CE to request resources for sidelink positioning. The WTRU may implicitly and / or explicitly indicate the number of resources for sidelink positioning. In an example, the WTRU may report a MAC CE for sidelink positioning as part of another MAC CE (e.g., an SL-BSR). The WTRU may use a dedicated destination ID (e.g., a dedicated destination index) to report the required number of resources for sidelink positioning (e.g., SL-PRS transmission and / or reception, and / or SL-PRS measurement reporting). The WTRU may implicitly indicate a dedicated destination to the network as a destination for sidelink positioning. Specifically, the WTRU may indicate one dedicated allocated destination ID and / or index in a message as a destination for sidelink positioning (e.g., via RRC).

[0326] The WTRU may receive sidelink positioning resources for a group of WTRUs and forward them to other WTRUs. The WTRU may receive sidelink positioning resources for a group of WTRUs. The WTRU may forward sidelink positioning resources to other WTRUs. The WTRU (e.g., a target WTRU) may receive scheduled sidelink positioning resources for a group of WTRUs (e.g., one or more WTRUs within a group of sidelink positioning WTRUs).

[0327] The WTRU may receive one or any combination of the following resources for sidelink positioning for a group of WTRUs, including a group ID associated with a scheduled SL-PRS. For example, in the case of a dynamic grant, the WTRU may be provided in DCI with an indication that the scheduled resources may be used for a particular group ID. In the case of a configured grant, the WTRU may be provided in DCI and / or RRC with an indication that the group ID is associated with the scheduled resources. Additional resources for sidelink positioning that the WTRU may receive for a group of WTRUs include sidelink resources for indicating and / or reserving other resources for sidelink positioning, SL-PRS transmission resources, SL-PRS reception resources, SL-PRS usage reporting resources in the sidelink direction, SL-PRS usage reporting resources in the uplink direction, SL-PRS measurement reporting resources in the sidelink, and SL-PRS measurement reporting resources in the uplink direction.

[0328] The WTRU may transfer scheduled resources for sidelink positioning to a sidelink positioning group. The WTRU may use one or more IDs (such as, for example, a target WTRU ID, a group ID, a sidelink positioning service ID, an L2 destination index, and / or an anchor WTRU ID, etc.) included in the message being transferred to assist in decoding messages transferred by other WTRUs (such as, for example, an anchor WTRU). In an example, the WTRU may use one sidelink resource (such as, for example, a resource indicating and / or reserving other resources for sidelink positioning) to transfer scheduled resources for sidelink positioning to other WTRUs within the group. The WTRU may use one or any combination of sidelink messages (such as, for example, an SCI, a MAC CE, a PC5-RRC, and / or NAS (such as, for example, LPP)) that include everything related to sidelink positioning of the scheduling message being transferred to WTRUs within the group. In an example, the WTRU may process message scheduling resources for sidelink positioning (such as, for example, a DCI, a DL MAC CE, an RRC, and / or LPP). The WTRU may then perform transmission on the scheduled transmission resources. The WTRU may then transfer the scheduled resources (such as, for example, in a sidelink resource, using an SCI, a MAC CE, an RRC, and / or NAS (such as, for example, LPP) message to indicate and / or reserve other resources for sidelink positioning) for its reception and / or the transmission of other WTRUs to other WTRUs.

[0329] The WTRU may perform transmission with one or any combination of the following resources: a sidelink resource indicating and / or reserving other resources for sidelink positioning, an SL-PRS transmission resource, an SL-PRS usage reporting resource in the sidelink direction, an SL-PRS usage reporting resource in the uplink direction, and / or an SL-PRS measurement reporting resource in the sidelink.

[0330] In an example, the WTRU may process a scheduling message and determine the scheduled resources for each WTRU. The WTRU may then use a unicast message (e.g., unicast PC5-RRC) to transfer the scheduled resources to each individual WTRU. In an example, the WTRU may process a scheduling message (e.g., from a network) and / or determine the scheduled resources for a group of WTRUs (e.g., a group of anchor WTRUs). The WTRU may then use a groupcast message (e.g., groupcast PC5-RRC) to transfer the scheduled resources for the group of WTRUs.

[0331] The WTRU may transfer one or any combination of the following resources for its reception and / or transmission by other WTRUs, including SL-PRS reception resources, SL-PRS usage reporting resources in the sidelink direction, and / or SL-PRS measurement reporting resources in the sidelink.

[0332] The WTRU may determine the scheduled resources used for a group ID. The WTRU may maintain multiple positioning groups. The WTRU may determine for which group ID the scheduled resources are used. The WTRU may be provided with an indication of the group ID in a resource scheduling message (e.g., DCI, MAC CE, and / or DCI). The WTRU may determine the group ID based on whether the WTRU has requested SL-PRS for any positioning group. The WTRU may use the scheduled SL-PRS for the most recent group that requests SL-PRS resources (e.g., the group ID indicated by the SL-BSR).

[0333] A WTRU may determine whether to transfer scheduled SL-PRS resources to another WTRU. A WTRU (e.g., an anchor WTRU) may receive scheduled SL-PRS provided with resources from another WTRU (e.g., an anchor WTRU). The WTRU may first determine whether to transfer the scheduled SL-PRS to another WTRU based on the content of the scheduled SL-PRS resources. If the scheduled resources do not have an SL-PRS Rx resource (e.g., a resource for another WTRU to perform SL-PRS transmission and for the WTRU to perform SL-PRS reception), the WTRU may not transfer the scheduled resources to another WTRU. This technique may be applied when the scheduling message indicates whether the resource can be used for the transmission of the WTRU or for the transmission of another WTRU.

[0334] A WTRU may determine SL-PRS transmission resources for another WTRU. A WTRU that may receive scheduled SL-PRS resources from the network may not receive an indication of which WTRU the resources can be used for transmission. The WTRU may then determine one or any combination of the resources used for itself and / or the resources used by another WTRU based on the set of SL-PRS scheduled by the network. For example, based on the scheduled resources for a group, the WTRU may select one or more resources for itself. The WTRU may then select resources for another WTRU.

[0335] Next, the WTRU may also determine a positioning method. For example, based on the characteristics of the scheduled resources for SL-PRS (e.g., the number of SL-PRS resources, the distance between two SL-PRS resources, the number of resource clusters, etc.), the WTRU may determine whether to perform SL-TDOA and / or RTT. Each resource cluster may be defined as a set of consecutive resources and / or a set of nearby resources in the time domain.

[0336] The WTRU may determine the index and / or ID of each WTRU. The WTRU (e.g., the target WTRU) may determine the index and / or member ID of each WTRU within the sidelink positioning group. The WTRU may make these determinations based on the WTRU ID and / or the number of WTRUs within the group. Next, the WTRU may indicate the index and / or member ID to each WTRU within the group. The WTRU may use one or any combination of AS (e.g., SCI, MAC CE, group PC5-RRC) and / or NAS (e.g., LPP) to transmit the index and / or member ID to each WTRU within the group. Other WTRUs within the group (e.g., the anchor WTRU) may receive its index and / or member ID, as well as the number of WTRUs within the group.

[0337] The WTRU may receive a configuration for sidelink positioning. For example, the WTRU (e.g., the target WTRU) may receive a configuration for sidelink positioning for a group of WTRUs from the network. In an example, the WTRU may determine a configuration for sidelink positioning for a group of WTRUs. In an example, the WTRU (e.g., the target WTRU) and / or the network may configure sidelink positioning for a group of WTRUs. The network and / or the WTRU (e.g., the target WTRU) may determine one or more parameters.

[0338] The configuration may include one or any combination of a resource pool for sidelink communication to facilitate sidelink positioning, a resource pool for SL-PRS transmission / reception, and / or the characteristics of one SL-PRS measurement report. For example, the WTRU may be (pre-)configured with the number of subchannels used for each SL-PRS measurement report.

[0339] The configuration may include multiplexing and / or indexing order of SL-PRS measurement report resources. For example, the WTRU may be (pre-)configured with the indexing order for a group of SL-PRS measurement report resources. The WTRU may be (pre-)configured with the indexing order from the frequency domain to the time domain. Additionally or alternatively, the WTRU may be (pre-)configured with the indexing order from the time domain to the frequency domain.

[0340] The configuration may include the characteristics of one SL-PRS resource. For example, the WTRU may be (pre-)configured with one or any combination of the following parameters of one SL-PRS resource: the bandwidth of one SL-PRS resource, the comb value and offset of one SL-PRS resource, the cyclic shift of one SL-PRS resource, the number of transmission symbols for one SL-PRS resource, the SL-PRS resource repetition pattern, and / or the cover code associated with the resource.

[0341] The configuration may include the number of SL-PRS resources in the frequency domain, code domain, and / or cover code domain.

[0342] The configuration may include multiplexing and / or indexing order of SL-PRS resources. For example, the WTRU may (pre-)configure an indexing order for a group of SL-PRS resources. The WTRU may (pre-)configure an indexing order from the time domain to the frequency domain and / or then, respectively, to the code domain and / or the cover code domain. Additionally or alternatively, the WTRU may (pre-)configure an indexing order from the frequency domain to the time domain, to the cover code domain and / or then, respectively, to the code domain.

[0343] The WTRU may send a configuration for sidelink positioning to other WTRUs. The WTRU (e.g., the target WTRU) may, upon receiving a configuration for sidelink positioning from the network and / or its own determination of one or more parameters for the configuration for sidelink positioning, send that configuration to other WTRUs (e.g., the anchor WTRU within the group). The WTRU may use one or any combination of AS messages (e.g., SCI, MAC CE, group PC5-RRC) and / or NAS messages (e.g., LPP) to convey the sidelink positioning configuration to a group of WTRUs. The anchor WTRU may then receive the configuration from the target WTRU and / or apply the configuration for sidelink positioning of the group of WTRUs. The anchor WTRU may be one of the members of the group.

[0344] The WTRU may determine the SL-PRS reception resources of each WTRU within the group. The WTRU (e.g., the target WTRU) may have scheduled SL-PRS reception resources. The reception resources may be used by other WTRUs (e.g., a set of anchor WTRUs) to perform SL-PRS transmissions. The WTRU may then determine the SL-PRS resources of each WTRU (e.g., each anchor WTRU).

[0345] The SL-PRS resource can be based on one or any combination of a set of scheduled SL-PRS resources for a group, an index within the group and / or member WTRU IDs, the ID of the WTRU that transfers and / or indicates the SL-PRS resource for the group, the number of WTRUs within the group, the number of allocated / (pre-)configured OCCs for each WTRU, the slot index of the scheduled SL-PRS resource, and / or the (pre-)configured multiplexing rule between multiple SL-PRS resources.

[0346] Figure 13 depicts an exemplary diagram of SL-PRS scheduling for a group of user WTRUs. In the example shown in Figure 13, the target WTRU can have SL-PRS reception resources scheduled for a group of 4 WTRUs (e.g., WTRU1 to WTRU4). Each SL-PRS resource can have a comb-4 pattern, and the WTRU can multiplex 2 SL-PRSs in the frequency domain. Each SL-PRS resource can occupy half of a slot. The WTRU can be (pre-)configured to index from the frequency domain to the time domain. The target WTRU can then determine that the SL-PRS resources for WTRU1 1302 and / or WTRU2 1304 can be in the first half of the slot where they multiplex in the frequency domain with different offsets. The WTRU can then determine that the SL-PRS resources for WTRU3 1306 and / or WTRU4 1308 can be in the second half of the slot where they multiplex in the frequency domain with different offsets. The SL-PRS resources for WTRU1 1302 and / or WTRU2 1304 multiplex with the SL-PRS resources for WTRU3 1306 and / or WTRU4 1308 in the time domain.

[0347] Figure 14 depicts an exemplary diagram of an anchor WTRU using an orthogonal cover code (OCC) for one SL-PRS resource. As depicted in Figure 14, a target WTRU may schedule one SL-PRS resource for a group of anchor WTRUs 1402a-d. Each anchor WTRU 1402a-d may apply a different OCC 1404a-d to assist the target WTRU in differentiating between the different anchor WTRUs 1402a-d. The OCC of each anchor WTRU may be configured and / or determined (a priori) by the target WTRU. The target WTRU may indicate to each anchor WTRU which OCC code to use. This technique may help the target WTRU determine transmissions from each anchor WTRU.

[0348] A WTRU may determine its SL-PRS transmission resources. A WTRU (e.g., an anchor WTRU) may receive scheduled SL-PRS transmission resources for a group of WTRUs including itself. The WTRU may then determine its SL-PRS resources for performing an SL-PRS transmission.

[0349] Similar to the target WTRU, an anchor WTRU may determine its SL-PRS based on one or any combination of: a set of scheduled SL-PRS resources for a group, an index and / or member WTRU ID within the group, the ID of the WTRU transferring / indicating the SL-PRS resources for the group, the number of WTRUs within the group, the (a priori) configured OCC assigned to each WTRU, the slot index of the scheduled SL-PRS resources, and / or the (a priori) configured multiplexing rule between multiple SL-PRS resources.

[0350] The WTRU may determine SL-PRS measurement reporting resources from each WTRU within the group. The WTRU (e.g., target WTRU) may be the scheduled SL-PRS measurement reporting resource for a group of WTRUs (e.g., anchor WTRUs). The WTRU may then transfer the resources for the group of WTRUs. The WTRU may determine the SL-PRS measurement reporting resources for each WTRU (e.g., each anchor WTRU) based on one or any combination of a set of scheduled SL-PRS measurement reporting resources for the group, an index and / or member WTRU ID within the group, the number of WTRUs within the group, a (pre-)configured indexing rule between multiple SL-PRS measurement reporting resources, the ID of the WTRU (e.g., target WTRU ID) transferring and / or indicating the SL-PRS resources for the group, and / or the slot index of the scheduled SL-PRS measurement reporting resource.

[0351] Figure 15 depicts an exemplary diagram of SL-PRS measurement reporting scheduling for a group of WTRUs. As depicted in Figure 15, the target WTRU may be the scheduled SL-PRS measurement reporting resource. The SL-PRS measurement reporting resource may include four resources 1502a-d for a group of four anchor WTRUs. The WTRU may be (pre-)configured to index the resources in order from frequency to time. The WTRU (e.g., target WTRU) may then determine the measurement reporting resources for each WTRU according to the (pre-)configured rule and the WTRU index.

[0352] A WTRU may determine SL-PRS measurement reporting resources for itself. A WTRU (e.g., an anchor WTRU) may receive SL-PRS measurement reporting resources for a group of WTRUs (e.g., from a target WTRU). Similar to the target WTRU, the anchor WTRU may then determine its SL-PRS measurement reporting resources based on one or any combination of: a set of scheduled SL-PRS measurement reporting resources for the group, an index and / or member WTRU ID within the group, the number of WTRUs within the group, a (pre-)configured indexing rule between multiple SL-PRS measurement reporting resources, the ID of the WTRU (e.g., the target WTRU) that transfers and / or indicates the SL-PRS resources for the group, and / or the slot index of the scheduled SL-PRS measurement reporting resources.

[0353] A WTRU may determine resources for reporting and / or indicating SL-PRS resource usage from the scheduled SL-PRS resources for the group. A WTRU (e.g., an anchor WTRU) may determine to feedback SL-PRS resource usage from a set of scheduled SL-PRS resources for the group. A WTRU may determine resources for feedbacking SL-PRS resource usage based on one or any combination of: an indication from the requesting WTRU, resources that indicate and / or reserve SL-PRS transmission and / or reception resources, an index and / or member WTRU ID within the group, the number of WTRUs within the group, the ID of the WTRU that transfers and / or indicates the SL-PRS resources (e.g., the target WTRU) for the group, the slot index of the scheduled SL-PRS measurement reporting resources, the slot index of the scheduled SL-PRS resources, the earliest and / or latest scheduled SL-PRS resources, and / or the channel and / or message used for feedbacking SL-PRS resource usage.

[0354] The WTRU may report positioning group synchronization offset information to the network. The WTRU (e.g., a target WTRU) may receive synchronization offset information from another WTRU (e.g., an anchor WTRU). Additionally or alternatively, the WTRU may derive the synchronization offset information itself. The positioning group synchronization offset information may include the synchronization offset between itself and another WTRU (e.g., an anchor WTRU), the synchronization offset between two other WTRUs within the group (e.g., two anchor WTRUs), or any suitable combination thereof.

[0355] The WTRU may report positioning group synchronization offset information to a network (e.g., an LMF). The WTRU may use one or any combination of MAC (e.g., MAC CE), RRC, and / or NAS (e.g., LPP) messages to convey the synchronization offset to the network (e.g., an LMF). The WTRU may trigger sending such a report based on one or any suitable combination of the following, including periodic reporting. For example, the WTRU may periodically report synchronization offset information to the network (e.g., an LMF).

[0356] The WTRU may trigger sending such a report based on the WTRU being able to report SL-PRS measurement reports to the network (e.g., an LMF). For example, the WTRU may report the group synchronization offset information in a measurement report message.

[0357] The WTRU may trigger sending such a report based on a synchronization offset greater than a (pre-)configured threshold. For example, the WTRU may report the synchronization offset between two WTRUs (e.g., between two anchor WTRUs and / or between an anchor WTRU and a target WTRU) if the synchronization offset between them is greater than the (pre-)configured threshold.

[0358] A WTRU may indicate a synchronization offset based on the resource allocation modes of two WTRUs. A WTRU (e.g., a target WTRU) may determine a synchronization offset between itself and another WTRU (e.g., a target WTRU). Additionally or alternatively, a WTRU may determine a synchronization offset between two other WTRUs (e.g., two anchor WTRUs). A WTRU may receive synchronization offset information from an anchor WTRU. When two WTRUs use two different resource allocation modes, the WTRU may determine synchronization offset information between the two WTRUs. For example, if the WTRU is using network-scheduled resource allocation for SL-PRS and one anchor WTRU is autonomously selecting resources, the WTRU may determine synchronization offset information between itself and that anchor WTRU.

[0359] A WTRU may be configured for periodic and / or semi-static resources for sidelink positioning. A WTRU (e.g., a target WTRU) may be scheduled for one or more semi-static (e.g., periodic, or semi-persistent) resources for sidelink positioning. For example, a WTRU may be scheduled for one or more semi-persistent resources (e.g., uplink resources, sidelink resources), and / or one or more periodic resources (e.g., uplink resources, sidelink resources) for sidelink positioning. NAS messages (e.g., LPP) and / or AS messages (e.g., RRC) may configure periodic and / or semi-persistent resources. Semi-persistent resources may require the WTRU to receive MAC CE for activation and / or deactivation of the resources.

[0360] A WTRU may be configured (in advance) with one or more semi-static resources, and each semi-static resource may be used for one or more of other resources for sidelink positioning and / or sidelink resources for indicating, reserving, and / or requesting the WTRU (e.g., resources for transmitting sidelink positioning request messages), SL-PRS transmission resources, SL-PRS reception resources (which may be used by one anchor WTRU or a group of anchor WTRUs for SL-PRS transmission), SL-PRS usage reporting resources in the sidelink direction (which may be used for reporting SL-PRS resource usage), SL-PRS usage reporting resources in the uplink direction, SL-PRS measurement reporting resources in the sidelink, and / or SL-PRS measurement reporting resources in the uplink direction.

[0361] FIG. 16 depicts an exemplary diagram of semi-static resources for sidelink positioning. As shown in FIG. 16, a WTRU may be configured with semi-static resources for sidelink positioning. The WTRU may be configured with semi-static SL-PRS transmission, SL-PRS reception, SL-PRS usage reporting, and / or SL-PRS measurement reporting. The WTRU may be configured with semi-static SL-PRS transmission resource 1602 and reception resource 1604 having the same period. The WTRU may be configured with semi-static SL-PRS resource usage reporting resources that may occur periodically after every N (e.g., N = 2) SL-PRS transmission / reception periods. The WTRU may be configured with SL-PRS measurement reporting resources after every N (e.g., N = 4) SL-PRS transmission and / or reception periods.

[0362] The behavior of the WTRU may be based on the status of feedback regarding SL-PRS resource usage from other WTRUs. The WTRU (e.g., the target WTRU) may be a scheduled SL-PRS resource. The WTRU may forward scheduled SL-PRS resources for a group of WTRUs. The WTRU may receive SL-PRS resource usage reports from zero or more WTRUs within the group.

[0363] The WTRU may trigger one or any combination of the following procedures, including performing resource allocation for sidelink positioning and / or requesting additional dynamic resources (e.g., SL-PRS resources, sidelink positioning request messages, etc.). For example, the WTRU may request additional dynamic SL-PRS transmission and / or reception resources during one SL-PRS transmission / reception period if the WTRU lowers the priority of one or more SL-PRS transmissions and / or receptions. For example, the WTRU may request additional resources for transmitting a sidelink positioning request message if the WTRU has not received at least N ACK feedbacks (e.g., from a set of anchor WTRUs within a sidelink positioning group).

[0364] The WTRU may trigger a procedure for reporting SL-PRS resource usage to the network. The WTRU may trigger a procedure for initializing SL-PRS transmission and / or reception. For example, the WTRU may initialize SL-PRS transmission and / or reception if it has received at least N ACK feedbacks (e.g., from a set of anchor WTRUs within a sidelink positioning group).

[0365] The WTRU may trigger a procedure for not performing SL-PRS transmission and / or reception on scheduled resources. For example, in an RTT-based sidelink positioning method, during one SL-PRS transmission and / or reception period, the WTRU may determine to lower the priority of all SL-PRS transmissions if the WTRU lowers the priority of SL-PRS reception during that period.

[0366] The WTRU may trigger a procedure to request the network to release one or more semi-static resources for sidelink positioning. For example, the WTRU may request the network to release one or more semi-static SL-PRS reception resources when one or more WTRUs leave a sidelink positioning group. For example, the WTRU may request the network to release all semi-static resources for itself when the WTRU ends a sidelink positioning session.

[0367] The WTRU may trigger a procedure to request the network to activate one or more semi-static resources for sidelink positioning.

[0368] The WTRU may trigger a procedure to request the network to change the configuration of one or more semi-static resources. For example, the WTRU may request the network to reduce the periodicity of one semi-static resource or increase the number of SL-PRS transmission resources in the SL-PRS transmission period when receiving feedback from at least N WTRUs requesting additional resources for SL-PRS measurement.

[0369] The trigger event may be based on one or any combination of the events described herein and / or whether the WTRU has received ACK feedback from at least N WTRUs for a request message. For example, in the case of an ACK / NACK scheme for a positioning request message, when the WTRU receives N ACKs (e.g., N is equal to the number of anchor WTRUs in the group) from other WTRUs (e.g., anchor WTRUs), the WTRU may initiate SL-PRS transmission and / or reception.

[0370] The trigger event may be based on whether the WTRU has received less than N ACK feedbacks for a request message. For example, if the WTRU receives less than N ACK feedbacks, it may trigger a request for more sidelink resources for the request message. This approach may be motivated to help the WTRU find enough anchor WTRUs to support sidelink positioning.

[0371] The trigger event may be based on whether the WTRU has received NACK feedbacks from at least N WTRUs for a request message. For example, if the WTRU receives at least N NACK feedbacks (e.g., N = 1) for a request message, it may trigger a request for more sidelink resources for the request message.

[0372] The trigger event may be based on whether the WTRU has received feedback from at least N WTRUs indicating that the WTRU may perform SL-PRS transmission and / or reception. For example, if the WTRU receives at least N WTRUs indicating that the WTRU may perform SL-PRS transmission / reception, the WTRU may initialize SL-PRS transmission and / or reception.

[0373] The trigger event may be based on whether the WTRU has received feedback from at least N WTRUs indicating that the WTRU may not perform SL-PRS transmission and / or reception. For example, if the WTRU receives feedback from at least N WTRUs indicating that the WTRU may not perform SL-PRS transmission and / or reception, the WTRU may trigger a request for more sidelink resources for the request message.

[0374] The trigger event may be based on whether the WTRU receives feedback from at least N WTRUs indicating that the WTRU has performed SL-PRS transmission and / or reception. For example, the WTRU may trigger an SL-PRS resource usage report to the network if at least N WTRUs indicate that the WTRU has performed SL-PRS transmission and / or reception.

[0375] The trigger event may be based on whether the WTRU receives feedback from at least N WTRUs indicating that the WTRU is not performing SL-PRS transmission / reception. For example, the WTRU may trigger a request for more SL-PRS resources if at least N WTRUs indicate that the WTRU is not performing SL-PRS transmission and / or reception. For example, the WTRU may trigger an SL-PRS resource usage report to the network if at least N WTRUs indicate that the WTRU is not performing SL-PRS transmission and / or reception.

[0376] The trigger event may be based on whether the WTRU receives feedback from at least N WTRUs indicating that the WTRU has lowered the priority of SL-PRS transmission and / or reception. For example, the WTRU may trigger a request for more SL-PRS resources if at least N WTRUs indicate that the WTRU has lowered the priority of SL-PRS transmission and / or reception. For example, the WTRU may trigger an SL-PRS resource usage report to the network if at least N WTRUs indicate that the WTRU has lowered the priority of SL-PRS transmission and / or reception.

[0377] The trigger event may be based on whether the WTRU receives feedback from at least N WTRUs indicating that the WTRU requires more resources for SL-PRS transmission / reception. For example, the WTRU may trigger a request for more sidelink resources for the request message if the WTRU receives feedback from at least N WTRUs indicating that the WTRU requires more resources for SL-PRS transmission and / or reception.

[0378] The trigger event may be based on whether the WTRU changes the set of WTRUs within the sidelink positioning group. For example, if the set of WTRUs within the sidelink positioning group is changed, the WTRU may request the network to increase and / or decrease the number of SL-PRS reception resources and / or the number of SL-PRS measurement report resources in each period.

[0379] The trigger event may be based on whether the WTRU terminates the sidelink positioning session. For example, if the WTRU decides to terminate the sidelink positioning session, the WTRU may request the network to deactivate and / or release all semi-static resources associated with the WTRU.

[0380] The value of N in the trigger event may be determined based on one or any combination of the following, i.e., whether the resources are fixed and / or (pre-)configured. For example, if the WTRU does not receive ACK feedback from one WTRU (e.g., N = 1), the WTRU may trigger a request for more resources until the WTRU receives ACK feedback from all WTRUs. For example, in some scenarios, if the WTRU receives NACK feedback from one WTRU (e.g., N = 1), the WTRU may trigger a request for more resources until the WTRU receives ACK feedback from the WTRU.

[0381] The value of N in a trigger event may be determined based on the number of WTRUs in a group and / or the number of anchor WTRUs. For example, in some scenarios, if a WTRU does not receive ACK feedback from one WTRU (e.g., N = 1), the WTRU may request more resources for transmission and / or reception until the WTRU receives ACK feedback from all WTRUs.

[0382] The value of N in a trigger event may be determined based on the QoS (e.g., latency, accuracy) requirements of the positioning service.

[0383] In the case of relaxed sidelink positioning accuracy requirements, the WTRU may require the support of a small number of anchor WTRUs. However, in the case of high sidelink positioning accuracy requirements, the WTRU may require the support of a large number of anchor WTRUs.

[0384] The WTRU may request periodic and / or aperiodic SL-PRS resources. The WTRU may request and / or select periodic and / or aperiodic SL-PRS resources (e.g., the WTRU may request SL-PRS from the network (e.g., gNB and / or LMF) and / or another WTRU (e.g., RSU, peer WTRU, target WTRU, and / or anchor WTRU)). The WTRU may determine one and / or any suitable combination of parameters (e.g., offset, periodicity, and / or latency) in the SL-PRS configuration for periodic SL-PRS based on one and / or any combination of the following: Selected, requested, and / or available SL-PRS configurations from a peer WTRU. For example, in the case of an RTT positioning method, one WTRU (e.g., a target WTRU) may first request and / or select periodic SL-PRS resources. The WTRU may then notify other WTRUs (e.g., an anchor WTRU) of the requested, selected, and / or scheduled periodic SL-PRS resources. The other WTRU (e.g., the anchor WTRU) may then determine parameters (e.g., offset, delay, periodicity, SL-PRS bandwidth, and / or SL-PRS pattern) in its SL-PRS configuration based on the requested, selected, and / or scheduled periodic SL-PRS resources from the peer WTRU.

[0385] In an example, when the WTRU determines to request and / or select periodic SL-PRS resources, the WTRU may select and / or request an SL-PRS configuration similar to the SL-PRS configuration of the target WTRU. However, the offset may have a gap with respect to the requested, selected, and / or scheduled SL-PRS from the peer WTRU. The gap may be (pre-)configured and / or determined by the WTRU based on the QoS of the positioning service (e.g., delay and / or accuracy).

[0386] In an example, when the WTRU determines to request and / or select aperiodic SL-PRS resources, the WTRU may select an SL-PRS configuration similar to the SL-PRS configuration of the target WTRU, except for delay and / or periodicity. Specifically, the WTRU may not request and / or select periodic resources, and the WTRU may request and / or select an aperiodic SL-PRS having a delay smaller than the periodicity of the periodic SL-PRS. The WTRU may select and / or request the aperiodic SL-PRS based on the timing of the periodic SL-PRS of other WTRUs and / or the QoS requirements of the positioning service.

[0387] The WTRU may trigger a change in the SL-PRS configuration (e.g., SL-PRS offset and / or periodicity). The WTRU (e.g., target WTRU and / or anchor WTRU) may trigger a request and / or selection of a new SL-PRS that may be a new periodic SL-PRS and / or a new aperiodic SL-PRS based on one and / or any suitable combination of the following.

[0388] The SL-PRS configuration of another WTRU may be changing. For example, in the case of an RTT positioning method, the WTRU may select a periodic SL-PRS based on the periodic SL-PRS from another WTRU. The WTRU may trigger a request and / or selection of a new periodic SL-PRS (e.g., having a new value for the offset and / or periodicity) if the WTRU detects that the associated periodic SL-PRS has changed.

[0389] The WTRU may detect a collision of existing periodic SL-PRS. For example, the WTRU may trigger a selection of a new SL-PRS if the WTRU detects a collision with another SL-PRS transmission.

[0390] The WTRU receives an indication from another WTRU to change its SL-PRS configuration. For example, another WTRU (e.g., target WTRU) may indicate to the WTRU (e.g., anchor WTRU) to change its SL-PRS configuration. The WTRU may then trigger a request and / or selection of a new periodic SL-PRS to accommodate the other WTRU (e.g., target WTRU).

[0391] A WTRU may indicate the priority of a sidelink positioning service. The WTRU (e.g., a target WTRU) may initiate its sidelink positioning service. In an example, the WTRU may determine the priority of its sidelink positioning and / or indicate the determination to the network. In an example, the WTRU may propose, indicate, and / or request a priority level for its sidelink positioning. The WTRU may then receive an assigned priority for its sidelink positioning from the network. The WTRU may then determine the priority for one or any combination of the following transmissions and / or receptions based on the priority of the sidelink positioning service: Sidelink positioning request transmission, SL-PRS transmission, SL-PRS reception, SL-PRS measurement report, SL-PRS resource usage report in sidelink, and / or SL-PRS resource usage report in uplink.

[0392] The WTRU may report its SL-PRS resources to the network. In an example, the WTRU may receive a request from another WTRU (e.g., an anchor WTRU) to perform SL-PRS reception (e.g., semi-static SL-PRS reception). The WTRU may then indicate and / or report the SL-PRS reception resources to the network. The WTRU may indicate the processing time of each SL-PRS resource to the network. This approach may help the network avoid scheduling Uu transmissions and / or receptions during SL-PRS reception times. In an example, the WTRU may receive a measurement gap (MG) and / or positioning processing window (PPW) configuration from the network. In an example, the WTRU may lower the priority of SL-PRS reception if the WTRU has not received feedback from the network regarding SL-PRS reception prioritization. In one example, during a measurement gap, the WTRU may not transmit or receive a channel or signal and may only perform measurements. During a positioning processing window, the WTRU may determine to receive SL-PRS or other channels (e.g., SLCCH, SLSCH) or signals (e.g., SSB) according to the priority level associated with the signal or channel.

[0393] The WTRU may determine whether to perform SL-PRS resource reception. Upon receiving an SL-PRS reception request from another WTRU, the WTRU may determine whether to perform SL-PRS reception. The WTRU may then indicate and / or report its decision to other nodes (e.g., gNB or another WTRU).

[0394] The WTRU may determine whether to perform SL-PRS reception based on one or any combination of the following, including the priority of the SL-PRS. For example, the WTRU may determine to perform SL-PRS reception if the priority of the SL-PRS is greater than a threshold. The threshold may be (pre)-configured and / or determined based on its existing sidelink communication service in the PC5 interface and / or the existing Uu service in the Uu interface.

[0395] The WTRU may determine whether to perform SL-PRS reception based on the priority of overlapping sidelink communication (e.g., sidelink transmission and / or reception). For example, the WTRU may determine to perform SL-PRS reception if the priority of the SL-PRS is greater than the priority of the overlapping sidelink communication. The WTRU may then trigger resource reselection for the overlapping sidelink transmission. The WTRU may indicate and / or request the WTRU performing the overlapping sidelink communication to reselect and / or lower the priority of the overlapping sidelink communication. For example, the WTRU may determine to lower the priority of the SL-PRS reception if the priority of the SL-PRS is less than the priority of the overlapping sidelink communication. The WTRU may then indicate its decision to lower the priority of the SL-PRS reception to the SL-PRS transmitting WTRU. The SL-PRS transmitting WTRU may change the configuration of the SL-PRS transmission resources.

[0396] The WTRU may determine whether to perform SL-PRS reception based on the duration of SL-PRS reception in a period. For example, the WTRU may determine to perform SL-PRS reception if the duration of SL-PRS reception in a period is less than a threshold. Otherwise, the WTRU may determine not to perform SL-PRS reception.

[0397] The WTRU may determine whether to perform SL-PRS reception based on the periodicity of the SL-PRS reception resource. For example, the WTRU may determine to perform SL-PRS reception if the periodicity of the SL-PRS reception is less than a threshold. Otherwise, the WTRU may determine not to perform SL-PRS reception.

[0398] The WTRU may determine whether to perform SL-PRS reception based on the number and / or duration of existing SL-PRS receptions in a period. For example, the WTRU may be (pre-)configured to receive a maximum of N SL-PRS receptions in a period. Then, the WTRU may determine whether to perform an additional SL-PRS reception. Determining whether to perform an additional SL-PRS reception may be based on whether the additional SL-PRS reception would exceed its configured and / or pre-configured SL-PRS reception capabilities.

[0399] FIG. 17 depicts an exemplary diagram of an overlap between an SL-PRS reception and a resource pool for SL communication. As shown in FIG. 17, the WTRU may perform SL-PRS reception in one resource pool 1702 and perform sidelink communication in another resource pool 1704. When the WTRU performs an SL-PRS reception 1706 (e.g., for an SL-PRS signal), the WTRU may require more time for SL-PRS processing. Thus, the WTRU may not perform other sidelink transmissions and / or receptions 1708.

[0400] The WTRU may request an MG and / or a PPW for SL-PRS reception. The WTRU may determine to perform SL-PRS reception for an SL-PRS resource (e.g., a semi-static SL-PRS resource). The WTRU may then request the network for an MG / PPW configuration. The MG and / or PPW configuration may include one and / or any combination of the periodicity of the MG and / or PPW and / or the duration of the MG and / or PPW in each periodicity.

[0401] In an example, the WTRU may request one MG and / or one PPW for each semi-static SL-PRS reception. In an example, the WTRU may determine an MG and / or PPW configuration based on a plurality of (e.g., all) semi-static SL-PRS reception resources. The WTRU may then request the determined MG and / or PPW to perform reception of the plurality of semi-static SL-PRS reception resources.

[0402] The WTRU may indicate its SL-PRS reception resources to other WTRUs. In an example, upon receiving a request to perform SL-PRS reception, the WTRU may indicate its (e.g., semi-static) SL-PRS reception resources to other nodes (e.g., a WTRU having existing sidelink communication with a WTRU or a gNB). This approach may help to avoid other nodes from scheduling and / or transmitting resources that overlap with the WTRU's SL-PRS reception resources.

[0403] The WTRU may prioritize between SL-PRS reception and / or other sidelink transmission and / or reception. In an example, the WTRU may perform prioritization between SL-PRS reception and / or other overlapping transmission and / or reception in Uu and / or sidelink. In an example, the WTRU may determine whether to perform Tx and / or Rx in SL-PRS reception and / or in Uu and / or sidelink. The WTRU may make this determination based on the relative priorities between SL-PRS and / or Tx and / or Rx resources in Uu and / or sidelink. For example, the WTRU may prioritize SL-PRS reception if the priority of SL-PRS is greater than the priority of Tx / Rx resources in SL and / or Uu. Otherwise, the WTRU may lower the priority of SL-PRS.

[0404] In an example, the WTRU may prioritize Tx and / or Rx in Uu and / or sidelink if the priority of Tx and / or Rx in Uu and / or sidelink is greater than a threshold. Otherwise, the WTRU may prioritize SL-PRS. The threshold may be (pre-)configured. In some examples, the WTRU may prioritize SL-PRS reception if the priority of SL-PRS is greater than a threshold. Otherwise, the WTRU may prioritize Tx and / or Rx in Uu and / or sidelink. The threshold may be (pre-)configured.

[0405] In an example, the WTRU may prioritize SL-PRS reception if the priority of SL-PRS reception is greater than a first threshold. Otherwise, the WTRU may prioritize Tx and / or Rx in Uu and / or sidelink if the priority of Tx and / or Rx in Uu and / or sidelink is greater than a second threshold. Otherwise, if both SL-PRS reception and Tx and / or Rx in Uu and / or sidelink are less than their respective thresholds, the WTRU may randomly determine which to prioritize. The WTRU may perform prioritization based on other criteria. The thresholds may be (pre-)configured.

[0406] In an example, the WTRU may prioritize Tx and / or Rx in Uu and / or SL when the priority of Tx and / or Rx in Uu and / or SL is greater than a first threshold. Otherwise, the WTRU may prioritize SL-PRS reception when the priority of SL-PRS reception is greater than a second threshold. Otherwise, when both SL-PRS reception and Tx and / or Rx in Uu and / or SL are less than their respective thresholds, the WTRU may perform prioritization based on other criteria. The thresholds may be (pre-)configured.

[0407] In the case of hybrid positioning, the WTRU may be configured independently with SL and / or Uu positioning. In an example, the WTRU may report measurements related to SL positioning (e.g., RSRP, RSTD, and / or Rx-Tx time difference related to SL PRS) and / or Uu positioning (e.g., RSRP, RSTD, and / or Rx-Tx time difference related to PRS transmitted from a TRP or gNB) in the same report associated with a timestamp. The network may use the timestamp to track when a measurement report containing measurements related to SL positioning and / or Uu positioning was sent. For example, the target WTRU may determine that it is in a corner of a room based on Uu positioning results (e.g., location information, zone ID, SSB measurement values, etc.). If the target WTRU determines that it is in a corner of a room (e.g., based on the zone ID and / or location information), the target WTRU may determine to start SL positioning and / or use one or more anchor WTRUs for SL positioning.

[0408] The WTRU may determine whether to measure the RSTD between two RATs. The WTRU may use one node of one radio access technology (RAT) as a reference node to measure the measurement quantity difference (e.g., RSTD and / or PDOA) between the reference node and / or the node to be measured. The measurement may be performed in both the same RAT and / or different RATs compared to the reference node. The WTRU may use one node of one RAT as a reference for nodes of the same RAT. The WTRU may determine whether to use one node of one RAT as a reference for nodes of both RATs. The WTRU may make this determination based on whether the PC5 RAT is (pre-)configured to use the same BWP as Uu. If the PC5-RAT is (pre-)configured to use the same carrier as Uu, the WTRU may use one node (e.g., serving gNB) as a reference node for nodes of both RATs. Otherwise, if the PC5 RAT is (pre-)configured to use a different BWP as Uu, the WTRU may use the nodes of each RAT as a reference for all nodes of the same RAT.

[0409] The WTRU may determine a reference node for RSTD measurement. The WTRU may determine which node measures the measurement quantity difference as the reference node. The WTRU may make this determination based on one and / or a combination of the types of the WTRU, and the WTRU may prioritize the RSU as the reference node, and / or the WTRU may prioritize the in-coverage WTRU as the reference node.

[0410] When the WTRU receives an MG and / or PPW configuration over the Uu, it may trigger resource reselection and / or preemption. The WTRU (e.g., the target WTRU) may receive an MG and / or PPW configuration from the network (e.g., the gNB). Then, if the WTRU detects that one or more of its reserved sidelink resources are within the MG and / or PPW duration over the Uu, the WTRU may trigger resource reselection and / or preemption. Then, the WTRU may select another resource considering the configured MG and / or PPW. The WTRU may first exclude all candidate resources within the configured MG and / or PPW and then select a resource outside the configured MG / PPW.

[0411] When the WTRU receives an MG and / or PPW over the Uu of a peer, it may trigger resource reselection and / or preemption. When the WTRU receives an MG and / or PPW over the Uu of a peer WTRU, if it detects that its reserved sidelink transmission resources to the peer WTRU are within the MG and / or PPW of the peer WTRU, it may decide to trigger resource reselection and / or preemption. Then, the WTRU may select another resource outside the MG and / or PPW of the peer WTRU.

[0412] The WTRU may avoid transmitting to a peer WTRU during its MG and / or PPW. The WTRU may avoid transmitting to a peer WTRU during the MG and / or PPW duration of the peer WTRU. For any resource within the MG and / or PPW of the peer WTRU, the WTRU may perform an LCP procedure where it may not select data and / or SL-PRS for transmission to the peer WTRU. The WTRU may select data and / or SL-PRS for transmission to the peer WTRU outside its MG and / or PPW period. If one of its reserved resources is within the MG and / or PPW of the peer WTRU, the WTRU may trigger resource reselection.

[0413] The WTRU may indicate its MG and / or PPW network (e.g., LMF). The WTRU may indicate one or any suitable combination of the following MGs and / or PPWs to another node including its MG and / or PPW in Uu (e.g., to another WTRU, to a network such as LMF and / or gNB). For example, the WTRU may indicate its MG and / or PPW to another WTRU, such that the other WTRU and / or gNB may avoid transmitting channels (e.g., SLCCH and / or SLSCH) and / or signals to the WTRU during the MG and / or PPW duration and / or may request the WTRU to transmit / receive signals (e.g., SL-PRS).

[0414] The WTRU may indicate its MG and / or PPW in the sidelink. For example, the WTRU may indicate its MG and / or PPW to another WTRU such that the other WTRU and / or gNB may avoid transmitting to the WTRU during the MG and / or PPW duration. Alternatively, the gNB may avoid scheduling Uu resources during its MG and / or PPW in the sidelink.

[0415] The WTRU may indicate the MG and / or PPW of one or more other WTRUs. For example, the WTRU may indicate the MG and / or PPW of another WTRU in the sidelink to the gNB. The gNB may be implicitly requested to schedule transmission resources (e.g., sidelink transmission resources and / or SL-PRS transmission resources) to one or more WTRUs outside the indicated MG and / or PPW period.

[0416] In positioning methods such as multi-RTT, SL-TDOA, SL-AoD, and / or SL-AoA, the target WTRU may receive configurations for two or more anchor WTRUs. When the target WTRU determines its relative position with respect to a reference node (e.g., distance and angle with respect to the reference node), the WTRU may define what to use as the reference node. If the reference node is a mobile node (e.g., a vehicle), the relative location with respect to such a node may quickly become stale and / or inaccurate.

[0417] Given a set of anchor WTRUs, the target WTRU may determine the reference node based on at least one of the following conditions: The reference node may be an anchor WTRU indicated by one of the anchor WTRUs and / or the network (e.g., gNB, LMF). The reference node may be a stationary anchor WTRU (e.g., a roadside unit, a positioning reference unit). In one example, if the target WTRU receives configurations for two or more anchor WTRUs and one of the anchor WTRUs is a stationary WTRU (e.g., a roadside unit), the target WTRU may use that WTRU as the reference node. If there are two or more stationary WTRUs, the target WTRU may randomly select one of them and report to the network and / or the anchor WTRUs which WTRU the target WTRU selected. Additionally or alternatively, the target WTRU may use measurement results (e.g., RSRP) to select a WTRU as the reference node.

[0418] The target WTRU determines the reference node based on measurements of the SL-PRS transmitted by the anchor WTRU. For example, the target WTRU may determine to use as the reference node the anchor WTRU with the highest SL-PRS RSRP.

[0419] When a set of anchor WTRUs is provided, the target WTRU may determine a reference node based on whether the target WTRU receives a list of priority levels associated with the anchor WTRUs. The target WTRU may determine the reference node based on the priority levels (e.g., the anchor WTRU having the highest level of priority is selected as the reference node. If the anchor WTRU having the highest level of priority is not available for PRS transmission and / or the anchor is a mobile anchor WTRU, the target WTRU may determine to use the anchor WTRU having the second highest level of priority as the reference node).

[0420] When a set of anchor WTRUs is provided, the target WTRU may determine the reference node based on the location of the reference node and / or the identification information of the reference node (e.g., the anchor WTRU ID). The network may indicate the reference node and / or the anchor WTRU, and / or the target WTRU may determine to report the relative location to the reference node.

[0421] When a set of anchor WTRUs is provided, the target WTRU may determine the reference node based on whether the reference node is one of the sources for SL positioning and / or SL communication (e.g., the source of synchronization and / or the reference WTRU for which the RSTD is determined). In the example, the target WTRU may receive the priority levels associated with the sources. For example, the priority level of the source of synchronization may have a higher priority level than the level associated with the reference WTRU for calculating the RSTD.

[0422] In an example, the target WTRU may indicate information related to a reference node (e.g., a WTRU ID, an SL PRS resource ID, and / or an SL PRS ID associated with an SL-PRS transmitted by the reference node) in relative location information. In an example, during positioning, the target WTRU may determine to change the reference node. In such a case, the target WTRU may end the current positioning session and send a request to resume the session to the anchor WTRU and / or the network.

[0423] In an example, the WTRU may determine to include information related to the reference node when there is a change in the reference node. If the reference node is not changed, the target WTRU may determine to include a timestamp in the measurement report, and the timestamp may indicate the time when the reference node is configured. For example, if the target WTRU may determine to use anchor WTRU_A as the reference node at time T1, the target WTRU may indicate to the network that WTRU_A is used as the reference node at time T1. At a time T2 after T1, if the reference node is not changed, the target WTRU may associate T1 with the relative location information determined at T2. The network may refer to the report at T1 to determine which reference node is used. At a time T3 later than T2, if the target WTRU may determine to change the reference node (e.g., to anchor WTRU_B), the target WTRU may indicate reference node information (e.g., information related to anchor WTRU_B such as its location information, WTRU ID, and / or PRS resource ID) in the report and associate T3 with the information. At a time T4 after T3, if the reference node is not changed, the target WTRU may indicate T3 to the network with respect to the reference node information.

[0424] In an example, for each reference node, the target WTRU may receive a period of time during which the target WTRU may use the reference node with respect to the relative location. In an example, the target WTRU may determine to use two or more reference nodes based on the conditions described above. The target WTRU may include relative location information corresponding to each reference node in its report transmitted to the anchor WTRU and / or the network.

[0425] The WTRU may request resources for sidelink positioning and transfer the schedule to the group. In an example, the WTRU (e.g., the target WTRU) may receive scheduled sidelink resources for a group of WTRUs for sidelink positioning (e.g., via DCI). The WTRU may then determine a positioning method to use for the group based on the set of scheduled sidelink resources (e.g., in DCI). The target WTRU may then use a groupcast message associated with the group for potential SL-PRS transmissions and / or measurement reports of the anchor WTRU to transfer the scheduled SL-PRS reception (if available) and / or SL-PRS measurement report resources (if available) indicated in the scheduled sidelink resources (e.g., DCI).

[0426] In such a case, the WTRU may perform the following steps. The WTRU may perform a discovery procedure to determine a set of anchor WTRUs and / or determine a group ID to represent the positioning group. The WTRU may notify the gNB of the positioning group information. The WTRU may request sidelink resources for the group of WTRUs to perform sidelink positioning. The WTRU may receive scheduled sidelink resources for the group of WTRUs to perform sidelink positioning (e.g., via DCI).

[0427] The WTRU may determine a positioning method based on the content of the scheduled sidelink resources. For example, if the scheduled resources have both SL-PRS transmission resources and SL-PRS reception resources, the WTRU may perform RTT-based sidelink positioning. If the scheduled resources have SL-PRS transmission resources, the WTRU may perform an SL-PRS transmission-based method. If the scheduled resources have SL-PRS reception resources, the WTRU may perform an SL-PRS reception-based method.

[0428] Additional steps that the WTRU may perform occur when the scheduled sidelink resources have SL-PRS reception resources and / or SL-PRS measurement reporting resources, and the WTRU may transfer the scheduled resources for the anchor WTRU using the groupcast ID. The WTRU may perform SL-PRS transmission in the scheduled resources for SL-PRS transmission. The WTRU may perform SL-PRS reception in the scheduled resources for SL-PRS reception.

[0429] The WTRU may determine sidelink resources for each WTRU within the group. In the example, for the RTT-based method, the WTRU (e.g., the target WTRU) may perform SL-PRS reception and / or SL-PRS measurement report reception from the group of WTRUs (e.g., the group of anchor WTRUs). The WTRU may determine the SL-PRS resources and / or measurement report resources for each anchor WTRU based on the anchor WTRU ID, the number of WTRUs within the group, the (pre)-configured OCC for each WTRU, the set of scheduled sidelink resources for the group, and / or the (pre)-configured multiplexing rules. The WTRU may then transmit the derived positioning (e.g., relative positioning) using the groupcast message associated with the group.

[0430] For example, the WTRU may perform one or any combination of the following steps. The WTRU may determine a group of WTRUs for sidelink positioning, the WTRU may configure each anchor WTRU with one OCC (e.g., based on the WTRU ID), the WTRU may receive an SL-PRS resource configuration and / or an SL-PRS measurement report configuration from the gNB, which may include the bandwidth, duration, comb size, number of repetitions, and / or the resource size of each measurement report for each SL-PRS resource. The SL-PRS resource configuration and / or the SL-PRS measurement report configuration from the gNB may also include the order of SL-PRS multiplexing for a group of resources (e.g., OCC, then frequency, then time) and / or the order of multiplexing of SL-PRS measurement report resources (e.g., time, then frequency).

[0431] The WTRU may also transfer the configuration to the group using the group ID. The WTRU may receive (e.g., via DCI) a scheduled sidelink resource for the group of WTRUs to perform sidelink positioning and / or transfer the scheduled resource to the anchor WTRU. The WTRU may perform an SL-PRS transmission in the scheduled sidelink resource for its SL-PRS transmission. The WTRU may determine the SL-PRS resources and measurement report resources for each anchor WTRU based on the anchor WTRU ID, the number of WTRUs in the group, the OCC configured (in advance) for each WTRU, the set of scheduled sidelink resources for the group, and / or the (preconfigured) multiplexing rules. The WTRU may calculate the RTT between each WTRU based on the measured Tx-Rx of the WTRU's SL-PRS and the Tx-Rx reported from each anchor WTRU. The WTRU may include the calculated relative positioning for anchoring the WTRU in one message and / or transmit it to the group using the group ID.

[0432] Figure 18 depicts an exemplary diagram of the multiplexing of SL-PRS 1802 and SL-PRS measurement reports 1804 among WTRUs within a group. As shown in Figure 18, the WTRU may schedule SL-PRS resources 1806a-d and SL-PRS measurement report resources 1808a-d for the group of WTRUs. The WTRU may then determine the SL-PRS resources 1806a-d and SL-PRS measurement report resources 1808a-d for each WTRU.

[0433] The WTRU may determine its SL-PRS resources and / or its SL-PRS measurement report resources from the resources for the group. In the example, in the case of an RTT-based method, the WTRU (e.g., the anchor WTRU) may receive a set of resources for SL-PRS transmission and a set of resources for SL-PRS measurement reports (e.g., from a target WTRU). The WTRU may then determine its SL-PRS transmission resources and / or its SL-PRS measurement report resources (e.g., for reporting the Tx-Rx difference) based on its WTRU ID, the number of WTRUs within the group, the OCC configured (a priori) for the WTRU, and / or the multiplexing rules configured (a priori).

[0434] For example, to determine its SL-PRS transmission resource and / or its SL-PRS measurement report resource, the WTRU may perform one or any combination of the following. Determine its WTRU ID within the group and the number of WTRUs within the positioning group, receive a dedicated OCC for SL-PRS transmission (e.g., based on the WTRU ID), receive an SL-PRS resource configuration and / or an SL-PRS measurement report configuration from the target WTRU, receive a scheduled sidelink resource for a group of WTRUs for performing sidelink positioning and / or from the target WTRU, and determine its SL-PRS and measurement report resources for each anchor WTRU based on its WTRU ID, the number of WTRUs within the group, the configured OCC of the WTRU, the set of scheduled sidelink resources for the group, and / or the (pre)-configured multiplexing rules, and / or perform SL-PRS transmission and / or SL-PRS measurement reporting on the determined resources.

[0435] FIG. 19 depicts an exemplary signal flow diagram for coverage round trip time (RTT) positioning. At 1902, the target WTRU may transmit a positioning request, for example, to a network (e.g., an LMF, etc.). Such a request may include a MO-LR request (e.g., sent within an LPP or LCS message), an LPP message (e.g., an LPP request for sidelink positioning, an LPP request for assistance data, LPP capability information), and / or an AS layer message (e.g., an RRC message, a MAC CE).

[0436] In 1904, the anchor WTRU may receive a PRS configuration (e.g., PRS parameters such as a comb value, number of slots, bandwidth, and / or positioning method) for the anchor WTRU and / or the target WTRU. In 1906, the anchor WTRU may send a request to the gNB to schedule resources for the transmission of PRS for the anchor WTRU and / or the target WTRU. In 1908, the gNB may respond to the anchor WTRU with SL-PRS resources and / or an SL-PRS configuration.

[0437] In 1910, the target WTRU may receive resource information (e.g., the location of the SL-PRS in the time and / or frequency domain) from the anchor WTRU. Next, although not shown in FIG. 19, the target WTRU may receive a set of resources and / or an SL PRS configuration from the anchor WTRU and / or the gNB. In the example, the target WTRU may receive an indication of the sidelink positioning method (e.g., RTT) to be applied from the anchor WTRU and / or the gNB. The target WTRU may determine the resources and / or configuration for its SL-PRS transmission based on the aforementioned set of resources and / or SL PRS configuration. The target WTRU may receive such information and / or indication in, for example, any of an SCI, MAC-CE, PC5-RRC, and / or LPP message.

[0438] In 1912, the target WTRU may monitor the SCI from the anchor WTRU and / or receive the SL-PRS from the anchor WTRU at the resources indicated by the SCI. In 1914, the target WTRU may perform measurements on the received PRS (e.g., received timing, RSRP, and / or AoA). In 1914, the target WTRU may send the SL-PRS to the anchor WTRU.

[0439] In 1918, the target WTRU may report the target WTRU Rx-Tx time difference to the anchor WTRU (e.g., via any of an LPP message, a PC5-RRC message, an SL MAC CE, and / or an SCI), and the target WTRU Tx-Rx time difference may be the difference between the time the target WTRU received the SL-PRS from the anchor WTRU and the time the target WTRU transmits the SL-PRS. In an example, the target WTRU may report the target WTRU Tx-Rx time difference and / or other measurements (e.g., RSRP per SL-PRS resource) to the LMF via an LPP message.

[0440] In 1920, the anchor WTRU may receive the SL-PRS from the target WTRU and / or perform measurements (e.g., reception timing, RSRP, AoA, and / or the anchor WTRU Rx-Tx time difference), and the anchor WTRU Rx-Tx time difference may be the difference between the time the anchor WTRU transmits the SL-PRS and / or the time the anchor WTRU receives the SL-PRS from the target WTRU. In an example, the anchor WTRU may send the anchor WTRU Rx-Tx time difference to the LMF in an LPP message.

[0441] In 1922, the anchor WTRU may send the measurements performed by the anchor WTRU and the target WTRU to the LMF. In an example, the anchor WTRU may determine the relative position between the anchor WTRU and the target WTRU and / or the absolute position of the target WTRU and send that position to the LMF in an LPP message. In 1924, the LMF may then receive the positioning and / or determine location information based on the measurements. In 1926, the target WTRU may receive the location information determined by the LMF based on the measurements.

[0442] Figure 20 depicts an exemplary signal flow diagram for SL positioning (e.g., SL-TDOA and / or SL-AoD) within the coverage of a WTRU. In 2002, the target WTRU may send a request to the network (e.g., LMF and / or gNB) to obtain its location information. For example, the WTRU may send a request to obtain location information in an LCS message (e.g., MT-LR), an LPP message (e.g., an LPP request for sidelink positioning, an LPP request for location information, and / or an LPP request for capability information), and / or an AS layer message (e.g., RRC and / or MAC CE).

[0443] In 2004, the target WTRU may receive from the anchor WTRU support information related to the SL-PRS configuration (e.g., the comb value, the number of slots, and / or the symbols containing SL-PRS) and the WTRU-based positioning method.

[0444] In 2006, the anchor WTRU may receive SL-PRS resource information (e.g., the location of SL-PRS in the time domain and / or frequency domain) from the gNB. The target WTRU may then receive the SL-PRS configuration from one or more anchor WTRUs to perform SL-PRS measurements. In 2008, the target WTRU may receive SL-PRS configuration information from the anchor WTRU. In 2010, the target WTRU may receive the anchor WTRU location from the LMF if the anchor WTRU is stationary (e.g., via an LPP message including, but not limited to, RSU, LPP support data). In the example, if some of the anchor WTRUs are mobile, the target may receive location information from the anchor WTRU (e.g., via any of an LPP message, PC5-RRC, MAC CE, and / or SCI).

[0445] In 2012, the target WTRU may monitor an SCI (e.g., received from the gNB and / or the anchor WTRU) regarding the SL-PRS transmitted from the anchor WTRU. In 2014, the target WTRU may receive the SL-PRS from the anchor WTRU. In 2016, the target WTRU may perform measurements (e.g., RSRP and / or RSTD) on the received SL-PRS. In 2018, the target WTRU may determine its absolute position based on the measurements.

[0446] In 2020, the target WTRU may report its absolute position to the LMF (e.g., via an LPP message). In an example, if the WTRU is configured with a WTRU-assisted SL positioning method, the WTRU may return a measurement report to the LMF.

[0447] FIG. 21 depicts an exemplary process for SL positioning where WTRU information may be provided by the anchor WTRU and / or multiple WTRUs. For example, the target WTRU may receive the anchor WTRU location if the anchor WTRU is mobile.

[0448] In 2102, the target WTRU may receive a request from the network (e.g., the LMF and / or the gNB) to obtain its location information. For example, the WTRU may receive a request to obtain location information in an LCS message (e.g., MT-LR), an LPP message (e.g., an LPP request for sidelink positioning, an LPP request for location information, an LPP request for capability information), and / or an AS layer message (e.g., RRC, and / or MAC CE).

[0449] In 2104, the target WTRU may receive from the anchor WTRU the SL-PRS configuration (e.g., the comb value, the number of slots, and / or the symbols including the SL-PRS) and assistance information related to the WTRU-based positioning method.

[0450] At 2106, the anchor WTRU may receive SL-PRS resource information (e.g., the location of the SL-PRS in the time and / or frequency domain) from the anchor WTRU. At 2108, the target WTRU may receive the anchor WTRU location from the anchor WTRU (e.g., via any of an LPP message, PC5-RRC, MAC CE, and / or SCI).

[0451] At 2110, the target WTRU may monitor an SCI (e.g., received from a gNB and / or the anchor WTRU) regarding the SL-PRS transmitted from the anchor WTRU. At 2112, the target WTRU may receive the SL-PRS from the anchor WTRU. At 2114, the target WTRU may perform measurements (e.g., RSRP and / or RSTD) on the received SL-PRS. At 2116, the target WTRU may determine an absolute position based on the measurements.

[0452] At 2118, the target WTRU may report the absolute position to the LMF (e.g., via an LPP message). In an example, if the WTRU is configured with a WTRU-assisted SL positioning method, the WTRU may return a measurement report to the LMF.

[0453] Figure 22 depicts an exemplary flow diagram of SL positioning (WTRU - based), anchor WTRU information coming from the LMF, and PRS configuration coming from the LMF to the target WTRU within the coverage. At 2202, the target WTRU may send a request for SL positioning data to the LMF. At 2204, the target WTRU may receive the PRS configuration from the LMF in an LPP message (e.g., either an LPP assistance data message and / or an LPP request message for location information). For example, the WTRU may receive a request for location information in an LCS message (e.g., MT - LR), an LPP message (e.g., an LPP request for sidelink positioning, an LPP request for location information, and / or an LPP request for capability information), and / or an AS layer message (e.g., RRC, and / or MAC CE).

[0454] At 2206, the target WTRU may receive from the LMF the SL - PRS configuration (e.g., the comb value, the number of slots, and / or the symbols containing SL - PRS) and assistance information related to the WTRU - based positioning method. At 2208, the gNB may receive from the LMF the SL - PRS configuration (e.g., the comb value, the number of slots, and / or the symbols containing SL - PRS) and assistance information related to the WTRU - based positioning method.

[0455] At 2210, the anchor WTRU may receive SL - PRS resource information (e.g., the location of SL - PRS in the time domain and / or frequency domain) from the gNB. At 2212, the target WTRU may receive the anchor WTRU location from the LMF if the anchor WTRU is stationary (e.g., via an RSU, an LPP message including but not limited to LPP assistance data). In the example, if some of the anchor WTRUs are mobile, the target may receive location information from the anchor WTRU (e.g., via any of an LPP message, PC5 - RRC, MAC CE, and / or SCI).

[0456] At 2214, the target WTRU may monitor an SCI (e.g., received from a gNB and / or the anchor WTRU) regarding the SL-PRS transmitted from the anchor WTRU. At 2216, the target WTRU may receive the SL-PRS from the anchor WTRU. At 2218, the target WTRU may perform measurements (e.g., RSRP and / or RSTD) on the received SL-PRS. At 2220, the target WTRU may determine its absolute position based on the measurements.

[0457] At 2222, the target WTRU may report its absolute position to the LMF (e.g., via an LPP message). In an example, if the WTRU is configured using the WTRU-assisted SL positioning method, the WTRU may return a measurement report to the LMF.

[0458] Figure 23 depicts a process for two-sided RTT SL positioning. At 2302, the target WTRU may send a request for positioning to the LMF in an LPP message. At 2304, the anchor WTRU may receive a PRS configuration from the LMF (e.g., in an LPP assistance data message). At 2306, the anchor WTRU may send a request for time and / or frequency resources for the transmission of SL-PRS from the anchor WTRU and / or the target WTRU. At 2308, the anchor WTRU may receive the SL-PRS resources and / or configuration from the gNB in response to the request. At 2310, the target WTRU may receive resource information from the anchor WTRU (e.g., via any of LPP, PC5-RRC, MAC CE, and / or SCI). At 2312, the target WTRU may monitor an SCI (e.g., received from a gNB and / or the anchor WTRU) regarding the transmitted SL-PRS.

[0459] At 2314, the target WTRU may receive the SL-PRS transmitted by the anchor WTRU, and the resources for the SL-PRS are indicated by the SCI. At 2316, the target WTRU may perform measurements (e.g., RSRP and / or ToA) on the SL-PRS. At 2318, the target WTRU may perform resource selection based on the measurements. At 2320, the target WTRU may transmit the SL-PRS based on the resources determined to be used by the target WTRU. At 2322, the target WTRU may send a first measurement report to the LMF in an LPP message, and the report may include, for example, the target WTRU Tx-Rx time, the RSRP for each SL-PRS resource, and / or the associated AoA measurement values.

[0460] At 2324, the anchor WTRU may perform measurements on the SL-PRS transmitted by the target WTRU. At 2326, the target WTRU may monitor the SCI (e.g., received from the gNB and / or the anchor WTRU) regarding the transmitted SL-PRS. At 2328, the anchor WTRU may send a measurement report (e.g., the anchor WTRU Rx-Tx time, AoA, and / or RSRP). At 2330, the target WTRU may receive a second SL-PRS from the anchor WTRU, and the resource information thereof is indicated by the SCI. At 2332, the target WTRU may perform measurements (e.g., RSRP and / or ToA) on the SL-PRS. At 2334, the target WTRU may send a second measurement report to the LMF in an LPP message, and the report may include, for example, the target WTRU Rx-Tx time, the RSRP for each SL-PRS resource, and / or the associated AoA measurement values.

[0461] The second target WTRU Rx-Tx time may be defined by the difference between the reception time of the second SL-PRS (from the anchor WTRU) and the transmission time of the SL-PRS (from the target WTRU). In the example, the target WTRU may combine the first and second measurement reports and send the combined measurement report to the LMF.

[0462] At 2336, the LMF may determine the location of the target WTRU based on the measurement report. At 2338, the target WTRU may receive the location information determined by the LMF.

[0463] The sidelink positioning method described herein may support the SL-TDOA method and / or the RTT method. To guarantee positioning QoS such as accuracy and latency, resources may be adjusted to reduce the time gap between SL-PRS Tx and / or Rx for the RTT method. Each WTRU may be required to independently request its sidelink Tx resources. This may result in uncoordinated SL-PRS transmissions in SL-TDOA and / or an extended time gap between SL-PRS Tx and / or Rx in RTT.

[0464] In an example, a WTRU (e.g., the target WTRU) may request resources (e.g., SL-PRS Tx resources) for a group of WTRUs. FIG. 24 depicts an exemplary diagram showing a WTRU that obtains and provides sidelink resources associated with a group of WTRUs. FIG. 25 depicts another exemplary diagram showing a WTRU that obtains and provides sidelink resources associated with a group of WTRUs.

[0465] As depicted in FIG. 24, a WTRU 2402 (e.g., the shown target WTRU) may request side link positioning reference signal (SL-PRS) transmission (Tx) resources for a group of WTRUs 2404a-d (e.g., the shown anchor WTRUs). The target WTRU 2402 may indicate, in the request, the number of resources required for itself and the anchor WTRUs 2404a-d. The target WTRU 2402 may receive an indication of the requested resources and transfer the scheduled SL-PRS resources to the group (e.g., the anchor WTRUs 2404a-d). The target WTRU 2402 may request a change in the SL-PRS configuration based on the measurement report status of the other WTRUs 2404a-d within the group. In the case of network-assisted positioning, the target WTRU 2402 may determine a set of received measurements and / or WTRUs for reporting to the network based on one or more (pre-)configured conditions.

[0466] The target WTRU 2402 may form a side link positioning group via a discovery procedure. The target WTRU 2402 may determine a positioning method (e.g., an RTT method, an SL-TDOA method, and / or any suitable combination thereof). The target WTRU 2402 may indicate positioning group information, such as a group identifier (ID) and / or a WTRU number, to a network entity.

[0467] The network entity may include any network entity, e.g., gNB1 2406a and / or gNB2 2406b. The target WTRU 2402 may request SL-PRS resources for a group of WTRUs from a network entity (e.g., gNB1 2406a and / or gNB2 2406b). The request may include a group ID, the number of resources for SL-PRS Tx of the target WTRU 2402, the number of resources for SL-PRS Tx of the anchor WTRUs 2404a-d, and / or any combination thereof.

[0468] As depicted in Figure 24, the target WTRU 2402 may directly provide the request 2408 to gNB1 2406a. The target WTRU 2042 may proceed indirectly to gNB2 2406b via another network entity, such as the LMF 2410. The target WTRU 2402 may receive the requested resources from the network entity. The target WTRU 2402 may receive SL-PRS resources for the group from gNB1 2406a. The indication may be received via DCI.

[0469] The target WTRU 2402 may provide and / or transfer the scheduled resources for the SL-PRS to the group. The scheduled resources may be provided and / or transferred via any mechanism, such as the PC5-RRC interface.

[0470] As depicted in Figure 25, the WTRU 2502 (e.g., the shown target WTRU) may request side link positioning reference signal (SL-PRS) transmission (Tx) 2504 resources for the group of WTRU 2504 (e.g., the shown anchor WTRU). The target WTRU 2502 may indicate, in the request, the number of resources required for itself and the anchor WTRUs 2504a - d. The target WTRU 2502 may receive an indication of the requested resources and transfer the scheduled SL-PRS resources to the group (e.g., the anchor WTRUs 2504a - d). The target WTRU 2402 may request a change in the SL-PRS configuration based on the measurement report status of the other WTRUs 2504a - d within the group. In the case of network-assisted positioning, the target WTRU 2502 may determine the received measurements and / or set of WTRUs for reporting to the network based on one or more (pre-)configured conditions.

[0471] As depicted in Figure 25, the target WTRU 2502 may form a sidelink positioning group via a discovery procedure. The target WTRU 2502 may determine a positioning method (e.g., RTT method, SL-TDOA method, and / or any suitable combination thereof). The target WTRU 2502 may indicate positioning group information, such as a group identifier (ID) and / or a WTRU number, to a network entity.

[0472] The network entity may include any network entity, e.g., gNB1 2506. The target WTRU 2502 may request SL-PRS resources for the group of WTRUs from a network entity (e.g., gNB1 2506a). The request may include the group ID, the number of resources for the SL-PRS Tx 2508 of the target WTRU 2502, the number of resources for the SL-PRS Tx2510a-d of the anchor WTRUs 2504a-d, and / or any combination thereof.

[0473] Figure 25 depicts an RTT-based positioning method, where the target WTRU 2502 may determine to transmit SL-PRS 2508 in a groupcast-based transmission. Each SL-PRS transmission 2508 may target all of the anchor WTRUs 2504a-d. Each anchor WTRU 2504a-d may then reply with SL-PRS 2510a-d using unicast-based transmission.

[0474] In the foregoing, the features and elements are provided in specific combinations, but it will be understood by those skilled in the art that each feature or each element can be used alone or in any combination with other features and elements. The present disclosure is not limited in terms of the specific embodiments described in this application, and these embodiments are intended as illustrations of various aspects. As will be apparent to those skilled in the art, many modifications and variations may be made without departing from the spirit and scope of the present invention. Any element, operation, or instruction used in the description of this application should not be construed as important or essential to the present invention unless explicitly presented as such. In addition to those listed herein, functionally equivalent methods, apparatuses, and articles of manufacture within the scope of the present disclosure will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is limited only by the terms of the appended claims, and is limited together with the full scope of equivalents to which such claims are entitled. It should be understood that the present disclosure is not limited to a particular method or system.

[0475] The foregoing embodiments may be considered with respect to specific terms and structures (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.) for the sake of simplicity, but the embodiments considered are not limited thereto and can be applied to other systems using other forms of electromagnetic or non-electromagnetic waves such as, for example, sound waves.

[0476] It should also be understood that the terms used in this specification are for the purpose of describing particular embodiments only and are not intended to be limiting. As used herein, the term "video" or the term "image" can mean any of a snapshot, a single image, and / or a plurality of images displayed over time, or any suitable combination thereof. As another example, when referred to herein, the term "user equipment" and its abbreviation "UE", the term "remote", and / or the term "head-mounted display" or its abbreviation "HMD" can mean or include (i) a wireless transmit and / or receive unit (WTRU), (ii) any of several embodiments of a WTRU, (iii) a wireless and / or wired (e.g., tetherable) device configured to have some or all of the structure and functionality of a WTRU, (iii) a wireless and / or wired device configured to have less structure and functionality than all of the structure and functionality of a WTRU, or (iv) the like. Details of an exemplary WTRU that can represent any WTRU described herein are provided herein with respect to FIGS. 1A-1D. As another example, the various embodiments disclosed above and below in this specification are described as utilizing a head-mounted display. One of ordinary skill in the art will recognize that devices other than a head-mounted display can be utilized and that some or all of the present disclosure and the various disclosed embodiments can be modified accordingly without undue experimentation. Examples of such other devices can include a drone or other device configured to stream information for providing an augmented reality experience.

[0477] In addition, the methods provided herein may be implemented in a computer program, software, or firmware embodied on a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media distinct from signals include magnetic media such as read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, internal hard disks, and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs), but are not limited thereto. A processor associated with the software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

[0478] Variations of the methods, apparatus, articles of manufacture, and systems provided above are possible without departing from the scope of the invention. Considering the various embodiments that may be applicable, it should be understood that the illustrated embodiments are merely examples and should not be construed as limiting the following claims. For example, the embodiments provided herein include a handheld device, which may include or be utilized with any suitable voltage source, such as a battery that provides any suitable voltage.

[0479] Furthermore, in the embodiments provided herein, mention is made of processing platforms, computing systems, controllers, and other devices including processors. These devices may include at least one central processing unit (“CPU”) and memory. According to the convention of those skilled in the art of computer programming, references to operations and symbolic representations of operations or instructions may be implemented by various CPUs and memories. Such acts and operations or instructions may be referred to as “executed,” “executed by a computer,” or “executed by a CPU.”

[0480] Those skilled in the art will understand that operations and symbolically represented operations or instructions include the manipulation of electrical signals by a CPU. An electrical system represents data bits that can cause a resulting conversion or reduction of electrical signals, maintains the data bits in a memory location of a memory system, thereby restructuring or otherwise changing the operation of the CPU and the processing of other signals. The memory location in which the data bits are maintained is a physical location having specific electrical, magnetic, optical, or organic characteristics corresponding to or representing the data bits. It should be understood that the embodiments are not limited to the platforms or CPUs mentioned above, and that other platforms and CPUs may support the provided methods.

[0481] The data bits may also be maintained on a computer-readable medium including a magnetic disk, an optical disk, and any other volatile (e.g., random access memory (RAM)) or non-volatile (e.g., read-only memory (ROM)) mass storage system readable by a CPU. The computer-readable medium may include a cooperative or interconnected computer-readable medium that exists exclusively on the processing system or is distributed among a plurality of interconnected processing systems that may be local or remote to the processing system. It should be understood that the embodiments are not limited to the memories mentioned above and that other platforms and memories may support the provided methods.

[0482] In an exemplary embodiment, any of the operations, processes, etc. described herein may be implemented as computer-readable instructions stored on a computer-readable medium. The computer-readable instructions may be executed by a processor of a mobile body, a network element, and / or any other computing device.

[0483] In the foregoing detailed description, various embodiments of devices and / or processes have been shown through the use of block diagrams, flowcharts, and / or examples. As long as such block diagrams, flowcharts, and / or examples include one or more functions and / or operations, it will be understood by those skilled in the art that each function and / or each operation in such block diagrams, flowcharts, or examples may be implemented individually and / or collectively by a wide variety of hardware, software, firmware, or substantially any combination thereof. In an exemplary embodiment, some portions of the subject matter described herein may be implemented via application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs), and / or other integrated formats. Those skilled in the art will recognize that some aspects of the embodiments disclosed herein may be equivalently implemented in an integrated circuit as one or more computer programs operating on one or more computers (e.g., as one or more programs operating on one or more computer systems), as one or more programs operating on one or more processors (e.g., as one or more programs operating on one or more microprocessors), as firmware, or as substantially any combination thereof, and that designing the circuitry and / or writing the code for the software and / or firmware are within the scope of the skill of those in the art in light of the present disclosure. Those skilled in the art will understand that the mechanisms of the subject matter described herein may be distributed in various forms of program products and that the exemplary embodiments of the subject matter described herein apply regardless of the particular type of signal carrying medium used to actually carry out the distribution. Examples of signal transmission media include, but are not limited to, recordable media such as floppy disks, hard disk drives, CDs, DVDs, digital tapes, com...

Claims

1. A wireless transmit - receive unit (WTRU) comprising a transceiver and a processor, wherein the processor transmits, via the transceiver, a first message comprising sidelink positioning information associated with a group of WTRUs, the sidelink positioning information including an indication of a sidelink positioning method for determining the position of the WTRUs within the group of WTRUs transmits, via the transceiver, a second message comprising a request for sidelink positioning reference signal (SL - PRS) resources for the group of WTRUs receives, via the transceiver, an indication of the allocated SL - PRS resources for the group of WTRUs is configured to send, via the transceiver, the indication of the allocated SL - PRS resources to the group of WTRUs WTRU

2. The WTRU according to claim 1, wherein the requested resources are at least partially based on the sidelink positioning method, the number of WTRUs within the group of WTRUs, and the quality of service (QoS) associated with the sidelink positioning method

3. The sidelink positioning information in the first message includes a group identifier (ID) associated with the group of WTRUs, and the request for SL - PRS resources in the second message includes the group ID, The WTRU according to claim 1

4. The WTRU according to claim 1, wherein the sidelink positioning method includes at least one of round - trip time (RTT) positioning, sidelink time difference of arrival (SL - TDOA) positioning, or sidelink angle of departure (SL - AoD) positioning

5. The WTRU is one of the WTRUs within the group of WTRUs, and the request for SL - PRS resources includes a request for SL - PRS transmission resources for the WTRU, and the request for SL - PRS resources includes a request for SL - PRS transmission resources for other WTRUs within the group of WTRUs The WTRU according to claim 1

6. The request for SL - PRS resources includes the number of SL - PRS transmission resources requested for the WTRU, and The WTRU according to claim 5, further comprising the number of SL-PRS transmission resources requested for the other WTRUs within the group of the WTRU. **Claim 7** The WTRU according to claim 1, wherein the second message comprises a media access control (MAC) control element (CE). **Claim 8** The WTRU according to claim 1, wherein the processor is further configured to perform a sidelink discovery procedure to identify the group of the WTRU. **Claim 9** The WTRU according to claim 1, wherein the processor is configured to transmit the first message and the second message to a node including at least one of a network node, another WTRU, or a roadside unit (RSU). **Claim 10** A method performed by a wireless transmit receive unit (WTRU), comprising: transmitting a first message comprising sidelink positioning information associated with a group of WTRUs, the sidelink positioning information including an indication of a sidelink positioning method for determining the position of the WTRUs within the group of the WTRU; transmitting a second message comprising a request for sidelink positioning reference signal (SL-PRS) resources for the group of the WTRU; receiving an indication of the allocated SL-PRS resources for the group of the WTRU; sending the indication of the allocated SL-PRS resources to the group of the WTRU; A method comprising the above steps. **Claim 11** The method according to claim 10, wherein the requested resources are at least partially based on the sidelink positioning method, the number of WTRUs within the group of the WTRU, and the quality of service (QoS) associated with the sidelink positioning method. **Claim 12** The sidelink positioning information in the first message includes a group identifier (ID) associated with the group of the WTRU, the request for the SL-PRS resources in the second message includes the group ID, The method according to claim 10. **Claim 13** The method according to claim 10, wherein the sidelink positioning method includes at least one of round trip time (RTT) positioning, sidelink time difference of arrival (SL-TDOA) positioning, or sidelink angle of departure (SL-AoD) positioning. **Claim 14** The WTRU is one of the WTRUs within the group of the WTRU, The request for the SL-PRS resource includes a request for an SL-PRS transmission resource for the WTRU, The request for the SL-PRS resource includes a request for an SL-PRS transmission resource for another WTRU within the group of the WTRU, The method according to claim 10.

15. The request for the SL-PRS resource, The number of SL-PRS transmission resources requested for the WTRU, and The method according to claim 14, further including the number of SL-PRS transmission resources requested for the other WTRUs within the group of the WTRU.

16. The method according to claim 10, wherein the second message includes a media access control (MAC) control element (CE).

17. The method according to claim 10, further including performing a sidelink discovery procedure to identify the group of the WTRU.

18. The method according to claim 10, further including transmitting the first message and the second message to a node including at least one of a network node, another WTRU, or a roadside unit (RSU).

19. At least one computer-readable storage medium storing executable instructions, wherein when the executable instructions are executed by a processor, the processor is configured to: Transmit a first message including sidelink positioning information associated with a group of WTRUs, the sidelink positioning information including an indication of a sidelink positioning method for determining the positions of the WTRUs within the group of the WTRUs, Transmit a second message including a request for a sidelink positioning reference signal (SL-PRS) resource for the group of the WTRUs, Receive an indication of the allocated SL-PRS resource for the group of the WTRUs, and Send the indication of the allocated SL-PRS resource to the group of the WTRUs.

20. The at least one computer-readable storage medium according to claim 19, wherein the requested resource is at least partially based on the sidelink positioning method, the number of WTRUs within the group of the WTRUs, and the quality of service (QoS) associated with the sidelink positioning method.

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