Method for SL positioning with multiple reference WTRUs

Abstract

Procedures are provided for how a target WTRU and an LMF negotiate supported WTRU-initiated positioning methods, and how a target WTRU detects a reference WTRU for SL positioning and performs appropriate SL positioning using multiple reference WTRUs. Procedures are provided for how to perform SL positioning between a target WTRU and a reference WTRU in cooperation with the LMF. If the number of available reference WTRUs changes, the appropriate SL positioning method may be updated. Each WTRU positioning method requires a different number of reference WTRUs for SL positioning. As a WTRU moves, there may not be enough reference WTRUs available for SL positioning. Negotiation between the WTRU and the network may be considered for the positioning method to be adopted. If a particular WTRU positioning method is not available, the requested positioning method may be updated to one or more other available positioning methods.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 410,826, filed September 28, 2022, and U.S. Provisional Application No. 63 / 526,835, filed July 14, 2023, which are incorporated by reference as if fully set forth. [Background technology]

[0002] Even when a WTRU is within the coverage of a 5G system, the WTRU may be unavailable for Uu-based positioning. This unavailability may occur, for example, due to an insufficient number of reachable gNBs. In such cases, positioning of the WTRU using PC5 channels, i.e., SL positioning, is considered to obtain the WTRU's location. To perform SL positioning, the WTRU may need to connect multiple WTRUs for a given WTRU positioning method or methods. Information about WTRUs connected via PC5 and involved in the WTRU's SL positioning is also required in the NW, including, for example, allocating resources for the PC5 connection, sharing assistance information for SL positioning, or coordinating on the WTRU to collect sufficient measurement information to determine the WTRU's location. Summary of the Invention

[0003] According to an example, when selecting the SL positioning method, the target WTRU reports a list of available reference WTRUs, and the LMF takes into account the reported list of reference WTRUs from the target WTRU.

[0004] According to an example, if the requested SL positioning cannot be performed due to a lack of available reference WTRUs, the target WTRU may negotiate with the LMF about the SL positioning method.

[0005] A WTRU can initiate a location request using multiple reference WTRUs when the WTRU is in-coverage. An SL-based location request can be initiated by a target WTRU when the target WTRU is in-coverage. An overall procedure is provided on how a target WTRU and an LMF negotiate supported WTRU-initiated positioning methods, as well as how a target WTRU finds reference WTRUs for SL positioning and performs appropriate SL positioning using multiple reference WTRUs.

[0006] When a WTRU is in-coverage, a NW initiated location request may be supported with multiple reference WTRUs. An SL-based location request may be initiated by the NW. After receiving a location request from the LMF, the target WTRU may be triggered to detect the reference WTRUs and set up a connection with them. With this in mind, an overall procedure is provided on how to perform SL positioning between a target WTRU and a reference WTRU in cooperation with the LMF.

[0007] If the number of available reference WTRUs changes, the appropriate SL positioning method may be updated. Each WTRU positioning method requires a different number of reference WTRUs for SL positioning. As the WTRU moves, there may not be a sufficient number of reference WTRUs available for SL positioning. Negotiation between the WTRU and the network may be considered for the positioning method to be adopted. If a particular WTRU positioning method is not available, the requested positioning method may be updated to one or more other available positioning methods. [Brief explanation of the drawings]

[0008] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which like reference numerals refer to like elements and in which:

[0009] [Figure 1A] FIG. 1 is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a system diagram illustrating an exemplary wireless transmit / receive unit (WTRU) that may be used within the communications system shown in FIG. 1A, according to one embodiment. [Figure 1C] 1B is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communication system shown in FIG. 1A, according to one embodiment. [Figure 1D] 1B is a system diagram illustrating a further example RAN and a further example CN that may be used within the communication system shown in FIG. 1A, according to one embodiment. [Figure 2] FIG. 1 illustrates a reference model of a potential architecture for a 5G or NextGen network. [Figure 3] FIG. 3 illustrates a reference model 300 of a 5G / NextGen network for location-based services. [Figure 4] FIG. 1 illustrates an NR positioning CP / UP architecture that can use defined protocols that enable several positioning techniques and methods. [Figure 5] FIG. 5G MO-LR signaling diagram with multiple reference WTRUs. [Figure 6] FIG. 5G MT-LR signaling diagram with multiple reference WTRUs. [Figure 7] FIG. 10 illustrates signaling related to a positioning method update procedure. [Figure 8] FIG. 1 illustrates a method for sidelink (SL) positioning of a wireless transmit / receive unit (WTRU). DETAILED DESCRIPTION OF THE INVENTION

[0010] A system, method, and device for SL positioning with multiple reference WTRUs are described.

[0011] A method for sidelink (SL) positioning in a wireless transmit / receive unit (WTRU) includes triggering a location information request including one or more quality metrics, detecting at least one SL Reference WTRU, determining a list of available Reference WTRUs, the list including the at least one SL Reference WTRU, where the including of the at least one SL Reference WTRU is based on at least one of the one or more quality metrics, transmitting an SL positioning service request to a network, the SL positioning service request including the list of available Reference WTRUs, negotiating SL positioning capabilities with the network taking into account the list of available Reference WTRUs, receiving assistance information from the network, and performing an SL positioning procedure via the negotiated SL positioning capabilities using the assistance information. The detected at least one SL Reference WTRU may be identified in the mobile-originated location information request. The method may include renegotiating SL positioning capabilities with the network based on the list of available Reference WTRUs, provided that a Reference WTRU is missing. The one or more quality metrics may include at least one of the group consisting of accuracy, response time, and LCS QoS class. The assistance information may include information for communicating with at least one WTRU from a list of available reference WTRUs. The assistance information may include acquisition assistance data. Using the assistance information may include utilizing at least one of accessible sources of positioning, measurement, and processing of positioning signals. The method may include calculating a location of the WTRU in two or more dimensions and reporting the location to the network. Negotiating SL positioning capabilities with the network may include transmitting a request including a list of preferred and supported capabilities, and receiving a response to the transmitted request indicating an SL positioning procedure. The method may include indicating one or more priority levels associated with the SL positioning procedure, and selecting a procedure to use based on the indicated one or more priority levels. The indicating and selecting may be performed via the network.

[0012] A wireless transmit / receive unit (WTRU) for sidelink (SL) positioning includes a processor and a transceiver communicatively coupled to the processor. The processor and transceiver, operable to trigger a location information request including one or more quality metrics, perform the following operations: detect at least one SL Reference WTRU; determine a list of available Reference WTRUs, the list including the at least one SL Reference WTRU, where the including of the at least one SL Reference WTRU is based on at least one of the one or more quality metrics; send an SL positioning service request to the network, the SL positioning service request including the list of available Reference WTRUs; negotiate SL positioning capabilities with the network taking into account the list of available Reference WTRUs; receive assistance information from the network; and perform an SL positioning procedure via the negotiated SL positioning capabilities using the assistance information. The detected at least one SL Reference WTRU may be identified in the mobile-originated location information request. The processor and transceiver may be further operative to renegotiate SL positioning capabilities with the network based on a list of available reference WTRUs, provided that a reference WTRU is lacking. The one or more quality metrics may be at least one of the group consisting of accuracy, response time, and LCS QoS class. The assistance information may be information for communicating with at least one WTRU in the list of available reference WTRUs. The assistance information may be acquisition assistance data. The processor and transceiver may be further operative to calculate a position of the WTRU in two or more dimensions and report the position to the network. Negotiating SL positioning capabilities with the network may include the processor and transceiver being further operative to send a request including a list of preferred and supported capabilities, and to receive a response to the sent request indicating the SL positioning procedure. The processor and transceiver may be further operative to indicate one or more priority levels associated with the SL positioning procedure, and to select a procedure to use based on the indicated priority level or levels.

[0013] 1A illustrates an exemplary 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, and broadcasts, to multiple wireless users. The communication system 100 may enable the multiple wireless users to access such content through the 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-tailed unique word discrete Fourier transform spread OFDM (ZT-UW-DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multicarrier (FBMC).

[0014] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, and 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, and 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, the WTRUs 102a, 102b, 102c, and 102d, all of which may be referred to as “stations (STAs),” may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, notebooks, personal computers, wireless sensors, hotspots, or Mi-Fi devices, IoT devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronic devices, devices operating on commercial and / or industrial wireless networks, etc. The WTRUs 102a, 102b, 102c, and 102d may all be referred to interchangeably as UEs.

[0015] The communications 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 at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communications networks, such as the CN 106, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a Base Transceiver Station (BTS), a NodeB, an eNodeB (eNB), a Home NodeB, a Home eNodeB, a Next Generation NodeB such as a gNodeB (gNB), a New Radio (NR) NodeB, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each depicted as a single element, it will be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0016] The base station 114a may be part of the RAN 104, 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), relay nodes, etc. The base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for wireless services in a particular geographic area, which may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0017] 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).

[0018] More particularly, as noted above, the communications 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 and the WTRUs 102a, 102b, 102c in the RAN 104 may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 116 using Wideband CDMA (WCDMA). 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 ​​Uplink (UL) Packet Access (HSUPA).

[0019] In one 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).

[0020] In one 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 NR.

[0021] In one 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 jointly implement LTE and NR radio access, e.g., using a dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to and from multiple types of base stations (e.g., eNBs and gNBs).

[0022] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), GSM EDGE (GERAN), or the like.

[0023] 1A 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 workplace, a home, a vehicle, a premises, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. 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 one 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 femtocell. 1A, the base station 114b may have a direct connection to the Internet 110. Therefore, the base station 114b may not need to access the Internet 110 through the CN 106.

[0024] The RAN 104 may be in communication with the CN 106, which may be any type of network configured to provide voice, data, application, and / or VoIP services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have various quality of service (QoS) requirements, such as different throughput, latency, error resilience, reliability, data throughput, mobility, etc. The CN 106 may provide call control, billing services, mobile location services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions such as user authentication. Although not shown in FIG. 1A , it will be understood that the RAN 104 and / or CN 106 may be in direct or indirect communication with other RANs employing the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, 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.

[0025] The CN 106 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 providing 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 TCP, UDP, and / or IP in the TCP / IP Internet protocol suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.

[0026] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications 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 over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a, which may employ a cellular-based wireless technology, and with a base station 114b, which may employ an IEEE 802.2 wireless technology.

[0027] 1B is a system diagram illustrating an example of a WTRU 102. As shown in FIG. 1B, 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 GPS chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any subcombination of the foregoing elements while remaining consistent with an embodiment.

[0028] The processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple 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), other types of integrated circuits (ICs), a state machine, etc. The processor 118 may perform signal coding, 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. While FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0029] The transmit / receive element 122 may be configured to transmit and receive signals to and from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0030] 1B depicts the transmit / receive element 122 as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More particularly, 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.

[0031] 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 mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as, for example, NR and IEEE 802.11.

[0032] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from 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). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Furthermore, the processor 118 may access information and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include RAM, ROM, a hard disk, or any other type of memory storage device. The removable memory 132 may include a SIM card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information and store data in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

[0033] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control the power to 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.

[0034] The processor 118 may also be coupled to a 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 instead of, information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (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 obtain location information by way of any suitable location-determination method while remaining consistent with an embodiment.

[0035] The processor 118 may also be coupled to other peripherals 138, which may include one or more software 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 e-compass, a satellite transceiver, a digital camera (for photos and / or videos), 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. The peripherals 138 may include one or more sensors. The sensors may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, a humidity sensor, etc.

[0036] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with a particular subframe for both the UL (e.g., for transmission) and DL (e.g., for reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference either through hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for transmission and reception of some or all of the signals (e.g., associated with a particular subframe for either the UL (e.g., for transmission) or DL ​​(e.g., for reception)).

[0037] 1C is a system diagram illustrating the RAN 104 and the CN 106, according to one embodiment. As noted above, the RAN 104 may employ 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.

[0038] The RAN 104 may include eNode-Bs 160a, 160b, and 160c, although it will be understood that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0039] Each of the eNodeBs 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 the UL and / or DL, etc. As shown in FIG. 1C, the eNodeBs 160a, 160b, 160c may communicate with each other via an X2 interface.

[0040] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. While the above elements are shown as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0041] The MME 162 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface and may act as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activating / deactivating bearers, selecting a particular serving gateway during 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.

[0042] The SGW 164 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions such as anchoring the user plane during handovers between eNodeBs, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0043] The SGW 164 may be connected to a PGW 166 that 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.

[0044] 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 fixed communication devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0045] Although the WTRU is depicted in FIGS. 1A-1D as a wireless terminal, it is contemplated that in some representative embodiments such a terminal may use a wired communication interface with the communication network (e.g., temporarily or permanently).

[0046] In an exemplary embodiment, the other network 112 may be a WLAN.

[0047] A WLAN in infrastructure basic service set (BSS) mode has 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 from the BSS. Traffic to a STA originating from outside the BSS may arrive through the AP and be sent to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP and delivered to the respective destination. Traffic between STAs within a BSS may be sent through the AP; for example, a source STA may send traffic to the AP, which then delivers the traffic to the destination STA. Traffic between STAs within a BSS may be considered or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent (e.g., directly) between a source STA and a destination STA using direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (e.g., all STAs) may communicate directly with each other. The IBSS communication mode is sometimes referred to herein as an "ad hoc" communication mode.

[0048] When using 802.11ac infrastructure mode operation or a similar mode of operation, an AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a wide 20 MHz bandwidth) or a dynamically configured width. The primary channel may be the operating channel of the BSS and may be used by STAs to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access with collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. With CSMA / CA, STAs (e.g., all STAs), including the AP, may sense the primary channel. If the primary channel is sensed / detected by a particular STA and / or determined to be busy, the particular STA may back off. One STA (e.g., only one station) may transmit on a given BSS at any time.

[0049] High-throughput (HT) STAs may use 40 MHz wide channels for communication, for example, by combining a primary 20 MHz channel with adjacent or non-adjacent 20 MHz channels to form the 40 MHz wide channel.

[0050] A Very High Throughput (VHT) STA can support channels of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz width. A 40 MHz and / or 80 MHz channel can be formed by combining contiguous 20 MHz channels. A 160 MHz channel can be formed by combining eight contiguous 20 MHz channels or two non-contiguous 80 MHz channels, sometimes referred to as an 80+80 configuration. In the 80+80 configuration, the channel-encoded data passes through a segment parser, which splits the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing can be performed separately on each stream. The streams are mapped to two 80 MHz channels, and the data is transmitted by the transmitting STA. At the receiver of the receiving STA, the above operations for the 80+80 configuration can be reversed, and the combined data can be transmitted to the Medium Access Control (MAC).

[0051] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. The channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah can support meter-type control / machine-type communication (MTC), such as MTC devices in macro coverage areas. MTC devices may have limited functionality, including specific features, such as support for (e.g., only support for) specific and / or limited bandwidths. MTC devices may include batteries with above-threshold battery life (e.g., maintaining a very long battery life).

[0052] A WLAN system may support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, and the WLAN system includes a channel that may be designated as a primary channel. The bandwidth of the primary channel may be equal to the largest common operating bandwidth supported by all STAs in a BSS. The bandwidth of the primary channel may be configured and / or limited by the STA from among all STAs operating in the BSS that support the smallest bandwidth operating mode. In an 802.11ah example, the primary channel of a STA (e.g., an MTC-type device) that supports (e.g., only supports) 1 MHz mode may be 1 MHz wide, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) configuration may depend on the status of the primary channel. For example, if the primary channel is busy because a STA (that only supports a 1 MHz mode of operation) is transmitting to the AP, all available frequency bands may be considered busy, even if most of the available frequency bands remain idle.

[0053] In the United States, the available frequency bands available for 802.11ah are 902MHz to 928MHz. In South Korea, the available frequency bands are 917.5MHz to 923.5MHz. In Japan, the available frequency bands are 916.5MHz to 927.5MHz. The total available bandwidth for 802.11ah is 6MHz to 26MHz depending on the country code.

[0054] 1D is a system diagram illustrating the RAN 104 and the CN 106, according to one embodiment. As noted above, the RAN 104 may employ NR 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.

[0055] While the RAN 104 may include gNBs 180a, 180b, and 180c, it will be understood that the RAN 104 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, and 180c may implement MIMO technology. For example, the gNBs 180a, 180b may transmit and / or receive signals to and from the gNBs 180a, 180b, and 180c using beamforming. Thus, for example, the gNB 180a may transmit and / or receive wireless signals to and from the WTRU 102a using multiple antennas. In one embodiment, the gNBs 180a, 180b, and 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 the unlicensed spectrum, and the remaining component carriers may be on the licensed spectrum. In one embodiment, the gNBs 180a, 180b, and 180c may implement Coordinated Multi-Point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or 180c).

[0056] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable numerology. For example, the 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 transmission time intervals (TTIs) of different or scalable lengths (e.g., including different numbers of OFDM symbols and / or different lengths of absolute time duration).

[0057] 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 can communicate with the gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNodeBs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c can utilize one or more gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c can communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with a gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as an eNode-B 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement a DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c at approximately the same time. In a non-standalone configuration, the eNode-Bs 160a, 160b, 160c may act as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0058] 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 the UL and / or DL, support for network slicing, DC, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a, 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D , the gNBs 180a, 180b, 180c may communicate with each other via an Xn interface.

[0059] 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While the above elements are shown as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0060] The AMF 182a, 182b may be connected to one or more gNBs 180a, 180b, 180c in the RAN 104 via an N2 interface and may function as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, managing registration areas, terminating non-access stratum (NAS) signaling, mobility management, etc. Network slicing may be used by the AMF 182a, 182b to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service being utilized by the WTRUs 102a, 102b, 102c. Different network slices may be established for different use cases, for example, services relying on Ultra-Reliable Low-Latency (URLLC) access, services relying on enhanced Massive Mobile Broadband (eMBB) access, services for MTC access, etc. The AMFs 182a, 182b may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that use other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0061] The SMFs 183a, 183b may be connected to the AMFs 182a, 182b in the CN 106 via an N11 interface. The SMFs 183a, 183b may also be connected to the UPFs 184a, 184b in the CN 106 via an N4 interface. The SMFs 183a, 183b may select and control the UPFs 184a, 184b and configure the routing of traffic through the UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions such as managing and assigning WTRU 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.

[0062] The UPFs 184a, 184b may be connected to one or more gNBs 180a, 180b, 180c in the RAN 104 via an N3 interface, which provides the WTRUs 102a, 102b, 102c with access to packet-switched networks such as the Internet 110 and facilitates communication between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184, 184b may perform other functions such as routing and forwarding packets, enforcing user plane policy, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing a mobility anchor, etc.

[0063] The CN 106 may facilitate communication with other networks. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to their local DNs 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0064] 1A-1D and the corresponding description thereof, one or more, or all, of the functions described herein with respect to one or more of the WTRUs 102a-d, base stations 114a-b, eNodeBs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functionality.

[0065] The emulation device can be designed to implement one or more tests of other devices in a lab environment and / or an operator network environment. For example, one or more emulation devices can be fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to perform one or more, or all, functions for testing other devices in the communication network. One or more emulation devices can be temporarily implemented / deployed as part of a wired and / or wireless communication network to perform one or more, or all, functions. The emulation device can be directly coupled to another device for testing purposes and / or can perform testing using wireless communication.

[0066] One or more emulation devices may also perform one or more functions (including all functions) without being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in test scenarios in a test lab and / or in test scenarios in non-deployed (e.g., test) wired and / or wireless communication networks to implement testing of one or more components. One or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may, for example, include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0067] FIG. 2 shows a reference model 200 of a potential architecture for a 5G or NextGen network. The architecture of model 200 defines individual interfaces between control plane elements. RAN 210 represents a radio access network based on 5G RAT or Evolved E-UTRA that connects to a NextGen core network. Access control and mobility management function (AMF) 220 includes at least the following functions: registration management, connection management, reachability management, mobility management, etc. Session management function (SMF) 230 includes at least the following functions: session management (including session establishment, modification, and release), WTRU IP address allocation, UP function selection and control, etc. User plane function (UPF) 240 includes at least the following functions: packet routing and forwarding, packet inspection, traffic usage reporting, etc.

[0068] 5G Location Services (LCS) may provide functionality for providing location information for the WTRU 250. Positioning of the WTRU 250 may be supported by RAT-dependent positioning methods. RAT-dependent positioning methods may rely, for example, on 3GPP RAT measurements obtained by the target WTRU and / or measurements obtained by the access network of 3GPP RAT signals transmitted by the target WTRU. Positioning of the WTRU may be supported by RAT-independent positioning methods. RAT-independent positioning methods may rely on non-RAT measurements and / or other information obtained by the WTRU. Location information for one or more target WTRUs may be requested and reported by an LCS client or an application function (AF) 260 within or outside the 3GPP operator network, or a control plane NF within the 3GPP system. In the case of a location information request from the LCS client or AF 260, privacy validation of the target WTRU may be enabled to verify whether it is authorized to obtain the WTRU location information.

[0069] Several different types of location information requests may be supported. In a Mobile Terminated Location Request (MT-LR), which may occur with a Mobile Terminated Location Request (MT-LR), the LCS client or AF sends a location request to the 5G network for the location of a target WTRU. In a Mobile Originated Location Request (MO-LR), which may occur with a Mobile Originated Location Request (MO-LR), the WTRU sends a request to the 5G network for location-related information of the WTRU. In an Immediate Location Request, which occurs with an Immediate Location Request, the LCS client or AF 260 sends or initiates a location information request for the target WTRU and expects to receive a response containing the target WTRU's location information within a short period of time. An Immediate Location Request may be used for an MT-LR or an MO-LR. In a Deferred Location Request, which occurs with a Deferred Location Request, the LCS client or AF 260 sends a location information request for the target WTRU to the 5G network and expects to receive a response at some point in the future when a specified event occurs for the target WTRU. It may be used for an MT-LR.

[0070] The Authentication Server Function (AUSF) 270 verifies users' identities and provides access to network resources based on their security level.

[0071] The Unified Data Management (UDM) 280 stores and manages user data, including the user's IMSI and authentication data. The UDM 280 provides user data, e.g., authentication data, to other network functions, i.e., AMF 220, SMF 230, when requested.

[0072] The Policy Control Function (PCF) 290 is responsible for enforcing policies that control user access to network resources. The PCF 290 provides, when requested, other network functions, i.e., AMF 220, SMF 230, for example, user policy data. A Data Network (DN) 295 is present in the system as shown and described herein.

[0073] FIG. 3 shows a 5G / NextGen network reference model 300 for location-based services. (R)AN 310 represents NG-RAN, trusted non-3GPP access, or untrusted non-3GPP access. The access network is responsible for handling various positioning procedures, including positioning the target WTRU, provisioning location-related information not associated with a specific target WTRU, and forwarding positioning messages between the AMF 320 or LMF 305 and the target WTRU. The AF 360 and NF can access LCS services from a Gateway Mobile Location Center (GMLC) 315 within the same 3GPP operator network. The LCS client 345 can access LCS services from the GMLC 315, and the external AF 360 can access LCS services from the NEF 335. The GMLC 315 processes requests from the external LCS client 345, AF 360 via the NEF 335 if the AF 360 is an external AF 360, and forwards the location information request to the appropriate NF. The Location Acquisition Function (LRF) 325 is responsible for acquiring or verifying location information and may be collocated with or independently of the GMLC 315. The Location Management Function (LMF) 305 manages the overall coordination and scheduling of resources required for the location of WTRUs 350 registered with or accessing the 5GCN. The LMF 305 may calculate or verify the final location-related information and the accuracy achieved.

[0074] The Unified Data Management (UDM) 380 stores and manages user data, including the user's IMSI and authentication data. The UDM 380 provides the AMF 320, the GMLC 315, and the NEF 335 with user data, such as privacy profiles or subscription data for location-based services, when requested.

[0075] FIG. 4 illustrates an NR positioning CP / UP architecture 400 that can use defined protocols to enable several positioning technologies and methods (e.g., GNSS, sensors, positioning signals, etc.). Positioning protocols and RAN-based positioning signals are specified to enable emergency services and location-based services. The 3GPP NR positioning protocol is supported by the Control Plane (CP) 415 positioning architecture over the Uu interface (NG-RAN node to WTRU). The NR positioning architecture can also be supported by a Secure User Plane Location (SUPL) server, also known as the SUPL Location Platform (SLP) 425 or location server 430, which may leverage any IP bearer. Interworking of the CP 415 and User Plane (UP) 410 provides the positioning solution, and the SUPL 455 may also be used as a tunnel for the CP positioning protocol (e.g., LPP 460), as shown in FIG. 4.

[0076] The primary protocol, LTE Positioning Protocol (LPP) 460, is terminated between the WTRU 450 and the Location Management Function (LMF) 405. LPP 460 is a point-to-point LCS and NAS messaging protocol. It has been agreed that LPP 460 will be reused for NR and will continue to be leveraged for the foreseeable future. Radio Resource Control (RRC) is another protocol used to provide transport for LPP messages and other positioning procedures over the NR-Uu interface, which is terminated between the gNB and the WTRU 450. On the network side, the NG Application Protocol (NGAP) is terminated between the AMF 420 and the NG-RAN node 440 (i.e., gNB / TRP) and is used as transport for LPP 460 and NRPPa 445 messages over the NG-C interface. Finally, the NR Positioning Protocol A (NRPPPa) 445 carries information between the NG-RAN node 440 and the LMF 405.

[0077] In the NR positioning mode, positioning can be performed as a standalone mode, a WTRU-based mode, or a WTRU-assisted mode. In standalone positioning, the WTRU 450 handles all aspects of positioning, scanning for accessible sources of positioning, making measurements, and processing positioning signals / sources. Finally, the WTRU 450 calculates its own position in two or three dimensions. In standalone positioning, the Uu interface impact includes exchanging WTRU capabilities and reporting the WTRU position. In WTRU-based positioning (WTRU-B), the network provides acquisition assistance data, and the WTRU 450 scans for accessible sources of positioning, making measurements, and processing positioning signals / sources (based on assistance information from the network). Finally, the WTRU 450 can calculate its own position in two or three dimensions and report the position to the network.

[0078] In WTRU-assisted positioning (WTRU-A), the network provides acquisition assistance, and the WTRU 450 scans for accessible sources of positioning and measures the positioning signals / sources (based on assistance information from the NW). Finally, the WTRU 450 returns the measurements to the network, which calculates the device's position (at the location server 430 / LMF 405).

[0079] The following table (Table 1) provides the supported technologies for WTRU positioning methods.

[0080] [Table 1]

[0081] In the LPP 460, the LPP message related to the WTRU-assisted location information request includes at least the following steps: - Feature requests such as requesting LMF405 to WTRU450; - Providing functions such as WTRU450 responding to LMF405; - Requests for assistance data, such as requests for positioning assistance data / information from the WTRU 450 to the LMF 405; - Providing assistance data such as positioning assistance data information / configuration from the LMF405 to the WTRU (furthermore, broadcasting of positioning assistance data (AD) is supported via the Positioning System Information Block (posSIB) and carried in SI messages); - Requests for location information, such as requests for location / measurements from the LMF405 to the WTRU450; - Providing location information, such as location and / or measurements, from the WTRU 450 to the LMF 405; - Cancellation of LPP sessions, etc.; and - Errors, such as errors related to the positioning procedure.

[0082] The QoS requirements and LCS QoS class of the location information request may indicate the accuracy or response time of the location information response. Because the QoS requirements and LCS QoS class may indicate accuracy requirements, the QoS requirements and LCS QoS class may be used to determine the procedure used to perform the location information calculation. Because the QoS requirements and LCS QoS class may indicate accuracy requirements, the QoS requirements and LCS QoS class may be used to determine the number of other WTRUs with which the first WTRU can interact to perform the location information calculation. For example, it may be possible to improve the accuracy of the location information calculation by collecting location information from more WTRUs and using location information from other WTRUs to improve the accuracy of the location information calculation. Because the QoS requirements and LCS QoS class may indicate response time, the QoS requirements and LCS QoS class may be used to determine the procedure used to perform the location information calculation. For example, a QoS requirement and LCS QoS class indicating a relatively short response time may be used to determine the use of a location information calculation procedure that takes a relatively short time.

[0083] Even if a WTRU is within the coverage of a 5G system, the WTRU may not be available for Uu-based positioning due to, for example, an insufficient number of reachable gNBs. In these cases, positioning of the WTRU using a PC5 channel, i.e., SL positioning, is considered to obtain the WTRU's location. To perform SL positioning, the WTRU may need to connect multiple WTRUs for each WTRU positioning method. Information about WTRUs connected via PC5 and involved in the WTRU's SL positioning is also required in the NW, for example, to allocate resources for the PC5 connection, share assistance information for SL positioning, or coordinate on the WTRU to collect sufficient measurement information to determine the WTRU's location.

[0084] The WTRU 450 can initiate a location information request using multiple reference WTRUs when the WTRU is in-coverage. An SL-based location information request can be initiated by the target WTRU when the target WTRU is in-coverage. An overall procedure is provided for how the target WTRU and the LMF 405 negotiate supported WTRU-initiated positioning methods, as well as how the target WTRU finds reference WTRUs for SL positioning and performs appropriate SL positioning using multiple reference WTRUs.

[0085] When a WTRU is in-coverage, a NW-initiated location information request may be supported with multiple reference WTRUs. An SL-based location information request may be initiated by the NW. In this case, the target WTRU may be triggered to detect and establish a connection with the reference WTRUs after receiving a location information request from the LMF 405. With this in mind, an overall procedure is provided on how to perform SL positioning between a target WTRU and a reference WTRU in cooperation with the LMF 405.

[0086] If the number of available reference WTRUs changes, the appropriate SL positioning method may be updated. Each WTRU positioning method requires a different number of reference WTRUs for SL positioning. As the WTRU 450 moves, there may be a shortage of reference WTRUs available for SL positioning. In this case, this may be taken into consideration when negotiating a positioning method between the WTRU 450 and the network. If a particular WTRU positioning method is unavailable, the requested positioning method may be updated to another available positioning method.

[0087] The WTRU 450 may support PC5 signaling, which may be supported, for example, by a ProSe layer in the WTRU. The WTRU 450 in the illustrated example includes ranging and sidelink positioning capabilities. Sidelink positioning generally refers to positioning over a PC5 interface, and ranging refers to determining the distance between two or more WTRUs and / or determining the direction and / or relative positioning from one WTRU to another.

[0088] For a 5G MO-LR request, the target WTRU may check for available reference WTRUs, and the target WTRU may notify the network of the available reference WTRUs. The LMF 405 may consider the available reference WTRUs, the target WTRU's capabilities, and QoS requirements to determine the SL positioning method. After determining the SL positioning method, the LMF 405 may notify the target WTRU and the involved reference WTRUs. The target WTRU and reference WTRU perform SL positioning and notify the LMF 405 of the results.

[0089] From the 5G MT-LR request, the target WTRU and the LMF 405 may communicate for capability negotiation for SL positioning. During this time, the target WTRU may inform the LMF 405 of available reference WTRUs, and the LMF 405 may determine the SL positioning method based on the list of reference WTRUs, the capabilities of the target WTRU, and the QoS requirements. After the SL positioning method is determined by the LMF 405, the target WTRU and the reference WTRU perform SL positioning as requested by the LMF 405.

[0090] If the target WTRU is unable to perform the SL positioning requested by the LMF 405 due to a lack of available reference WTRUs, the target WTRU may provide this information to the LMF 405. The LMF 405 may perform an alternative SL positioning method for the WTRU 450, taking into account the available reference WTRUs, the target WTRU's capabilities, and QoS requirements. The target WTRU may perform the SL positioning as indicated by the LMF 405 using the available reference WTRUs.

[0091] The NW may provide a list of reference WTRUs and detection / selection configuration parameters, and the NW may provide a list of configurations for SL positioning methods with priorities and other details.

[0092] 5 shows a 5G MO-LR signaling diagram 500 with multiple reference WTRUs. WTRU1 5501 may be triggered for a location information request at 502. The location information request may include its destination, for example, an LCS client or an AF. The location information request may include any QoS requirements needed (e.g., accuracy, response time, LCS QoS class).

[0093] For example, an application at WTRU1 5501 may trigger a location request that sends location information of WTRU1 5501 along with some QoS requirements to an AF or LCS client. For example, an application hosted at the WTRU may decide to trigger a location request when the application is launched, upon user request entered via a GUI, or upon expiration of a time period.

[0094] As another example, WTRU1 5501 may be configured with several trigger conditions for location information reporting with several QoS requirements to an AF or LCS client by the 5GC system. For example, the WTRU may be configured to trigger a location information request upon expiration of a period.

[0095] WTRU1 5501 may detect reference WTRUs (i.e., WTRU2 5502, WTRU3, WTRU4, etc.). Based on the QoS requirements of the location information request and the SL positioning capabilities of WTRU1 5501, WTRU1 5501 may select as many reference WTRUs (denoted as WTRU2 5502) as necessary for SL positioning that meets the QoS requirements and establish PC5 connections with the selected WTRUs at 504. When selecting reference WTRUs, WTRU1 5501 may select as many reference WTRUs as necessary to support SL positioning that meets the highest QoS requirement of the location information request. If the number of available reference WTRUs is not sufficient to perform SL positioning that meets the highest QoS requirement, WTRU1 5501 may select as many reference WTRUs as possible. Alternatively, WTRU1 5501 may postpone the establishment of a PC5 connection with the selected WTRU after receiving an SL positioning service request from LMF 505, which may include, for example, a selected positioning method and / or a selected list of reference WTRUs.

[0096] WTRU1 5501 may send a ranging / sidelink positioning service request 506 to the AMF 520, which may include its destination information. The destination information may include, for example, an LCS client or AF and required QoS information. WTRU1 5501 may include a list of reference WTRUs available for the ranging / sidelink positioning service request. WTRU1 5501 may include an indication of preference in the list of reference WTRUs or may order the reference WTRUs in the list according to their preference. The priority may be determined based on, for example, signal strength, delay, or PLMN.

[0097] The AMF 520 may select the LMF 505 at 508 to process the location information request from WTRU1 5501.

[0098] The AMF 520 may send a ranging / sidelink positioning service request with a list of available reference WTRUs to the selected LMF 505 at 512. The AMF 520 may inform the LMF 505 of the capabilities of WTRU1 5501 for positioning.

[0099] The LMF 505 and WTRU1 5501 may communicate to exchange SL positioning capability negotiation at 514. This communication may be used to communicate the WTRU's sidelink positioning capabilities from WTRU1 5501 to the LMF 505. For example, the LMF 505 may send a Capability request to WTRU1 5501 to inquire about the SL positioning capabilities of WTRU1 5501 (e.g., supported positioning methods), and WTRU1 5501 may respond to the LMF 505 with a Capability response including the SL positioning capabilities of WTRU1 5501 (e.g., supported positioning methods such as DL-TDOA, DL-AOA, etc.).

[0100] Alternatively, WTRU1 5501 may perform a discovery procedure for available reference WTRUs (i.e., WTRU2 5502, WTRU3, WTRU4, etc.) and notify the list of available reference WTRUs during the SL positioning capability negotiation or as a separate signaling procedure.

[0101] The LMF 505 may select a positioning method based on the QoS information included in the location information request, the negotiated capabilities of WTRU1 5501 for SL positioning, and the list of available reference WTRUs from WTRU1 5501. The LMF 505 may select a list of reference WTRUs from those in the list that will participate for SL positioning with WTRU1 5501. When the LMF 505 selects a list of reference WTRUs, it may select as many reference WTRUs as required for the selected QoS, more reference WTRUs than required for the selected QoS, or all WTRUs in the list regardless of priority. After selecting a positioning method, the LMF 505 may send assistance information to the selected reference WTRU for SL positioning with WTRU1 5501 at 516. For example, the assistance information at 516 may include information about a selected reference signal used for positioning by the selected positioning method, such as DL-TDOA, DL-AOA, etc. For example, the assistance information at 516 may include information used by the WTRU to communicate with at least one WTRU selected from the list. Communicating with the at least one WTRU selected from the list may include performing a sidelink positioning procedure with the at least one WTRU selected from the list. For example, the assistance information at 516 may include information used by the WTRU to receive reference signals from the WTRU selected from the list and use information from the reference signals in its position calculation. When the LMF 505 selects from the list of reference WTRUs, the LMF 505 may take into account an indication of priority to the reference WTRU from WTRU1 5501, if available.

[0102] The LMF 505 may transmit assistance information to the NG-RAN 540 at 518. The assistance information at 518 may indicate, for example, WTRU1 5501 and a selected list of reference WTRUs if resource allocation for SL positioning is required. The NG-RAN 540 may perform resource allocation for the reference WTRU for SL positioning at 522.

[0103] Some of the above signaling may occur if the reference WTRU does not belong to the same PLMN as the target WTRU.

[0104] The LMF 505 may send a ranging / SL positioning service request to WTRU1 5501 at 524. The LMF 505 may indicate the selected positioning method. The LMF 505 may include a selected list of reference WTRUs. If a selected list of reference WTRUs is not included in the request from the LMF 505, WTRU1 5501 may consider all reference WTRUs included in the request (ranging / sidelink positioning service request) for participation in the SL positioning.

[0105] WTRU1 5501 and a selected reference WTRU (denoted as WTRU2 5502) may perform a ranging / SL positioning procedure at 526. Location information of the reference WTRU may be shared with WTRU1 5501. Before performing the ranging / SL positioning procedure at 526, WTRU1 5501 and the selected reference WTRU may set up a PC5 connection if one is not already available for SL positioning.

[0106] WTRU1 5501 may transmit the SL positioning result to the LMF 505 at 528.

[0107] The LMF 505 may determine the location of WTRU1 5501 based on the received SL positioning results and the known location of the reference WTRU. If necessary, the LMF 505 may perform Uu positioning with the reference WTRU if the reference WTRU is available for Uu positioning with the LMF 505. The LMF 505 may transmit the location of WTRU1 5501 to the AMF 520 at 532, as required above.

[0108] The AMF 520 may transmit the location of WTRU1 5501 to the indicated destination at 534 as provided above.

[0109] As an alternative to or in addition to the above-described reference WTRU detection, the AMF 520 or LMF 505 may provide a list of reference WTRUs for each known WTRU location, and the WTRU may provide the available reference WTRU list in response after performing a detection or PC5 connection setup procedure. In this case, the selection of the positioning method may be performed and shared after receiving the reference WTRU list.

[0110] Alternatively, or additionally, the target WTRU's location determination may be performed by the LMF 505, the target WTRU, or another location server (in the WTRU or in a NW entity). When the location determination is performed by the target WTRU, WTRU1 5501 may send the determined location information to the LMF 505. Further signaling exchanges may occur if the LMF 505 or WTRU1 5501 operate to exchange further information to determine the precise WTRU's location. When the location determination is performed by another location server, WTRU1 5501 or the LMF 505 may each send the SL positioning result and other information, such as the location information of the reference WTRU, to the location server. After the location server determines the location information of WTRU1 5501, the location server may send the location information to the LMF 505.

[0111] 6 shows a 5G MT-LR signaling diagram 600 with multiple reference WTRUs. The AMF 620 may receive a location information request at 602 from an LCS client or AF via the GMLC and / or NEF requesting location information for WTRU1 6501. The location information request may include several QoS requirements to be met (e.g., accuracy, response time, LCS QoS class).

[0112] The AMF 620 may select the LMF 605 to handle location-based services for WTRU1 6501 at 604 .

[0113] The AMF 620 may forward 606 a location information request for positioning by WTRU1 6501 to the LMF 605, which may include the received QoS requirements.

[0114] The LMF 605 may communicate with WTRU1 6501 at 608 to determine the capability of WTRU1 6501 for Uu or SL based positioning methods. The LMF 605 may provide a list of potential reference WTRUs for each WTRU's location and the information necessary to detect and set up a PC5 connection.

[0115] After receiving the positioning capability request at 608 from the LMF 605, WTRU1 6501 may check whether Uu-based positioning or SL-based positioning is available, for example, based on channel monitoring results regarding the number of available cells, based on the detected number of reference WTRUs, or based on registered PLMN information. WTRU1 6501 may detect reference WTRUs (i.e., WTRU2 6502, WTRU3, WTRU4, etc.) for SL positioning at 612. When provided with a list of candidate reference WTRUs, WTRU1 6501 may attempt to find the reference WTRU among those reference WTRUs in the list.

[0116] Based on WTRU1 6501's capabilities for SL positioning, i.e., the supported SL positioning methods, WTRU1 6501 may select several reference WTRUs and establish a PC5 connection with the selected WTRUs. If QoS requirements are indicated by the LMF 605, when selecting a reference WTRU, WTRU1 6501 may select as many reference WTRUs as necessary to support SL positioning that meets the highest QoS requirement of the location information request. If the number of available reference WTRUs is not sufficient to perform SL positioning by meeting the highest QoS requirement, or if QoS requirements are not indicated, WTRU1 6501 may select as many reference WTRUs as possible. Alternatively, WTRU1 6501 may postpone establishing a PC5 connection with the selected WTRU, for example, after receiving an SL positioning service request from the LMF 605, which may include a selected positioning method and / or a selected list of reference WTRUs.

[0117] Alternatively, WTRU1 6501 may signal the list of available reference WTRUs during the SL positioning capability negotiation or as a separate signaling procedure.

[0118] WTRU1 6501 may send a positioning capability response 614 to the LMF 605 including its capabilities for positioning (e.g., supported positioning methods such as DL-TDOA, DL-AOA, etc.). WTRU1 6501 may indicate whether Uu positioning is available and / or whether SL positioning is available. WTRU1 6501 may include information regarding available cells for Uu positioning and / or a list of available reference WTRUs for SL positioning. WTRU1 6501 may include an indication of priority in the list of reference WTRUs or may order the reference WTRUs in the list according to their priority. The priority may be determined based on, for example, the ProSe application code, ProSe application ID, PLMN, or monitored signal quality (e.g., average SINR) between WTRU1 6501 and the reference WTRU.

[0119] The LMF 605 may select a positioning method based on the QoS information included in the location information request, the negotiated capabilities of WTRU1 6501 for SL positioning, and the list of available reference WTRUs from WTRU1 6501. Once the SL positioning method is selected, the LMF 605 may select a list of reference WTRUs from the list of reference WTRUs in the list to join WTRU1 6501 for SL positioning. When the LMF 605 selects the list of reference WTRUs, it may select as many reference WTRUs as needed for the selected QoS, more reference WTRUs than needed for the selected QoS, or all reference WTRUs in the list. After selecting the positioning method, the LMF 605 may send assistance information to the selected reference WTRU for SL positioning with WTRU1 6501 at 616. For example, the assistance information at 616 may include information about a selected reference signal used for positioning by the selected positioning method, such as DL-TDOA, DL-AOA, etc. For example, the assistance information at 616 may include information used by the WTRU to communicate with at least one WTRU selected from the list. Communicating with the at least one WTRU selected from the list may include performing a sidelink positioning procedure with the at least one WTRU selected from the list. For example, the assistance information at 616 may include information used by the WTRU to receive reference signals from a WTRU selected from the list and use information from the reference signals in position calculations. When the LMF 605 selects a list of reference WTRUs, the LMF 605 may consider an indication of priority for the reference WTRU from WTRU1 6501, if available.

[0120] The LMF 605 may transmit the assistance information to the NG-RAN 640 at 618. The assistance information at 618 may indicate, for example, a selected list of WTRU1 6501 and a reference WTRU if resource allocation for SL positioning is required.

[0121] The NG-RAN 640 may perform resource allocation 622 for the reference WTRU for SL positioning.

[0122] If the reference WTRU does not belong to the same PLMN as the target WTRU, the above signaling may be omitted.

[0123] The LMF 605 may send a ranging / SL positioning service request to WTRU1 6501 at 624. The LMF 605 may indicate the selected positioning method. The LMF 605 may include a selected list of reference WTRUs. If a selected list of reference WTRUs is not included in the request from the LMF 605, WTRU1 6501 may consider all reference WTRUs included in the request to be capable of participating in the SL positioning.

[0124] WTRU1 6501 and the selected reference WTRU may perform a ranging / SL positioning procedure at 626. The location information of the reference WTRU may be shared with WTRU1 6501. Before performing the ranging / SL positioning procedure at 626, WTRU1 6501 and the selected reference WTRU may set up a PC5 connection if there is not currently a PC5 connection available for SL positioning.

[0125] WTRU1 6501 may transmit the SL positioning result to the LMF 605 at 628.

[0126] The LMF 605 may determine the location of WTRU1 6501 based on the received SL positioning results and the known location of the reference WTRU. If necessary, the LMF 605 may perform Uu positioning with the reference WTRU if the reference WTRU is available for Uu positioning with the LMF 605. The LMF 605 may transmit the location of WTRU1 6501 to the AMF 620 upon request, at 632.

[0127] The AMF 620 may transmit 634 the location of WTRU1 6501 to the destination indicated in the received location information request.

[0128] Alternatively, or additionally, the target WTRU's location determination may be performed by the LMF 605, the target WTRU, or another location server (in the WTRU or in a NW entity). When the location determination is performed by the target WTRU, WTRU1 6501 may send the determined location information to the LMF 605. If the LMF 605 or WTRU1 6501 requires more information to more accurately determine the location of WTRU1 6501, further signaling exchanges may occur. When the location determination is performed by another location server, WTRU1 6501 or the LMF 605 may send the SL positioning results and other information, such as the location information of the reference WTRU, to the location server. After the location server determines the location information of WTRU1 6501, the location server may send the location information to the LMF 605.

[0129] 7 shows signaling 700 associated with a positioning method update procedure. The LMF 705 may send a ranging / SL positioning service request to WTRU1 7501 at 702. The LMF may indicate the selected positioning method based on known WTRU1 7501 capabilities (e.g., supported positioning methods such as DL-TDOA, DL-AOA, etc.) and requested QoS requirements, if available. The LMF 705 may include the QoS requirements in the ranging / SL positioning service request. The LMF 705 may provide a list of potential reference WTRUs per WTRU location and the information necessary to discover and set up a PC5 connection.

[0130] To perform SL positioning as requested by the LMF 705, WTRU1 7501 may attempt to detect reference WTRUs and perform PC5 connection setup at 704. Once provided with a list of potential reference WTRUs, WTRU1 7501 attempts to detect those reference WTRUs. Alternatively, WTRU1 7501 may postpone PC5 connection setup with the detected WTRUs until after receiving an SL positioning service request from the LMF 705, which may include, for example, a selected positioning method and / or a selected list of reference WTRUs.

[0131] If the detected reference WTRUs are not sufficient to perform the requested SL positioning, WTRU1 7501 may indicate that the requested SL positioning cannot be performed. WTRU1 7501 may include an identifier of a list of available reference WTRUs at 706. When determining whether the SL positioning will be successful, it may be considered that the requested QoS requirements can be met by the detected reference WTRUs if the QoS requirements are available, for example, by sharing, configuration, or other means.

[0132] When the LMF 705 receives a response at 706, if the response indicates that WTRU1 7501 is unable to perform SL positioning as requested, the LMF 705 may select another positioning method based on the QoS requirements, the capabilities of WTRU1 7501 for SL positioning, and, if provided by WTRU1 7501, a list of available reference WTRUs. The LMF 705 may select a list of reference WTRUs to participate in SL positioning with WTRU1 7501 from among the reference WTRUs in the list. When the LMF 705 selects a list of reference WTRUs, the LMF 705 may select as many reference WTRUs as required for the selected QoS, more reference WTRUs than the number of reference WTRUs required for the selected QoS, or all reference WTRUs on the list. After selecting a positioning method, the LMF 705 may send assistance information to the selected reference WTRU for SL positioning with WTRU1 7501. The LMF 705 may send a ranging / SL positioning service request to WTRU1 7501. The LMF 705 may indicate a selected positioning method at 708. The LMF 705 may include a selected list of reference WTRUs. If a selected list of reference WTRUs is not included in the request from the LMF 705, WTRU1 7501 may consider all reference WTRUs included in the request to be involved in the sidelink positioning. For example, the assistance information may include information about selected reference signals used for positioning by a selected positioning method, such as DL-TDOA, DL-AOA, etc. For example, the assistance information may include information used by the WTRU to communicate with at least one WTRU selected from the list. Communicating with at least one WTRU selected from the list may include performing a sidelink positioning procedure with at least one WTRU selected from the list. For example, the assistance information may include information used by the WTRU to receive reference signals from a WTRU selected from the list and use information from the reference signals in position calculations.

[0133] WTRU1 7501 and the selected reference WTRU may perform a ranging / SL positioning procedure at 712. Location information of the reference WTRU may be shared with WTRU1 7501. Before performing the ranging / SL positioning procedure at 712, WTRU1 7501 and the selected reference WTRU may set up a PC5 connection if there is no PC5 connection currently available for SL positioning.

[0134] WTRU1 7501 may transmit the SL positioning result to the LMF 705 at 714 .

[0135] Alternatively, or in addition to the above, the LMF 705 may transmit a list of SL positioning methods. The list may be ordered by reference or by priority value. The LMF 705 may provide a required or recommended number of reference WTRUs for each SL positioning method. If available, based on the list, the priority of the method, the number of available reference WTRUs, and a comparison with the required or recommended number of reference WTRUs provided for each method, the target WTRU may determine the SL positioning method that can achieve the best QoS in a given situation. The target WTRU may report the results of the selected or used SL positioning method to the LMF 705.

[0136] Alternatively, or additionally, the target WTRU's location determination may be performed by the LMF 705, the target WTRU, or another location server (in the WTRU or in a NW entity). When the location determination is performed by the target WTRU, WTRU1 7501 may send the determined location information to the LMF 705. Further signaling exchanges may occur if the LMF 705 or WTRU1 7501 exchange further information to determine the precise location of WTRU1 7501. When the location determination is performed by another location server, WTRU1 7501 or the LMF 705 may send, for example, the SL positioning result and other information. The other information may include location information of a reference WTRU to the location server. After the location server determines the location information of WTRU1 7501, the location server may send the location information to the LMF 705.

[0137] FIG. 8 shows a method 800 for sidelink (SL) positioning of a wireless transmit / receive unit (WTRU). The method 800 includes, at 810, triggering a location information request. The location information request may include one or more quality metrics. At 820, the method 800 includes detecting at least one SL reference WTRU. The detected at least one SL reference WTRU may be identified in a mobile-originated location information request. At 830, the method 800 includes determining a list of available reference WTRUs. The list may include the at least one SL reference WTRU, for example, based on at least one of the one or more quality metrics. At 840, the method 800 includes sending an SL positioning service request to the network, the SL positioning service request including the list of available reference WTRUs. At 850, the method 800 includes negotiating SL positioning capabilities with the network taking into account the list of available reference WTRUs. At 860, the method 800 includes receiving assistance information from the network. At 870, the method 800 includes performing an SL positioning procedure via the negotiated SL positioning capability using the assistance information. At 880, the method 800 may include renegotiating the SL positioning capability with the network based on a list of available reference WTRUs, provided that a reference WTRU is missing.

[0138] Although features and elements have been described above in particular combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with the other features and elements. Furthermore, the methods described herein can be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired and / or wireless connections) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and / or digital versatile disks (DVDs). A processor in combination with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. 1. A method for sidelink (SL) positioning of a wireless transmit / receive unit (WTRU), comprising: triggering a location information request, the location information request including one or more quality metrics; Detecting at least one SL reference WTRU; determining a list of available reference WTRUs, the list including the at least one SL reference WTRU, and the inclusion of the at least one SL reference WTRU is based on at least one of the one or more quality metrics; sending a SL positioning service request to a network, the SL positioning service request including a list of available reference WTRUs; negotiating SL positioning capabilities with the network taking into account the list of available reference WTRUs; receiving assistance information from the network; performing a SL positioning procedure via the negotiated SL positioning capability using the assistance information; and A method comprising:

2. 10. The method of claim 1, wherein the detected at least one SL reference WTRU is identified in a mobile-originated location information request.

3. The method of claim 1 , further comprising: renegotiating SL positioning capabilities with the network based on the list of available reference WTRUs, provided that the number of reference WTRUs is less than a threshold.

4. The method of claim 1 , wherein the one or more quality metrics include at least one of accuracy, response time, and LCS QoS class.

5. The method of claim 1 , wherein the assistance information includes information for communicating with at least one WTRU in the list of available reference WTRUs.

6. The method of claim 1 , wherein the assistance information includes acquisition assistance data.

7. The method of claim 1 , wherein using the aiding information includes utilizing at least one of accessible sources of positioning, measurement, and processing of positioning signals.

8. The method of claim 1 , further comprising calculating a position of the WTRU in two or more dimensions.

9. The method of claim 8 , further comprising reporting the location to the network.

10. Negotiating SL positioning capabilities with the network includes: sending a request including a list of preferred and supported capabilities; receiving a response to the transmitted request indicating an SL positioning procedure; 2. The method of claim 1, comprising:

11. receiving a signal indicating one or more priority levels associated with a single-lower-level positioning procedure; selecting an SL positioning procedure based on the indicated priority level or levels; The method of claim 1 further comprising:

12. The method of claim 11 , wherein the indicating and selecting are performed over the network.

13. 1. A wireless transmit / receive unit (WTRU) for sidelink (SL) positioning, comprising: a processor; a transceiver communicatively coupled to the processor; wherein the processor and the transceiver triggering a location information request, the location information request including one or more quality metrics; Detecting at least one SL reference WTRU; determining a list of available reference WTRUs, the list including the at least one SL reference WTRU, and the inclusion of the at least one SL reference WTRU is based on at least one of the one or more quality metrics; sending a SL positioning service request to a network, the SL positioning service request including a list of available reference WTRUs; negotiating SL positioning capabilities with the network taking into account the list of available reference WTRUs; receiving assistance information from the network; performing a SL positioning procedure via the negotiated SL positioning capability using the assistance information; and a WTRU configured to perform

14. The WTRU of claim 13 , wherein the processor and the transceiver are further configured to renegotiate SL positioning capabilities with the network based on the list of available reference WTRUs, provided that the number of reference WTRUs is less than a threshold.

15. The WTRU of claim 13 , wherein the one or more quality metrics include at least one of accuracy, response time, and LCS QoS class.

16. The WTRU of claim 13 , wherein the assistance information includes information for communicating with at least one WTRU in the list of available reference WTRUs.

17. The WTRU of claim 13 , wherein the assistance information includes acquisition assistance data.

18. The processor and the transceiver Calculating a position of the WTRU in two or more dimensions; reporting said location to said network; The WTRU of claim 13 , further configured to perform the following:

19. Negotiating SL positioning capabilities with the network includes: the processor and the transceiver sending a request including a list of preferred and supported capabilities; receiving a response to the transmitted request indicating an SL positioning procedure; The WTRU of claim 13 , further configured to perform the following:

20. The processor and the transceiver receiving a signal indicating one or more priority levels associated with a single-lower-level positioning procedure; selecting a SL positioning procedure to use based on the indicated priority level or levels; The WTRU of claim 13 , further configured to perform the following:

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