Wireless transmitting / receiving unit and method performed by same

Abstract

A wireless transmit / receive unit (WTRU) and a method performed by the wireless transmit / receive unit (WTRU) are disclosed. The wireless transmit / receive unit (WTRU) includes: a processor and a memory configured to: receive configuration information indicating a first resource pool and a second resource pool and information associated with one or more sidelink positioning reference signals (SL-PRS); receiving side link control information (SCI); one or more SL-PRSs indicated by the SCI are received via a resource associated with the first resource pool or via a resource associated with the second resource pool.

Description

[0001] This application is a divisional application of the application with application number 202380025612.3, application date February 9, 2023, and invention name “Sending SL-PRS under the condition that the associated parameters are within a predetermined range”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 308,307 filed on February 9, 2022, U.S. Provisional Patent Application No. 63 / 334,815 filed on April 26, 2022, U.S. Provisional Patent Application No. 63 / 395,945 filed on August 8, 2022, and U.S. Provisional Patent Application No. 63 / 410,849 filed on September 28, 2022, the entire contents of which are incorporated herein by reference. Background Art

[0004] In vehicle-to-vehicle communications (V2X), resources for sidelink transmission / reception may be structured as resource pools. A resource pool may include a set of contiguous frequency resources that repeat in time following a bitmap pattern. A wireless transmit / receive unit (WTRU) may be configured with one resource pool or multiple resource pools. For a WTRU in coverage, the resource pool may be configured via a system information block (SIB) and / or a radio resource control (RRC). For a WTRU out of coverage, a resource pool may be configured (e.g., pre-configured).

[0005] The sidelink transmission may span one time slot and may include a physical sidelink shared channel (PSSCH) and / or a physical sidelink control channel (PSCCH). PSSCH and PSCCH are frequency division multiplexed (FDM) and time division multiplexed (TDM). Sidelink control information (SCI) is typically divided into two parts: a first-level SCI and a second-level SCI. The first-level SCI may indicate the resources used for the sidelink transmission, the quality of service (QoS) of the transmission (e.g., priority), a demodulation reference signal (DMRS), a phase tracking reference signal (PTRS) for the sidelink transmission, and a second SCI format. The second-level SCI may indicate the remaining control information. The SCI may be used to reserve resources within a resource pool for future transmissions.

[0006] The sidelink resources may be scheduled by the network or selected by the WTRU. If the sidelink resources are selected by the WTRU, the WTRU may perform sensing by decoding SCIs from other WTRUs before selecting the sidelink resources to avoid selecting resources reserved by other WTRUs. Summary of the invention

[0007] Methods and apparatus are provided for sidelink positioning (e.g., autonomous sidelink positioning) discovery. Methods and apparatus are provided for dynamic sidelink positioning (e.g., autonomous sidelink positioning). Methods and apparatus are provided for semi-static sidelink positioning (e.g., autonomous sidelink positioning). Methods and apparatus are provided for sidelink positioning (e.g., autonomous sidelink positioning) reference signal (SL-PRS) measurements. Methods and apparatus are provided for WTRU determination of a receiver for sidelink measurement reports. Methods and apparatus are provided for round trip time (RTT) based (e.g., one-sided or two-sided) positioning for out-of-coverage.

[0008] A wireless transmit / receive unit (WTRU) may receive a positioning request message from another WTRU. The positioning request message may indicate one or more parameters and one or more ranges associated with the one or more parameters. The one or more parameters may include one or more of a distance, a sidelink reference signal received power, a departure angle, line-of-sight / non-line-of-sight, and / or a set of area identifiers. The positioning request message from the other WTRU may include a resource allocation request indicating that the WTRU should perform resource allocation. The positioning request message may indicate a request type, which includes one or more of performing sidelink reception, performing sidelink transmission, performing sidelink transmission and reception, or performing positioning measurement reporting. The positioning request message may indicate a priority, latency, and / or periodicity associated with one or more of the sidelink transmission, the sidelink reception, and / or the sidelink measurement report. The WTRU may calculate a value of a first parameter of the one or more parameters indicated in the positioning request message. The WTRU may determine that the value is within a first range of the one or more ranges associated with the first parameter. The WTRU may use the one or more parameters indicated in the positioning request message to perform resource allocation for one or more of sidelink transmission / reception or measurement reporting. For example, the WTRU may perform the resource allocation in response to the positioning request message including the resource allocation request.

[0009] When the positioning request message from the other WTRU requests the WTRU to perform sidelink reception, the WTRU may use the resources indicated in the positioning request message to perform sidelink reception. When the positioning request message from the other WTRU requests the WTRU to perform sidelink transmission, the WTRU may use the allocated resources to perform sidelink transmission. The positioning request message may indicate a request type, which includes one or more of performing sidelink reception, performing sidelink transmission, performing sidelink transmission and reception, and / or performing positioning measurement reporting. The WTRU may use the priority indicated in the positioning request message to perform sidelink reception and priority division. The WTRU may use the measurement gap indicated in the positioning request message to perform sidelink reception.

[0010] The WTRU may determine a broadcast type associated with sidelink positioning. The WTRU may be configured (e.g., pre-configured) with a set of SL-PRS configurations. The WTRU may indicate which SL-PRS configuration to use. The WTRU may determine whether to feedback a sidelink positioning request message. The WTRU may determine whether to feedback a SL-PRS transmission. The WTRU may determine a priority associated with the transmission of feedback. The WTRU may determine a priority associated with the reception of a feedback message. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented.

[0012] Figure 1B is an example of a method that can be used according to one embodiment. Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within an illustrated communication system.

[0013] Figure 1C is an example of a method that can be used according to one embodiment. Figure 1A System diagram of an example Radio Access Network (RAN) and an example Core Network (CN) used within an illustrated communication system.

[0014] Figure 1D is an example of a method that can be used according to one embodiment. Figure 1A System diagram of yet another example RAN and yet another example CN for use within the illustrated communication system.

[0015] Figure 2 An example process for a WTRU to determine one or more sidelink positioning reference signal (SL-PRS) parameters is described.

[0016] Figure 3 Depicted are example parameters included in a locate request message.

[0017] Figure 4 An example process is depicted in which a WTRU reserves periodic SL-PRS resources and determines whether to perform SL-PRS transmission.

[0018] Figure 5 An example procedure for a WTRU to adjust the range requirement for acknowledgement (ACK) feedback is depicted.

[0019] Figure 6 An example SL-PRS for a group of WTRUs is described.

[0020] Figure 7 is a diagram illustrating example measurement gap (MG) patterns and parameters.

[0021] Figure 8 Examples associated with sidelink positioning using HARQ-enabled transmissions are illustrated.

[0022] Fig. 9 Examples associated with sidelink positioning of HARQ enabled transmissions using multicast option 2 are illustrated.

[0023] Fig.10 An example signal flow for an out-of-coverage round trip time (RTT) method is illustrated.

[0024] Fig.11 An example RTT positioning method for out of coverage is illustrated, where the target WTRU performs Mode 2 resource allocation.

[0025] Fig.12 An example one-sided positioning method for out-of-coverage is illustrated.

[0026] Fig.13 An example two-sided RTT positioning method for out of coverage is illustrated.

[0027] Fig.14 A flow chart describing the WTRU behavior upon receiving a SL-PRS request is depicted. DETAILED DESCRIPTION

[0028] Figure 1A 1 is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple 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 multi-carrier (FBMC), etc.

[0029] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110 and other networks 112, but it should 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 send and / or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0030] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with one or more of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be base transceiver stations (BTS), Node Bs, eNode Bs, Home Node Bs, Home eNode Bs, gNBs, NR Node Bs, site controllers, access points (APs), wireless routers, and the like. Although the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0031] The base station 114a may be part of the RAN 104 / 113, which 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. The base station 114a and / or the base station 114b may be configured to send and / or receive wireless signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Therefore, in one embodiment, the base station 114a may include three transceivers, for example, one transceiver for each sector of the cell. In an embodiment, the 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 send and / or receive signals in a desired spatial direction.

[0032] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an 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.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0033] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 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 (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0034] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0035] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0036] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may together implement LTE radio access and NR radio access, for example using dual connectivity (DC) principles. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0037] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as IEEE 802.11 (e.g., Wireless Fidelity (WiFi)), IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), GSM Enhanced Data Rates for Evolution (EDGE), GSM EDGE (GERAN), etc.

[0038] Figure 1AThe base station 114b in the example may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a local area, such as a business location, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio 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 may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As Figure 1A As shown, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106 / 115.

[0039] The RAN 104 / 113 may be in communication with the 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 the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not described in detail in the specification, the CN 106 / 115 may be configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Figure 1A Although not shown in the figure, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0040] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides 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) in the TCP / IP Internet protocol suite. The networks 112 may include wired communication networks and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0041] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0042] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, the WTRU 102 may 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, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0043] The processor 118 may be a general purpose processor, a special purpose 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 may perform signal decoding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0044] The send / receive element 122 may be configured to send a signal to a base station (e.g., base station 114a) or receive a signal from a base station via an air interface 116. For example, in one embodiment, the send / receive element 122 may be an antenna configured to send and / or receive an RF signal. In an embodiment, the send / receive element 122 may be a transmitter / detector configured to send and / or receive, for example, an IR, UV, or visible light signal. In another embodiment, the send / receive element 122 may be configured to send and / or receive both an RF signal and an optical signal. It should be understood that the send / receive element 122 may be configured to send / receive any combination of wireless signals.

[0045] Although the transmit / receive element 122 Figure 1B 102 as a single element, but 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 over the air interface 116.

[0046] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0047] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a 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, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a 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, and the like. 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).

[0048] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0049] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0050] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may 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 modulation (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. Peripheral device 138 may include one or more sensors, which may be one or more of the following: 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.

[0051] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit 139 for reducing and / or substantially eliminating self-interference via hardware (e.g., choke) or via signal processing performed by a processor (e.g., a separate processor (not shown) or via the processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0052] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0053] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0054] Each of the evolved Node Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0055] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements is depicted as being part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0056] The MME 162 may be connected to each of the evolved Node-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0057] The SGW 164 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-evolved Node-B handover, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0058] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0059] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include or may be in communication with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers.

[0060] Although the WTRU Figures 1A to 1D Although described as a wireless terminal, it is contemplated that in certain representative embodiments such a terminal may (eg, temporarily or permanently) employ a wired communications interface with a communications network.

[0061] In a representative embodiment, the other network 112 may be a WLAN.

[0062] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or carries traffic away from the BSS. Traffic originating from outside the BSS and directed to the STA may arrive through the AP and may be delivered to the STA. Traffic originating from the STA and directed to a destination outside the BSS may be transmitted to the AP to be delivered to the corresponding destination. Traffic between STAs within the BSS may be transmitted through the AP, for example, where the source STA may transmit traffic to the AP, and the AP may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Point-to-point traffic may be transmitted between the source STA and the destination STA (e.g., directly between them) using direct link establishment (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs (eg, all STAs) within or using the IBSS may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad-hoc" communication mode.

[0063] When using the 802.11ac infrastructure operating mode or a similar operating mode, the AP may send beacons on a fixed channel (such as a primary channel). The primary channel may be a fixed width (e.g., a 20MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (including the AP) may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a specific STA, the specific STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0064] High throughput (HT) STAs may communicate using a 40 MHz wide channel, for example, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0065] Very High Throughput (VHT) STAs may support 20MHz, 40MHz, 80MHz, and / or 160MHz wide channels. 40MHz channels and / or 80MHz channels may be formed by combining consecutive 20MHz channels. A 160MHz channel may be formed by combining 8 consecutive 20MHz channels, or by combining two non-contiguous 80MHz channels (this may be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, the data may pass through a segment parser that may divide the data into two streams. Each stream may be individually processed by an inverse fast Fourier transform (IFFT) and time domain processing. These streams may be mapped to two 80MHz channels, and data may be sent by a transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed, and the combined data may be transmitted to the medium access control (MAC).

[0066] 802.11af and 802.11ah support operating modes below 1GHz. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support meter type control / machine type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0067] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include 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 may be set and / or limited by a STA (which supports the minimum bandwidth operating mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (supporting only the 1MHz operating mode) is sending to the AP, the entire available frequency band may be considered busy even if most of the frequency bands remain idle and may be available.

[0068] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0069] Figure 1D 1 is a system diagram illustrating the RAN 113 and the CN 115 in accordance with an embodiment. As noted above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0070] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 180b may utilize beamforming to send signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may, for example, use multiple antennas to send wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNB 180a and the gNB 180b (and / or the gNB 180c).

[0071] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with parameter sets that may be scalable. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmit time intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or varying absolute time lengths over time).

[0072] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c while also not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with the gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as the eNode-B 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNode-B 160a, 160b, 160c may act as a mobility anchor for the WTRUs 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0073] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards a user plane function (UPF) 184a, 184b, routing of control plane information towards an access and mobility management function (AMF) 182a, 182b, etc. As shown in FIG. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0074] Figure 1DThe illustrated CN 115 may include one or more of the AMFs 182a, 182b, one or more of the UPFs 184a, 184b, one or more of the session management functions (SMFs) 183a, 183b, and possible data networks (DNs) 185a, 185b. While each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0075] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, support for network slicing (e.g., handling of different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of NAS signaling, mobility management, etc. The AMF 182a, 182b may use network slicing to customize CN support for the WTRU 102a, 102b, 102c based on the type of services utilized by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0076] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0077] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0078] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b via the UPFs 184a, 184b via the N3 interfaces to the UPFs 184a, 184b and the N6 interfaces between the UPFs 184a, 184b and the DNs 185a, 185b.

[0079] Given that Figures 1A to 1D as well as Figures 1A to 1D , one or more or all of the functions described herein for one or more of the following may be performed by one or more simulation devices (not shown): WTRU 102a-d, base station 114a-b, evolved Node B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-ab, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any one or more other devices described herein. A simulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, a simulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0080] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices may perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device for testing purposes and / or may use over-the-air wireless communications to perform testing.

[0081] One or more simulation devices may perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device may be used in a test lab and / or in a test scenario in a non-deployed (e.g., testing) wired communication network and / or wireless communication network to enable testing of one or more components. One or more simulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas) may be used by the simulation device to send and / or receive data.

[0082] Vehicle-to-everything (V2X) communications can support sidelink communications between different vehicles.

[0083] In V2X, resources used for sidelink transmission / reception may be structured as a resource pool. A resource pool may include a set of continuous frequency resources that repeat in time following a bitmap pattern.

[0084] A WTRU may be configured for one resource pool and / or multiple resource pools. For a WTRU in coverage, the resource pools may be configured via a system information block (SIB) and / or a radio resource control (RRC). For a WTRU out of coverage, the resource pools may be configured (e.g., pre-configured).

[0085] Each sidelink transmission may span one time slot and may include a physical sidelink shared channel (PSSCH) and a physical sidelink control channel (PSCCH). PSSCH and PSCCH are frequency division multiplexed (FDM) and time division multiplexed (TDM). Sidelink control information (SCI) may be divided into two parts: a first-level SCI and a second-level SCI. The first-level SCI may indicate the resources used for sidelink transmissions, the quality of service (QoS) of the transmission (e.g., priority), a demodulation reference signal (DMRS), a phase tracking reference signal (PTRS) for sidelink transmissions, and a second SCI format. The second-level SCI may indicate the remaining control information. The SCI may be used to reserve resources within a resource pool for future transmissions.

[0086] From the sidelink scheduling perspective, the sidelink resources may be scheduled by the network (e.g., Mode 1) and selected autonomously by the WTRU (e.g., Mode 2). If the WTRU performs Mode 2, the WTRU may perform sensing by decoding the SCI from other WTRUs before selecting the sidelink resources to avoid selecting resources reserved by other WTRUs.

[0087] The Sidelink Channel State Information Reference Signal (SL-CSI-RS) may be supported for unicast to support the transmitting (Tx) WTRU in determining Tx parameters (e.g., power and rank). The Tx WTRU may indicate the presence of the SL-CSI-RS by using the SCI. The CSI-RS transmission may trigger a CSI report. The CSI reporting latency may be configurable via PC5-RRC. Each report may be associated with one SL-CSI-RS transmission.

[0088] The present invention also considers downlink (DL) based, uplink (UL) based and / or DL ​​and UL based positioning methods specified by New Radio (NR) Uu positioning.

[0089] In an example, in a DL-based positioning method, a downlink positioning reference signal (DL-PRS) is transmitted to the WTRU from multiple transmit / receive points (TRPs). The WTRU may observe and measure downlink signals from the TRPs. For the WTRU-B method, the WTRU may calculate its positioning, and for the WTRU-A method, the WTRU may return downlink measurement results to the network. For the angle-based method, the WTRU may report the angle of arrival (AoA) and / or reference signal received power (RSRP) of the downlink signal from the TRP. For the timing-based method, the WTRU may report the reference signal time difference (RSTD). The above methods may require transmission timing synchronization between TRPs. Positioning calculation errors mainly come from synchronization errors and / or multipath.

[0090] In an example, in a UL-based positioning method, the WTRU transmits an uplink positioning reference signal (UL-PRS) configured by RRC to a TRP for positioning. The network may then calculate the positioning of the WTRU based on the coordination of multiple (e.g., all) TRPs that receive the UL-PRS from the WTRU.

[0091] In the UL and DL based methods, the WTRU may measure the Rx-Tx time difference between the received DL-PRS and the transmitted UL-PRS. The Rx-Tx time difference and RSRP may be reported to the network. The network may then coordinate the TRP to calculate the WTRU's positioning.

[0092] A timing / angle positioning method may refer to a positioning method that uses a reference signal such as a sidelink positioning reference signal (SL-PRS). The WTRU may receive multiple reference signals from the WTRU and may measure RSTD, RSRP, and / or AoA. Examples of angle / timing positioning methods may include sidelink angle of departure (SL-AoD) positioning or sidelink time difference of arrival (SL-TDOA) positioning. In an example, the WTRU may send a SL-PRS to the WTRU, and the receiver may perform measurements (e.g., RSTD, AoA, RSRP) to determine the location of the WTRU that has sent the SL-PRS.

[0093] A round trip time (RTT) positioning method may refer to a positioning method that requires two WTRUs to send SL-PRS to each other. In an example, an anchor WTRU may send a SL-PRS to a target WTRU. Once the target WTRU receives the SL-PRS from the anchor WTRU, the target WTRU may send the SL-PRS to the anchor WTRU. The target WTRU may measure the Tx-Rx time difference of the WTRU. The time difference may be calculated as the difference between the transmission time of the SL-PRS from the target WTRU and the reception time of the SL-PRS sent from the anchor WTRU. The target WTRU may report the Tx-Rx time difference of the WTRU to the anchor WTRU.

[0094] The absolute positioning of a WTRU may be expressed in terms of a geographic coordinate system (GCS) or a local coordinate system (LCS). The relative positioning of a target WTRU may be expressed in terms of distance and / or angle to another WTRU (eg, an anchor WTRU) and / or a reference point with a known location.

[0095] For sidelink positioning (e.g., autonomous sidelink positioning), it is assumed that an assisting WTRU (e.g., A-WTRU) may also be used to help determine the positioning of a target WTRU (e.g., T-WTRU) subject to determine its positioning. The terms assisting WTRU (e.g., A-WTRU) and anchoring WTRU may be used interchangeably herein. The terms positioning WTRU (e.g., P-WTRU) and target WTRU (e.g., T-WTRU) may be used interchangeably herein. The relative positioning between the A-WTRU and the T-WTRU may be calculated based on the SL-PRS measurements. The absolute positioning of the target WTRU may then be derived based on the relative positioning with multiple A-WTRUs and the absolute positioning of the A-WTRUs.

[0096] In NR Uu positioning, the location management function (LMF) may act as a central entity to coordinate multiple TRPs to schedule PRS resources, measurement reports, and / or implement algorithms to derive the location of the T-WTRU. Since the LMF may be placed in the core network, semi-static PRS transmission / reception and measurement reporting are desirable. For out-of-coverage sidelink positioning (e.g., autonomous sidelink positioning), it may not be necessary to have a central entity because the LMF may control the positioning procedures. In addition, in the example NRV2X scenario, the vehicle may move at high speed. A vehicle moving at high speed may result in a dynamic sidelink environment. Therefore, in these examples, a dynamic approach to SL-PRS transmission, reception, and / or measurement reporting may be more desirable.

[0097] For out-of-coverage sidelink positioning (e.g., autonomous sidelink positioning), it may be necessary to address the following issues: how a WTRU (e.g., T-WTRU) can initialize the sidelink positioning (e.g., autonomous sidelink positioning) procedure, dynamically control a group of A-WTRUs to support locating their positions, dynamically select resources for SL-PRS transmission / reception and / or perform positioning measurement reporting.

[0098] The examples described herein for positioning may be used for ranging without limitation. Specifically, one or more of the positioning solutions described herein may be applicable to ranging problems. In an example, positioning may be referred to as a method and / or scheme for estimating the geographic location of a WTRU. In an example, ranging may be referred to as a method and / or scheme for estimating the distance between WTRUs. When the examples refer to ranging, the terms "positioning of a WTRU" and / or "location information of a WTRU" may be used interchangeably with "distance between WTRUs". The positioning of a WTRU may include an absolute positioning (e.g., coordinates, area ID) or a relative positioning, which may include a range, distance, propagation time, and / or RTT to another node (e.g., another WTRU, a roadside unit (RSU), a positioning reference unit (PRU), a gNB).

[0099] The WTRU may use one or any of the following reference signals as the SL-PRS: DMRS of PSSCH, DMRS of PSCCH, sidelink synchronization signal (SLSS) (e.g., sidelink primary synchronization signal (S-PSS) and / or sidelink secondary synchronization signal (S-SSS)), PTRS, physical sidelink feedback channel (PSFCH), SL-CSI-RS and / or another RS ​​designed for positioning purposes.

[0100] The WTRU may determine the SL-PRS configuration. Additionally or alternatively, the WTRU may receive the SL-PRS configuration from another node (e.g., another WTRU and / or a gNB). The SL-PRS configuration may include one or more of the following: a resource pool for SL-PRS transmission, reception and / or sidelink measurement reporting, a SL-PRS resource ID, a SL-PRS sequence ID and / or other IDs for generating SL-PRS sequences, a time-frequency of SL-PRS resources, a SL-PRS resource element offset, a SL-PRS resource slot offset, a SL-PRS symbol offset, SL-PRS QCL information, a SL-PRS resource set ID, a list of SL-PRS resources in a resource set, the number of SL-PRS symbols, a muting mode of SL-PRS (muting parameters may include repetition factor, muting option), SL-PRS resource power, periodicity of 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 for receiving SL-RS, angle of arrival), frequency layer ID, WTRU ID and / or SL-PRS ID.

[0101] The WTRU may be configured to perform sidelink positioning discovery. The sidelink positioning discovery may include determining the QoS of the positioning service, transmitting a positioning initialization message, and / or triggering a positioning initialization message.

[0102] The WTRU may determine the QoS associated with the positioning service. For example, the WTRU may be configured to determine one or more QoS parameters associated with the positioning service. In an example, the WTRU may initialize a positioning service that may be used to determine the location of the WTRU itself or other WTRUs. The positioning may include an absolute location of the WTRU and / or a relative location of the WTRU.

[0103] The initiated positioning service may have an associated QoS of the positioning service and may include one or more of the following parameters: priority of the positioning service, positioning accuracy requirement, range requirement of the positioning service, latency requirement of the positioning service and / or reliability requirement of the positioning service.

[0104] In an example, the positioning accuracy requirement may be associated with a maximum positioning error. The positioning range requirement may be the maximum range that two WTRUs can support to determine their relative positioning with respect to each other. For example, if the request comes from a WTRU within the required range, then the A-WTRU within the range requirement may need to support determining the positioning of the T-WTRU by performing SL-PRS transmission, reception and / or positioning measurement reporting. The latency requirement for positioning services may be associated with the latency and / or periodicity of positioning measurement reporting, location update, positioning reference signal transmission / reception and / or positioning request messages. The reliability requirement for positioning services may be associated with the reliability of positioning request messages, positioning measurement report messages and / or SL-PRS transmissions, which may be used to determine the number of times each message (e.g., positioning measurement report, SL-PRS transmission and / or positioning request message) is transmitted (retransmitted).

[0105] In an example, a WTRU (e.g., a T-WTRU or an A-WTRU) may perform a positioning initialization transmission. The positioning initialization transmission may be a message and / or a sequence. For example, a WTRU (e.g., a T-WTRU or an A-WTRU) may transmit a positioning initialization message.

[0106] The positioning initialization transmission may implicitly and / or explicitly include one or any combination of the following information and / or parameters: type of positioning initialization transmission, coarse location of the WTRU (e.g., area ID) or fine location of the WTRU (e.g., coordinates), supported positioning methods, supported positioning outputs (e.g., whether the WTRU supports or requests absolute and / or relative positioning), supported positioning measurement parameters (e.g., RSTD, AoA, AoD, Time of Arrival (ToA), Tx-Rx, Phase of Arrival (PoA), Phase of Departure (PoD), Phase Difference of Arrival (DPoA), Phase Difference of Departure (DPoD), Line of Sight / Non-Line of Sight (LOS / NLOS), associated broadcast type, positioning calculation capabilities, and / or listening capabilities.

[0107] The type of positioning initialization transmission may indicate whether the WTRU sends a message and / or signal to request positioning support (e.g., requesting support for an A-WTRU) or whether the WTRU sends a message to provide positioning support (e.g., unsolicited support for a T-WTRU). For example, a T-WTRU may transmit a positioning initialization message to request positioning support, and an A-WTRU may transmit a positioning initialization message to unsolicited support.

[0108] In an example, the supported positioning methods may be associated with the WTRU.The WTRU may indicate whether the WTRU supports transmission of SL-PRS, reception of SL-PRS, and / or both transmission and reception of SL-PRS.

[0109] In an example, the WTRU may indicate which positioning measurements the WTRU supports (e.g., DPoA, PoA, AoA, AoD, RSTD, ToA, Tx-Rx timing, LOS / NLOS, etc.). For example, the WTRU may indicate whether the WTRU supports SL-TDOA, RTT (e.g., one-sided RTT, two-sided RTT, AoA, and / or AoD methods).

[0110] In an example, the broadcast type may be information and / or parameters for positioning initialization transmission. The broadcast type may be associated with a sidelink positioning request, feedback, SL-PRS transmission / reception, and / or a sidelink positioning measurement report. For example, the WTRU may indicate in the message whether the positioning request, feedback, SL-PRS transmission / reception, and / or sidelink positioning measurement report is transmitted using unicast, multicast, and / or broadcast for each transmission.

[0111] In an example, the positioning calculation capability may include information and / or parameters associated with the positioning initialization transmission. For example, a WTRU (e.g., a T-WTRU) may indicate in a message whether the WTRU has the capability of positioning calculation. For example, the WTRU may indicate in a message whether the WTRU needs another WTRU (e.g., an A-WTRU) to receive measurement reports and determine the positioning of the WTRU. The WTRU may also indicate whether the WTRU needs any other WTRU.

[0112] In an example, the listening capability may include information and / or parameters for positioning initialization transmission. For example, a WTRU (e.g., a T-WTRU and / or an A-WTRU) may indicate the listening capability of the WTRU in a message. Specifically, the WTRU may indicate whether the WTRU is capable of performing partial listening, full listening, and / or no listening for SL-PRS transmission. In addition, the WTRU may indicate whether the WTRU may support inter-WTRU coordination (IUC). Specifically, the WTRU may indicate whether the WTRU may transmit listening information (e.g., a conflict indication or a set of preferred / non-preferred resources) to another WTRU during a positioning procedure.

[0113] A WTRU (e.g., a T-WTRU or an A-WTRU) may trigger the positioning initialization transmission based on one or any combination of the following: the coverage status of the WTRU, Uu RSRP, SL-RSRP, the location of the WTRU, the number of supported WTRUs, the CR of the WTRU, the channel busy rate (CBR) of the resource pool, and / or the receipt of an implicit and / or explicit request from another node (e.g., another WTRU, an RSU, or a gNB).

[0114] In an example, the WTRU may perform a SL-PRS transmission. The WTRU may determine one or more SL-PRS transmission parameters. The SL-PRS transmission parameters may include one or more of the following: parameters of SL-PRS resources, type of SL-PRS multiplexing, number of SL-PRS resource repetitions / retransmissions in a period, type of SL-PRS transmission, periodicity of a SL-PRS process, number of periods of a SL-PRS process, sidelink positioning sessions and / or windows, intended receivers of the SL-PRS transmission, hybrid automatic repeat request (HARQ) type of the SL-PRS transmission, and / or broadcast type of the SL-PRS transmission.

[0115] The parameters of the SL-PRS resources may include: QoS associated with the SL-PRS resources, transmit power, the number of subchannels used for each SL-PRS resource, the number of symbols and / or time slots used for each SL-PRS transmission resource, a reference resource pattern (e.g., comb size and / or comb pattern), sequence ID, cyclic shift and / or time and / or frequency resources for SL-PRS transmission.

[0116] The WTRU may be configured (e.g., pre-configured) for multiple types of SL-PRS multiplexing. In an example, the SL-PRS may not be multiplexed with other sidelink transmissions. In another type of SL-PRS multiplexing, the SL-PRS may be multiplexed with sidelink control information (e.g., SCI, medium access control-control element (MAC CE) and / or PC5-RRC). In another type of SL-PRS multiplexing, the SL-PRS may be multiplexed with both sidelink control and sidelink data.

[0117] The WTRU may be configured (e.g., pre-configured) for two types of SL-PRS transmission. In the first type, the SL-PRS is transmitted dynamically. In the second type, the SL-PRS is transmitted periodically. The WTRU may determine the number of periods that the WTRU may use for SL-PRS transmission. The WTRU may indicate the L2 ID of one or more receivers. For example, the WTRU may include the L2 ID of a WTRU group.

[0118] A WTRU (e.g., a T-WTRU) may indicate in an SCI (e.g., a second SCI) whether HARQ feedback associated with SL-PRS transmission is enabled or disabled. When HARQ is disabled, a receiving WTRU (e.g., an A-WTRU) may not send HARQ feedback. When HARQ is enabled, a receiving WTRU may send HARQ feedback. Specifically, if the WTRU measures a SL-PRS with a measurement accuracy greater than a threshold (e.g., the value of the measured value is within an indicated range), the WTRU may send an acknowledgment (ACK).

[0119] Additionally or alternatively, if the WTRU performs SL-PRS reception and / or measurement, the WTRU may send an ACK. For example, if the WTRU measures a specific number of SL-PRS resources, the WTRU may send an ACK. Otherwise, if the SL-PRS reception is deprioritized, the WTRU may send a negative acknowledgement (NACK). If the number of measured SL-PRS resources is less than a threshold, and / or the accuracy of the SL-PRS measurement is less than a threshold, the WTRU may feedback a NACK. The threshold (e.g., the threshold of the number of measured SL-PRS resources and / or the threshold of the SL-PRS measurement accuracy) may be configured (e.g., pre-configured), which may be based on the QoS of the positioning service, the parameters to be measured, and / or the latency of the positioning service.

[0120] In an example, feedback for SL-PRS transmission may be information and / or parameters for positioning initialization transmission. In an example, a WTRU (e.g., a T-WTRU) may indicate and / or request feedback for SL-PRS transmission after a certain number of SL-PRS resources (e.g., N SL-PRS resources, where N may be one or more). The feedback indication and / or feedback request may be transmitted in a transmission associated with the SL-PRS resources (e.g., in an SCI associated with the SL-PRS resources). The WTRU may expect an Rx WTRU (e.g., an anchor WTRU) to provide feedback on information regarding SL-PRS reception. Such information may implicitly and / or explicitly include: how many SL-PRS resources the Rx WTRU has received, whether the WTRU requires more SL-PRS resources for measurement reporting, how many SL-PRS resources the WTRU has not yet measured, whether specific SL-PRS resources are received and / or deprioritized, and / or the measurement quality associated with each SL-PRS resource (e.g., whether the SL-PRS is LOS / NLOS, the RSRP associated with the resource and / or whether the RSRP is greater than / less than a threshold).

[0121] The Tx WTRU (e.g., the target WTRU) may wait for feedback from the N SL-PRS resources before performing resource allocation and / or transmitting SL-PRS transmissions of future SL-PRSs. If the Tx WTRU does not receive feedback from the Rx WTRU, the Tx WTRU may stop SL-PRS transmission. Additionally or alternatively, for example, if the Tx WTRU does not receive feedback from the Rx WTRU, the WTRU may resend the feedback request.

[0122] In an example, a WTRU (e.g., a T-WTRU) may indicate whether the WTRU needs to receive feedback for each SL-PRS transmission. Such an indication may be transmitted in a transmission associated with the SL-PRS resource (e.g., in an SCI associated with the SL-PRS resource). For example, if feedback is enabled, the Tx WTRU may expect feedback from the Rx WTRU. For example, after receiving feedback from the Rx WTRU, the Tx WTRU may perform resource selection and / or future SL-PRS transmission. The feedback may be related to the reception of the SL-PRS. For example, the feedback may implicitly and / or explicitly include: whether the WTRU needs more SL-PRS resources for measurement reporting, whether the SL-PRS resources are received and / or deprioritized, and / or the measurement quality associated with the SL-PRS resources (e.g., whether the SL-PRS is LOS / NLOS, the RSRP associated with the resource and / or whether the RSRP is greater than / less than a threshold).

[0123] The WTRU may indicate the type of transmission of the SL-PRS. Specifically, the WTRU may indicate whether the SL-PRS transmission is unicast, multicast and / or broadcast. The type of transmission may be indicated in an SCI (eg, a second SCI).

[0124] Figure 2 An example process 200 is depicted in which a WTRU 202 (eg, a target WTRU) determines one or more SL-PRS parameters. Figure 2 As shown, the target WTRU 202 may determine one or more SL-PRS transmission parameters. As shown in option 1 at 210 or option 2 at 220, the target WTRU 202 may determine the SL-PRS transmission parameters, respectively. In option 1 at 210, the target WTRU 202 may perform aperiodic SL-PRS 212 with HARQ 214 enabled. For example, the target WTRU may aperiodically transmit the SL-PRS transmission 212 with HARQ 214 enabled. In option 2 at 220, the target WTRU 202 may perform periodic SL-PRS 222 with HARQ disabled. For example, the target WTRU may periodically transmit the SL-PRS transmission 222 with HARQ disabled. The SL-PRS transmission 222 may include the SCI 216.

[0125] In an example, the WTRU may indicate (e.g., in an associated message) one or more of the SL-PRS transmission parameters. One or more of the SL-PRS transmission parameters may be indicated in an SCI, a MAC CE, a PC5-RRC, and / or a non-access stratum (NAS) message (e.g., a Long Term Evolution (LTE) Positioning Protocol (LPP) message). One or more of the SCI, MAC CE, PC5-RRC, and / or NAS for indicating one or more of the SL-PRS transmission parameters may be sent in the same and / or different messages.

[0126] In an example, the WTRU may use an SCI (e.g., such as SCI 216) to indicate one or more SL-PRS transmission parameters. The WTRU may use the SCI to indicate the availability of the SL-PRS. For example, the WTRU may use a bit field to indicate whether the SL-PRS is available or unavailable in an associated transmission. The WTRU may also use a code point of another bit field (e.g., the SL-PRS mode bit field) to indicate the availability of the SL-PRS in an associated transmission. The WTRU may use the SCI to indicate a parameter of a SL-PRS resource. The parameter may include one or more of the following: QoS associated with the SL-PRS resource (e.g., priority, latency and / or accuracy requirements for positioning services), transmit power and / or number of symbols, subchannels, reference resource patterns, sequence IDs, cyclic shifts and / or time / frequency resources).

[0127] The WTRU may use an SCI (e.g., such as SCI 216) to indicate a priority of a positioning service, which may be indicated in a first SCI. For example, an SCI may include a first SCI and a second SCI. The first SCI may be sent in a PSCCH transmission, and the second SCI may be sent in a PSCCH transmission. The priority of the positioning service may be used to indicate a priority of SL-PRS transmission and / or reception. The WTRU may use an SCI (e.g., such as SCI 216) to indicate an accuracy requirement for a positioning service. For example, the positioning service accuracy requirement may be indicated in the first SCI.

[0128] In an example, the WTRU may indicate the transmit power of the SL-PRS in a first SCI. In other examples, the WTRU may indicate the transmit power of the SL-PRS in a second SCI. Additionally or alternatively, the WTRU may implicitly indicate the transmit power of the SL-PRS based on another parameter. For example, for maximum and / or minimum transmit power, the WTRU may be configured (e.g., pre-configured) based on the range requirements of the positioning service. The WTRU may then implicitly indicate the transmit power by the indicated range requirements. In an example, the WTRU may be configured (e.g., pre-configured) for multiple SL-PRS patterns. The WTRU may then indicate the pattern used in the SCI. In other examples, the WTRU may indicate the time / frequency resources used for SL-PRS transmission.

[0129] The WTRU may use an SCI (e.g., such as SCI 216) to indicate the number of SL-PRS resource repetitions and / or retransmissions in a period, the type of SL-PRS transmission, the periodicity of the SL-PRS process, the number of periods of one SL-PRS process, the sidelink positioning session, the window, and / or the intended receiver of the SL-PRS transmission. The WTRU may implicitly indicate the type of SL-PRS transmission in the SCI. Specifically, the WTRU may reserve and / or indicate periodic SL-PRS resources to indicate periodic SL-PRS transmission; otherwise, the WTRU may perform aperiodic SL-PRS transmission.

[0130] The WTRU may implicitly indicate the type of SL-PRS transmission in the SCI. Specifically, the WTRU may reserve and / or indicate periodic SL-PRS resources to indicate periodic SL-PRS transmission; otherwise, the WTRU may perform aperiodic SL-PRS transmission.

[0131] The WTRU may indicate in a second SCI (e.g., an SCI in a second SL-PRS transmission) the number of periods for SL-PRS transmission. Upon expiration of the indicated number of periods, the WTRU may stop SL-PRS transmission or select another SL-PRS process. This approach may help reduce persistent conflicts between different SL-PRS processes. In an example, the WTRU may use an SCI (e.g., such as SCI 216) to indicate a set of intended receivers for the SL-PRS. Specifically, the WTRU may indicate ID information (e.g., L2 ID, a portion of an L2 ID, and / or a member ID, etc.) of the intended receivers.

[0132] In an example, the WTRU may use a MAC CE to indicate one or more SL-PRS transmission parameters, such as the availability of the SL-PRS, the transmit power of the SL-PRS, the intended receivers for the SL-PRS transmission, and / or a reference resource pattern (e.g., comb size and / or comb pattern). In an example, the WTRU may use a MAC CE to indicate a set of intended receivers for the SL-PRS. Specifically, the WTRU may indicate ID information of the intended receivers (e.g., L2 ID, a portion of the L2 ID and / or a member ID, etc.). In an example, the WTRU may use a MAC CE to indicate a resource pattern for SL-PRS transmission.

[0133] In an example, the WTRU may use PC5-RRC to indicate a configuration for SL-PRS transmission, which may implicitly indicate a range or value of one or more SL-PRS transmission parameters. For example, the WTRU may use PC5-RRC to indicate the priority, latency and / or accuracy of the positioning service.

[0134] In an example, the WTRU may use a NAS message (e.g., an LPP message) to indicate one or more SL-PRS transmission parameters. Specifically, the WTRU may be configured (e.g., pre-configured) with one or more SL-PRS configurations. The WTRU may then use a NAS message to indicate the SL-PRS configuration for SL-PRS transmission.

[0135] In an example, a WTRU (e.g., an A-WTRU or a T-WTRU) may be preconfigured with one or more parameters for SL-PRS transmission / reception in a resource pool and / or receive configuration of the one or more parameters (e.g., from a gNB, an LMF, or another WTRU). The WTRU may then determine other parameters for SL-PRS transmission and / or reception. The WTRU may then use an SCI, a MAC CE, a PC5-RRC, and / or a NAS (e.g., an LPP for a sidelink) to indicate one or more determined SL-PRS transmission and / or reception parameters. For example, the WTRU may be preconfigured in a resource pool that includes a bandwidth range, a comb value and / or pattern, a number of retransmissions, and / or a SL-PRS periodicity. The WTRU may then determine the bandwidth, the comb value and / or pattern, the number of retransmissions, and / or the SL-PRS periodicity from a set of values ​​configured (e.g., preconfigured) in the resource pool.

[0136] The WTRU may indicate the determined parameters of the SL-PRS transmission and / or reception in a transmission associated with the SL-PRS (e.g., in the SCI). For example, the WTRU may indicate one or more parameters of the SL-PRS transmission / reception using a second SCI (e.g., a new second SCI format design for indicating SL-PRS transmission / reception).

[0137] The WTRU may determine one or more broadcast types associated with sidelink positioning. In an example, the WTRU may determine a broadcast type associated with a sidelink positioning session. The WTRU may determine whether to use unicast, multicast, and / or broadcast for a sidelink positioning session. Specifically, the WTRU may determine whether to use unicast, multicast, and / or broadcast for a sidelink positioning request, feedback, and / or SL-PRS transmission / reception.

[0138] The WTRU may indicate the type of broadcast in the associated transmission. For example, the WTRU may indicate implicitly and / or explicitly in the SCI (e.g., the second SCI) and / or the SL-PRS transmission associated with the request. Such determination may be based on one or any combination of the following: the positioning method, the outcome of the positioning session, and / or the type of SL-PRS transmission and / or the type of measurement report (e.g., whether the SL-PRS transmission is periodic, semi-persistent, or aperiodic).

[0139] In an example, the positioning method may include: the WTRU may use multicast for SL-TDOA method. Additionally or alternatively, the WTRU may use unicast for RTT method. The output of the positioning session may include: whether the output is absolute positioning, relative positioning and / or range. For example, the WTRU may use multicast for absolute positioning. The WTRU may use unicast and / or broadcast for relative positioning and / or ranging. For example, the type of SL-PRS transmission and / or the type of measurement report may include: the WTRU may use multicast for periodic and / or semi-persistent SL-PRS transmission. For example, the WTRU may use unicast and / or multicast for non-periodic SL-PRS.

[0140] In an example, a WTRU (e.g., a T-WTRU or an A-WTRU) may determine whether to perform SL-PRS transmission. If the WTRU determines to perform SL-PRS transmission, the WTRU may determine one or any combination of SL-PRS transmission parameters. The determined SL-PRS transmission parameters may be used by the WTRU (e.g., a T-WTRU) to perform SL-PRS transmission. Additionally or alternatively, the determined SL-PRS transmission parameters may be indicated to other WTRUs (e.g., from a T-WTRU to an A-WTRU) to perform SL-PRS transmission.

[0141] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on one or more parameters. For example, the WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on one or more configured (e.g., preconfigured) parameters in a resource pool. Specifically, the WTRU may be configured (e.g., preconfigured) with one or more resource pools for SL-PRS transmission. In each resource pool, the WTRU may be configured (e.g., preconfigured) with one or more SL-PRS transmission parameters, which may be one of the following or any combination thereof: an exact value, minimum value, maximum value, and / or range of transmit power, the number of subchannels for each SL-PRS resource, a reference resource pattern (e.g., comb size and / or comb pattern), a set of sequence IDs, a cyclic shift, a type of SL-PRS multiplexing, a number of SL-PRS resources in a period, a periodicity of a SL-PRS process, a duration of SL-PRS transmission, a HARQ type of SL-PRS transmission, and / or a broadcast type of SL-PRS transmission. The WTRU may then determine which resource pool to select for SL-PRS transmission based on the QoS requirements of the positioning service.

[0142] For example, for positioning services with small range requirements, the WTRU may select a resource pool that allows small transmit power, small bandwidth, small number of SL-PRS transmit symbols, and / or small number of SL-PRS (retransmission) transmissions and / or repetitions. Additionally or alternatively, for positioning services with large range requirements, the WTRU may select a resource pool that allows large transmit power, large bandwidth, large number of SL-PRS transmit symbols, and / or large number of SL-PRS (retransmission) transmissions and / or repetitions.

[0143] For example, the WTRU may be configured (e.g., pre-configured) with two types of resource pools for SL-PRS transmission, where a first resource pool may allow the SL-PRS to be multiplexed with another side link transmission (e.g., side link data), and a second resource pool may not allow the SL-PRS to be multiplexed with another side link transmission (e.g., side link data). For low positioning accuracy requirements, the WTRU may select the first resource pool; otherwise, for high accuracy requirements, the WTRU may select the second resource pool.

[0144] For example, for each resource pool, the WTRU may be configured (e.g., pre-configured) with a minimum and / or maximum number of subchannels / bandwidths for SL-PRS transmission. The WTRU may then determine which resource pool to use to perform SL-PRS transmission based on the configured (e.g., pre-configured) minimum and / or maximum number of subchannels / bandwidths for SL-PRS transmission. Specifically, the WTRU may select a resource pool whose configured (e.g., pre-configured) maximum number of subchannels and / or bandwidths is greater than a threshold, which may be determined based on a QoS requirement (e.g., accuracy requirement) for the positioning service.

[0145] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on an indication from another node. Specifically, the WTRU (e.g., A-WTRU) may determine one or more SL-PRS transmission parameters based on an indication from another node (e.g., T-WTRU, gNB and / or LMF), and the one or more SL-PRS transmission parameters may be one of the following or any combination thereof: an exact value, a minimum value, a maximum value and / or a range of a resource selection window for SL-PRS transmission, a transmission power, a number of subchannels for each SL-PRS resource, a reference resource pattern (e.g., a comb size and / or a comb pattern), a set of sequence IDs, a cyclic shift, a type of SL-PRS multiplexing, a number of SL-PRS resources in a period, a periodicity of a SL-PRS process, a duration of SL-PRS transmission, a HARQ type of SL-PRS transmission, and / or a broadcast type of SL-PRS transmission.

[0146] For example, a minimum number of subchannels to be used for SL-PRS transmission may be indicated to a WTRU (e.g., A-WTRU). A-WTRU may represent an anchor WTRU. The WTRU may then perform SL-PRS transmission using a number of subchannels and / or bandwidth greater than or equal to the minimum bandwidth indicated from another WTRU (e.g., T-WTRU). T-WTRU may represent a target or target WTRU. For example, a priority of SL-PRS transmission from another WTRU (e.g., T-WTRU) may be indicated to the WTRU. The other WTRU (e.g., T-WTRU) may indicate a WTRU (e.g., A-WTRU). The WTRU may then perform SL-PRS resource selection and / or transmission using the priority indicated from the T-WTRU. For example, when a resource selection window for SL-PRS transmission from another WTRU (e.g., T-WTRU) indicates a WTRU (e.g., A-WTRU), then the WTRU may perform SL-PRS resource selection and / or transmission within the indicated window.

[0147] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on one or more QoS requirements of the positioning service. For example, the WTRU may determine the transmission power of the SL-PRS based on the range requirements of the positioning service. Specifically, the WTRU may be configured (e.g., pre-configured) with one or more maximum transmission power levels. The one or more maximum transmission power levels may be a function of the range requirements of the positioning service. The WTRU may determine the transmission power of the SL-PRS based on the associated range requirements. For example, for positioning services with small accuracy requirements, the WTRU may select SL-PRS transmission with a small bandwidth, a small number and / or a small number of SL-PRS (retransmission) transmissions / repetitions. Additionally or alternatively, for positioning services with high accuracy requirements, the WTRU may select SL-PRS transmission with a large bandwidth, a large number of symbols and / or a large number of SL-PRS (retransmission) transmissions / repetitions.

[0148] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on the distance to the receiving WTRU and / or the requesting WTRU. For example, the WTRU may determine the number of symbols and / or reference signal pattern used for SL-PRS transmission based on the distance to the receiving WTRU. Specifically, if the distance between the two WTRUs is small, the WTRU may use a smaller number of symbols for SL-PRS transmission; otherwise, the WTRU may use a larger number of symbols for SL-PRS transmission.

[0149] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on the sidelink channel to the receiving WTRU and / or the requesting WTRU. For example, the WTRU may determine the transmission power based on the sidelink channel between the sending WTRU and the receiving WTRU. Specifically, if the distance between the two WTRUs is small, the WTRU may use a smaller number of symbols for SL-PRS transmission; otherwise, the WTRU may use a larger number of symbols for SL-PRS transmission.

[0150] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on the CBR of the resource pool.

[0151] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on the positioning accuracy of the WTRU or the positioning accuracy of an associated WTRU. For example, a WTRU (e.g., an A-WTRU or a T-WTRU) may determine the SL-PRS transmission parameters based on its positioning accuracy and the positioning accuracy of a receiving WTRU.

[0152] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on the positioning method. For example, the WTRU may determine the bandwidth of the SL-PRS transmission based on the positioning method. For example, for timing-based, phase-based and / or angle-based methods, the WTRU may be configured (e.g., pre-configured) with a minimum SL-PRS and / or maximum SL-PRS bandwidth. The WTRU may determine which bandwidth to use for SL-PRS transmission based on the positioning method used for associated SL-PRS transmission and / or reception.

[0153] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on one or more measurement parameters to be measured. For example, the WTRU may determine the bandwidth of the SL-PRS transmission based on the positioning measurement parameters used for the SL-PRS transmission. Specifically, the WTRU may be configured (e.g., pre-configured) and / or instructed in a range of numbers of subchannels and / or symbols used for SL-PRS transmission based on whether the associated measurement is a timing-related measurement (e.g., ToA and / or RSTD), an angle measurement (e.g., AoA and / or AoD), or a phase measurement (e.g., DPoA and / or PoA). The WTRU may then determine the bandwidth and / or number of symbols used for SL-PRS transmission based on the associated measurement parameters, so that the bandwidth and / or number of symbols used for SL-PRS transmission is within the configured (e.g., pre-configured) and / or instructed range.

[0154] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on the output of the positioning procedure. The output of the positioning procedure may be an absolute positioning or a relative positioning. For example, the WTRU may be configured (e.g., pre-configured) and / or indicated that there are two sets of SL-PRS transmission parameter ranges, one or more sets of ranges that may be used for absolute positioning and another set of ranges that may be used for relative positioning. The WTRU may then determine which set(s) of ranges will be used for its SL-PRS transmission. The WTRU may select which set of ranges to use based on whether the WTRU uses SL-PRS transmission for determining an absolute positioning or a relative positioning.

[0155] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on the amount of SL-PRS transmission within the period. For example, the WTRU may determine whether to perform SL-PRS transmission based on the number of SL-PRS transmissions and / or the amount of resources that the WTRU has performed during the period. Specifically, if the number of SL-PRS transmissions and / or the amount of resources is greater than a threshold, the WTRU may not perform SL-PRS transmission; otherwise, the WTRU may perform SL-PRS transmission.

[0156] The WTRU may determine whether to perform SL-PRS transmission and / or one or more SL-PRS transmission parameters based on the prohibition time associated with the SL-PRS transmission and / or the SL-PRS request. For example, the WTRU may determine whether to perform SL-PRS transmission based on the time gap (e.g., time period) between the current SL-PRS transmission and the last SL-PRS transmission and / or the last SL-PRS transmission request. Specifically, the WTRU may be configured (e.g., pre-configured) with a minimum time gap between two SL-PRS transmissions or a time gap between the last SL-PRS request and the current SL-PRS transmission. If the time gap between the two SL-PRS transmissions or the time gap between the current SL-PRS transmission and the last SL-PRS transmission request is greater than the configured (e.g., pre-configured) value, the WTRU may perform the current SL-PRS transmission. If the time gap between the two SL-PRS transmissions or the time gap between the current SL-PRS transmission and the last SL-PRS transmission request is less than or equal to the configured value, the WTRU may not perform SL-PRS transmission.

[0157] The WTRU may determine whether to perform a SL-PRS transmission and / or one or more SL-PRS transmission parameters based on one or more parameters for the SL-PRS transmission from the requesting WTRU. For example, the WTRU may determine one or more SL-PRS transmission parameters for its SL-PRS transmission based on one or more SL-PRS transmission parameters from the requesting WTRU. For example, the WTRU may use a similar priority, periodicity, bandwidth, reference signal pattern, and / or transmit power of the SL-PRS transmission from the requesting WTRU for its SL-PRS transmission. For example, the offset of the SL-PRS may be determined based on the SL-PRS offset of the peer WTRU plus an increment. The value of the increment may be a function of the WTRU's processing capability.

[0158] The WTRU may be configured (e.g., preconfigured) with a set of SL-PRS configurations. In an example, the WTRU may be configured (e.g., preconfigured) with multiple SL-PRS configurations (e.g., each configuration may be associated with one or more sets of SL-PRS transmission / reception parameters). The SL-PRS transmission / reception parameters may include, for example, bandwidth, comb pattern, resource offset, periodicity, number of retransmissions, transmit power and / or muting mode. The WTRU may be configured (e.g., preconfigured) with one or more SL-PRS configurations in a resource pool and / or receive the configuration from another node (e.g., another WTRU and / or gNB). The WTRU may receive the configuration described in the present disclosure (e.g., preconfiguration related to SL-PRS, transmission and / or reception procedures, priority of SL-PRS) from the network (e.g., LMF and / or gNB).

[0159] The WTRU may indicate which SL-PRS configuration to use. The WTRU may indicate the SL-PRS configuration in one or more transmissions associated with the SL-PRS transmission. For example, the WTRU may use an SCI (e.g., a first-level SCI or a second-level SCI) to indicate which SL-PRS configuration the WTRU is using. Specifically, the WTRU may be configured (e.g., pre-configured) with multiple SL-PRS configurations. The WTRU may indicate an index of the SL-PRS configuration in a set of SL-PRS configurations (e.g., in the SCI). The WTRU (e.g., an anchor WTRU) may indicate the index to the target WTRU. In an example, the WTRU may be configured (e.g., pre-configured) with multiple priority levels (e.g., a subset of priority levels) by the network (e.g., LMF and / or gNB) or a peer WTRU. Based on the criteria described herein (e.g., QoS), the WTRU may determine to associate one of the pre-configured priority levels with the SL-PRS, feedback, and / or measurement report. For example, the WTRU may be pre-configured with a subset of priority levels 2, 3, and 4, where the highest priority level is 1. The WTRU may determine to associate a priority level 2, 3, or 4 with the SL-PRS. The priority level associated with the SL-PRS may be indicated in an associated SCI, MAC-CE, RRC, or LPP message.

[0160] In an example, the target WTRU may indicate the index to the anchor WTRU. Whether the anchor and / or target WTRU indicates the index to the target and / or anchor WTRU, respectively, may depend on the positioning method (eg, SL-TDOA, RTT) implemented between the target WTRU and the anchor WTRU.

[0161] In an example, a WTRU (eg, a T-WTRU) may request one or more A-WTRUs to perform SL-PRS reception, SL-PRS transmission, transmission to feedback the request (eg, ACK / NACK transmission), and / or positioning measurement reporting.

[0162] In an example, for a SL-PRS reception based positioning method (similar to DL based positioning), a WTRU (e.g., T-WTRU) may request one or more A-WTRUs to perform SL-PRS transmission. For a WTRU based (WTRU-B) positioning method, the WTRU may then perform SL-PRS reception and determine its position. Additionally or alternatively, for a WTRU assisted (WTRU-A) positioning method, the WTRU may perform SL-PRS reception, SL-PRS reception, and measurement reporting to another node.

[0163] In an example, for a positioning method based on SL-PRS transmission (similar to UL-based positioning), a WTRU (e.g., a T-WTRU) may request one or more A-WTRUs to perform SL-PRS reception and positioning measurement reporting. The WTRU may then perform SL-PRS transmission for the A-WTRUs to perform measurements and reporting.

[0164] In an example, for a method based on SL-PRS transmission and reception (eg, a multi-RTT based method), the WTRU may request one or more A-WTRUs to perform SL-PRS transmission, reception, and measurement reporting.

[0165] A WTRU (e.g., a T-WTRU) may indicate to an A-WTRU a range, a maximum value, and / or a minimum value of one or more positioning request parameters in a first set of positioning request parameters. The A-WTRU may then determine whether to perform an associated request based on whether the measured and / or calculated values ​​of one or more parameters in the first set of parameters are within a certain range. The range may be configured (e.g., pre-configured) or indicated by the T-WTRU.

[0166] The first set of parameters may include a distance to another node (e.g., a requesting WTRU, a gNB). For example, a WTRU (e.g., a T-WTRU) may indicate a range of distances to itself or to a gNB (e.g., minimum and / or maximum distances). The T-WTRU may also indicate its location or the location of the gNB (e.g., coordinates or region ID). After receiving an indication from the T-WTRU, the A-WTRU may determine whether to perform an associated request based on the distance between the WTRU and the other node (e.g., the requesting WTRU, the T-WTRU, or the gNB). The associated request may include sending feedback (e.g., ACK / NACK) to the request, sending a SL-PRS, receiving a SL-PRS, and / or performing a sidelink measurement report. Specifically, if the distance between the A-WTRU and the other node is within the range, the A-WTRU may perform the associated request. If the distance between the A-WTRU and the other node is outside the range, the A-WTRU may not perform the associated request. For example, if the distance between the A-WTRU and the T-WTRU is less than the indicated threshold, the A-WTRU may perform the associated request (e.g., SL-PRS transmission, reception, and / or measurement reporting). If the distance between the A-WTRU and the T-WTRU is greater than the indicated threshold, the WTRU may not perform the associated request (e.g., perform SL-PRS transmission, reception, and / or measurement reporting).

[0167] The first set of parameters may include the positioning accuracy of the A-WTRU. For example, the WTRU (e.g., T-WTRU) may indicate a range of positioning accuracy (e.g., maximum positioning error) for the A-WTRU to determine whether to perform an associated request. Specifically, after receiving an indication from the T-WTRU, the A-WTRU may determine (based on the maximum positioning error of the WTRU) whether to perform an associated request. The associated request may include sending feedback (e.g., ACK / NACK) to the request, sending SL-PRS, receiving SL-PRS, and / or performing a sidelink measurement report. Specifically, if the maximum positioning error of the A-WTRU is less than the maximum positioning error indicated from the T-WTRU, the A-WTRU may perform the associated request. If the maximum positioning error of the A-WTRU is greater than the indicated maximum positioning error, the A-WTRU may not perform the associated request.

[0168] The first set of parameters may include Uu RSRP. For example, a WTRU (e.g., a T-WTRU) may indicate a range of Uu RSRP (e.g., a minimum Uu RSRP and / or a maximum Uu RSRP) for the A-WTRU to determine whether to perform an associated request. The A-WTRU may determine whether to perform an associated request based on the Uu RSRP of the A-WTRU. The associated request may include, for example, sending feedback (e.g., ACK / NACK) for the request, sending SL-PRS, receiving SL-PRS, and / or performing a sidelink measurement report. Specifically, if the Uu RSRP of the A-WTRU is within the indicated range, the A-WTRU may perform the associated request. If the Uu RSRP of the A-WTRU is not within the indicated range, the A-WTRU may not perform the associated request.

[0169] The first set of parameters may include the SL-RSRP in the sidelink channel of the requesting WTRU. For example, the WTRU (e.g., T-WTRU) may indicate a range of SL-RSRP (e.g., minimum SL-RSRP and / or maximum SL-RSRP) for the A-WTRU to determine whether to perform the associated request. The A-WTRU may determine whether to perform the associated request based on the SL-RSRP of the sidelink channel between the T-WTRU and the A-WTRU. The associated request may include, for example, sending feedback (e.g., ACK / NACK) to the request, sending SL-PRS, receiving SL-PRS, and / or performing a sidelink measurement report. Specifically, if the SL-RSRP in the sidelink channel between the T-WTRU and the A-WTRU is within the indicated range, the A-WTRU may perform the associated request. If the SL-RSRP in the sidelink channel between the T-WTRU and the A-WTRU is not within the indicated range, the A-WTRU may not perform the associated request.

[0170] The first set of parameters may include the AoA and / or AoD transmitted from and / or to the requesting WTRU. For example, the WTRU (e.g., T-WTRU) may indicate the range of the AoA for the A-WTRU to determine whether to perform the associated request. The A-WTRU may determine whether to perform the associated request based on the AoA transmitted from the requesting WTRU (e.g., the transmission of the request message). The associated request may include, for example, sending feedback (e.g., ACK / NACK) to the request, sending SL-PRS, receiving SL-PRS, and / or performing sidelink measurement reporting. Specifically, if the AoA transmitted from the requesting WTRU is within the range of the SL-RSRP in the sidelink channel between the T-WTRU and the A-WTRU, and the A-WTRU is within the indicated range, the A-WTRU may perform the associated request. If the AoA transmitted from the requesting WTRU is not within the range of the SL-RSRP in the sidelink channel between the T-WTRU and the A-WTRU, the A-WTRU may not perform the associated request.

[0171] The first set of parameters may include a LOS / NLOS parameter. LOS / NLOS is a parameter that may indicate the probability that a link is LOS or NLOS. The LOS / NLOS parameter may be represented by a value from 0 to 1. A LOS / NLOS value of 0 may indicate that the corresponding link is NLOS. A LOS / NLOS value of 1 may indicate that the link is LOS. The closer the LOS / NLOS value is to 0, the higher the probability that the corresponding link may be NLOS. And the closer the LOS / NLOS parameter is to 1, the higher the probability that the corresponding link may be LOS. In other words, the LOS / NLOS parameter may be used to indicate the possibility of a LOS channel between two nodes, wherein the higher the value of the LOS / NLOS parameter, the greater the possibility that the channel between the two nodes is LOS. For example, a WTRU (e.g., a T-WTRU) may indicate a range of LOS / NLOS for the A-WTRU to determine whether to perform an associated request. The A-WTRU may determine whether to perform an associated request based on the LOS / NLOS parameter of the channel between the requesting WTRU and the A-WTRU. The associated request may include, for example, sending feedback (e.g., ACK / NACK) to the request, sending SL-PRS, receiving SL-PRS, and / or performing sidelink measurement reporting. Specifically, if the LOS / NLOS parameter between the requesting WTRU and the A-WTRU is within the indicated range, the A-WTRU may perform the associated request. If the LOS / NLOS parameter between the requesting WTRU and the A-WTRU is outside the indicated range, the A-WTRU may not perform the associated request.

[0172] The first set of parameters may include a synchronization offset and / or error. The synchronization offset and / or error may be determined based on an offset and / or error between time slot boundaries of two WTRUs. The synchronization offset and / or error may be determined based on an offset and / or error between a received timing of a signal from one WTRU and a reference timing (e.g., a time slot boundary) of the WTRU. For example, a WTRU (e.g., a T-WTRU) may indicate a maximum synchronization offset and / or error to an A-WTRU to determine whether to perform an associated request. The A-WTRU may determine whether to perform an associated request based on whether the synchronization offset and / or error is less than the indicated maximum value. The associated request may include, for example, sending feedback (e.g., ACK / NACK) to the request, sending a SL-PRS, receiving a SL-PRS, and / or performing a sidelink measurement report. Specifically, if the synchronization offset and / or error is greater than a threshold, the WTRU may not perform the associated request. If the synchronization offset and / or error is less than or equal to the threshold, the WTRU may perform the associated request.

[0173] The first set of parameters may include the type of synchronization source for another WTRU (e.g., A-WTRU). Specifically, the WTRU (e.g., T-WTRU) may indicate whether the other WTRU (e.g., A-WTRU) should be synchronized to a gNB (e.g., a specific cell ID, TRPID), a reference WTRU synchronized to a gNB, a GNSS, and / or a reference WTRU synchronized to a GNSS to perform an associated request. For example, the WTRU (e.g., T-WTRU) may indicate the type of synchronization source for another WTRU (e.g., A-WTRU) to determine whether to perform an associated request. The A-WTRU may determine whether to perform an associated request based on whether the synchronization source belongs to a set of synchronization sources indicated in the positioning request message. The associated request may include, for example, sending feedback (e.g., ACK / NACK) to the request, sending SL-PRS, receiving SL-PRS, and / or performing sidelink measurement reporting. Specifically, if the synchronization source belongs to a set of sources indicated in the positioning request message, the WTRU may perform the associated request. If the synchronization source does not belong to the set of sources indicated in the positioning request message, the WTRU may not perform the associated request.

[0174] The first set of parameters may include the type of synchronization source of the requesting WTRU. Specifically, the WTRU may indicate its synchronization source, which may include one or any of a gNB (e.g., a specific cell ID and / or TRP ID), a reference WTRU synchronized to a gNB, a GNSS, and / or a reference WTRU synchronized to a GNSS. For example, a WTRU (e.g., a T-WTRU) may indicate its synchronization source. The A-WTRU may then determine whether to perform the associated request based on its synchronization source and the synchronization source of the T-WTRU. The associated request may include, for example, sending feedback (e.g., ACK / NACK) to the request, sending a SL-PRS, receiving a SL-PRS, and / or performing a sidelink measurement report. Specifically, if the WTRU is synchronized to the T-WTRU, the A-WTRU may perform the associated request. The A-WTRU may use the timing of the positioning request message to perform the SL-PRS transmission. Additionally or alternatively, if the WTRU is synchronized to the same synchronization source as the T-WTRU, the A-WTRU may determine to perform the associated request.

[0175] The first set of parameters may include the coverage status of another WTRU (e.g., A-WTRU). For example, a WTRU (e.g., T-WTRU) may indicate a desired coverage status of an A-WTRU, which may include a cell ID and / or a TRP ID. After receiving a positioning request message from a T-WTRU, the A-WTRU may determine whether to perform an associated request based on the coverage status of the A-WTRU. Specifically, if the WTRU is under the coverage of the cell and / or TRP indicated in the request message, the WTRU may perform the associated request. If the WTRU is not under the coverage of the cell and / or TRP indicated in the request message, the A-WTRU may not perform the associated request.

[0176] The first set of parameters may include the coverage status of the requesting WTRU (e.g., T-WTRU). For example, the WTRU (e.g., T-WTRU) may indicate its coverage status (e.g., whether the WTRU is out of coverage or in coverage of the cell / TRP). After receiving the positioning request message from the T-WTRU, the A-WTRU may determine whether to perform the associated request based on its coverage status and the coverage status of the T-WTRU. For example, if the T-WTRU is out of coverage, the WTRU may perform the associated request regardless of its coverage status. However, if the T-WTRU is within the coverage of a gNB and / or TRP, the WTRU may perform the associated request if the WTRU is within the coverage of the same gNB and / or TRP. If the T-WTRU is within the coverage of a gNB and / or TRP, the WTRU may perform the associated request if the WTRU is within the coverage of a gNB and / or TRP with the same PLMN ID as the gNB and / or TRP of the requesting T-WTRU.

[0177] The first set of parameters may include a set of area IDs to respond to. For example, a WTRU (e.g., a T-WTRU) may indicate a set of area IDs for the A-WTRU to determine whether to perform an associated request. The associated request may include, for example, sending feedback (e.g., ACK / NACK) to the request, sending SL-PRS, receiving SL-PRS, and / or performing a sidelink measurement report. Specifically, if the area ID of the A-WTRU is within the set of area IDs indicated in the positioning request message, the WTRU may perform the associated request. If the area ID of the A-WTRU is not within the set of area IDs, the A-WTRU may not respond to the associated request.

[0178] The first set of parameters may include a positioning method. For example, the WTRU (e.g., T-WTRU) may indicate a positioning method that the WTRU may use (e.g., carrier phase-based positioning, timing-based positioning (e.g., TDOA), angle-based positioning). The A-WTRU may then determine whether to perform an associated request based on whether the WTRU supports the positioning method. Specifically, if the WTRU supports the positioning method, the WTRU may perform the associated request. If the WTRU does not support the positioning method, the WTRU may not perform the associated request.

[0179] The first set of parameters may include one or more positioning measurement parameters. For example, the WTRU may indicate one or more positioning measurement parameters (e.g., DPoA, PoA, AoA, AoD, RSTD, ToA, Tx-Rx timing and / or LOS / NLOS, etc.). The A-WTRU may determine whether to perform the associated request based on whether the WTRU supports the measurement parameter. Specifically, if the WTRU supports the measurement / calculation parameter, the WTRU may perform the associated request. If the WTRU does not support the measurement and / or calculation parameter, the WTRU may not perform the associated request.

[0180] The first set of parameters may include one or more reported positioning measurement parameters. For example, a WTRU (e.g., a T-WTRU) may indicate an expected range for a positioning measurement parameter. In one approach, if the measurement value is within the expected range, the WTRU may perform an associated request (e.g., perform a measurement report). If the measurement value is outside the expected range, the WTRU may not perform the associated request. In an example, if the measurement value is outside the expected range, the WTRU may still perform the associated request and the A-WTRU may notify the T-WTRU of the error.

[0181] A WTRU (eg, a T-WTRU) may indicate one or more parameters of the second set of positioning request parameters for the A-WTRU to perform the associated request.

[0182] The second set of positioning request parameters may include one or more of the following. The second set of positioning request parameters may include the type of positioning request. Specifically, a WTRU (e.g., a T-WTRU) may instruct another WTRU (e.g., an A-WTRU) to perform one or any combination of SL-PRS transmission, SL-PRS reception, feedback on the request (e.g., ACK / NACK), and positioning measurement reporting.

[0183] The second set of positioning request parameters may include QoS of the positioning request message, associated SL-PRS transmission and / or reception, positioning measurement reports and / or associated positioning services.

[0184] The second set of positioning request parameters may include a time window for SL-PRS transmission and / or reception. Specifically, the T-WTRU may request the A-WTRU to perform SL-PRS transmission and / or reception. The T-WTRU may indicate a time window for the requested SL-PRS transmission and / or reception. The WTRU (e.g., T-WTRU) may determine the time window for SL-PRS transmission and / or reception based on the QoS (e.g., latency requirements) of the positioning service to indicate to other WTRUs (e.g., A-WTRU). Specifically, for low latency requirement positioning services, the WTRU may indicate a short SL-PRS transmission and / or reception window; otherwise, the WTRU may indicate a long SL-PRS transmission and / or reception window.

[0185] In an example, the T-WTRU may request the A-WTRU to perform SL-PRS transmission. The WTRU may indicate a desired time window for SL-PRS transmission. The desired time window may include a minimum and / or maximum timing for SL-PRS transmission. In an example, the T-WTRU may request the A-WTRU to perform SL-PRS reception. The WTRU may then indicate a desired time window for SL-PRS reception. The desired time window may include a minimum and / or maximum timing for SL-PRS reception.

[0186] The second set of positioning request parameters may include a time window for sidelink measurement reporting. For example, the T-WTRU may request the A-WTRU to perform sidelink measurement reporting. The WTRU may indicate a desired time window for reporting, which may include a minimum and / or maximum timing for reporting.

[0187] The second set of positioning request parameters may include one or any combination of SL-PRS transmission parameters for the A-WTRU to perform SL-PRS transmission. In a first example, the T-WTRU may request the A-WTRU to perform SL-PRS transmission. The WTRU may indicate one or any combination of SL-PRS transmission parameters for the A-WTRU to perform SL-PRS transmission. In an example, the WTRU may indicate one or any combination of parameters for one SL-PRS transmission. Specifically, the T-WTRU may indicate the minimum and / or maximum number of subchannels, the number of symbols and / or time slots, and / or the comb value for each SL-PRS resource. In an example, the WTRU may indicate one or any combination of parameters for multiple SL-PRS transmissions. For example, the WTRU may indicate the type of SL-PRS transmission. Specifically, the WTRU may request and / or indicate whether the A-WTRU performs aperiodic SL-PRS transmission or periodic SL-PRS transmission. For SL-PRS transmission within a period, the T-WTRU may indicate and / or request a minimum and / or maximum number of SL-PRS transmissions. The WTRU may also indicate / request the periodicity, number of periods and / or duration of SL-PRS transmissions.

[0188] In an example, the T-WTRU may be configured (e.g., pre-configured) with one or more combinations of SL-PRS transmission parameters. The one or more combinations of SL-PRS transmission parameters may include one or more ranges of SL-PRS transmission parameters. The T-WTRU may then indicate a combination of SL-PRS transmission parameters for the A-WTRU to perform SL-PRS transmission.

[0189] The second set of positioning request parameters may include one or any combination of information for supporting the A-WTRU to perform SL-PRS reception. For example, the T-WTRU may request the A-WTRU to perform SL-PRS reception. The request may be sent from the T-WTRU or another A-WTRU. The T-WTRU may then indicate one or any combination of SL-PRS transmission parameters for the A-WTRU to perform SL-PRS reception and / or measurements.

[0190] The second set of positioning request parameters may include one of the SL-PRS measurement reporting parameters or any combination thereof. For example, the T-WTRU may request the A-WTRU to perform SL-PRS measurement reporting. The T-WTRU may indicate one of the SL-PRS measurement reporting parameters or any combination thereof. The T-WTRU may indicate the type of positioning measurement report (e.g., whether the A-WTRU needs to perform periodic or aperiodic positioning measurement reporting). The T-WTRU may indicate the priority, latency, measurement parameters to be reported, and / or the value range for each reported parameter.

[0191] The second set of positioning request parameters may include one or more resources for SL-PRS transmission / reception and / or sidelink measurement reporting. For example, the WTRU may request the A-WTRU to perform SL-PRS transmission and / or reception and / or sidelink measurement reporting. The WTRU may indicate possible resources for each request. In an example, the WTRU may request one or more A-WTRUs to perform SL-PRS transmission. The WTRU may determine a set of available resources for the A-WTRU to select and perform SL-PRS transmission. In other examples, the WTRU may request resources (e.g., from the network) for the A-WTRU to perform SL-PRS transmission. The WTRU may then indicate the selected / requested resources to the A-WTRU to perform SL-PRS transmission.

[0192] The WTRU may determine a set of resources for the A-WTRU to perform SL-PRS transmission. This approach may allow the A-WTRU to use (e.g., directly use) SL-PRS resources indicated from the T-WTRU without listening. In an example, the WTRU may request one or more A-WTRUs to perform SL-PRS reception. The WTRU may then request SL-PRS transmission resources from the network (e.g., gNB). Additionally or alternatively, the WTRU may perform resource selection for SL-PRS transmission. The WTRU may then indicate the requested and / or selected resources for the A-WTRU to perform SL-PRS reception and measurement.

[0193] The second set of positioning request parameters may include one or any combination of SL-PRS transmission parameters used by the requesting WTRU (e.g., T-WTRU) to support the A-WTRU in performing SL-PRS reception. For example, the WTRU (e.g., T-WTRU) may indicate in the positioning request message whether the SL-PRS is embedded in the request message.

[0194] A WTRU (e.g., a T-WTRU) may use an SCI, a MAC CE, and / or a NAS message (e.g., an LPP message and / or a Sidelink Positioning Protocol (SLPP) message) to indicate a range, a maximum value, and / or a minimum value for one or more parameters in the first set of positioning request parameters and the second set of positioning request parameters.

[0195] In an example, the WTRU may use the SCI to indicate one or more parameters in a set of positioning request parameters (eg, a first set of positioning request parameters and a second set of positioning request parameters).

[0196] The WTRU may use the SCI to indicate the type of positioning request. For example, the WTRU may be configured (e.g., pre-configured) with multiple types of positioning requests. The WTRU may indicate the type of positioning request in the SCI. In one method, the WTRU may indicate the type of positioning request in the first SCI. Additionally or alternatively, the WTRU may indicate the type of positioning request in the second SCI. The WTRU may indicate the first type of positioning request in both the first SCI and the second SCI. For example, the WTRU may indicate in the first SCI whether the A-WTRU should perform a set of requests (e.g., whether the WTRU should perform SL-PRS transmission and / or reception), and the WTRU may indicate in the second SCI whether the A-WTRU should perform another set of requests (e.g., whether the WTRU should send an ACK / NACK for a positioning request message).

[0197] The WTRU may use the SCI to indicate the QoS of the positioning request message, the associated SL-PRS transmission / reception, the positioning measurement report, and / or the associated positioning service. For example, the WTRU may indicate the priority of the positioning request in the SCI. Other WTRUs (e.g., A-WTRUs) may determine the priority of the associated SL-PRS transmission / reception, the positioning measurement report, and / or the associated positioning service based on the priority indicated in the positioning request in the SCI (e.g., the priority of the associated SL-PRS transmission and / or reception, the positioning measurement report, and / or the associated positioning service may be equal to the priority indicated in the positioning request message).

[0198] The WTRU may use the SCI to indicate a time window for SL-PRS transmission and / or reception and / or sidelink measurement reporting. For example, the WTRU may indicate a window for SL-PRS transmission / reception and / or sidelink measurement reporting in an SCI (eg, a second SCI).

[0199] The WTRU may use the SCI to indicate one or more of SL-PRS transmission parameters (e.g., for the A-WTRU and / or T-WTRU) and / or SL-PRS measurement parameters. For example, the WTRU may indicate possible resources for the A-WTRU to perform SL-PRS transmission and / or measurement reporting.

[0200] The WTRU may use the SCI to indicate a distance range to another node (e.g., a requesting WTRU and / or a gNB), positioning accuracy of the A-WTRU, Uu RSRP, SL-RSRP, AoA / AoD, LOS / NLOS, synchronization offset and / or error, type of synchronization source, coverage status of the A-WTRU and / or T-WTRU, positioning measurement parameters and / or area ID set. For example, the WTRU may be configured (e.g., pre-configured) to indicate multiple parameters in a second SCI, and the WTRU may use the second SCI to indicate which parameters and their associated ranges are indicated in the positioning request message. For example, the WTRU may indicate a range of distances to the requesting WTRU in the second SCI.

[0201] The WTRU may use the SCI to indicate the positioning method. For example, the WTRU may indicate the positioning method in the first SCI of the positioning request message. The WTRU may be configured (e.g., pre-configured) with multiple positioning methods (e.g., angle-based, timing-based, and / or carrier phase-based methods). The WTRU may then indicate which positioning method to use in the positioning request message.

[0202] In an example, the WTRU may use a MAC CE to indicate one or more of a set of positioning request parameters. The WTRU may use a MAC CE to indicate one or more of SL-PRS transmission parameters (e.g., for an A-WTRU and / or a T-WTRU) and / or SL-PRS measurement parameters. For example, the WTRU may use a MAC CE to indicate possible resources for the A-WTRU to perform SL-PRS transmission and / or measurement reporting.

[0203] In an example, the WTRU may use a group PC5-RRC that may be established for a WTRU group to indicate one or more parameters in a set of positioning request parameters. The WTRU may use the group PC5-RRC to indicate the QoS of the positioning request message, the associated SL-PRS transmission / reception, the positioning measurement report and / or the associated positioning service. The WTRU may use the group PC5-RRC to indicate the time window of the SL-PRS transmission / reception and / or the sidelink measurement report. The WTRU may use the group PC5-RRC to indicate one or any combination of SL-PRS transmission parameters (e.g., for A-WTRU and / or T-WTRU) and / or SL-PRS measurement parameters. The WTRU may use the group PC5-RRC to indicate the positioning method used in the WTRU group. The WTRU may use the group PC5-RRC to indicate one or more measurement parameters.

[0204] In an example, the WTRU may use group PC5-RRC to indicate and / or negotiate the configuration for SL-PRS transmission / reception and / or measurement reporting of the WTRU (e.g., T-WTRU). The group PC5-RRC message may be used to indicate and / or negotiate the configuration of SL-PRS transmission / reception and / or measurement reporting for each WTRU in the group. After the group PC5-RRC is established, the WTRUs in the group may perform associated SL-PRS transmission / reception and / or measurement reporting.

[0205] In an example, the WTRU may use a group NAS message (e.g., an LPP message) to indicate and / or negotiate a configuration for SL-PRS transmission / reception and / or measurement reporting. The group NAS message may be used to indicate and / or negotiate a configuration for SL-PRS transmission / reception and / or measurement reporting for each WTRU in the group. After exchanging NAS messages between the WTRUs in the group, the WTRUs in the group may perform associated SL-PRS transmission / reception and / or measurement reporting.

[0206] The WTRU may use one of the timing parameters or any combination thereof as a reference point for the timing of the indicated parameters. For example, the WTRU may use direct frame number (DFN) timing as a reference point. Specifically, the T-WTRU may request the A-WTRU to perform SL-PRS transmission and / or reception. The T-WTRU may indicate a time window for SL-PRS transmission / reception, which may include the first and last possible side link time slots for the A-WTRU to perform SL-PRS transmission and / or reception. The first possible time slot for SL-PRS transmission / reception may be indicated as the minimum DFN offset, and the last possible time slot for SL-PRS transmission / reception may be indicated as the maximum DFN offset.

[0207] The WTRU may use the requested timing as a reference point. For example, the T-WTRU may request the A-WTRU to perform SL-PRS transmission / reception. The T-WTRU may indicate a time window for SL-PRS transmission and / or reception, which may include a minimum time gap between the requested timing and the SL-PRS transmission / reception timing and / or a maximum time gap between the requested timing and the SL-PRS transmission / reception timing.

[0208] The WTRU may use one of the timings indicated in the request as a reference point. For example, the T-WTRU may request the A-WTRU to perform a SL-PRS measurement report. In the request message, the WTRU may include the timing of the SL-PRS transmission. The WTRU may indicate a time window for the SL-PRS measurement report, which may include a minimum time gap and / or a maximum time gap between the SL-PRS transmission and the SL-PRS measurement report. The SL-PRS measurement report may be used to report the measurements of the indicated SL-PRS transmission.

[0209] Figure 3 An example process 300 is depicted for determining parameters to include in a positioning request message 304. Figure 3 In the illustrated example process 300, a T-WTRU 302 may send a positioning request message 304, wherein the T-WTRU 302 may use an SCI (e.g., a first SCI) to indicate the type of positioning request. Specifically, the T-WTRU 302 may request the A-WTRU 306 to perform SL-PRS measurements and reporting. The T-WTRU 302 may use an SCI (e.g., a second SCI) to indicate a range requirement 308 for the positioning service (e.g., WTRUs within a circle around the T-WTRU may be considered within the range requirement 308 of the T-WTRU). In the positioning request message 304, the T-WTRU 302 may indicate SL-PRS transmission parameters for its SL-PRS transmissions (e.g., showing the time and frequency resources for its SL-PRS transmissions). The WTRU may also indicate (e.g., in the SCI, MAC CE, and / or RRC) Figure 3 A desired measurement reporting window 312 following a SL-PRS transmission resource 310 is depicted.

[0210] In an example, a WTRU (e.g., T-WTRU 302) may determine whether to send a positioning request message 304 based on one or any combination of the following to request the A-WTRU 306 to perform an associated positioning request (e.g., requesting to send feedback (e.g., ACK / NACK) to the request, send SL-PRS, receive SL-PRS, and / or send side link measurement reports).

[0211] The T-WTRU 302 may determine whether to send a positioning request message 304 to request the A-WTRU 306 to perform an associated positioning request based on the requested prohibition time. For example, the T-WTRU 302 may be configured (e.g., pre-configured) with a prohibition period for positioning requests. In an example, if the T-WTRU 302 receives a response from one or more A-WTRUs (e.g., such as the A-WTRU 306), the T-WTRU 302 may be allowed to perform another positioning request. If the T-WTRU 302 does not receive one or more positioning responses from a peer WTRU (e.g., such as the A-WTRU 306), the T-WTRU 302 may not be allowed to perform another positioning request. After the prohibition period after the first positioning request, the T-WTRU 302 may be allowed to send another positioning request. For example, the T-WTRU 302 may be allowed to send another positioning request after the prohibition period expires. The prohibition period may be configured (e.g., pre-configured) by one or any combination of QoS parameters of the positioning service and / or by resource pool.

[0212] The T-WTRU 302 may determine whether to send a positioning request message 304 to request the A-WTRU 306 to perform an associated positioning request based on the number of positioning request messages and / or the number of positioning request transmissions within a period. In an example, the T-WTRU 302 may be configured (e.g., pre-configured) with a maximum number of positioning request transmission blocks (TBs) within a period. If the number of positioning request TBs is less than a threshold, the T-WTRU 302 may determine to send the TBs. If the number of positioning request TBs is greater than or equal to the threshold, the WTRU may not send a positioning request TB.

[0213] In an example, the WTRU may be configured (e.g., preconfigured) with a maximum number of positioning request (retransmission) transmissions and / or a maximum number of resources within a period. If the number of positioning request transmissions is less than the configured (e.g., preconfigured) maximum value, the WTRU may determine to send a positioning request message. If the number of positioning request transmissions is greater than or equal to the configured (e.g., preconfigured) maximum value, the WTRU may not perform positioning request transmission.

[0214] In an example, a WTRU (e.g., a T-WTRU) may determine the type of positioning request, where each type of positioning request message may request the A-WTRU to perform one or any combination of SL-PRS transmission, SL-PRS reception, feedback (e.g., ACK / NACK) on the request, and / or positioning measurement reporting. The WTRU may determine the type of positioning request based on one or any combination of the following:

[0215] The WTRU may determine the type of positioning request based on the positioning accuracy of the WTRU (e.g., T-WTRU). For example, if the positioning accuracy of the WTRU is less than a threshold, the WTRU may determine to perform one type of positioning request; if the positioning accuracy of the WTRU is greater than the threshold, the WTRU may switch to another type of positioning request. For example, if the positioning accuracy of the WTRU is less than a threshold, the WTRU may request the A-WTRU to perform SL-PRS transmission, reception and / or measurement reporting. If (e.g., only if) the positioning accuracy of the WTRU is greater than the threshold, the WTRU may request the A-WTRU to perform SL-PRS transmission.

[0216] The WTRU may determine the type of positioning request based on the synchronization error between the two WTRUs. For example, if the synchronization error between the two WTRUs (e.g., the requesting WTRU and the A-WTRU) is greater than a threshold, the WTRU may request the A-WTRU to perform SL-PRS transmission, reception, and measurement reporting. Otherwise, if the synchronization error between the two WTRUs is less than the threshold and / or the WTRU has information about the synchronization error between the two WTRUs, the WTRU may request the A-WTRU to perform SL-PRS transmission, and / or SL-PRS reception and / or measurement reporting.

[0217] A WTRU (e.g., an A-WTRU) may monitor a positioning request from another WTRU (e.g., a T-WTRU). The WTRU may be indicated with an ID (e.g., an L2 ID) to determine whether to respond to the request. Specifically, if the ID included in the request message is associated with the indicated ID, the WTRU may respond to the request; otherwise, the WTRU may not respond to the message.

[0218] The WTRU may determine whether to feedback a sidelink positioning request. In an example, the WTRU may receive a positioning request message to request the WTRU to participate in sidelink positioning. If the WTRU participates in a sidelink positioning group, the WTRU may be required to send / receive SL-PRS and / or sidelink measurement reports. In an example, the WTRU may feedback ACK / NACK based on whether the WTRU participates in sidelink positioning. In an example, if the WTRU participates in sidelink positioning, the WTRU may feedback ACK, but if the WTRU does not participate in sidelink positioning, the WTRU may not feedback the request.

[0219] The WTRU may determine whether to feedback the SL-PRS transmission. In an example, a WTRU (e.g., an A-WTRU) may receive a transmission associated with the SL-PRS transmission (e.g., a PSCCH / PSSCH containing an SCI, a MAC CE, a PC5-RRC), which may require the WTRU to feedback (e.g., in the SCI of the associated transmission) information associated with the SL-PRS transmission.

[0220] The WTRU may determine a priority associated with the transmission of feedback. The WTRU may determine a priority associated with feedback (e.g., a feedback positioning request message and / or a feedback SL-PRS transmission). The WTRU may use the priority of the feedback to perform prioritization between the transmission of the message and the transmission / reception of another message.

[0221] The priority associated with the feedback may be determined based on one or any combination of the following factors: fixation of the feedback, configured (e.g., pre-configured) content, QoS of the positioning service, and / or QoS associated with the positioning request message. The priority determined based on configuration (e.g., pre-configuration) may include, for example, that the WTRU may be configured (e.g., pre-configured) with a priority value associated with feedback of the sidelink positioning request.

[0222] The content of the feedback may include, for example, that the WTRU may be configured (e.g., pre-configured) with two priorities. A first priority may be associated with ACK feedback (e.g., ACK feedback may be used to indicate that the WTRU may participate in positioning and / or indicate that the WTRU has received the SL-PRS). A second priority may be associated with NACK feedback (e.g., NACK feedback may be used to indicate that the WTRU may not participate in positioning and / or indicate that the WTRU did not receive the SL-PRS and / or the RSRP of the received SL-PRS is less than a threshold). The WTRU may determine the priority associated with the feedback based on the content of the feedback. The QoS associated with the positioning request message may include, for example, that the priority of the feedback may be associated with the priority of the positioning request. The priority of the positioning request may be indicated in the SCI of the request message.

[0223] The WTRU may determine a priority associated with the reception of a feedback message. The WTRU may perform a SL-PRS transmission. The WTRU may then expect to receive feedback (e.g., a measurement report, which may include RSRP and / or LOS / NLOS indicators for the SL-PRS) from a receiving WTRU (Rx WTRU). The WTRU may determine a priority associated with the reception of the feedback. The WTRU may use the priority associated with receiving the feedback to perform prioritization between the transmission of the message and the reception of the feedback if the transmission and reception occur simultaneously.

[0224] The priority of the desired feedback may be determined based on one or any combination of the following factors: a predetermined value (e.g., 1), a configured (e.g., preconfigured) QoS of the positioning service, and / or a QoS associated with the positioning request message. The priority of the desired feedback determined by a fixed method may include, for example, that the desired feedback may have the highest priority. The WTRU may receive the desired feedback with priority.

[0225] Upon receiving the positioning request message, the WTRU (eg, A-WTRU) may determine the type of positioning request, which may be included in the positioning request message. If the WTRU determines to participate in the positioning procedure, the WTRU may perform the associated request.

[0226] A WTRU (e.g., an A-WTRU) may receive a request (e.g., a request to send an ACK / NACK to feedback the request, send an SL-PRS, receive an SL-PRS, and / or send a sidelink measurement report) from a T-WTRU. In an example, if an ID (e.g., an L2 ID) associated with the request message belongs to a positioning service to which the WTRU subscribes, the WTRU may determine whether to perform the associated request (e.g., the WTRU may determine whether to send feedback (e.g., ACK / NACK) to the request, send an SL-PRS, receive an SL-PRS, and / or send a sidelink measurement report). The method may ensure that the WTRU responds (e.g., responds only) to an authorized WTRU. The WTRU may then determine whether to perform the associated request based on one of the following or any combination thereof.

[0227] The WTRU may determine whether to perform the associated request based on the type of positioning request. For example, based on the capabilities of the WTRU and / or the type of positioning request, the WTRU may determine whether to perform the associated request. For example, the WTRU may perform a SL-PRS send request. However, the WTRU may not perform a SL-PRS receive and measurement report request.

[0228] The WTRU may determine whether to perform an associated request based on a distance to another node (e.g., a requesting WTRU and / or a gNB). For example, if the distance to the requesting WTRU is less than a threshold, and / or the distance to the gNB is greater than a threshold, the WTRU may determine to perform the associated request. The threshold may be configurable (e.g., preconfigured). The threshold may be based on the QoS of the location service (e.g., the range requirement of the location service).

[0229] The WTRU may determine whether to perform the associated request based on the positioning accuracy of the A-WTRU. For example, if the positioning accuracy of the WTRU is within a threshold, the WTRU may perform the associated request; otherwise, the WTRU may not perform the associated request. The threshold may be configured (e.g., pre-configured), which may be based on the QoS of the positioning service (e.g., the accuracy requirement of the positioning service).

[0230] The WTRU may determine whether to perform an associated request based on the Uu RSRP. For example, the WTRU may determine whether to perform SL-PRS transmission based on the Uu RSRP. Specifically, if the Uu RSRP is greater than a threshold, the WTRU may not perform SL-PRS transmission; otherwise, the WTRU may perform SL-PRS transmission. The Uu RSRP threshold may be configurable (e.g., preconfigured). The UuRSRP threshold may be indicated in the SIB of the cell. The method may be activated to restrict WTRUs close to the gNB from performing SL-PRS transmission.

[0231] The WTRU may determine whether to perform the associated request based on the SL-RSRP in the sidelink channel with the requesting WTRU. For example, if the SL-RSRP is greater than a threshold, the WTRU may determine to perform the associated request. If the SL-RSRP is less than or equal to the threshold, the WTRU may not perform the associated request. The threshold may be configured (e.g., pre-configured) by resource pool, positioning request type, and / or QoS of the positioning service.

[0232] The WTRU may determine whether to perform the associated request based on the AoA and / or AoD sent from and / or to the requesting WTRU. For example, if the AoA of the positioning request is within a certain range, the WTRU may determine to perform the associated request. If the AoA of the positioning request is outside the range, the WTRU may not perform the associated request. The range may be configured (e.g., pre-configured) by resource pool, positioning request type, and / or QoS of the positioning service.

[0233] The WTRU may determine whether to perform the associated request based on the LOS / NLOS parameter. For example, if the LOS / NLOS value of the channel between the requesting WTRU and the A-WTRU is greater than a threshold, the WTRU may determine to perform the associated request. If the LOS / NLOS value of the channel between the requesting WTRU and the A-WTRU is less than or equal to a threshold, the WTRU may not perform the associated request. The threshold may be configured (e.g., pre-configured) based on a resource pool, a positioning request type, and / or a QoS of the positioning service.

[0234] The WTRU may determine whether to execute the associated request based on the synchronization offset and / or error, the type of synchronization source, and / or the priority of the synchronization source. For example, if the synchronization offset and / or error of the WTRU is less than a threshold, the WTRU may determine to execute the associated request; otherwise, the WTRU may not execute the associated request. The threshold may be configured (e.g., pre-configured) based on the resource pool, the location request type, and / or the QoS requirements of the location service. For example, if the WTRU is synchronized to the requesting WTRU, the WTRU may execute the associated request; otherwise, the WTRU may not execute the associated request.

[0235] The WTRU may determine whether to perform the associated request based on the coverage status of the A-WTRU and / or the requesting WTRU. In an example, if the A-WTRU is within the network coverage, the A-WTRU may perform the associated request. In an example, if the T-WTRU is within the network coverage, the A-WTRU may perform the associated request. In an example, if both the A-WTRU and the T-WTRU are within the network coverage, the A-WTRU may perform the associated request.

[0236] The WTRU may determine whether to execute the associated request based on the cell ID of the WTRU and / or the requesting WTRU. For example, if the WTRU is within the coverage of the same cell ID as the requesting WTRU, the WTRU may execute the associated request; otherwise, the WTRU may not execute the associated request.

[0237] The WTRU may determine whether to perform an associated request based on the area ID of the WTRU. For example, if the area ID of the WTRU is within a set of areas, the WTRU may perform an associated request. The WTRU may determine whether the area ID is within the set of areas. For example, the network may configure (e.g., preconfigure) a set of area IDs to feedback positioning requests. The set of area IDs may be determined based on the area ID of the requesting WTRU. Requesting WTRUs in a specific set of area IDs to perform an associated request may help limit the number of responding WTRUs. If the area ID of the WTRU is within a set of areas, the WTRU may perform an associated request. If the area ID of the WTRU is not within the set of area IDs, the WTRU may not perform the associated request. Using this set of area IDs may reduce the number of responding WTRUs to positioning services.

[0238] The WTRU may determine whether to perform the associated request based on the positioning method. For example, based on the capabilities of the WTRU, for timing-based positioning, the WTRU may perform the associated request. Additionally or alternatively, for carrier phase-based positioning and / or angle-based positioning, the WTRU may not perform the associated request.

[0239] The WTRU may determine whether to perform the associated request based on one or more positioning measurement parameters. For example, based on the capabilities of the WTRU, if the measurement parameter is related to timing measurement (e.g., RSTD and / or ToA), the WTRU may perform the associated request. If the measurement parameter is related to phase and / or angle (e.g., DPoA, PoA, and / or AoA), the WTRU may not perform the associated request.

[0240] The WTRU may determine whether to perform the associated request based on the positioning request message and / or the QoS of the service. For example, if the QoS requirement (e.g., accuracy requirement) of the positioning service is less than a threshold, the WTRU may perform the associated request; otherwise, the WTRU may not perform the associated request.

[0241] The WTRU may determine whether to perform the associated request based on the output of the positioning procedure. For example, if the output of the positioning procedure is a relative positioning, the WTRU may perform the associated request. In this example, if the output of the positioning procedure is an absolute positioning, the WTRU may not perform the associated request.

[0242] In an example, a WTRU (e.g., a T-WTRU) may determine one or more transmission parameters for a positioning request message (e.g., a message for requesting an A-WTRU to perform SL-PRS transmission, SL-PRS reception, and / or sidelink measurement reporting). The transmission parameters of the positioning request message may include one or any combination of the following factors as described below.

[0243] The sending parameters of the positioning request message may include a resource pool for the positioning request message. For example, the WTRU may be configured (e.g., pre-configured) with a dedicated resource pool to send the positioning request message. The T-WTRU may then perform resource selection or request to send resources for the positioning request message in the dedicated resource pool. The A-WTRU may then monitor the dedicated resource pool to determine whether to perform the associated request in the positioning message.

[0244] The transmission parameters of the positioning request message may include the priority of the positioning request message. For example, the WTRU may be configured (e.g., pre-configured) with a fixed priority (e.g., the highest priority) for the positioning request message. For example, the WTRU may determine the priority of the positioning request message based on the QoS (e.g., accuracy and latency requirements) of the positioning service. For example, the WTRU may assign a higher priority to the positioning request message for a positioning service with low latency requirements; otherwise, the WTRU may assign a lower priority to the positioning request message.

[0245] The transmission parameters of the positioning request message may include the transmission power. The WTRU may determine the transmission power of the request message based on one or more of the positioning request type and / or the QoS of the positioning service. For example, the WTRU may determine the transmission power of the positioning request message based on the range requirement of the positioning service. Specifically, the WTRU may be configured (e.g., pre-configured) with one or more maximum transmission power levels, which may be a function of the range requirement of the positioning service. The WTRU may then determine the transmission power of the positioning request message based on the associated range requirement.

[0246] The transmission parameters of the positioning request message may include a number of retransmissions for each request. The WTRU may be configured (e.g., pre-configured) with a maximum number of retransmissions for the request message, which may be a function of the QoS of the positioning service. The WTRU may then determine a number of retransmissions for each request message that is less than the configured value.

[0247] The transmission parameters of the positioning request message may include the time and frequency resources for the request transmission. In an example, the WTRU may be configured (e.g., pre-configured) with a dedicated resource pool to perform the positioning request transmission. The WTRU may then trigger resource selection to perform the positioning request transmission.

[0248] The sending parameters of the positioning request message may include the number of positioning request transmissions / number of messages within a period. In an example, the WTRU may be configured (e.g., pre-configured) with the maximum number of positioning request transmissions and / or the maximum number of messages within a period. If the number of positioning request transmissions within a period is less than a threshold, the WTRU may perform the positioning request transmission. If the number of positioning request transmissions is greater than the threshold, the WTRU may discard the transmission. In an example, the WTRU may be configured (e.g., pre-configured) with the validity period of the request message. After transmitting the request message, the WTRU may not be allowed to send another positioning request message within the validity period. Then, the WTRU may perform another positioning request message transmission after the validity period of the previous request message.

[0249] In an example, a WTRU (e.g., a T-WTRU) may determine whether to perform a retransmission of a positioning request TB based on the number of ACK feedbacks from an A-WTRU, which retransmission may use reserved resources from a previous transmission. Specifically, the WTRU may be configured (e.g., preconfigured) with a minimum number of ACKs in response to the A-WTRU. The WTRU may monitor feedback from the A-WTRU by monitoring the PSFCH resources associated with the PSCCH and / or PSSCH channels used by the positioning request transmission. If the number of ACK feedbacks from the A-WTRU is less than a configured (e.g., preconfigured) threshold, the WTRU may perform further retransmissions of the positioning request message. If the number of ACK feedbacks from the A-WTRU is not less than the configured (e.g., preconfigured) threshold, the WTRU may stop performing positioning request retransmissions. The WTRU may then discard the retransmission resources reserved for the sidelink positioning (e.g., autonomous sidelink positioning) request transmission.

[0250] In an example, a WTRU (e.g., a T-WTRU) may perform a positioning request message. The WTRU may then reserve and / or indicate SL-PRS resources for potential SL-PRS transmissions (e.g., in an SCI). If the WTRU receives ACK feedback from one or more A-WTRUs within a period (e.g., before the reserved SL-PRS resources), the WTRU may perform SL-PRS transmissions in the reserved resources. If the WTRU does not receive ACK feedback from one or more A-WTRUs within a period (e.g., before the reserved SL-PRS resources), the WTRU may discard the reserved SL-PRS resources. Since there is no A-WTRU to support determining the positioning of the WTRU, the method may be motivated to reduce resource waste.

[0251] In an example, the WTRU may then send (e.g., in an SCI) a reservation / indication of SL-PRS resources for potential SL-PRS from the A-WTRU. If the WTRU receives ACK feedback from one or more A-WTRUs within the period (e.g., before the reserved SL-PRS resources), the WTRU may perform SL-PRS reception in the reserved resources. If the WTRU does not receive ACK feedback from one or more A-WTRUs within the period (e.g., before the reserved SL-PRS resources), the WTRU may discard the reserved SL-PRS resources. The WTRU may broadcast a message that may indicate the release of the reserved resources.

[0252] Figure 4 An example process 400 is depicted in which a WTRU reserves periodic SL-PRS resources 410 and determines whether to perform SL-PRS transmission 420. For example, Figure 4 As shown, the WTRU may perform SL-PRS reservation 405 in the same positioning request message. The process 400 may be a positioning process that includes an ACK reception period 415 and a subsequent SL-PRS reservation period 420. The WTRU may determine whether to perform SL-PRS transmission 420 in the reserved resources 410 in the SL-PRS reservation period 420 based on the availability of ACK feedback in the ACK reception period 415. Specifically, if the WTRU does not receive any ACK feedback in the ACK reception period 415, the WTRU may discard the reserved SL-PRS resources 410; otherwise, if the WTRU receives one or more ACK feedback in the ACK reception period 415, the WTRU may perform one or more SL-PRS transmissions 420 in the one or more reserved SL-PRS resources 410. Each of the one or more SL-PRS transmissions 420 may be associated with a period 425. For example, the SL-PRS transmissions 420 may be periodic.

[0253] A WTRU (e.g., a T-WTRU) may indicate to an A-WTRU the value, range, maximum value, and / or minimum value of one or more parameters. If the measured value and / or calculated value and / or range of the one or more parameters is within a certain range, the A-WTRU may determine to perform the associated request.

[0254] The indicated parameters may include one or more of the following: distance to another node (e.g., requesting WTRU, gNB), positioning accuracy of the A-WTRU, Uu RSRP, SL-RSRP and / or AoA or AoD transmitted from / to the requesting WTRU, LOS / NLOS, synchronization offset, a set of area IDs to respond to, a range of one or more reported positioning measurement parameters, priority of the positioning request, a time window for SL-PRS transmission and / or reception, a time window for sidelink measurement reporting, one or any combination of SL-PRS transmission parameters, one or any combination of information used to support the A-WTRU to perform SL-PRS reception, and / or one or any combination of SL-PRS measurement reporting parameters.

[0255] The value and / or range of one or more of the indicated parameters may be determined based on one or more of the following: the QoS of the positioning service, the positioning method, the type of positioning request, the number of responding A-WTRUs from the previous positioning request message, the area ID of the WTRU and / or the CBR of the resource pool.

[0256] In an example, a WTRU (e.g., a T-WTRU) may perform transmission of one or more positioning request messages (e.g., messages for requesting an A-WTRU to perform SL-PRS transmission, SL-PRS reception, and / or sidelink measurement reporting). The WTRU may then monitor feedback from potential A-WTRUs. Based on the feedback from zero or more potential A-WTRUs, the WTRU (e.g., a T-WTRU) may adjust the range of one or more parameters associated with the request message and / or adjust one or more transmission parameters of the positioning request message.

[0257] For example, if the number of responding A-WTRUs (e.g., one A-WTRU transmitting ACK feedback) is less than a threshold (e.g., three A-WTRUs), the T-WTRU may adjust one or more ranges of the parameters indicated in the positioning request message. Specifically, the T-WTRU may perform one or any combination of the following.

[0258] If the number of responding A-WTRUs is less than a threshold, the WTRU may extend the distance range. The WTRU (e.g., T-WTRU) may increase the maximum distance and / or decrease the minimum distance. A-WTRUs within the indicated distance range may respond to the associated request. By extending the distance range, the T-WTRU may then receive more responses from the A-WTRUs to support the T-WTRU in determining its location.

[0259] If the number of responding A-WTRUs is less than a threshold, the WTRU may extend the range of positioning errors. The WTRU may increase the maximum positioning error of the A-WTRUs. A-WTRUs with positioning errors less than the indicated maximum value may respond to the associated request. By increasing the maximum positioning error, the T-WTRU may then receive more responses from the A-WTRUs to support the T-WTRU in determining its position.

[0260] If the number of responding A-WTRUs is less than a threshold, the WTRU may extend the range of Uu RSRP. The T-WTRU may lower the minimum Uu RSRP and / or increase the maximum Uu RSRP to indicate this to the A-WTRUs. An A-WTRU with a Uu RSRP within the indicated range may respond to the associated request.

[0261] If the number of responding A-WTRUs is less than a threshold, the WTRU may extend the range of SL-RSRP in the sidelink channel with the requesting WTRU. The T-WTRU may lower the minimum SL-RSRP and / or increase the maximum SL-RSRP to indicate this to the A-WTRUs. An A-WTRU whose SL-RSRP between itself and the requesting WTRU (e.g., T-WTRU) is within the indicated range may respond to the associated request.

[0262] If the number of responding A-WTRUs is less than a threshold, the WTRU may extend the range of the AoA or AoD with the requesting WTRU. The T-WTRU may decrease the minimum AoA and / or AoD and / or increase the maximum AoA and / or AoD to indicate this to the A-WTRU. An A-WTRU whose AoA and / or AoD to the requesting WTRU (e.g., T-WTRU) is within the indicated range may respond to the associated request.

[0263] If the number of responding A-WTRUs is less than a threshold, the WTRU may extend the range of LOS / NLOS. The T-WTRU may reduce the minimum LOS / NLOS parameter to indicate this to the A-WTRUs. An A-WTRU having a LOS / NLOS parameter greater than the indicated value in the channel between itself and the requesting WTRU (e.g., T-WTRU) may respond to the associated request.

[0264] For example, if the number of responding A-WTRUs (e.g., one A-WTRU transmitting ACK feedback) is less than a threshold (e.g., three A-WTRUs), the T-WTRU may adjust one or more ranges of the parameters indicated in the positioning request message. Specifically, the WTRU may perform one or any combination of the following operations as described below.

[0265] If the number of responding A-WTRUs is less than a threshold, the WTRU may reduce the distance range. The WTRU (e.g., T-WTRU) may reduce the maximum distance and / or increase the minimum distance. A-WTRUs within the indicated distance range may respond to the associated request. By reducing the distance range, the T-WTRU may then receive fewer responses from the A-WTRUs to support the T-WTRU in determining its location.

[0266] If the number of responding A-WTRUs is less than a threshold, the WTRU may reduce the range of positioning errors. The WTRU (e.g., T-WTRU) may reduce the maximum positioning error of the A-WTRU. A-WTRUs with positioning errors less than the indicated maximum value may respond to the associated request. By reducing the maximum positioning error, the T-WTRU may then receive fewer responses from the A-WTRUs to support the T-WTRU in determining its position.

[0267] If the number of responding A-WTRUs is less than a threshold, the WTRU (e.g., T-WTRU) may reduce the range of Uu RSRP. The T-WTRU may increase the minimum Uu RSRP and / or decrease the maximum Uu RSRP to indicate this to the A-WTRUs. A-WTRUs with Uu RSRP within the indicated range may respond to the associated request.

[0268] If the number of responding A-WTRUs is less than a threshold, the WTRU (e.g., T-WTRU) may reduce the range of SL-RSRP in the sidelink channel with the requesting WTRU. The T-WTRU may increase the minimum SL-RSRP and / or reduce the maximum SL-RSRP to indicate this to the A-WTRUs. An A-WTRU whose SL-RSRP between itself and the requesting WTRU (e.g., T-WTRU) is within the indicated range may respond to the associated request.

[0269] If the number of responding A-WTRUs is less than a threshold, the WTRU (e.g., T-WTRU) may reduce the range of AoA and / or AoD to the requesting WTRU. The T-WTRU may increase the minimum AoA and / or AoD and / or reduce the maximum AoA and / or AoD to indicate this to the A-WTRU. The A-WTRU whose AoA and / or AoD to the requesting WTRU (e.g., T-WTRU) is within the indicated range may respond to the associated request.

[0270] If the number of responding A-WTRUs is less than a threshold, the WTRU (e.g., T-WTRU) may reduce the range of LOS / NLOS. The T-WTRU may increase the minimum LOS / NLOS parameter to indicate this to the A-WTRUs. An A-WTRU having a LOS / NLOS parameter greater than the indicated value in the channel between itself and the requesting WTRU (e.g., T-WTRU) may respond to the associated request.

[0271] If the A-WTRU participates in sidelink positioning (e.g., autonomous sidelink positioning) to support the T-WTRU in determining its positioning, the T-WTRU may request the potential A-WTRU to feed back its positioning request message. The WTRU (e.g., T-WTRU) may then determine whether to adjust the transmission parameters of the positioning request message based on the number of A-WTRUs that respond to the request. Specifically, if the number of responding A-WTRUs is less than a threshold (e.g., three A-WTRUs), the T-WTRU may increase its transmit power and / or the number of retransmissions for the positioning request message. Additionally or alternatively, if the number of responding WTRUs is greater than another threshold (e.g., five A-WTRUs), then (e.g., T-WTRU) may reduce its transmit power and / or reduce the number of retransmissions for the positioning request message.

[0272] For example, a WTRU (e.g., a T-WTRU) may send a positioning request message, wherein the T-WTRU may request a potential A-WTRU to perform ACK / NACK feedback. If the number of ACKs is outside a threshold range, the T-WTRU may adjust the sending parameters of the positioning request message. If the number of ACK feedback is within a threshold range, the WTRU may not adjust the sending parameters of the positioning request message.

[0273] For example, if the number of received ACKs is less than a threshold, the WTRU (e.g., T-WTRU) may increase the transmit power and / or the number of retransmissions for the positioning request message. If the number of received ACKs is greater than another threshold, the T-WTRU may decrease the transmit power and / or the number of retransmissions for the positioning request message.

[0274] Figure 5 An example process 500 is depicted in which a WTRU 502 adjusts the range requirement for an acknowledgement (ACK) feedback. Figure 5 As shown, a WTRU 502 (e.g., a T-WTRU) may first perform a positioning request with a small range requirement 506. The WTRU 502 may obtain a positioning request from one of the A-WTRUs (e.g., Figure 5504) receives ACK feedback. However, the positioning procedure (e.g., autonomous positioning procedure) requires feedback from more A-WTRUs (e.g., A-WTRU 508 outside the small range requirement 506 but within the large range requirement 510). The T-WTRU 502 may adjust the range requirement (e.g., from the small range requirement 506 to the large range requirement 510). The T-WTRU 502 may receive feedback from two or more A-WTRUs 504, 508 to perform the positioning procedure.

[0275] A WTRU (e.g., an A-WTRU) may trigger resource allocation (e.g., for Mode 2 resource allocation) or request resources (e.g., for Mode 1 resource allocation) for SL-PRS transmission (e.g., a WTRU may trigger resource selection for its SL-PRS transmission or for other WTRUs to perform SL-PRS transmission) based on one or any combination of the following: positioning.

[0276] The WTRU may trigger resource allocation for SL-PRS transmission positioning based on SL-PRS transmission from other WTRUs (e.g., T-WTRUs). For example, the WTRU may be requested to perform both SL-PRS transmission and reception. The WTRU may perform resource selection for its SL-PRS transmission based on its reception of SL-PRS from the T-WTRU (e.g., successful reception and successful measurement).

[0277] The WTRU may trigger resource allocation for SL-PRS transmission positioning based on NACK feedback from another WTRU. For example, the WTRU may perform SL-PRS transmission with feedback (e.g., ACK / NACK) enabled. If the WTRU receives feedback (e.g., NACK feedback) from a receiving WTRU, the WTRU may perform resource selection for SL-PRS, which may implicitly and / or explicitly request more SL-PRS resources for transmission.

[0278] The WTRU may trigger resource allocation for SL-PRS transmission positioning based on detecting a conflict with one or more other transmissions. For example, the WTRU may perform periodic SL-PRS transmissions. The WTRU may detect a conflict between its SL-PRS transmissions and other sidelink transmissions. The conflict may be indicated from another WTRU (e.g., T-WTRU) via an inter-WTRU coordination message (e.g., an IUC message), or the conflict may be detected by the WTRU.

[0279] The WTRU may trigger resource allocation for SL-PRS transmission positioning based on the expiration of the duration of the periodic SL-PRS reservation. For example, if the duration of the periodic SL-PRS reservation expires, the WTRU may trigger resource selection for SL-PRS transmission.

[0280] The WTRU may trigger resource allocation for SL-PRS transmission positioning based on the number of NACK feedbacks from the receiving WTRU being greater than a threshold. For example, if the number of NACK feedbacks from the receiving WTRU is greater than a threshold, the WTRU may trigger resource reselection for SL-PRS transmission. The threshold may be configured (e.g., preconfigured), which may be based on the QoS of the positioning service.

[0281] The WTRU may trigger resource allocation for SL-PRS transmission positioning based on whether the received SL-PRS resources may be insufficient to derive accurate SL-PRS measurement results. For example, the WTRU may be configured (e.g., preconfigured) to measure one or more N SL-PRS resources (e.g., SL-PRS resources with an RSRP greater than a threshold). If the received SL-PRS resources are insufficient for SL-PRS measurement, the WTRU may trigger resource allocation for SL-PRS transmission. For SL-PRS transmission by another WTRU, the WTRU may determine whether to trigger further resource selection for the other WTRU based on the number of SL-PRS resources successfully received within a period. For SL-PRS transmission by the WTRU itself, the WTRU may receive an indication from another WTRU to determine whether to trigger resource allocation.

[0282] The WTRU may trigger resource allocation for SL-PRS transmission positioning based on whether one or more SL-PRS resources are deprioritized. For example, the WTRU may be scheduled to perform periodic SL-PRS transmission / reception. The WTRU may determine whether to trigger resource selection or trigger a request for SL-PRS resources for the WTRU or another WTRU based on whether one or more SL-PRS resources are deprioritized (e.g., in the periodic SL-PRS resources). Specifically, if the number of SL-PRS resources that are deprioritized (e.g., within a window) is greater than a threshold, the WTRU may trigger resource allocation and / or request SL-PRS resources. The threshold may be configured by the network, which may be associated with the QoS of the periodic SL-PRS transmission / reception and / or sidelink positioning service.

[0283] The WTRU may use one or any combination of the following parameters in the resource allocation procedure: resource allocation resource pool, priority of SL-PRS transmission, latency of SL-PRS transmission, remaining packet delay budget (PDB) for SL-PRS transmission, number of subchannels to be used for SL-PRS transmission, periodicity of SL-PRS transmission, window for resource allocation (e.g., [n+T1, n+T2]). One or any combination of these parameters used for resource allocation may be determined based on one or any combination of the following.

[0284] One or more parameters for resource allocation may be determined based on a fixed priority. For example, the WTRU may use a fixed priority (e.g., a highest priority) for SL-PRS transmission. One or more parameters for resource allocation may be determined based on a configured (e.g., pre-configured) resource pool. For example, the WTRU may be configured (e.g., pre-configured) with a resource pool for SL-PRS transmission. The WTRU may then perform resource allocation for SL-PRS transmission in the configured (e.g., pre-configured) resource pool. For example, the WTRU may be configured (e.g., pre-configured) with a priority for SL-PRS transmission. The WTRU may indicate the priority of the SL-PRS in an associated transmission (e.g., an associated SCI).

[0285] One or more parameters for resource allocation may be determined based on the QoS of the positioning service. For example, the WTRU may determine the priority, latency, and / or remaining PDBs for resource allocation for SL-PRS transmission based on the QoS of the positioning service (e.g., accuracy and / or latency). Specifically, the WTRU may use the priority of resource allocation for SL-PRS transmission based on the accuracy requirement of the positioning service. The WTRU may then determine the remaining PDBs for resource allocation for SL-PRS transmission based on the latency requirement of the positioning service.

[0286] One or more parameters for resource allocation may be determined based on an indication from another WTRU. For example, a WTRU (e.g., A-WTRU) may be indicated from another WTRU (e.g., T-WTRU) to the WTRU (e.g., A-WTRU) of the priority, latency, resource selection window, and / or periodicity of positioning measurement reports for that WTRU. The WTRU may then use one or any combination of these parameters to perform resource selection and reservation.

[0287] In an example, a WTRU (e.g., a T-WTRU) may determine to perform multiple (e.g., two) levels of positioning. Specifically, when the positioning accuracy of the WTRU (e.g., the T-WTRU) is within a first range (e.g., greater than a threshold), the WTRU may perform a first positioning method. When the positioning accuracy of the WTRU is within a second range (e.g., less than a threshold in the first level), the WTRU may perform a second positioning method.

[0288] In an example, when a WTRU (e.g., T-WTRU) has coarse positioning information or no positioning information, the WTRU may determine to perform timing-based positioning (e.g., TDOA) in a first period. After obtaining its positioning information, the WTRU may trigger a carrier phase-based positioning method in a second period to obtain greater positioning accuracy, wherein the positioning information may have an accuracy greater than a threshold (e.g., a higher accuracy). In each positioning method and associated period, the WTRU may determine the SL-PRS transmission parameters based on the positioning method and the time required to obtain a specific positioning accuracy.

[0289] In an example, a WTRU (e.g., a T-WTRU) may determine to perform multiple positioning methods simultaneously. The WTRU may determine whether to perform multiple positioning methods simultaneously based on the QoS of the positioning service. In an example, the WTRU may perform both an angle-based positioning method and a timing-based positioning method. In an example, the WTRU may perform both a timing-based positioning method and a carrier phase-based positioning method. The method may be activated to help the WTRU obtain a more accurate position and reduce latency. The WTRU may then request the WTRU to perform SL-PRS transmission, reception, and / or measurement reporting for both positioning methods. In an example, for a timing-based positioning method and a carrier phase-based positioning method, the WTRU may request the A-WTRU to perform SL-PRS transmission for both carrier phase measurements and timing-related measurements. The A-WTRU may report two types of parameters in one period (e.g., within a window or in the same message).

[0290] In an example, a WTRU may initialize a group PC5-RRC to establish a PC5 connection between the WTRUs in the group to exchange configurations for SL-PRS transmission, SL-PRS reception, and / or measurement reporting. The WTRU group may include two (e.g., one T-WTRU and one A-WTRU) or multiple WTRUs (e.g., one T-WTRU and multiple A-WTRUs). The A-WTRU group may include one or more A-WTRUs.

[0291] When establishing a group PC5-RRC, a WTRU (e.g., T-WTRU) may perform one or any combination of the following to determine and / or obtain SL-PRS resources for the group: request SL-PRS transmission resources for the WTRU group and / or perform resource selection for the WTRU group. The SL-PRS transmission resources for the WTRU group may include one or any combination of the following parameters.

[0292] The SL-PRS resources for a WTRU may include one or any combination of the following. The SL-PRS resources for a WTRU may include one or more parameters of a SL-PRS resource for a WTRU. The one or more parameters of a SL-PRS resource for a WTRU may include one or more of the following: QoS associated with the SL-PRS resource, transmit power, number of subchannels used for each SL-PRS resource, number of symbols and / or slots used for each SL-PRS transmission resource, reference resource pattern (e.g., comb size and / or comb pattern), sequence ID, cyclic shift, and / or time / frequency resource for SL-PRS transmission.

[0293] The SL-PRS resources for a WTRU may include the number of SL-PRS resource repetitions and / or retransmissions in a period. The SL-PRS resources for a WTRU may include a type of SL-PRS transmission. For example, the type of SL-PRS transmission may include whether the SL-PRS transmission resources for the group are periodic or aperiodic. For example, the WTRU may be configured (e.g., pre-configured) with two types of SL-PRS transmissions. In the first type, the SL-PRS may be sent dynamically. In the second type, the SL-PRS may be sent periodically. The SL-PRS resources for a WTRU may include the periodicity of the SL-PRS process. The SL-PRS resources for a WTRU may include the number of periods for a SL-PRS process, sidelink positioning session, and / or window. The SL-PRS resources for a WTRU may include the HARQ type of the SL-PRS transmission.

[0294] The SL-PRS transmission resources for the WTRU group may include a set of SL-PRS configurations to be used for SL-PRS transmission / reception.

[0295] The SL-PRS transmission resources for the WTRU group may include the number of WTRUs that share the group resources. The SL-PRS transmission resources for the WTRU group may include a multiplexing type or order that may determine which resource in the resource group may be used first. For example, CDM, FDM, and / or TDM may be used to multiplex the group SL-PRS resources.

[0296] Figure 6 The SL-PRS 600 for a WTRU group is described. Figure 6 As shown, in one SL-PRS resource group 604, the group may use a comb pattern 605 that first FDMs the resources. The comb pattern 605 may include the number of symbols for the PRS (e.g., SL-PRS), the RE offset, and the periodicity of the REs containing the PRS in each symbol of the PRS. For example, for WTRU1, the PRS spans 4 symbols, the RE offsets are 0, 1, 2, 3 for symbols 0, 1, 2, and 3, respectively, and the periodicity of the REs containing the PRS is 4 (e.g., 1 out of every 4 REs contains the PRS). Thereafter, the resources are TDMed. The maximum number of FDM resources is 2. WTRU1 and WTRU2 may then use a first resource in the time resources 606, and WTRU3 and WTRU4 may use a second resource in the time resources 608.

[0297] The WTRU may then select and / or request one of the group SL-PRS resources 604 for the WTRU group. The WTRU may then determine one or more parameters for the group SL-PRS resources based on one or more of: parameters configured (e.g., pre-configured) in the resource pool, an indication from another node, QoS requirements for positioning services, distance to the receiving WTRU and / or the requesting WTRU, a sidelink channel to the receiving WTRU and / or the requesting WTRU, a CBR of the resource pool, a positioning accuracy of the WTRU or an associated WTRU, a positioning method, a measurement parameter to be measured, an output of the positioning procedure (e.g., absolute positioning or relative positioning), an amount of SL-PRS transmissions within a period, an inhibit time associated with SL-PRS transmissions and / or SL-PRS requests, parameters for SL-PRS transmissions from the requesting WTRU, a number of WTRUs in the group, and / or a maximum CDM and FDM multiplexing capability. For example, if the group is larger than a threshold size, the WTRU may request more SL-PRS resources. If the group is less than or equal to the threshold size, the WTRU may request fewer SL-PRS resources.

[0298] In an example, a WTRU may apply resource randomization to determine its SL-PRS resources. A WTRU (e.g., A-WTRU) upon receiving the SL-PRS resources for its group. The WTRU may then determine the SL-PRS resources to use based on one or more of: member WTRU IDs of the group, the number of WTRUs in the group, the timing of the group SL-PRS resources, and / or the maximum number of SL-PRS resources in the code, frequency, and / or time domain of the SL-PRS resource group.

[0299] In an example, a WTRU (eg, T-WTRU) may determine to change the SL-PRS resource group based on changes in group size and / or membership. For example, if one or more WTRUs join or leave the group, the WTRU may reselect / request another SL-PRS resource group.

[0300] The WTRU may determine resources (e.g., amount of resources) for the WTRU group. In an example, the WTRU may perform resource allocation for the WTRU group. For example, the WTRU may perform resource allocation for SL-PRS transmission resources, SL-PRS reception resources, and / or SL-PRS measurement reporting resources.

[0301] A WTRU (e.g., a T-WTRU) may perform resource allocation for a group of WTRUs. In an example, a WTRU may use a frequency resource (e.g., one time-frequency resource) for a group of WTRUs. Each WTRU in the group may perform multiplexing (e.g., in the time-frequency resource) using any suitable multiplexing technique (e.g., CDM). In certain implementations, the WTRU may determine the time-frequency resources (e.g., the number of time-frequency resources) for each type of transmission and / or reception (e.g., resources for SL-PRS transmission, reception, and / or measurement reporting) based on one or more of the number of WTRUs in the group, the multiplexing rule, and / or the number (e.g., maximum number) of frequency multiplexing resources for (e.g., one) time slot.

[0302] The WTRU may determine multiplexing rules associated with different WTRUs in the group. In certain implementations, the WTRU may select resources for the WTRU group. The WTRU may determine the multiplexing rules for the resources for each WTRU. For example, the WTRU may determine the comb size based on the number of WTRUs that are multiplexed in a resource (e.g., the same time resource). For example, if the WTRU allows multiple (e.g., two) WTRUs to transmit in (e.g., one) time resource, the WTRU may use comb 2. Additionally or alternatively, if the WTRU allows four WTRUs to transmit in one timing resource, the WTRU may use comb 4. If, for example, the WTRU allows multiple WTRUs to share resources (e.g., timing resources), the WTRU may determine the cyclic shift for each WTRU.

[0303] The WTRU may determine whether to perform resource allocation for a WTRU group, for example, based on an output (e.g., positioning output). One or more of the following may apply: A WTRU (e.g., a T-WTRU) may determine whether to perform resource allocation for a WTRU group based on a positioning output. In some implementations, if the output of positioning is an absolute position of the WTRU, then the WTRU may determine to perform resource allocation for the WTRU group. For example, if the output of positioning is a relative position (e.g., between different WTRUs), then the WTRU may not perform resource allocation for the WTRU group.

[0304] The WTRU may determine a structure of SL-PRS resources for the WTRU. One or more of the following may apply: A WTRU (e.g., an A-WTRU) may determine a structure of SL-PRS resources for the WTRU from resources for a group of WTRUs, for example, based on the number of WTRUs in the group. For example, if there are 2 A-WTRUs in the group, the WTRU may determine to use comb 2 for (e.g., 1) SL-PRS resources. In an example, if there are 4 A-WTRUs in the group, the WTRU may use comb 4 for (e.g., 1) SL-PRS resources. In an example, if there are 2 A-WTRUs in the group, the WTRU may use multiple (e.g., 10) symbols for each SL-PRS resource. In an example, if there are 4 A-WTRUs in the group, the WTRU may use multiple (e.g., 4) symbols for each SL-PRS resource.

[0305] The WTRU may be configured to determine measurement gaps to be used in the sidelink. In an example, when the WTRU measures and processes the SL-PRS, the WTRU (e.g., T-WTRU) may determine to request another WTRU (e.g., A-WTRU) to suspend / terminate sending data or control channels / signals to the WTRU.

[0306] Figure 7 700 is a diagram illustrating example measurement gap (MG) 702 patterns and parameters. A WTRU (eg, a T-WTRU) may be configured (eg, pre-configured) with a list 704 of MGs (eg, Figure 7 704). In these examples, T-WTRU and A-WTRU may be used interchangeably. For example, the A-WTRU may transmit a request to the T-WTRU to suspend and / or terminate the transmission of data. The A-WTRU may transmit a request to the T-WTRU to configure the MG 704. During the MG 704, the WTRU may determine to perform measurements of the SL-PRS and the processing of the measurements.

[0307] In an example, the T-WTRU may indicate the IDs in the list to the A-WTRU or the network (e.g., the gNB and / or LMF) so that the A-WTRU may use the IDs in the measurement gap (e.g., Figure 7 No data or control signals and / or channels are transmitted during the interval (in the interval indicated by the measurement gap length L in the measurement gap). In an example, the T-WTRU may transmit a request to the A-WTRU or the network (e.g., LMF and / or gNB) to activate the MG704. The request may be transmitted in the SCI or MAC-CE. The T-WTRU may receive an MG configuration from the A-WTRU or the network, which may be different from the MG requested by the T-WTRU. The T-WTRU may determine the MG configuration based on the parameters of the SL-PRS configured by the A-WTRU (e.g., number of symbols, periodicity and / or repetition factor). The T-WTRU may transmit a request to the A-WTRU to activate the MG via a PC5-RRC, SCI, MAC-CE, or LPP (LTE Positioning Protocol) message. The T-WTRU may transmit the request in a PC5-RRC, SCI, MAC-CE, and / or LPP message before sending the PRS. The T-WTRU may transmit a request to the A-WTRU or the network (e.g., LMF, gNB) to deactivate the measurement gap. The T-WTRU may include an ID to indicate which measurement gaps should be deactivated. The T-WTRU may receive an indication from the A-WTRU or the network to deactivate the MG having the associated ID.

[0308] The T-WTRU may transmit a request for the MG in a unicast, multicast, or broadcast. The request may depend on the type of broadcast used for PRS transmission. The MG may be associated with an area ID. For example, once the MG is activated, the WTRUs in the area may not send data and / or control information to other WTRUs during the measurement gap. The WTRU may determine to send PRS to other WTRUs and / or receive PRS (e.g., only PRS) from other WTRUs during the measurement gap in the area associated with the MG. The WTRU may be configured (e.g., pre-configured) with a measurement gap pattern associated with the area ID. The WTRU may receive a PC5-RRC, SCI, MAC-CE, and / or LPP message indicating activation of one of the MG modes associated with the area.

[0309] The WTRU may be configured (e.g., preconfigured) with measurement gaps associated with a configured (e.g., preconfigured) resource pool. The WTRU may receive a PC5-RRC, SCI, MAC-CE, and / or LPP message that enables a MG for a configured (e.g., preconfigured) resource pool. The WTRU may determine to activate the MG for one of the configured (e.g., preconfigured) resource pools. In such a case, the WTRU may determine to activate the MG for one or more (e.g., all) resources belonging to the resource pool.

[0310] If the WTRU receives a message to activate the MG from the T-WTRU, A-WTRU and / or the network, the WTRU may determine to send and / or receive PRS in resources (eg, subchannels, bandwidth) configured (eg, preconfigured) in a resource pool.

[0311] The T-WTRU may determine the MG to request based on the SL PRS resource. The T-WTRU may be configured (e.g., pre-configured) with a list of measurement gap parameters, where each set of parameters (e.g., gap length, periodicity) is associated with a SL-PRS resource in a SL-PRS resource pool. For example, the T-WTRU may determine which measurement gap to request based on the configured (e.g., pre-configured) list, depending on which SL-PRS resource is configured.

[0312] The T-WTRU may determine to use a configured (e.g., pre-configured) list, depending on the coverage state. For example, if the T-WTRU is out of coverage, the T-WTRU may determine to use a configured (e.g., pre-configured) list. If the T-WTRU is in an in-coverage state, the T-WTRU may request a MG list and / or request a MG from the network (e.g., LMF and / or gNB).

[0313] In an example, a WTRU (e.g., an A-WTRU) may use an SCI to indicate activation and / or deactivation of an MG. For example, in a first SCI, the WTRU may transmit a type of positioning request. The type of positioning request may include a list of MG configurations. The WTRU may use a second SCI to indicate which MG in the list is activated and / or deactivated. In an example, the WTRU may determine to include a list of MGs in the first SCI or the second SCI. The WTRU may include an activation and / or deactivation message in the SCI after the second SCI.

[0314] In an example, if the T-WTRU determines that there is no MG configured for the T-WTRU, the T-WTRU may receive both data and SL-PRS. In an example, if the T-WTRU and / or the request for MG configuration is not granted by other WTRUs (e.g., A-WTRU) or the network, the T-WTRU may receive both data and SL-PRS. The data and SL-PRS may be multiplexed in the frequency domain or the time domain.

[0315] In an example, the T-WTRU may determine to receive the SL-PRS over other channels in priority according to a configured (e.g., pre-configured) priority configuration. For example, if the configured (e.g., pre-configured) priority rule indicates that the SL-PRS has a higher priority than the data channel, then if the SL-PRS and the data channel partially or completely overlap in the time domain, the T-WTRU may determine to receive the SL-PRS over the data channel (e.g., discard the data channel).

[0316] The priority level may be determined by one or more of the following. The priority level may be determined based on the coverage status. For example, in an out-of-coverage state, the SL-PRS may have a lower priority than other channels (e.g., data and / or control channels). On the other hand, in an in-coverage state, the SL-PRS may have a higher priority than other channels.

[0317] The priority level may be determined based on the type of SL-PRS. For example, aperiodic and / or semi-static SL-PRS may have a higher priority than other channels (e.g., data and / or control channels). Periodic SL-PRS may have a lower priority than other channels.

[0318] The priority level may be determined based on the positioning method. For example, if RTT-based positioning is implemented, the T-WTRU may determine that the SL-PRS has a higher priority than other channels. If TDOA-based positioning is implemented, the T-WTRU may determine that the SL-PRS has a lower priority than other channels.

[0319] The priority level may be determined based on the configuration of the SL-PRS. If the T-WTRU receives the configuration of the SL-PRS dynamically (e.g., via SCI), the T-WTRU may determine that the SL-PRS has a higher priority than other channels. If the T-WTRU receives the configuration of the SL-PRS semi-statically (e.g., via SL-RRC), the T-WTRU may determine that the SL-PRS has a lower priority than other channels.

[0320] The priority level may be determined based on a configured (e.g., pre-configured) priority level. The T-WTRU may receive a configured (e.g., pre-configured) priority level from the network (e.g., gNB and / or LMF), PRU, and / or A-WTRU. The T-WTRU may determine the priority of the SL-PRS compared to other channels based on the list.

[0321] The priority level may be determined based on the QoS of the positioning service. For example, the accuracy and / or latency requirements of the positioning service may be above a threshold (e.g., a threshold configured by the A-WTRU and / or the network). The T-WTRU may then associate the SL-PRS with a higher priority than the data and / or control channels. For example, if the accuracy requirement is 30 cm and the threshold is 1 m, the WTRU may associate the SL-PRS with a high priority. In the same example, if the threshold is 5 cm, the WTRU may associate the SL-PRS with a low priority.

[0322] The priority level may be determined based on the area ID. For example, the WTRU may determine the priority level of the SL-PRS based on the area ID. The WTRU may receive a configuration (e.g., pre-configuration) that associates the area ID and / or the priority level of the SL-PRS. The WTRU may determine the priority level of the SL-PRS based on the area in which the WTRU is located. For example, if a high priority level of the SL-PRS is associated with area 1 in the (pre-) configuration, the WTRU may determine that the WTRU is in area 1 and that the SL-PRS has a higher priority than data or control channels. The WTRU may receive a (pre-) configuration from the A-WTRU and / or the network.

[0323] The priority level may be determined based on the CBR. For example, the WTRU may determine the priority level of the SL-PRS based on the CBR of the resource pool. If the CBR is higher than or equal to a configured (e.g., pre-configured) threshold, the WTRU may determine that the SL-PRS is associated with a low priority. If the CBR is lower than a configured (e.g., pre-configured) threshold, the WTRU may determine that the SL-PRS is associated with a higher priority than other SL-PRS data or control channels.

[0324] In an example, a WTRU (e.g., an A-WTRU) may use an SCI to indicate a prioritization rule (e.g., SL-PRS has a higher priority than data). For example, in a first SCI, the WTRU may transmit a type of positioning request that may include a prioritization rule. The WTRU may use a second SCI to indicate which prioritization rules are activated. For example, there may be three rules where the SL-PRS has the highest priority, the lowest priority, or a higher priority than other channels (e.g., data that does not contain (Ultra-Reliable and Low-Latency Communications) URLLC data). The T-WTRU may determine the priority level associated with the SL-PRS from the second SCI sent by the A-WTRU.

[0325] In an example, the A-WTRU may determine that a list of prioritization rules is included in the first SCI or the second SCI. In an example, the A-WTRU may determine that an activation and / or deactivation message for one of the prioritization rules is included in the SCI after the second SCI.

[0326] The T-WTRU may determine the prioritization rules associated with the SL-PRS from PC5-RRC, SCI, MAC-CE and / or LPP messages. The T-WTRU may determine whether the prioritization rules and / or MG have been configured from the PC5-RRC, SCI, MAC-CE and / or LPP messages.

[0327] In an example, if the T-WTRU is not configured with any prioritization rules, the MG has not received any configuration (e.g., pre-configuration) indicating the priority level of the SL-PRS from other WTRUs (e.g., A-WTRUs) and / or the network, the T-WTRU may determine that the SL-PRS is associated with the lowest priority. If the SL-PRS is associated with the lowest priority and the SL-PRS partially and / or completely overlaps with other channels (e.g., data and / or control SL channels) in the time domain, the T-WTRU may determine to discard the overlapping SL-PRS.

[0328] In an example, the WTRU may determine a receiver for a sidelink measurement report. The WTRU may transmit its measurement report to one or more nodes. For example, the WTRU may transmit its measurement report to the network (e.g., a gNB and / or LMF). For example, for a WTRU assisted positioning method (WTRU-A), the WTRU may determine to report positioning measurement information to the network (e.g., a gNB and / or LMF). For example, the WTRU may determine whether to report positioning measurement information to the network based on whether the output of the positioning procedure is absolute positioning or relative positioning. Specifically, if the output of the positioning procedure is absolute positioning, the WTRU may report positioning measurements to the network. If the output of the positioning procedure is relative positioning, the WTRU may not report positioning measurements to the network.

[0329] The WTRU may transmit its measurement reports to the RSU and / or PRU.

[0330] The WTRU may transmit its measurement reports to the WTRU that performed the positioning request transmission. For example, the A-WTRU may report positioning measurements to the requesting WTRU (eg, T-WTRU).

[0331] The WTRU may transmit its measurement reports to WTRUs within a group under network coverage. For example, a WTRU (e.g., an A-WTRU and / or a T-WTRU) may determine to report positioning measurements to one WTRU within network coverage. In one method, the WTRU within network coverage may be an A-WTRU or a T-WTRU. Additionally or alternatively, the WTRU within network coverage may be another WTRU that may not participate in SL-PRS transmission / reception. The WTRU within network coverage may then relay the positioning report to the network (e.g., a gNB and / or LMF). The WTRU within network coverage may then relay feedback from the network (e.g., the positioning of the WTRU) to the WTRU (e.g., an A-WTRU and / or a T-WTRU).

[0332] A WTRU may transmit its measurement reports to a WTRU-to-network (U2N) and / or WTRU-to-WTRU (U2U) relay. For example, a WTRU (e.g., a T-WTRU or an A-WTRU) may determine to report positioning measurements to a relay WTRU (e.g., a U2N relay or a U2U relay). If the WTRU already has a connection with a relay, the WTRU may report positioning measurements to the relay. The WTRU may trigger a connection establishment to a relay (e.g., a U2N relay) to perform positioning measurement reporting. The WTRU may give priority to U2N relays when performing relay selection (e.g., (re)selection).

[0333] In an example, a WTRU (e.g., a T-WTRU) may collect positioning measurement reports from other WTRUs (e.g., A-WTRUs). The WTRU may then forward the measurement reports to a relay (e.g., a U2N relay). The relay may then determine to forward the report to the network. The relay may then forward the feedback (e.g., the positioning of the WTRU) to the T-WTRU. The T-WTRU may combine the positioning measurements of multiple A-WTRUs to report to the relay.

[0334] In an example, the WTRUs in a group may perform positioning calculations. For example, the WTRU may receive an indication of positioning calculation capabilities from one or more WTRUs in the group. Specifically, one or more WTRUs may indicate that the WTRU supports receiving measurement reports and / or deriving the positioning of other WTRUs. The WTRU may receive these indications during a discovery procedure. The WTRU may then transmit measurement reports to one or more WTRUs in the group to support the WTRU in performing positioning calculations.

[0335] In an example, a WTRU (e.g., an A-WTRU or a T-WTRU) may perform SL-PRS measurement reporting. The SL-PRS measurement reporting parameters may include one or more of the following: a priority of the SL-PRS measurement reporting, a latency of the SL-PRS measurement reporting, a type of positioning measurement reporting, a periodicity of the positioning measurement reporting, a time window of the positioning measurement reporting, a number of SL-PRS measurement resources per measurement reporting, a measurement parameter to be reported, and / or a value range of each reported parameter. Specifically, the value range of the reported parameter may be associated with a maximum error and / or deviation of the measured parameter.

[0336] The WTRU may determine one or any combination of SL-PRS measurement reporting parameters to perform SL-PRS measurement reporting. One or any combination of these parameters may be determined based on one or more of the following: One or more of the SL-PRS measurement reporting parameters may be determined based on an indication from another node (e.g., a T-WTRU, an RSU, a gNB, and / or a PRU, etc.). For example, the WTRU (e.g., an A-WTRU) may indicate the type of measurement report (e.g., whether the measurement report is periodic or aperiodic). The WTRU may perform the request based on the indication. For example, the WTRU may indicate (e.g., by the T-WTRU) the periodicity for performing positioning measurement reporting and / or the minimum number of SL-PRS resources for performing measurements. The WTRU may then determine the periodicity and / or number of SL-PRS resources for performing measurements based on the indication (e.g., from the T-WTRU).

[0337] One or more of the SL-PRS measurement reporting parameters may be based on one or more of the SL-PRS transmission parameters. For example, the WTRU may determine the periodicity of the SL-PRS measurement report based on the periodicity of the SL-PRS transmission. In an example, the WTRU may perform a SL-PRS measurement report for each SL-PRS transmission and / or reception. The periodicity of the SL-PRS measurement report may be equal to the periodicity of the SL-PRS transmission / reception. The WTRU may determine the time gap between the SL-PRS reception and / or transmission and the SL-PRS measurement report based on the processing capability of the WTRU.

[0338] In an example, the WTRU may perform SL-PRS measurement reporting at one or more (e.g., each) of N SL-PRS transmission and / or reception periods. The value of N may be configured (e.g., preconfigured), which may be determined based on the QoS of the positioning service. For example, the WTRU may determine the priority of the SL-PRS measurement reporting based on the priority of the SL-PRS transmission and / or the associated positioning request. Specifically, the priority of the SL-PRS measurement reporting may be equal to the priority of the SL-PRS transmission and / or positioning request message. In an example, the WTRU may determine the priority of the SL-PRS measurement reporting based on the priority indicated in the SCI associated with the SL-PRS received by the WTRU (e.g., the WTRU measures the received SL-PRS and includes the measurement in the measurement report). For example, the WTRU may perform SL-PRS measurement reporting after N measurements of the SL-PRS transmission. The value of N may be configured (e.g., preconfigured). The configured (e.g., preconfigured) value of N may be based on the QoS of the positioning service (e.g., accuracy requirements). For example, the WTRU may perform an SL-PRS positioning measurement report based on the accuracy level of the obtained measurement parameters being greater than a threshold (e.g., the error bound of the measured parameters is less than a threshold, the deviation of the measured parameters is less than a threshold and / or the measured parameters are within an indicated range).

[0339] One or more of the SL-PRS measurement report parameters may be determined based on the QoS requirements of the positioning service. For example, the WTRU may determine the periodicity of the positioning measurement report and / or the number of SL-PRS resources used to perform the measurement based on the QoS of the positioning service. Specifically, for high positioning accuracy requirements, the WTRU may measure more SL-PRS resources to perform the measurement report. However, for low positioning accuracy requirements, the WTRU may measure fewer SL-PRS resources to perform the measurement report. Specifically, for positioning services with strict latency requirements, the WTRU may perform periodic measurement reports with smaller periodicity. For positioning services with large latency delays, the WTRU may perform periodic measurement reports with larger reporting periodicity.

[0340] One or more of the SL-PRS measurement reporting parameters may be determined based on a positioning method.

[0341] One or more of the SL-PRS measurement reporting parameters may be determined based on the CBR of the resource pool.

[0342] One or more of the SL-PRS measurement reporting parameters may be determined based on an output of a positioning procedure (eg, whether the output of the positioning procedure is a relative positioning or an absolute positioning).

[0343] In an example, a WTRU may perform a measurement report to a WTRU, wherein the measurement report may include measurement information used to determine the location of the WTRU. In an example, a WTRU may include measurement reports to multiple WTRUs. The measurement reports may be used to determine the location of multiple WTRUs.

[0344] The WTRU may include one or more of the following information in the positioning measurement report.

[0345] The WTRU may include in the positioning measurement report a set of SL-PRS resources on which the WTRU performed measurements.

[0346] The WTRU may include a set of source WTRU IDs that may send associated SL-PRS signals in the positioning measurement report.

[0347] The WTRU may include positioning measurement values ​​of one or more parameters in the positioning measurement report. The one or more parameters may include RSTD, time gap between PRS transmission and reception, AoA, AoD, ToA, ToD, SL-RSRP, SL-RSSI, LOS / NLOS values, POA, and / or DPOA.

[0348] The WTRU may include error information associated with the reported measurement value. For example, the WTRU may report a measurement parameter (e.g., RSTD). The WTRU may also indicate an error bound associated with the reported parameter (e.g., RSTD). The WTRU may indicate a confidence level associated with the reported parameter (e.g., RSTD).

[0349] The WTRU may include information about the positioning measurement request in the positioning measurement report. The information about the positioning measurement request may trigger the WTRU to perform the positioning measurement report. The information may include one or more of the following: an ID of the request, IDs of the SL-PRS sender WTRU, the reference WTRU, and the reporting WTRU (e.g., L2 source and destination IDs, L2 IDs of the T-WTRU and A-WTRU), resources used for the positioning measurement request (time and frequency information), and / or one or more resources indicated in the positioning measurement request.

[0350] The WTRU may include information about the measured resources in the positioning measurement report. The detected SL-PRS resources and / or resource pairs may include one or more of a reference resource pattern (eg, comb values), a sequence ID, a cyclic shift, and / or a time / frequency resource.

[0351] The WTRU may perform positioning measurement reporting using one or more of SCI, MAC CE, PC5-RRC, and / or NAS messages (eg, LPP). The WTRU may determine which container to perform measurement reporting based on one or more of the following.

[0352] The WTRU may determine which container to perform the measurement reporting based on the receiver of the report. For example, if the receiver of the report is the network (e.g., LMF and / or gNB), the WTRU may use NAS messages. For example, if the receiver of the report is a relay WTRU (e.g., U2N relay or U2U relay) or a T-WTRU, the WTRU may use group PC5-RRC.

[0353] The WTRU may determine which container to perform the measurement reporting based on the reported connection status between the sender and the receiver. For example, if the sender and the receiver have established a PC5-RRC connection, the WTRU may use group PC5-RRC.

[0354] The WTRU may determine which container to perform the measurement reporting based on the type of report. For example, for aperiodic reporting, the WTRU may use access stratum (AS) layer messages (e.g., second SCI, MAC CE, and / or PC5-RRC). For periodic reporting, the WTRU may use non-access stratum (NAS) layer messages (e.g., LPP).

[0355] The WTRU may determine which container to perform the measurement reporting based on a set of parameters to be reported.

[0356] The WTRU may determine which container to perform the measurement reporting based on whether the output is a relative or absolute positioning. For example, the WTRU may determine to use for relative positioning. However, for absolute positioning, the WTRU may use NAS messages.

[0357] The WTRU may determine which container to perform the measurement report based on the amount of data reported. For example, if the number of reported bits is less than a threshold, the WTRU may use a second SCI to perform a positioning measurement report. If the number of bits is less than another threshold, the WTRU may use a MAC CE to perform a positioning measurement report. If the number of bits is less than another threshold, the WTRU may use a PC5-RRC to perform a measurement report. Finally, if the number of reported bits is greater than another threshold, the WTRU may use a NAS message.

[0358] The WTRU may determine which container to perform the measurement reporting based on the broadcast type of the positioning measurement report. For example, if the measurement report is multicast or unicast, the WTRU may use group PC5-RRC and / or group PC5-RRC.

[0359] The WTRU may determine which container to perform the measurement report based on the number of WTRUs involved in the positioning procedure. For example, if the positioning procedure involves two WTRUs (e.g., two WTRUs determine their relative positioning), the WTRU may use SCI, MAC CE and / or PC5-RRC to transmit the positioning measurement report message.

[0360] A WTRU (e.g., A-WTRU) may trigger resource allocation for positioning measurement reporting based on one or more of SL-PRS transmission and / or reception, incremental changes in measurement parameters, and / or measurement reports. When data is available, the WTRU may not have sidelink resources for sending reports within a PDB.

[0361] The WTRU may use one or any combination of the following parameters in the resource allocation procedure: resource allocation resource pool, priority of reporting, delay of reporting, remaining PDB for reporting, number of subchannels to be used for reporting, periodicity of reporting, window for resource allocation (e.g., [n+T1, n+T2]).

[0362] One or more of the parameters used for resource allocation may be determined based on one or more of the following.

[0363] One or more of the parameters used for resource allocation may be determined based on a fixed priority. For example, the WTRU may use a fixed priority (eg, the highest priority) for positioning measurement reports.

[0364] One or more of the parameters for resource allocation may be determined based on a configured (e.g., pre-configured) resource pool. For example, the WTRU may be configured (e.g., pre-configured) with one resource pool for positioning measurement reporting. The WTRU may then perform resource allocation for reporting in the configured (e.g., pre-configured) resource pool.

[0365] One or more of the parameters for resource allocation may be determined based on the QoS of the positioning service. For example, the WTRU may determine a resource selection window [n+T1, n+T2] for measurement reporting based on the latency requirement of the report. The WTRU may determine a resource selection window [n+T1, n+T2] for reporting such that the window is within two or N periodic SL-PRS transmission / reception resources, where N may be configured (e.g., pre-configured) based on the QoS of the positioning service.

[0366] One or more of the parameters for resource allocation may be determined based on an indication from another WTRU. For example, a priority, latency, resource selection window, and / or periodicity of positioning measurement reports for the WTRU may be indicated to a WTRU (e.g., A-WTRU) from another WTRU (e.g., T-WTRU). Such indications may be indicated / negotiated via group PC5-RRC. The WTRU may then use one or more of these parameters to perform resource selection and reservation.

[0367] In an example, a WTRU may determine to send sidelink positioning (e.g., autonomous sidelink positioning) assistance information to another node. The sidelink positioning (e.g., autonomous sidelink positioning) assistance information may include one or more of: synchronization offset and / or error between two WTRUs (e.g., A-WTRU and T-WTRU), panel information of the WTRUs, relative positioning between two panels (e.g., panels on the top and at the bumper of a vehicle), and / or timing error group (TEG) and / or positioning error group (PEG) information associated with each SL-PRS transmission / reception.

[0368] Communication-based sidelink positioning may be performed. One or more of the following may be applied. The WTRU may determine which RS to use for sidelink positioning measurements. For example, the WTRU (e.g., Tx WTRU) may determine to use an RS associated with data communication to determine the positioning of the WTRU. The WTRU may determine which RS in the data transmission of the TB for the Rx WTRU to perform positioning-based measurements (e.g., receive timing, transmit timing, transmit angle, and / or receive, etc.). In an example, the WTRU may use one or more of the following RSs to perform sidelink positioning: DMRS of PSSCH and / or PSCCH, SLSS (S-PSS, S-SSS), PTRS, PSFCH, SL-CSI-RS, and / or (e.g., new) RS embedded in PSCCH / PSSCH. The WTRU may indicate to the RxWTRU which RS will be used for sidelink positioning. The WTRU may use one or more of the following to indicate the RS to be used for sidelink positioning: SCI, MAC CE, and / or PC5-RRC, etc.

[0369] The WTRU may use specific transmissions (e.g., HARQ-enabled transmissions) to perform relative sidelink positioning. In an example, the WTRU may determine the relative positioning between itself and a peer WTRU (e.g., in a unicast link). For example, the WTRU may use HARQ-enabled transmissions to perform relative positioning between two WTRUs. The WTRU may send a HARQ-enabled TB to the Rx WTRU. The Rx WTRU may then send a PSFCH, for example, to provide the HARQ state of the transmission. The Tx WTRU may measure the Tx-Rx between the transmission of the TB and the associated PSFCH to derive the RTT between the two WTRUs.

[0370] Figure 8 An example associated with sidelink positioning 800 using HARQ-enabled transmission is illustrated. Figure 8 As shown, the WTRU may perform transmission of a HARQ-enabled TB 802. The Rx WTRU may transmit a PSFCH 804 in an associated PSFCH opportunity. The time gap between the PSCCH and / or PSSCH 808 and the PSFCH 804 may be determined, for example, according to a specific rule (e.g., a preconfigured mapping rule) between the PSCCH and / or PSSCH 808 and the PSFCH 804. The PSCCH and / or PSSCH 808 may include an SCI 810. The SCI 810 may indicate an associated PSFCH transmission 806 and / or a subsequent PSCCH / PSSCH transmission 812.

[0371] The Tx WTRU may indicate the transmission of the HARQ enabled TB 802 for sidelink positioning. In an example, the Tx WTRU may indicate to the Rx WRTU that one or more transmissions of the HARQ enabled TB 802 are to be used for sidelink positioning. The Tx WTRU may use the SCI 810 to indicate that the HARQ enabled transmissions are to be used for sidelink positioning. In an example, the WTRU may use one or more reserved bits in the first SCI 810 to indicate that the HARQ enabled transmissions are to be used for sidelink positioning (e.g., where the reserved bits are toggled (e.g., toggled to be equal to 1)) to indicate that they are to be used for sidelink positioning.

[0372] The Rx WTRU may use the timing of the Tx WTRU as a reference for sending the PSFCH 804. For example, upon receiving a transmission requesting sidelink positioning, the Rx WTRU may determine the send timing of the PSFCH 804 based on the receive timing of the transmission requesting HARQ feedback.

[0373] The WTRU may determine the number of transmissions of the TB 802. For example, the WTRU (e.g., Tx WTRU) may determine the number of transmissions of one or more TBs 802 for sidelink positioning based on the QoS requirements (e.g., accuracy and / or latency requirements) of the sidelink positioning service. In some implementations, the WTRU may be configured (e.g., pre-configured) with a range of the number of transmissions of one or more TBs 802 for the sidelink positioning service within an observation period (e.g., a maximum number of transmissions and / or a minimum number of transmissions). For example, based on the accuracy requirements of the sidelink positioning service. The WTRU may determine that the number of transmissions of the TB 802 is within the configured (e.g., pre-configured) range.

[0374] The WTRU may perform transmission of multiple TBs 802 for a sidelink positioning service. In an example, the WTRU (e.g., TxWTRU) may perform transmission of multiple TBs 802 within an observation period for sidelink positioning. For example, based on the QoS of the TBs 802, the WTRU may be configured (e.g., pre-configured) with a (e.g., maximum) number of transmissions of each TB 802.

[0375] The Tx WTRU may indicate the number of retransmissions for TB 802 to measure the RTT between two WTRUs. A WTRU (e.g., a Tx WTRU) may indicate the number of HARQ-enabled transmissions of TB 802 for sidelink positioning. The WTRU may perform the indicated number of transmissions of TB 802 without considering the HARQ feedback of TB 802. The WTRU may determine whether to perform further transmissions of TB 802 based on the HARQ feedback status of TB 802. For example, if the WTRU receives ACK feedback, the WTRU may not perform further transmissions of TB 802. If the WTRU does not receive ACK feedback, receives NACK and / or detects discontinuous transmission (DTX), the WTRU may perform further transmissions of TB 802.

[0376] The WTRU may determine whether to perform a retransmission of the TB 802. One or more of the following may apply. For example, the WTRU (e.g., the Tx WTRU) may determine whether to perform a retransmission of the TB 802 based on the HARQ feedback status from the Rx WTRU and / or the number of transmissions that the WTRU has performed for the TB 802. If the WTRU receives ACK feedback from the Rx WTRU and the number of transmissions of the TB 802 is not within the range of the number of transmissions configured (e.g., preconfigured) for the sidelink positioning, the WTRU may perform a retransmission. Additionally or alternatively, if the WTRU receives NACK feedback and if the number of transmissions of the TB 802 is within the range of the number of transmissions configured (e.g., preconfigured) for the sidelink positioning, the WTRU may perform a retransmission.

[0377] The WTRU may determine whether to perform a PSFCH 804 transmission to feedback the HARQ status of the TB 802. The WTRU (e.g., the RxWTRU) may determine whether to perform a PSFCH 804 transmission to feedback the HARQ status of the TB 802, for example, based on the number of TBs 802 that the WTRU has received for sidelink positioning. In an example, if the number of transmissions of the TB 802 that the WTRU has received is less than a configured (e.g., preconfigured) number of transmissions (e.g., a minimum number of transmissions), the WTRU may perform HARQ feedback to the Tx WTRU. In an example, if the WTRU has sent an ACK to the Tx WTRU in a previous feedback of the TB 802, the WTRU may feedback an ACK.

[0378] The WTRU may determine whether to report ACK / NACK. One or more of the following may apply. The WTRU (e.g., RxWTRU) may determine to report ACK / NACK, for example, based on whether the WTRU desires to perform additional transmissions for sidelink positioning. In an example, the WTRU may feedback ACK to indicate that the WTRU does not need more resources for sidelink positioning.

[0379] Additionally or alternatively, the WTRU may feedback a NACK to indicate that the WTRU needs more resources for sidelink positioning. For example, the WTRU may determine whether the WTRU needs to transmit more for sidelink positioning based on one or more of a timing offset (e.g., a timing offset between the PSFCH 804 transmit timing and the TB receive timing) and / or a Tx-Rx time difference (e.g., the WTRU determines that the Tx-Rx difference is within a bounded error).

[0380] The WTRU may determine the RTT between Tx and Rx. In an example, a WTRU (e.g., a Tx WTRU) may determine the RTT between Tx and Rx based on a Tx-Rx difference timing. For example, a Tx-Rx difference timing (e.g., a Tx-Rx timing difference between a transmit timing of TB 802 and a receive timing of PSFCH) may be determined / measured at the Tx WTRU. Additionally or alternatively, the WTRU may determine the RTT between Tx and Rx based on a Tx-Rx difference determined and / or measured at the Rx WTRU (e.g., a Tx-Rx timing difference between a receive timing of TB 802 and a transmit timing of PSFCH 804). For example, the Tx-Rx timing difference at the WTRU may be determined based on one or more of a report and / or mapping (e.g., an implicit mapping between PSCCH / PSSCH resources 808 and PSFCH 804 feedback) from the Rx WTRU.

[0381] The WTRU may filter and / or average the RTT of one or more transmissions for positioning. In an example, a WTRU (e.g., a Tx WTRU and / or an Rx WTRU) may perform measurements (e.g., RTT) for sidelink positioning. In an example, the WTRU may average / filter the Tx-Rx difference of one or more pairs of transmissions and corresponding HARQ feedback. The WTRU may report the filtered sidelink positioning measurement results (e.g., the filtered Tx-Rx difference).

[0382] The Rx WTRU may send assistance information to the Tx WTRU. In an example, a WRTU (e.g., an Rx WTRU) may trigger the sending of assistance information to the Tx WTRU (e.g., for use in a HARQ-enabled based positioning technique). For example, the WTRU may trigger the sending of assistance information based on several factors. For example, the WTRU may trigger the sending of assistance information based on the receipt of one or more HARQ-enabled transmissions (e.g., indicating that sidelink positioning is enabled). In an example, the WTRU may trigger the sending of assistance information based on the transmission of PSFCH 804 (e.g., to feedback the transmission for sidelink positioning).

[0383] The Rx WTRU may send one or more forms of assistance information to the Tx WTRU (e.g., to support the WTRU's position determination). The assistance information may include an offset (e.g., an offset between a slot boundary of the Rx WTRU and a reception time of a transmission from the Tx WTRU), a timing difference (e.g., a Tx-Rx timing difference between the reception timing of the TB 802 and the transmission timing of the PSFCH 804 to feed back TEG and / or PEG information of the TB 802 associated with the reception), and / or an absolute position of the Rx WTRU.

[0384] A WTRU (eg, an Rx WTRU) may send assistance information to another WTRU (eg, a Tx WTRU) using the SCI 810, MAC CE, and / or PC5-RRC.

[0385] In an example, when a WTRU (eg, an Rx WTRU) uses the SCI 810 to send assistance information to another WTRU (eg, a Tx WTRU), the WTRU may use a second SCI to send the assistance information.

[0386] In an example, when a WTRU (e.g., an Rx WTRU) uses MAC CE to send assistance information to another WTRU (e.g., a Tx WTRU), several factors may apply. For example, the WTRU may use MAC CE to send the Tx-Rx timing difference between the receive timing of the TB 802 and the transmit timing fed back by the PSFCH 804. For example, the WTRU may use MAC CE to send the offset (e.g., between the slot boundary of the Rx WTRU and the receive timing of the transmission from the Tx WTRU).

[0387] In an example, when a WTRU (e.g., an Rx WTRU) uses PC5-RRC to send assistance information to another WTRU (e.g., a Tx WTRU), several factors may apply. For example, the WTRU may use PC5-RRC to send one or more (e.g., semi-static) assistance information. In an example, the WTRU may use PC5-RRC to send TEG and / or PEG information associated with reception. For example, the WTRU may use PC5-RRC to send the location (e.g., absolute location) of the Rx WTRU.

[0388] The WTRU may use ACK / NACK based multicast to determine the location of the WTRU group (e.g., relative location to each WTRU in the group). In an example, the WTRU may determine its relative location to the WTRU group (e.g., relative location to each WTRU in the WTRU group). For example, the WTRU may use multicast option 2 HARQ enabled transmission (e.g., ACK / NACK based multicast) to determine the relative location to the WTRU group. The Tx WTRU may send a multicast option 2 HARQ enabled TB 802 to the WTRU group. The Rx WTRU may send a PSFCH 804 to feedback the HARQ status of the transmission. The Tx WTRU may measure the Tx-Rx between the transmission of the TB 802 and the associated PSFCH 804 of each WTRU, for example, to derive the RTT between the WTRU and each Rx WTRU.

[0389] Fig. 9 An example associated with sidelink positioning of HARQ-enabled transmissions using multicast option 2 is illustrated. Fig. 9As shown, the WTRU may perform multicast option 2 transmission of HARQ-enabled TBs 902. Each Rx WTRU may transmit a PSFCH 904 in an associated PSFCH opportunity, for example, based on its member WTRU ID. The time gap between the PSCCH / PSSCH transmission 908 and the PSFCH 906 may be determined according to a mapping rule (e.g., a preconfigured mapping rule between the PSCCH / PSSCH transmission 908 and the PSFCH 906). The PSCCH / PSSCH transmission 908 is an SCI 910.

[0390] The WTRU may determine whether to perform HARQ-based sidelink positioning. In an example, the WTRU may determine whether to use HARQ-based sidelink positioning (e.g., using HARQ-enabled transmissions and associated PSFCH 904 to determine the positioning of the WTRU) to determine (e.g., for unicast and / or multicast option 2) relative positioning between two or more WTRUs. The WTRU may determine the relative positioning between two or more WTRUs based on the QoS of the positioning service (e.g., latency and / or accuracy requirements). In an example, for lower accuracy positioning requirements, the WTRU may use HARQ-based sidelink positioning. If, for example, the positioning service uses higher accuracy positioning, the WTRU may use another suitable method, such as a dedicated SL-PRS-based method for sidelink positioning.

[0391] A WTRU (eg, an A-WTRU) may use one or more measurement parameters received from another WTRU (eg, a T-WTRU) to determine whether to perform a request from another WTRU. The request may be a send request, a receive request, and / or a measurement report request.

[0392] In an example, a WTRU (e.g., an A-WTRU) may determine whether to participate in a positioning procedure (e.g., an autonomous positioning procedure). For example, upon receiving one or more positioning requests (e.g., one or more positioning request messages) from another WTRU (e.g., a T-WTRU), the WTRU may determine whether to participate in a positioning procedure. Specifically, upon receiving a sidelink positioning (e.g., autonomous sidelink positioning) request from another WTRU (e.g., a T-WTRU), the A-WTRU may determine the type of request (e.g., whether the request requires the WTRU to perform ACK / NACK feedback to the request, perform SL-PRS transmission / reception and / or measurement reporting). The WTRU may then determine whether to participate in the positioning procedure based on the conditions indicated in the positioning request message. The WTRU may then determine whether the WTRU satisfies the indicated conditions. If the WTRU satisfies the indicated conditions, the WTRU may perform the request using the parameters indicated in the request.

[0393] The WTRU may receive a positioning request message (e.g., an L2 ID of a positioning service) from another node (e.g., a T-WTRU). The positioning request message may indicate a type of positioning request (e.g., indicated in an SCI of the request). The type of positioning request may include one or more of performing SL-PRS reception, performing SL-PRS transmission, performing SL-PRS transmission and reception, and / or performing positioning measurement reporting.

[0394] The positioning request message may indicate a range of one or more parameters (eg, distance, SL-RSRP, AoD, LOS / NLOS, and / or area ID set). In an example, the second SCI may indicate a positioning request message.

[0395] The positioning request message may indicate one or more parameters for SL-PRS transmission and / or reception and / or measurement reporting. The one or more parameters for SL-PRS transmission and / or reception and / or measurement reporting may include priority, latency and / or periodicity of the SL-PRS and / or measurement reporting.

[0396] The WTRU may measure and / or calculate one or more of the parameters indicated in the request message. The WTRU may determine whether to perform the associated request based on whether the measured parameters are within the indicated range. If the measured and / or calculated parameters are within the indicated range, the WTRU may use the parameters indicated in the positioning request message to perform resource allocation for SL-PRS transmission and / or reception and / or measurement reporting. If the request requires the WTRU to perform SL-PRS reception, the WTRU may perform SL-PRS reception in the resources indicated in the request message. If the request requires the WTRU to perform SL-PRS transmission, the WTRU may use the selected resources to perform SL-PRS transmission. If the request requires the WTRU to perform measurement reporting, the WTRU may use the selected resources to perform positioning measurement reporting. The WTRU may use the priority and / or MG indicated in the SCI 910 to perform SL-PRS reception and / or priority division.

[0397] Fig.10An example signal flow for an out of coverage RTT method 1000 is depicted. The out of coverage RTT method 1000 may be based on positioning. At 1004, the target WTRU 1002 may determine (e.g., via unicast) to establish a PC5-RRC connection with the anchor WTRU 1008. At 1006, the target WTRU 1002 may receive a positioning request from the anchor WTRU 1008. For example, at 1006, the target WTRU 1002 may receive the positioning request via an LPP message and / or a PC5-RRC message. Additionally or alternatively, the target WTRU 1002 may transmit a positioning request to the anchor WTRU 1008 (e.g., via LPP or PC5-RRC).

[0398] If the target WTRU 1002 determines to use the anchor WTRU 1008 as a synchronization source, the target WTRU 1002 may transmit a request to transmit a synchronization signal to the anchor WTRU 1008. At 1010, the target WTRU 1002 may receive a synchronization signal from the anchor WTRU 1008.

[0399] At 1012, based on the quality of the received RS and / or synchronization signal (e.g., RSRP above a preconfigured threshold), the target WTRU 1002 may determine whether the anchor WTRU 1008 may become the transmitter of the SL-PRS. At 1014, the anchor WTRU 1008 may perform a resource allocation procedure (e.g., using Mode 2 resource selection / allocation).

[0400] At 1016, the target WTRU 1002 may receive the SCI and / or associated SL-PRS from the anchor WTRU 1008. The SCI may indicate the location of the SL-PRS. Prior to receiving the SL-PRS, the target WTRU 1002 may receive one or more SL-PRS configurations (e.g., SL-PRS density in the time domain and / or frequency domain) from the anchor WTRU 1008, for example, in an LPP message and / or a PC5-RRC message.

[0401] At 1018, the target WTRU 1002 may receive a second SCI and / or MAC-CE from the anchor WTRU 1008. The second SCI and / or MAC-CE may indicate one or more SL-PRS resources (e.g., the location of the SL-PRS in time and / or frequency resources) and / or a PRS configuration that the target WTRU 1002 should use for its transmission of the SL-PRS.

[0402] The target WTRU 1002 may receive the SL-PRS sent from the anchor WTRU 1008. The target WTRU 1002 may perform one or more measurements on the SL-PRS at 1020 and / or select other available resources at 1022.

[0403] At 1024, the target WTRU 1002 may send a SL-PRS to the anchor WTRU 1008 based on the indicated resources and / or SL-PRS configuration. In an example, the target WTRU 1002 may determine the resources and / or SL-PRS configuration based on measurements (e.g., RSRP) of the SL-PRS sent from the anchor WTRU at 1024.

[0404] At 1026, the target WTRU 1002 may transmit the Tx-Rx time difference of the target WTRU 1102 to the anchor WTRU 1008. The Tx-Rx time difference of the target WTRU 1102 may be the difference between the transmit time of the SL-PRS (e.g., sent from the target WTRU at 1024) and the receive time of the SL-PRS sent from the anchor WTRU 1008 at 1016.

[0405] At 1028, the anchor WTRU 1008 may perform one or more measurements on the SL-PRS sent from the target WTRU 1002 at 1024. At 1030, the anchor WTRU 1008 may determine a relative location and / or an absolute location of the target WTRU 1002. The anchor WTRU 1008 may express the relative position of the target WTRU 1002 with respect to the anchor WTRU 1008.

[0406] At 1032, the anchor WTRU 1008 may transmit location information (e.g., relative location and / or absolute location of the target WTRU) to the LMF 1034. In an example, the anchor WTRU 1008 may transmit the location information if the anchor WTRU 1008 is within or enters coverage of the network. In an example, if the target WTRU 1002 transmits a request to the anchor WTRU 1008 to obtain location information, the anchor WTRU 1008 may transmit the location information to the target WTRU 1002 after determining the location of the target WTRU 1002.

[0407] Fig.11An example RTT positioning method 1100 for an out of coverage state is depicted, wherein a target WTRU 1102 performs a Mode 2 resource allocation. At 1104, the target WTRU 1102 may determine (e.g., via unicast) to establish a PC5-RRC connection with an anchor WTRU. At 1106, the target WTRU 1102 may receive a positioning request from an anchor WTRU 1108. For example, at 1106, the target WTRU 1102 may receive the positioning request via an LPP message and / or a PC5-RRC message. Additionally or alternatively, the target WTRU 1102 may transmit the positioning request to the anchor WTRU 1108 (e.g., via LPP or PC5-RRC).

[0408] At 1110, based on the quality of the received RS (e.g., RSRP above a preconfigured threshold), the target WTRU 1102 may determine whether the anchor WTRU 1108 may become a transmitter of the SL-PRS. At 1112, the target WTRU 1102 may receive assistance information (e.g., SL-PRS configuration information for the anchor WTRU 1108) from the anchor WTRU 1108. At 1114, the anchor WTRU 1108 may perform a resource allocation procedure (e.g., using Mode 2 resource selection / allocation).

[0409] like Fig.11 As illustrated, the target WTRU 1102 may not receive a second SCI or MAC-CE from the anchor WTRU 1108. At 1114, the target WTRU 1102 may perform a resource allocation procedure to find available resources for transmission of the SL-PRS (e.g., using Mode 2 resource selection / allocation). When the target WTRU 1102 transmits the SL-PRS, the target WTRU 1102 may send the SCI to the anchor WTRU 1108. For example, when the target WTRU 1102 transmits the SCI, the anchor WTRU 1108 may find resources in which the SL-PRS has been allocated. The target WTRU 1102 may transmit the PRS configuration information to the anchor WTRU 1108.

[0410] At 1116, the target WTRU 1102 may receive the SCI and / or associated SL-PRS from the anchor WTRU 1108. The SCI may indicate the location of the SL-PRS. Prior to receiving the SL-PRS, the target WTRU 1102 may receive one or more SL-PRS configurations (e.g., SL-PRS density in the time domain and / or frequency domain) from the anchor WTRU 1108, for example, in an LPP message and / or a PC5-RRC message.

[0411] At 1116, the target WTRU 1102 may receive the SL-PRS sent from the anchor WTRU 1108. At 1118, the target WTRU 1102 may perform one or more measurements on the SL-PRS. At 1120, the anchor WTRU 1108 may receive assistance information (e.g., SL-PRS configuration information for the target WTRU 1102) from the target WTRU 1102. At 1122, the anchor WTRU 1108 may perform a resource allocation procedure (e.g., using Mode 2 resource selection / allocation).

[0412] At 1124, the target WTRU 1102 may send a SL-PRS based on the indicated resources and / or SL-PRS configuration to the anchor WTRU 1108. In an example, the target WTRU 1112 may determine the resources and / or SL-PRS configuration based on measurements (e.g., RSRP) of the SL-PRS sent from the anchor WTRU 1108.

[0413] At 1126, the target WTRU 1102 may transmit the Tx-Rx time difference of the target WTRU 1102 to the anchor WTRU 1108. The Tx-Rx time difference of the target WTRU 1102 is equal to the difference between the transmission time of the SL-PRS (e.g., from the target WTRU) and the reception time of the SL-PRS sent from the anchor WTRU 1108.

[0414] At 1128, the anchor WTRU 1108 may determine a relative location and / or an absolute location of the target WTRU 1102. The anchor WTRU 1108 may express the relative position of the target WTRU 1102 with respect to the anchor WTRU 1108.

[0415] At 1130, the anchor WTRU 1108 may transmit location information (e.g., relative location and / or absolute location of the target WTRU) to the LMF 1132. In an example, the anchor WTRU 1108 may transmit the location information if the anchor WTRU 1108 is within or enters coverage of the network. In an example, if the target WTRU 1102 transmits a request to the anchor WTRU 1108 to obtain location information, the anchor WTRU 1108 may transmit the location information to the target WTRU 1102 after determining the location of the target WTRU 1102.

[0416] Fig.12An example one-sided positioning method 1200 for an out-of-coverage state is depicted. At 1204, the target WTRU 1202 may determine (e.g., via unicast) to establish a PC5-RRC connection with the anchor WTRU 1208. At 1206, the target WTRU 1202 may transmit a positioning request to the anchor WTRU 1208 via an LPP message and / or a PC5-RRC message. Additionally or alternatively, the target WTRU 1202 may receive a positioning request from the anchor WTRU 1208 (e.g., via LPP or PC5-RRC).

[0417] If the target WTRU 1202 determines to use the anchor WTRU 1208 as a synchronization source, the target WTRU 1202 may transmit a request to the anchor WTRU to transmit a synchronization signal. The target WTRU 1202 may receive the synchronization signal from the anchor WTRU 1208.

[0418] At 1210, based on the quality of the received RS and / or synchronization signal (e.g., RSRP above a preconfigured threshold), the target WTRU 1202 may determine whether the anchor WTRU 1208 may become a transmitter of the SL-PRS. At 1212, the anchor WTRU 1208 may transmit assistance information (e.g., SL-PRS configuration information for the anchor WTRU 1208) to the target WTRU 1202 via an LPP message and / or a PC5-RRC message. Additionally or alternatively, the anchor WTRU 1208 may receive a positioning request from the target WTRU 1202 (e.g., via LPP or PC5-RRC). At 1214, the anchor WTRU 1202 may perform a resource allocation procedure (e.g., a Mode 2 resource allocation procedure).

[0419] In an example, at 1216, the target WTRU 1202 may receive an SCI and an associated SL-PRS from the anchor WTRU 1208, e.g., where the SCI indicates a location of the SL-PRS. Prior to receiving the SL-PRS, the target WTRU 1202 may receive one or more SL-PRS configurations (e.g., SL-PRS density in the time domain and / or frequency domain) from the anchor WTRU 1208 in an LPP message. In an example, the target WTRU 1202 may receive a timestamp indicating a transmission time of the PRS from the anchor WTRU 1208. The target WTRU 1202 may determine a distance between the target WTRU 1202 and the anchor WTRU 1208, e.g., based on the timestamp. The target WTRU 1202 may receive the timestamp when (e.g., only when) the target WTRU 1202 uses the anchor WTRU 1208 as a synchronization signal.

[0420] The target WTRU 1202 may receive a second SCI and / or MAC-CE from the anchor WTRU 1208. The second SCI and / or MAC-CE may indicate one or more SL-PRS resources (e.g., the location of the SL-PRS in time and / or frequency resources) and / or one or more PRS configurations that the target WTRU 1202 should use for its transmission of the SL-PRS.

[0421] In an example, at 1216, the target WTRU 1202 may receive the SL-PRS sent from the anchor WTRU 1208. At 1218, the target WTRU 1202 may perform one or more measurements on the SL-PRS (e.g., RSRP, AoA, and / or RSTD if there are more than one anchor WTRU 1208). In an example, if the target WTRU 1202 receives a positioning request from the anchor WTRU 1208, the target WTRU 1202 may transmit the measurement results to the anchor WTRU 1208. In an example, at 1220, if the target WTRU 1202 receives a positioning request from the anchor WTRU 1208, the anchor WTRU 1208 may determine the relative position and / or absolute position of the target WTRU 1202. At 1220, the target WTRU 1202 may determine its relative position with respect to the anchor WTRU 1208.

[0422] Fig.13 An example dual-sided RTT positioning method 1300 for an out-of-coverage state is depicted. An anchor WTRU 1308 may send two or more SL-PRSs (e.g., a first SL-PRS and a second SL-PRS) to a target WTRU 1302. In an example, the anchor WTRU 1308 may send more than one SL-PRS via different resources. The target WTRU 1302 may transmit one or more SL-PRSs to the anchor WTRU 1308.

[0423] In the examples described herein, the target WTRU 1302 may receive a configuration and / or indication of a time and / or frequency resource for the target WTRU 1302 to transmit a measurement report. The measurement report may include a target Rx-Tx time difference. The measurement report transmitted by the target WTRU 1302 may include the Rx-Tx time, the RSRP for each SL-PRS resource, the AoA of the arrival time of each SL-PRS resource, and / or the AoD of the SL-PRS resource.

[0424] At 1304, the target WTRU 1302 may determine (e.g., via unicast) to establish a PC5-RRC connection with the anchor WTRU 1308. At 1306, the target WTRU 1302 may receive a positioning request via an LPP message and / or a PC5-RRC message from the anchor WTRU 1308. Additionally or alternatively, the target WTRU 1302 may transmit a positioning request to the anchor WTRU 1308.

[0425] If the target WTRU 1302 determines to use the anchor WTRU 1308 as a synchronization source, the target WTRU 1302 may transmit a request to the anchor WTRU 1308 to transmit a synchronization signal. At 1310, the target WTRU 1302 may receive the synchronization signal from the anchor WTRU 1308. At 1312, based on the quality of the received RS and / or synchronization signal (e.g., RSRP above a preconfigured threshold), the target WTRU 1302 may determine whether the anchor WTRU 1308 may become a transmitter of the SL-PRS. At 1314, the anchor WTRU 1308 may perform a resource allocation procedure (e.g., using Mode 2 resource selection / allocation).

[0426] At 1316, the target WTRU 1302 may receive the SCI and / or associated SL-PRS from the anchor WTRU 1308. The SCI may indicate the location of the first SL-PRS. Prior to receiving the SL-PRS, the target WTRU 1302 may receive one or more SL-PRS configurations (e.g., SL-PRS density in the time / frequency domain) from the anchor WTRU 1308, for example, in an LPP message. The SCI may include time and / or frequency resources of the second SL-PRS.

[0427] At 1318, the target WTRU 1302 may receive a second SCI or MAC-CE indicating one or more SL-PRS resources (e.g., locations of the SL-PRS in time and / or frequency resources) and / or one or more PRS configurations from the anchor WTRU 1308. The target WTRU 1302 may use the second SCI or MAC-CE for transmitting the SL-PRS of the target WTRU 1302. The second SCI or MAC-CE may include time and / or frequency resources of the second SL-PRS to be transmitted by the anchor WTRU 1308.

[0428] At 1320, the target WTRU 1302 may receive a first SL-PRS sent from the anchor WTRU 1308. The target WTRU 1302 may perform one or more measurements on the first SL-PRS. At 1322, the target WTRU 1302 may determine resources and / or SL-PRS configuration based on measurements (e.g., such as RSRP) of the SL-PRS sent from the anchor WTRU 1308. At 1324, the target WTRU 1302 may send the SL-PRS to the anchor WTRU 1308 based on the indicated resources and / or SL-PRS configuration.

[0429] At 1326, the target WTRU 1302 may transmit the Tx-Rx time difference of the target WTRU 1302 to the anchor WTRU 1308. The Tx-Rx time difference of the target WTRU 1302 may be the difference between the transmission time of the SL-PRS (e.g., from the target WTRU 1302) and the reception time of the SL-PRS sent from the anchor WTRU 1308. At 1328, the target WTRU 1302 may perform one or more measurements on the SL-PRS and / or select other available resources. At 1330, the anchor WTRU 1308 may perform a resource allocation procedure (e.g., using Mode 2 resource selection / allocation).

[0430] In an example, at 1326, the target WTRU 1302 may receive the SCI and / or associated SL-PRS from the anchor WTRU 1308. The SCI may indicate the location of the second SL-PRS. In an example, as described herein, the anchor WTRU 1308 may not include the SCI if the time and / or frequency location of the second SL-PRS has been transmitted to the target WTRU.

[0431] At 1332, the target WTRU 1302 may receive a second SL-PRS from the anchor WTRU 1308. At 1334, the target WTRU 1302 may receive a first SL-PRS sent from the anchor WTRU 1308. The target WTRU 1302 may perform one or more measurements on the first SL-PRS. At 1336, the target WTRU 1302 may determine resources and / or SL-PRS configuration based on measurements (e.g., such as RSRP) of the SL-PRS sent from the anchor WTRU 1308.

[0432] At 1338 , the target WTRU 1302 may transmit a measurement report including an Rx-Tx time difference of the target WTRU 1302 , which is the difference between the arrival time of the second PRS and the transmission time of the SL-PRS from the target WTRU 1302 .

[0433] At 1340, the anchor WTRU 1308 may determine, based on the measurements, a relative location and / or an absolute location of the target WTRU 1302. At 1342, the anchor WTRU 1308 may transmit location information (e.g., a relative location and / or an absolute location) related to the target WTRU 1302 to the LMF 1344 if certain factors are satisfied. These factors include whether the anchor WTRU 1308 is within the coverage of the network and / or enters the coverage of the network, and / or whether the anchor WTRU 1308 has received a request from the network to report the location of the target WTRU 1302.

[0434] Fig.14 A flowchart 1400 is depicted describing the operation of an A-WTRU upon receiving a SL-PRS. At 1402, an anchor A-WTRU (e.g., such as Figure 3 The anchor WTRU 306 is shown. Figure 5 The anchor WTRU 508 is shown. Fig.10 The anchor WTRU 1008 is shown. Fig.11 The anchor WTRU 1108 is shown. Fig.12 The anchor WTRU 1208 and / or Fig.13 The anchor WTRU 1308 is shown to receive the SL-PRS from the T-WTRU. The SL-PRS includes a request for the A-WTRU to perform SL-PRS Rx and / or Tx, parameters for SL-RSRP and / or LOS / NLOS thresholds, resources for SL-PRS Rx, and / or a window for SL-PRS Tx.

[0435] At 1404, the A-WTRU may measure the SL-RSRP. At 1404, the A-WTRU may determine the LOS / NLOS associated with the sidelink request message. At 1406, if the SL-RSRP and the LOS / NLOS are greater than their respective thresholds, the A-WTRU may perform SL-PRS reception. At 1408, if the SL-RSRP and the LOS / NLOS are not greater than their respective thresholds, the A-WTRU may not perform SL-PRS reception, and the A-WTRU may continue to measure the SL-RSRP and the LOS / NLOS.

[0436] At 1410, the A-WTRU may perform SL-PRS Rx in the indicated resources. At 1410, the A-WTRU may perform SL-PRS Tx in the indicated window.

Claims

1. A wireless transmit / receive unit (WTRU), the wireless transmit / receive unit (WTRU) comprising: A processor and a memory, wherein the processor and the memory are configured to: receiving configuration information indicating a first resource pool, a second resource pool, and information associated with one or more sidelink positioning reference signals (SL-PRSs), wherein the information associated with the one or more SL-PRSs includes an indication of an identification (ID) associated with the one or more SL-PRSs, wherein the one or more SL-PRSs are associated with the first resource pool or the second resource pool, wherein the first resource pool allows multiplexing of the SL-PRSs with sidelink data, and wherein the second resource pool does not allow multiplexing of the SL-PRSs with sidelink data; receiving side link control information (SCI), wherein the SCI includes an indication to receive one or more SL-PRS via resources associated with the first resource pool or via resources associated with the second resource pool; and wherein the SCI includes an indication that the transmission via the resources associated with the first resource pool includes one or more SL-PRSs, an indication of an ID associated with the one or more SL-PRSs, and a priority associated with the one or more SL-PRSs; and wherein the SCI comprises a broadcast type associated with the one or more SL-PRSs, an indication of the IDs of the one or more SL-PRSs, and a priority associated with the one or more SL-PRSs; The one or more SL-PRSs indicated by the SCI are received via resources associated with the first resource pool or via resources associated with the second resource pool.

2. The WTRU of claim 1 , wherein the information associated with the one or more SL-PRSs comprises a pattern associated with the one or more SL-PRSs.

3. The WTRU of claim 1 , wherein the information associated with the one or more SL-PRSs comprises time and frequency resources associated with the transmission of the one or more SL-PRSs.

4. The WTRU of claim 1, wherein the information associated with the one or more SL-PRSs comprises a SL-PRS resource element offset, a SL-PRS symbol offset, or a number of SL-PRS symbols.

5. The WTRU of claim 1 , wherein the broadcast type is one of unicast, multicast, or broadcast.

6. The WTRU of claim 1, wherein the SCI further comprises a bit field for indicating the availability of the one or more SL-PRSs.

7. The WTRU of claim 1 , wherein the processor and the memory are configured to: Transmitting measurement results associated with the one or more SL-PRSs.

8. The WTRU of claim 1 , wherein the processor and the memory are configured to: A transmission associated with the first resource pool or the second resource pool is decoded according to the SCI.

9. The WTRU of claim 1 , wherein the processor and the memory are configured to: receiving, via the resources associated with the first resource pool, the SCI associated with the one or more SL-PRSs; and The one or more SL-PRSs are received via the resources associated with the first resource pool.

10. The WTRU of claim 1 , wherein the processor and the memory are configured to: receiving, via the resources associated with the second resource pool, the SCI associated with the one or more SL-PRSs; and The one or more SL-PRSs are received via the resources associated with the second resource pool.

11. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: receiving configuration information indicating a first resource pool, a second resource pool, and information associated with one or more sidelink positioning reference signals (SL-PRSs), wherein the information associated with the one or more SL-PRSs includes an indication of an identification (ID) associated with the one or more SL-PRSs, wherein the one or more SL-PRSs are associated with the first resource pool or the second resource pool, wherein the first resource pool allows multiplexing of the SL-PRSs with sidelink data, and wherein the second resource pool does not allow multiplexing of the SL-PRSs with sidelink data; receiving side link control information (SCI), wherein the SCI includes an indication to receive one or more SL-PRS via resources associated with the first resource pool or via resources associated with the second resource pool; and wherein the SCI includes an indication that the transmission via the resources associated with the first resource pool includes one or more SL-PRSs, an indication of an ID associated with the one or more SL-PRSs, and a priority associated with the one or more SL-PRSs; and wherein the SCI comprises a broadcast type associated with the one or more SL-PRSs, an indication of the IDs of the one or more SL-PRSs, and a priority associated with the one or more SL-PRSs; The one or more SL-PRSs indicated by the SCI are received via resources associated with the first resource pool or via resources associated with the second resource pool.

12. The method of claim 11, wherein the information associated with the one or more SL-PRSs comprises a pattern associated with the one or more SL-PRSs.

13. The method of claim 11, wherein the information associated with the one or more SL-PRSs comprises time and frequency resources associated with transmission of the one or more SL-PRSs.

14. The method of claim 11, wherein the information associated with the one or more SL-PRSs comprises a SL-PRS resource element offset, a SL-PRS symbol offset, or a number of SL-PRS symbols.

15. The method of claim 11, wherein the broadcast type is one of unicast, multicast, or broadcast.

16. The method of claim 11, wherein the SCI further comprises a bit field for indicating availability of the one or more SL-PRSs.

17. The method according to claim 11, further comprising: Transmitting measurement results associated with the one or more SL-PRSs.

18. The method according to claim 11, further comprising: A transmission associated with the first resource pool or the second resource pool is decoded according to the SCI.

19. The method according to claim 11, further comprising: receiving, via the resources associated with the first resource pool, the SCI associated with the one or more SL-PRSs; as well as The one or more SL-PRSs are received via the resources associated with the first resource pool.

20. The method according to claim 11, further comprising: receiving, via the resources associated with the second resource pool, the SCI associated with the one or more SL-PRSs; as well as The one or more SL-PRSs are received via the resources associated with the second resource pool.

Images