Supporting relay node assisted positioning

Abstract

Systems, methods, and tools may be configured to support relay node assisted positioning. A first wireless transmit / receive unit (WTRU) may receive configuration information indicating a sounding reference signal (SRSp) configuration for positioning from a network node. The SRSp configuration may be associated with a second WTRU, a reference timing advance (TA) value associated with the first WTRU, a first threshold, and a second threshold. The first WTRU may receive a first RSRP measurement from the second WTRU. The first WTRU may determine a first TA value associated with the second WTRU, wherein the determination of the first TA value is based on the first RSRP measurement, the reference TA value, and a measurement associated with the network node. The first WTRU may transmit the SRSp configuration and the first TA value for the second WTRU to the second WTRU.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 410,799, filed on September 28, 2022, the content of which is hereby incorporated herein by reference. Background Art

[0003] Mobile communications using wireless communication continue to evolve. The fifth - generation mobile communication radio access technology (RAT) can be referred to as 5G New Radio (NR). The previous generation (conventional) of mobile communication RAT can be, for example, the fourth - generation (4G) Long - Term Evolution (LTE). Summary of the Invention

[0004] Systems, methods, and means can be configured to support relay - node - assisted positioning. A first wireless transmit / receive unit (WTRU) can receive configuration information from a network node, the configuration information indicating a sounding reference signal (SRSp) configuration for positioning. The SRSp configuration can be associated with a second WTRU, a reference timing advance (TA) value associated with the first WTRU, a first threshold, and a second threshold. The first WTRU can receive a first RSRP measurement from the second WTRU. The first WTRU can determine a first TA value associated with the second WTRU, wherein the determination of the first TA value is based on the first RSRP measurement, the reference TA value, and measurements associated with the network node. The first WTRU can send the SRSp configuration and the first TA value for the second WTRU to the second WTRU.

[0005] The first WTRU can receive a second RSRP measurement from the second WTRU. The first WTRU can send an indication to the second WTRU based on the first RSRP measurement and the second RSRP measurement.

[0006] If the difference between the first RSRP measurement and the second RSRP measurement is between the first threshold and the second threshold, the first WTRU can determine a second TA value for the second WTRU to be used in association with SRSp transmission. The determination of the second TA value can be based on the first RSRP measurement, the second RSRP measurement, and the first TA value.

[0007] The first TRU can send an indication to the second WTRU, and the indication can indicate the second TA value. If the difference between the first RSRP measurement and the second RSRP measurement is higher than the second threshold, the first WTRU can send the indication to the second WTRU. The indication can indicate the release of the SRSp configuration.

[0008] The first RSRP measurement may be associated with a Transmission Reference Point (TRP), and the second RSRP measurement may be associated with the TRP. The first TA value may indicate a timing advance associated with an SRSp transmission made with a second WTRU. The first WTRU may include a relay WTRU, and the second WTRU may include a target WTRU. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A is a system diagram showing an exemplary communication system in which one or more of the disclosed embodiments may be implemented.

[0010] Figure 1B is a system diagram showing an exemplary wireless transmit / receive unit (WTRU) that may be used within the communication system shown in Figure 1A in accordance with an embodiment.

[0011] Figure 1C is a system diagram showing an exemplary radio access network (RAN) and an exemplary core network (CN) that may be used within the communication system shown in Figure 1A in accordance with an embodiment.

[0012] Figure 1D is a system diagram showing another exemplary RAN and another exemplary CN that may be used within the communication system shown in Figure 1A in accordance with an embodiment.

[0013] FIG. 2 shows an example of a positioning reference signal (PRS) configuration hierarchy.

[0014] Figure 3 shows an example of area-region specific positioning.

[0015] Figure 4 shows an example in which a relay WTRU may trigger activation / deactivation of an SRSp transmission at a target WTRU.

[0016] Figure 5 shows an example in which a relay WTRU may assist in hybrid positioning.

[0017] Figure 6 shows an example in which a relay WTRU may forward an SRSp configuration. DETAILED DESCRIPTION

[0018] Figure 1AFIG. is a diagram illustrating an exemplary communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multi-access system that provides content (such as voice, data, video, messaging, broadcasting, etc.) to a plurality of wireless users. The communication system 100 may enable the plurality of wireless users to access such content by sharing system resources, including wireless bandwidth. In an example, the communication system 100 may employ one or more channel access technologies, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero-tail unique word DFT-spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), and so on.

[0019] As Figure 1A shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104 / 113, a CN 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a "station" and / or "STA") may be configured to transmit and / or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop computer, a netbook computer, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, a medical device and application (e.g., remote surgery), an industrial device and application (e.g., a robot and / or other wireless devices operating in the context of an industrial and / or automation processing chain), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, and so on. Any one of the WTRU102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0020] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a, 114b may be any type of device configured to facilitate access to one or more communication networks (such as CN 106 / 115, Internet 110, and / or other networks 112) by wirelessly interfacing with at least one of WTRUs 102a, 102b, 102c, 102d. As an example, base stations 114a, 114b may be base transceiver stations (BTSs), Node Bs, eNode Bs, home Node Bs, home eNode Bs, gNBs, NR Node Bs, site controllers, access points (APs), wireless routers, etc. Although each of base stations 114a, 114b is depicted as a single element, it will be understood that base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0021] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. 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 in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for wireless services to a specific geographical area, which may be relatively fixed or may change over time. A cell may also be divided into cell sectors. In an example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, that is, each transceiver corresponds to one sector of the cell. In an embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may use multiple transceivers for each sector of the cell. In an example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0022] Base stations 114a, 114b may communicate with one or more of WTRUs 102a, 102b, 102c, 102d via air interface 116, which may be any suitable wireless communication link (such as radio frequency (RF), microwave, centimeter wave, millimeter wave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interface 116 may be established using any suitable radio access technology (RAT).

[0023] More specifically, as described above, the communication system 100 may be a multi-access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. In an example, the radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA) may be implemented by the base station 114a and the WTRUs 102a, 102b, 102c in the RAN 104 / 113, and the UMTS UTRA may use Wideband CDMA (WCDMA) to establish the air interfaces 115 / 116 / 117. WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink (DL) Packet Access (HSDPA) and / or High-Speed Uplink (UL) Packet Access (HSUPA).

[0024] In an embodiment, the radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA) may be implemented by the base station 114a and the WTRUs 102a, 102b, 102c, and the E-UTRA technology may use Long-Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced Pro LTE (LTE-A Pro) to establish the air interface 116.

[0025] In an embodiment, the radio technology such as NR radio access may be implemented by the base station 114a and the WTRUs 102a, 102b, 102c, and the NR radio access may use New Radio NR to establish the air interface 116.

[0026] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. In an example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example, using the Dual Connectivity (DC) principle. Thus, the air interfaces utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNB and gNB).

[0027] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as, for example, IEEE 802.11 (i.e., Wi-Fi (Wireless Fidelity)), IEEE 802.16 (i.e., WiMAX (Worldwide Interoperability for Microwave Access)), 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), etc.

[0028] The base station 114b in Figure 1A may be, for example, a wireless router, a home Node B, a home eNode B, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a local area (such as a business premise, a home, a vehicle, a campus, an industrial facility, an air corridor (such as for drones), a road, etc.). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (such as WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. As Figure 1A shown, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0029] The RAN 104 / 113 may communicate with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications, and / or voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, location-based services for mobile devices, prepaid calling, Internet connectivity, video distribution, etc., and / or perform advanced security functions such as user authentication. Although in Figure 1A ​Although not shown, it will be understood that RAN 104 / 113 and / or CN 106 / 115 may communicate directly or indirectly with other RANs that employ the same RAT as RAN 104 / 113 or a different RAT. In an example, in addition to being connected to RAN 104 / 113 that may utilize NR radio technology, CN 106 / 115 may also communicate with another RAN (not shown) that employs GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0030] CN 106 / 115 may also act as a gateway for WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols (e.g., the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite). The network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. In an example, the network 112 may include another CN connected to one or more RANs that may employ the same RAT as RAN 104 / 113 or a different RAT.

[0031] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). In an example, Figure 1A the illustrated WTRU 102c may be configured to communicate with a base station 114a that may employ a cellular-based radio technology and with a base station 114b that may employ IEEE 802 radio technology.

[0032] Figure 1B is a system diagram showing an example WTRU 102. As Figure 1B shown, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keyboard 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138, among others. It will be understood that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with the embodiments.

[0033] The processor 118 can be a general-purpose processor, a dedicated 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) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 can perform signal decoding, data processing, power control, input / output processing, and / or any other function that enables the WTRU 102 to operate in a wireless environment. The processor 118 can be coupled to a transceiver 120, and the transceiver 120 can be coupled to a transmit / receive element 122. Although Figure 1B the processor 118 and the transceiver 120 are depicted as separate components, it will be understood that the processor 118 and the transceiver 120 can be integrated together in an electronic package or chip.

[0034] The transmit / receive element 122 can be configured to transmit signals to, or receive signals from, a base station (such as base station 114a) via an air interface 116. In an example, in one embodiment, the transmit / receive element 122 can be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 can be a transmitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 can be configured to transmit and / or receive both RF and optical signals. It will be understood that the transmit / receive element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0035] Although the transmit / receive element 122 is depicted as a single element in Figure 1B , the WTRU 102 can include any number of transmit / receive elements 122. More specifically, the WTRU 102 can employ MIMO technology. Thus, in one embodiment, the WTRU 102 can include two or more transmit / receive elements 122 (such as multiple antennas) for transmitting and receiving wireless signals via the air interface 116.

[0036] The transceiver 120 can be configured to modulate the signals to be transmitted by the transmit / receive element 122 and demodulate the signals received by the transmit / receive element 122. As described above, the WTRU 102 can have multi-mode capabilities. Thus, the transceiver 120 can include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs (such as NR and IEEE 802.11).

[0037] The processor 118 of the WTRU 102 can be coupled to a speaker / microphone 124, a keyboard 126, and / or a display / touchpad 128 (such as a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit), and can receive user input data from these components. The processor 118 can also output user data to the speaker / microphone 124, the keyboard 126, and / or the display / touchpad 128. In addition, the processor 118 can access information from any type of suitable memory (such as non-removable memory 130 and / or removable memory 132), and store data into these memories. The non-removable memory 130 can include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 can include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and so on. In other embodiments, the processor 118 can access information from a memory that is not physically located on the WTRU 102 (such as on a server or a home computer (not shown)), and store data into these memories.

[0038] The processor 118 can receive power from a power supply 134, and can be configured to distribute and / or control the power to other components in the WTRU 102. The power supply 134 can be any suitable device for powering the WTRU 102. In an example, the power supply 134 can include one or more dry batteries (such as nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, fuel cells, and so on.

[0039] The processor 118 can also be coupled to a GPS chipset 136, which can be configured to provide location information (such as longitude and latitude) related to the current location of the WTRU 102. As a supplement or replacement for the information from the GPS chipset 136, the WTRU 102 can receive location information from a base station (such as base stations 114a, 114b) via an 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 understood that the WTRU 102 can obtain location information through any suitable location determination technology while remaining consistent with the embodiments.

[0040] The processor 118 may also be coupled to other peripheral devices 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connections. In an example, the peripheral devices 138 may include an accelerometer, an electronic 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 console module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. The peripheral devices 138 may include one or more sensors, which 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, and / or a humidity sensor.

[0041] The WTRU 102 may include a full-duplex radio for which the transmission and reception of some or all signals (e.g., associated with a particular subframe for both UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference via hardware (e.g., a choke) or via signal processing by a processor (e.g., a separate processor (not shown) or via the processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which the transmission and reception of some or all signals (e.g., associated with a particular subframe for uplink (UL) (e.g., for transmission) or downlink (e.g., for reception)).

[0042] Figure 1C is a system diagram showing the RAN 104 and the CN 106 according to an embodiment. As described above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRU 102a, 102b, 102c via the air interface 116. The RAN 104 may also communicate with the CN 106.

[0043] The RAN 104 may include eNode-Bs 160a, 160b, 160c, although it will be understood that the RAN 104 may include any number of eNode-Bs while remaining consistent with the embodiments. Each of the eNode-Bs 160a, 160b, 160c may include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c via the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, for example, the eNode-B 160a may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0044] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in the UL and / or DL, etc. As Figure 1C shown, the eNode-Bs 160a, 160b, 160c may communicate with each other via the X2 interface.

[0045] Figure 1C The illustrated CN 106 may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (or PGW) 166. Although each of the above elements is depicted 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.

[0046] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via the S1 interface and may act as a control node. In an example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activation / deactivation of bearers, selection of a particular serving gateway during the initial attachment of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide control plane functions for handover between the RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0047] The SGW 164 can be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 can generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 can perform other functions, such as anchoring the user plane during handover between eNode Bs, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and so on.

[0048] The SGW 164 can be connected to the PGW 166, which can provide the WTRUs 102a, 102b, 102c with access to a packet switched network (such as the Internet 110) to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0049] The CN 106 can facilitate communication with other networks. In an example, the CN 106 can provide the WTRUs 102a, 102b, 102c with access to a circuit switched network (such as the PSTN 108), thereby facilitating communication between the WTRUs 102a, 102b, 102c and traditional fixed telephone communication devices. In an example, the CN 106 can include or communicate with an IP gateway (such as an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 can provide the WTRUs 102a, 102b, 102c with access to other networks 112, which can include other wired and / or wireless networks owned and / or operated by other service providers.

[0050] Although the WTRU is described as a wireless terminal in Figures 1A - 1D it is contemplated that in some representative embodiments, such a terminal can use a wired communication interface (e.g., temporary or permanent) with the communication network.

[0051] In a representative embodiment, the other network 112 can be a WLAN.

[0052] In an infrastructure basic service set (BSS) mode, a WLAN can have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP can access or interface with a distribution system (DS) or another type of wired / wireless network that carries traffic into and / or out of the BSS. Traffic destined for an STA from outside the BSS can reach the STA through the AP and can be delivered to the STA. Traffic originating from an STA to a destination outside the BSS can be sent to the AP to be delivered to the corresponding destination. Traffic between STAs within the BSS can be sent through the AP. For example, the source STA can send traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic can be sent between the source STA and the destination STA (e.g., directly between the source STA and the destination STA) using direct link setup (DLS). In some representative embodiments, DLS can use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode can sometimes be referred to as an "ad-hoc" communication mode in this document.

[0053] When using an 802.11ac infrastructure operation mode or a similar operation mode, the AP can send beacons on a fixed channel (e.g., the primary channel). The primary channel can be of a fixed width (e.g., a bandwidth of 20 MHz wide) or a width dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In some representative embodiments, carrier sense multiple access with collision avoidance (CSMA / CA) can be implemented, for example, in an 802.11 system. For CSMA / CA, STAs including the AP (e.g., each STA) can sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, that particular STA can back off. Only one STA (e.g., only one station) can transmit at any given time in a given BSS.

[0054] A high throughput (HT) STA can communicate using a channel with a width of 40 MHz, for example, by combining the primary 20 MHz channel with an adjacent or non-adjacent 20 MHz channel to form a channel with a width of 40 MHz.

[0055] A very high throughput (VHT) STA can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels or by combining two non - consecutive 80 MHz channels, which can be referred to as an 80 + 80 configuration. For the 80 + 80 configuration, the data after channel coding can be fed through a segment parser that can divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time - domain processing can be performed on each stream separately. The streams can be mapped to two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the above operations for the 80 + 80 configuration can be reversed, and the combined data can be sent to the Media Access Control (MAC).

[0056] Sub - 1GHz operation modes are supported by 802.11af and 802.11ah. Compared with the channel operation bandwidths and carriers used in 802.11n and 802.11ac, the channel operation bandwidths and carriers in 802.11af and 802.11ah are reduced. 802.11af supports bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV white space (TVWS) spectrum, and 802.11ah supports bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using non - TVWS spectrum. According to a representative embodiment, 802.11ah can support meter - type control / machine - type communication, such as MTC devices in a macro - coverage area. MTC devices can have certain capabilities, such as including (e.g., only including) limited capabilities that support certain and / or restricted bandwidths. MTC devices can include a battery with a battery life higher than a threshold (e.g., to maintain a very long battery life).

[0057] A WLAN system (e.g., 802.11n, 802.11ac, 802.11af, and 802.11ah) that can support multiple channels and channel bandwidths includes a channel that can be designated as the primary channel. The primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or restricted by the STA that supports the minimum bandwidth operation mode among all STAs operating in the BSS. In an example of 802.11ah, for an STA (e.g., an MTC type device) that supports (e.g., only supports) the 1 MHz mode, the primary channel can 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 operation modes. Carrier sensing and / or Network Allocation Vector (NAV) settings can depend on the state of the primary channel. If the primary channel (e.g., due to an STA that only supports the 1 MHz operation mode transmitting to the AP) is busy, the entire available frequency band can be considered busy even if most of the frequency band remains idle and can be available.

[0058] In the United States, the available frequency band for 802.11ah is from 902 MHz to 928 MHz. In Korea, the available frequency band is from 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is from 916.5 MHz to 927.5 MHz. Depending on the country code, the total available bandwidth for 802.11ah is 6 MHz to 26 MHz.

[0059] Figure 1D It is a system diagram showing RAN 113 and CN 115 according to an embodiment. As described above, RAN 113 can communicate with WTRUs 102a, 102b, 102c via air interface 116 using NR radio technology. RAN 113 can also communicate with CN 115.

[0060] The RAN 113 may include gNBs 180a, 180b, 180c, but it will be understood that the RAN 113 may include any number of gNBs while remaining consistent with the embodiments. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c via the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. In an example, the gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, for example, the gNB 180a may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. In an example, the gNB 180a may transmit multiple component carriers (not shown) to the WTRU 102a. A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. In an example, the WTRU 102a may receive a coordinated transmission from the gNB 180a and the gNB 180b (and / or gNB 180c).

[0061] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. In an example, the OFDM symbol interval and / or the OFDM subcarrier interval may vary according to different transmissions, different cells, and / or different portions of the radio transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of various or scalable lengths (e.g., including a varying number of OFDM symbols and / or an absolute time of continuously varying length).

[0062] gNBs 180a, 180b, 180c can be configured to communicate with WTRUs 102a, 102b, 102c in stand-alone configuration and / or non-stand-alone configuration. In stand-alone configuration, WTRUs 102a, 102b, 102c can communicate with gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNode-Bs 160a, 160b, 160c). In stand-alone configuration, WTRUs 102a, 102b, 102c can utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor. In stand-alone configuration, WTRUs 102a, 102b, 102c can communicate with gNBs 180a, 180b, 180c using signals in the unlicensed band. In non-stand-alone configuration, WTRUs 102a, 102b, 102c can communicate / connect with gNBs 180a, 180b, 180c while also communicating / connecting with another RAN (e.g., eNode-Bs 160a, 160b, 160c). In an example, WTRUs 102a, 102b, 102c can implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In non-stand-alone configuration, eNode-Bs 160a, 160b, 160c can act as a mobility anchor for WTRUs 102a, 102b, 102c, and gNBs 180a, 180b, 180c can provide additional coverage and / or throughput for serving WTRUs 102a, 102b, 102c.

[0063] Each of gNBs 180a, 180b, 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to user plane functions (UPFs) 184a, 184b, routing of control plane information to access and mobility management functions (AMFs) 182a, 182b, etc. As Figure 1D shown, gNBs 180a, 180b, 180c can communicate with each other via the Xn interface.

[0064] Figure 1DThe illustrated CN 115 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and may include data networks (DN) 185a, 185b. Although each of the foregoing elements is depicted as part of CN 115, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0065] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. In an example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different packet data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, managing the registration area, terminating non-access stratum (NAS) signaling, mobility management, etc. The AMF 182a, 182b may use network slicing in order to customize the CN support for the WTRUs 102a, 102b, 102c based on the type of service utilized by the WTRUs 102a, 102b, 102c. In an example, different network slices may be established for different use cases, such as services relying on ultra-reliable low-latency communication (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, etc. The AMF 162 may provide control plane functions for handover between the RAN 113 and other RANs (not shown) employing other radio technologies (e.g., LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi).

[0066] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0067] UPF 184a and 184b can be connected to one or more of gNBs 180a, 180b, and 180c in the RAN 113 via the N3 interface. The N3 interface can provide the WTRUs 102a, 102b, and 102c with access to a packet-switched network (such as the Internet 110) to facilitate communication between the WTRUs 102a, 102b, and 102c and IP-enabled devices. UPFs 184a and 184b can perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0068] The CN 115 can facilitate communication with other networks. In an example, the CN 115 can include or communicate with an IP gateway (such as an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. Additionally, the CN 115 can provide the WTRUs 102a, 102b, and 102c with access to other networks 112, which can include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, and 102c can be connected to local DNs 185a and 185b via the N3 interface to the UPFs 184a and 184b and the N6 interface between the UPFs 184a and 184b and the data networks (DNs) 185a and 185b.

[0069] In view of Figures 1A - 1D and Figures 1A - 1D In view of the corresponding descriptions, one or more or all of the functions related to one or more of the following descriptions herein can be performed by one or more emulation devices (not shown): WTRUs 102a - 102d, base stations 114a - 114b, eNode-Bs 160a - 160c, MME 162, SGW 164, PGW 166, gNBs 180a - 180c, AMFs 182a - 182b, UPFs 184a - 184b, SMFs 183a - 183b, DNs 185a - 185b, and / or any other devices described herein. The emulation device(s) can be one or more devices configured to emulate one or more or all of the functions described herein. In an example, the emulation device(s) can be used to test other devices and / or simulate network and / or WTRU functions.

[0070] A simulation device can be designed to perform one or more tests on other devices in a laboratory environment and / or an operator network environment. In an example, one or more simulation devices can perform one or more or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more simulation devices can perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device can be directly coupled to another device for testing and / or can perform tests using over-the-air wireless communication.

[0071] One or more simulation devices can perform one or more (including all) functions while not being implemented / deployed as part of a wired and / or wireless communication network. In an example, the simulation device can be used in a test laboratory and / or a test scenario in a non-deployed (e.g., test) wired and / or wireless communication network to perform tests on one or more components. One or more simulation devices can be test devices. The simulation device can send and / or receive data using direct RF coupling and / or wireless communication via an RF circuit (e.g., which can include one or more antennas).

[0072] As described herein, examples can support relay-assisted positioning. In an example, a target WTRU to be located can be at the cell edge, in a poor coverage or out-of-coverage (OOC) scenario. In an example, the target WTRU may not have auxiliary data / resources (e.g., sounding reference signal (SRSp) configuration and / or positioning reference signal (PRS) configuration) to support Uu-based positioning. In an example, the target WTRU can have connectivity to the network via one or more relay WTRUs.

[0073] In an example, a sidelink (SL) relay WTRU can be used to support / assist in the positioning of the target WTRU.

[0074] The relay WTRU may assist in triggering UL-SRSp transmission at the target WTRU. In an example, the relay WTRU may be configured to receive configuration information from the network, including: an SL distance threshold + other triggering conditions (e.g., based on round-trip time (RTT)), a UL-SRSp configuration associated with a reception point (RP), and one or more validity conditions associated with the UL-SRSp configuration (e.g., a TA timer at the relay WTRU). The relay WTRU may be configured to perform measurements on the SL (e.g., SL-PRS or reference signal received power (RSRP) or RTT measurement of the SL channel), and determine the distance to the target WTRU based on the SL measurements. If the distance to the target WTRU is higher than the SL distance threshold and one or more validity conditions are met (e.g., the TA timer at the relay WTRU is running), the relay WTRU may be configured to send the UL-SRSP configuration associated with the RP to the target WTRU, send an indication to the gNB regarding triggering SRSp transmission at the target WTRU, send an SRSp activation indication to the target WTRU (e.g., in an SL MAC control element (CE)), and send an SRSp deactivation indication to the target WTRU if SRSp was previously activated and the validity conditions are not met (e.g., the TA timer at the relay WTRU expires).

[0075] The relay WTRU may assist in triggering SRSp and SL-PRS transmissions at the target WTRU. In an example, the relay WTRU may be configured to perform the following operations. The relay WTRU may be configured to receive configuration information from a network (NW). The configuration information may include SL-PRS configuration intended for the target WTRU, UL-SRSp configuration associated with the RP, a first threshold (e.g., reference signal received power (RSRP) threshold, threshold 1, and / or upper bound), and a second threshold (e.g., threshold 2 and / or lower bound). The relay WTRU may be configured to send the SL-PRS configuration (e.g., via PC5 signaling (PC5)-radio resource control (RRC)) to the target WTRU, including timing information. The relay WTRU may be configured to receive (e.g., from the target WTRU) the RSRP measurement of the SSB of the serving cell determined by the target WTRU. If the RSRP measurement of the target WTRU is below the first threshold and above the second threshold (e.g., the target WTRU has a poor Uu link with the serving cell), the relay WTRU may be configured to send an SL-PRS activation indication (e.g., in an SL MAC control element (MAC CE)) to the target WTRU, perform measurements on the SL-PRS received from the target WTRU, and send a measurement report to the network, including the arrival time (e.g., timestamp) and the RSRP measurement of the SL-PRS. If the RSRP measurement of the target WTRU is below the second threshold (e.g., the target WTRU has no Uu link), the relay WTRU may be configured to send the UL-SRSp configuration associated with the RP to the target WTRU, send an indication to the gNB to trigger SRSp and SL-PRS transmissions at the target WTRU, send an SRSp activation indication and an SL-PRS activation indication (e.g., in an SL MAC CE) to the target WTRU, and send a measurement report to the network including the arrival time (e.g., timestamp) and the RSRP measurement of the SL-PRS.

[0076] Downlink, uplink, sidelink, and downlink, uplink, and sidelink positioning techniques may be used.

[0077] In an example including downlink positioning, PRS may be sent from multiple transmit receive points (TRP), and the PRS may be sent to the WTRU. The WTRU may observe multiple reference transmissions and measure the time difference of arrival (TDoA) between one or more (e.g., a pair) of PRS. The TDoA may be referred to as the received signal time difference (RSTD). The WTRU may send the measured RSTD to a location management function (LMF). The WTRU may send the measured RSRP of the PRS (e.g., each PRS). At least based on the returned measurements, the LMF may perform the positioning of the WTRU. The WTRU may report the RSRP of the DL angle-based positioning technique.

[0078] The LMF can be a non - limiting example of a node or entity (e.g., a network node or entity) that can be used for positioning or to support positioning. A node or entity can replace the LMF.

[0079] In an example including uplink positioning, the WTRU can send an SRS for positioning (e.g., an SRS for positioning configured by RRC) to the TRP. In a timing - based example, the TRP can measure the relative time of arrival (RTOA) of the received SRS and report the measurement to the LMF. The WTRU can report the RSRP of the SRS. In angle - based uplink positioning, the TRP can measure the angle of arrival and report it to the LMF.

[0080] In an example including both uplink and downlink positioning, the WTRU can measure the receive - transmit (Rx - Tx) time difference between the received PRS and the transmitted SRS. The WTRU can report the Rx - Tx time difference to the LMF. The WTRU can report the RSRP of the measured PRS. At the TRP, the Rx - Tx difference between the received SRS and the transmitted PRS can be calculated.

[0081] Positioning can be described herein. DL positioning can include positioning using a downlink reference transmission such as the PRS. The WTRU can receive multiple reference transmissions from the TP and can measure the DL RSTD and / or RSRP. Examples of DL positioning can include one or more of DL - angle of departure (AoD) or DL - TDOA positioning.

[0082] UL positioning can include positioning that can use an uplink reference transmission (e.g., an SRS such as for positioning). The WTRU can send the SRS to multiple RPs, and the RPs can measure the UL RTOA and / or RSRP. Examples of UL positioning techniques can include UL - TDOA or UL - angle of arrival (AoA) (UL - AOA) positioning.

[0083] SL positioning can include positioning and / or ranging that can use a sidelink reference transmission such as the SL - PRS for positioning / ranging. In an example, the WTRU (e.g., the target WTRU) can send the SL - PRS to one or more other WTRUs (e.g., the anchor WTRU, RSU), and (e.g., the other) WTRUs can measure the SL RTOA and / or SL RSRP. The WTRU can receive the SL - PRS from one or more WTRUs (e.g., the anchor WTRU, RSU), and the WTRU can measure the SL RTOA and / or SL RSRP. Examples of SL positioning can include one or more of SL - TDOA, SL - AoA, SL - AoD, or SL - based RTT positioning.

[0084] DL&UL positioning may include positioning that may use uplink and downlink (e.g., both uplink and downlink) reference transmissions for positioning. In an example, a WTRU may send SRS to multiple TRPs, and a gNB may measure the Rx-Tx time difference. The gNB may measure the RSRP of the received SRS. The WTRU may measure the Rx-Tx time difference of the PRS sent from multiple TRPs. The WTRU may measure the RSRP of the received PRS. The measured (e.g., measured at the WTRU and gNB) Rx-TX difference and RSRP may be used to calculate the round-trip time. The Rx and Tx difference may include the difference between the arrival time of the reference transmission sent by the TRP and the transmission time of the reference transmission sent from the WTRU. Examples of DL&UL positioning techniques may include multi-RTT positioning.

[0085] Timing / angle positioning may include positioning techniques that may use reference transmissions such as SL-PRS. The WTRU may receive multiple reference transmissions from the WTRU and may measure RSTD, RSRP, and / or AoA. Examples of angle / timing positioning techniques may include SL-AoD or SL-TDOA positioning. In an example, the WTRU may send SL-PRS to the WTRU, and the receiver may perform measurements (e.g., RSTD, AoA, RSRP) to determine the location of the WTRU that may have sent the SL-PRS.

[0086] RTT positioning may include positioning that may use two or more WTRUs to send SL-PRS between the WTRUs. In an example, an anchor WTRU may send SL-PRS to a target WTRU. The target WTRU may receive the SL-PRS from the anchor WTRU, and the target WTRU may send the SL-PRS to the anchor WTRU. The target WTRU may measure the WTRU Tx-Rx time difference (e.g., the difference between the transmission time of the SL PRS from the target WTRU and the reception time of the SL-PRS sent from the anchor WTRU). The target WTRU may report the WTRU Tx-Rx time difference to the anchor WTRU.

[0087] Enhanced cell ID (e-CID) positioning may include positioning that may use radio resource management (RRM) measurements (e.g., RSRP of SSB) of cells associated with multiple gNBs. The operating principle for this positioning may be similar to other positioning techniques based on DL reference transmissions (e.g., DL-AoD, DL-TDOA, etc.). The transmissions that may be measured may result in lower accuracy in positioning determination.

[0088] In an example, the network may include an AMF, an LMF, a base station, a TRP, or a gNB in an NG-RAN (Next Generation Radio Access Network). Positioning for DL-PRS measurement in RRC CONNECTED state may allow for a limited level of mobility within a gNB (e.g., within the coverage area of a TRP belonging to the same gNB) and mobility between gNBs (e.g., for scenarios where the same PRS configuration can be used by multiple gNBs). Reporting of measurements and / or location information to the LMF may be supported via the serving gNB / cell.

[0089] In an example, the relay WTRU may include one or more of a WTRU (e.g., any anchor WTRU, any reference WTRU), a positioning reference unit (PRU), an RSU, an IAB node, a drone, a robot, or a network node (e.g., a relay node, a TRP). The relay WTRU may use either the SL interface (e.g., PC5) or the Uu interface to transmit and receive data / control messages and reference transmissions (e.g., SL-PRS, SRSp, PRS) on one or more channels. The relay WTRU may operate as an L2 or L3 relay for forwarding positioning-related transmissions. The relay WTRU may be fixed or mobile (e.g., moving in a certain direction and / or at a certain speed) relative to one or more fixed or mobile WTRUs and / or other network nodes (e.g., a TRP, a gNB).

[0090] WTRU-based and LMF-based (e.g., WTRU-assisted) positioning may be provided (e.g., for RAT-dependent and RAT-independent positioning techniques). WTRU behavior and the processes for supporting positioning may include one or more steps in one or more positioning processes and may not be limited to reception of broadcast channels, configuration, transmission / reception of initial access messages, transmission / reception of positioning reference transmissions, measurements, and reporting, which may be supported by the WTRU with low latency, high reliability, high power savings, and high accuracy, regardless of whether the coverage scenario is unknown.

[0091] The procedures and transmissions for Uu interface-based positioning may include the transmission of capability information from the WTRU to the network, the reception of assistance data from the network to the WTRU, the reception of reference transmissions (e.g., PRS and / or SRSp) by the WRTU, or the transmission of reference transmissions (e.g., PRS and / or SRSp) by the WRTU. The request for location information and measurement reports can be supported via a combination of higher layer transmissions (e.g., LTE positioning protocol (LPP)) and AS layer transmissions (e.g., RRC, MAC CE, downlink control information (DCI)). The procedures and transmissions for SL-based positioning can be supported via one or more of higher layer transmissions (e.g., SL-LPP, ranging and sidelink positioning protocol (RSPP)) or AS layer transmissions (e.g., PC5-RRC, SL MAC CE, SCI). The procedures and transmissions for determining WTRU location information using a relay WTRU may be unknown.

[0092] In an example, the target WTRU to be located may be at the cell edge, in a poor coverage area (e.g., poor link quality) of any cell in the network, or out-of-coverage (OOC). The target WTRU may not have a direct connectivity to the network to receive positioning resources and / or configurations (e.g., PRS, SRSp, SL-PRS configuration) that can be used to support Uu or SL-based positioning techniques. The target WTRU may have an indirect connectivity to the network via a relay WTRU (e.g., multi-hop), where the target WTRU can be connected to the relay WTRU via an SL interface (e.g., PC5, NR SL), and the relay WTRU can be connected to the base station (e.g., via the Uu interface). If the target WTRU is indirectly connected to the network, the target WTRU may need to be located with high accuracy (e.g., relatively high accuracy) and low latency.

[0093] In DL-based positioning, the WTRU can perform measurements on resources associated with DL-PRS and send a measurement report to the LMF based on the assistance data provided by the network. In UL-based positioning, the WTRU can send SRS (SRSp) resources configured for positioning via RRC. The transmission of SRSp by the WTRU can be received by different TRP / gNBs (e.g., in the network) for performing positioning measurements and reporting the measurements to the LMF and determining the WTRU location. This kind of positioning that can determine the WTRU location with a certain accuracy can be performed (e.g., may need to be performed) knowing that the target WTRU can be accessed by the network via one or more relay WTRUs or vice versa.

[0094] In an example involving a relay, the LMF may not know that the target WTRU can be indirectly connected to the network via a relay WTRU. The LMF may provide assistance data (e.g., PRS configuration, location information of the TRP / cell) that may not be suitable for positioning the target WTRU. The relay WTRU (e.g., L2 relay) that can be used for the purpose of relaying data may not know that the target WTRU can support the positioning process and / or can be associated with the network (e.g., gNB, LMF) used for positioning. When the target WTRU is dynamically controlled by the network, this may result in a higher waiting time or incorrect triggering of certain positioning processes (e.g., SRSp transmission). The target WTRU can be served by the relay WTRU and may not know the timing information (e.g., system frame number (SFN)) of the serving cell of the relay WTRU. This may result in timing misalignment during PRS reception and / or SRSp transmission. Since the target WTRU to be positioned may be in a poor or out-of-cell (OOC) region relative to the serving cell of the relay WTRU, it may be challenging to position the target WTRU with high accuracy.

[0095] It can be determined how an SL relay WTRU can be used to support and / or assist in the positioning of a target WTRU.

[0096] In an example, positioning can be provided. In an example, the SRS for positioning as stated herein may refer to the SRS transmission for positioning. A higher layer (e.g., RRC) message can be used to define (e.g., send) the resources for the SRS (SRSp) for positioning. The set of SRS resources and the SRS resources configured for positioning can be specified. The SRS or SRS for positioning as stated herein can include one or more of the following: the SRS that can be configured under SRS-PosResourceSet-r16 and SRS-PosResource-r16; the SRS that can be configured under SRS-ResourceSet and SRS-Resource; the SRS that cannot be configured under SRS-PosResourceSet-r16 and SRS-PosResource-r16; the SRS that cannot be configured under SRS-ResourceSet and SRS-Resource; the SRS that is not associated with SRS-PosResourceSet-r16, SRS-PosResource-R16, SR ResourceSet, or SRS-Resource; the uplink reference transmission that can be provided for positioning; the demodulation reference signal (DM-RS) for the uplink; or the phase-tracking reference signal (PTRS) for the uplink.

[0097] The SRS for positioning can be denoted as SRSp. The PRS or SRS as used herein may not be limited to the reference signal (RS) for positioning. The techniques described herein can be applied to or used in conjunction with DL or UL reference transmissions (e.g., any DL or UL reference transmission).

[0098] The positioning configuration may include information related to positioning measurements and / or SRSp transmission. One or more of the following information may be included in the positioning configuration: one or more of the following positioning techniques: DL-TDOA, UL-TDOA, DL-AoD, UL-AoA, multi-RTT, SL-TDOA, SL-AOA, SL-AOD, or SL-RTT; PRS configuration; SRSp configuration; SL-PRS configuration; uplink resources for reporting positioning measurements (e.g., physical random access channel (PRACH), physical uplink shared channel (PUSCH), physical uplink control channel (PUCCH)); one or more thresholds for determining the quality of positioning measurements; or positioning operation mode (e.g., initial positioning operation mode).

[0099] The PRS resource configuration may include one or more of the following: PRS resource ID; PRS sequence ID (e.g., or other ID for generating the PRS sequence); PRS resource element offset; PRS resource time slot offset; PRS symbol offset; PRS quasi co-location (QCL) information; PRS resource set ID; list of PRS resources in the resource set; multiple PRS symbols; silent mode of the PRS, silent parameters such as repetition factor, silent options; PRS resource power; periodicity of PRS transmission; spatial direction information of PRS transmission (e.g., beam information, transmission angle); spatial direction information of UL reference signal (RS) reception (e.g., beam ID for receiving UL RS, angle of arrival); frequency layer ID; TRP ID; or PRS ID.

[0100] The SRSp resource configuration may include at least one of the following: resource ID; comb offset value, cyclic shift value; start position in the frequency domain; number of SRSp symbols; offset in the frequency domain for SRSp; frequency hopping pattern; type of SRSp (e.g., aperiodic, semi-persistent, or periodic); sequence ID for generating SRSp, or other ID for generating the SRSp sequence; spatial relationship information indicating with which reference transmission (e.g., DL RS, UL RS, channel state information (CSI)-RS, SRS, DM-RS) or SSB (e.g., SSB ID, cell ID of the SSB) the SRSp may be spatially associated; QCL information (e.g., QCL relationship between the SRSp and other reference transmission or SSB), QCL type (e.g., QCL type A, QCL type B, QCL type D); resource set ID; list of SRSp resources in the resource set; transmit power related information; path loss reference information, which may include the index of the SSB, CSI-RS, or PRS; periodicity of SRSp transmission; spatial direction information of SRSp transmission (e.g., beam information, transmission angle); or spatial direction information of DL RS reception (e.g., beam ID for receiving DL RS, angle of arrival).

[0101] The SL-PRS configuration may include one or more of the following: SL-PRS resource ID; SL-PRS sequence ID (e.g., or other ID for generating the SL-PRS sequence); SL-PRS resource element offset; SL-PRS resource time slot offset; SL-PRS symbol offset; SL-PRS QCL information; SL-PRS resource set ID; list of SL-PRS resources in the resource set; number of SL-PRS symbols; mute mode of SL-PRS; mute parameter including repetition factor; mute option; SL-PRS resource power; periodicity of SL-PRS transmission; spatial direction information of SL-PRS transmission (e.g., beam information, transmission angle); spatial direction information of SL-RS reception (e.g., beam ID for receiving SL-RS, angle of arrival); frequency layer ID; UE ID; or SL-PRS ID.

[0102] In an example, and as part of the configuration, the WTRU may receive information related to the cell ID, global cell ID, or TRP ID that may be associated with the PRS. The TRP that transmits the PRS may be identified by the TRP ID, which may belong to the cell identified by the cell ID. The WTRU may be configured with timing information such as the SFN offset for PRS or SRSp transmission. An offset may be introduced to prevent the WTRU from receiving overlapping PRS in the time domain.

[0103] The WTRU may obtain parameters or configurations related to SRSp or SRS in one or more of the RRC, MAC-CE, DCI, or LPP messages. The WTRU may obtain parameters, configurations, or thresholds related to SRSp or SRS (e.g., a threshold of RSRP) in a broadcast message (e.g., SIB) or in a dedicated transmission from the network for the WTRU.

[0104] As described herein, SRS and SRSp may be used interchangeably.

[0105] As described herein, the target WTRU or remote WTRU may be used interchangeably and may refer to any WTRU that can be located using a positioning method, including absolute positioning (e.g., using global coordinates), relative positioning (e.g., using local coordinates), or ranging (e.g., distance and / or direction relative to a reference node).

[0106] As described herein, the relay WTRU and the anchor WTRU may be used interchangeably. The relay WTRU or the anchor WTRU may refer to a WTRU that can be used to support and / or assist in the positioning of a target WTRU. The target WTRU may be fixed or mobile (e.g., relatively mobile) with respect to any network node (e.g., TRP, gNB, cell) or peer (e.g., another peer) WTRU (e.g., relay WTRU, anchor WTRU) that can be used for positioning. The target WTRU may perform PRS measurements, SRSp transmissions, and SL-PRS measurements / transmissions (e.g., any of them) from / to network nodes and / or other WTRUs during positioning.

[0107] In an example, relay-WTRU-assisted positioning may support positioning techniques (e.g., DL-based positioning techniques, UL-based positioning techniques, SL-based positioning techniques) for positioning a target WTRU located in a coverage scenario (e.g., in-coverage, partially-covered, out-of-coverage) with the assistance of one or more relay WTRUs. The relay WTRU may be used to forward positioning-related transmissions between the network and the target WTRU and / or to perform transmissions and / or measurements of positioning reference transmissions (e.g., SRSp, PRS, SL-PRS).

[0108] In an example, a target WTRU located at the cell edge, with poor coverage, or in an OOC scenario can be assisted by one or more relay WTRUs located in coverage to support Uu-link based positioning (e.g., DL-TDOA, UL-TDOA), SL-based positioning, and / or Uu+SL-based positioning. The relay WTRU can be used to extend the coverage of the network (e.g., gNB, LMF) by providing the target WTRU with appropriate assistance data (e.g., positioning SIB), positioning resources / configurations, and other network configurations / parameters (e.g., timing information, SFN) for positioning. When the target WTRU is in coverage (IC), the relay WTRU can be used by the target WTRU to receive and / or transmit (e.g., transmit any) positioning-related transmissions (e.g., LPP messages), while minimizing the overhead on the Uu link and minimizing the transmission power.

[0109] In an example involving DL-based positioning, the WTRU can measure DL transmissions (e.g., PRS) received from one or more TRPs. DL-based positioning can be used when the WTRU can be in (e.g., any) RRC state (e.g., CONNECTED, INACTIVE, or IDLE). In an example, the TRP can send PRS instead of SSB or SIB, which can include transmissions for synchronization and / or assistance data for positioning (e.g., PRS configuration, TRP location information). In an example, the TRP can send PRS, SSB, and / or limited assistance data. In an example, the coverage and transmission quality of the PRS sent by the TRP can be better than that of the SSB (e.g., due to the use of different transmission schemes and / or resources). This can allow the WTRU to receive PRS without receiving SSB. In an example, the WTRU can access the network to receive positioning assistance data and timing-related information (e.g., synchronization, SFN) via a relay WTRU on SL. In an example, the relay WTRU can provide assistance data to the target WTRU based on (e.g., some) conditions configured by the network. The relay WTRU can be used to forward any higher layer transmissions from the network (e.g., LCS / LPP / SL-LPP) to the target WTRU. Similarly, the target WTRU can forward positioning information (e.g., measurement reports, calculated WTRU location) to the network via the relay WTRU.

[0110] In an example involving UL-based positioning, the WTRU may send UL transmissions (e.g., SRSp) that can be measured by one or more TRPs (e.g., receiving points (RPs)). The TRP may, for example, send (e.g., any) SSB to the WTRU or provide (e.g., any) positioning configuration / resources (e.g., SRSp configuration). The WTRU may receive positioning configuration / resources and timing information (e.g., synchronization, TA) from the network via a relay WTRU on the SL. In an example, the relay WTRU may, for example, provide an SRSp and / or SL-PRS configuration and / or dynamically trigger the target WTRU to send an SRSp / SL-PRS to the target WTRU based on conditions configured by the NW. In an example, the relay WTRU may be configured to perform measurements of SRSp and / or SL-PRS sent by the target WTRU. The relay WTRU may send the measurement results to the NW, which may be used to determine the location of the target WTRU.

[0111] Techniques common to the relay WTRU and the target WTRU may support relay WTRU-assisted positioning. In an example, such positioning may be initiated when the target WTRU is connected to the relay WTRU. In an example, the WTRU (e.g., target WTRU or relay WTRU) may be triggered to initiate any positioning procedure (e.g., DL-based, UL-based, SL-based, hybrid Uu+SL-based) for positioning the target WTRU. When a positioning initiation message is received / detected, the WTRU target may connect to one or more relay WTRUs. When sending / receiving a positioning initiation message, the network (e.g., LMF) may know the connection status of the target WTRU to the relay WTRU. The positioning of the target WTRU may be initiated based on any of the following: triggering / receiving of a location service (LCS) message, receiving an LLP request / indication, or WTRU initiation (e.g., target WTRU or relay WTRU).

[0112] The positioning of the target WTRU can be initiated based on the triggering / receipt of an LCS message. In an example, an LCS client in the WTRU (e.g., for MO-LR) or the network / LMF (e.g., MT-LR) can trigger a request for the location information of the target WTRU and an (e.g., implicit or explicit) indication indicating the use of one or more relay WTRUs to assist in the positioning of the target WTRU. In an example, the LCS client / network can explicitly indicate to perform the positioning of the target WTRU with the help of one or more relay WTRUs. In an example, when available, when indicating relaxed waiting time requirements for positioning or when the WTRU is in an OOC scenario, for example, when performing positioning, the LCS client / network can implicitly indicate the use of relay WTRUs. For example, the LCS client / network can implicitly indicate the use of relay WTRUs when providing assistance data including relay WTRU information (e.g., ID, relay WTRU location information).

[0113] The positioning of the target WTRU can be initiated based on the receipt of an LPP request / indication. In an example, the WTRU (e.g., the target WTRU or a relay WTRU) can receive an indication from the network (e.g., the LMF, the gNB) that indicates to switch to a different positioning technique (e.g., from SL-based positioning to Uu-based positioning or vice versa) when (e.g., some) relay WTRUs are available / detectable (e.g., for the target WTRU). In an example, such an indication can be received based at least on an indication / message sent by the WTRU (e.g., the target WTRU or a relay WTRU) to the network notifying one or more of the following: the initial target WTRU location, the initial measurements of transmissions / channels on the Uu link (e.g., SSB, CSI-RS, PRS), the initial measurements of transmissions / channels on the SL (e.g., SL-SSB, channel busy rate (CBR), discovery message, SL-PRS), the initial estimate of the timing advance (TA) value at the relay WTRU and / or the target WTRU, or the detection (e.g., ID) of one or more relay WTRUs by the target WTRU. In an example, the target WTRU can be directly or indirectly connected to the network, and when a relay WTRU is within the range where the WTRU (e.g., the target WTRU) can detect (e.g., any) transmissions (e.g., discovery messages) from the relay WTRU, an ongoing LPP session can receive an indication / configuration information to use one or more relay WTRUs for positioning purposes (e.g., for performing SRSp / SL-PRS measurements).

[0114] The positioning of the target WTRU can be WTRU-initiated (e.g., the target WTRU or a relay WTRU). In an example, when the target WTRU can be within the coverage of at least one of the TRPs (e.g., the PRS is detectable) and / or within the coverage of the relay WTRU (e.g., when an SL transmission sent by the relay WTRU is detected or when the RSRP of the SL transmission can be higher / lower than an RSRP threshold), the relay WTRU-assisted positioning for performing one or more of DL-based, UL-based, or SL-based positioning can be initiated by the target WTRU. In an example, a target WTRU preconfigured with (e.g., some) initial PRS configuration can use the configuration for detecting one or more TRPs, and the TRPs can send the PRS continuously or periodically. The WTRU can use the PRS configuration associated with the TRP (e.g., the preconfigured PRS configuration) to perform the initial measurement of the PRS. The WTRU can establish connectivity with the network via the relay WTRU (e.g., after discovering and establishing an SL connection with the relay WTRU). If the PRS measurement meets the criteria / conditions (e.g., if the ToA / RSRP of the PRS is higher than a threshold and / or remains higher than the threshold for a certain duration), the WTRU can report, via the relay WTRU, for example, the location estimate of the WTRU or the PRS measurement to the network. In an example, the relay WTRU-assisted positioning for performing the positioning of the target WTRU can be initiated by the relay WTRU when preconfigured to assist the positioning of one or more target WTRUs and / or when detecting a transmission sent by the target WTRU on the SL. In an example, the relay WTRU can trigger the positioning of the target WTRU by initiating the transmission of positioning-related discovery messages and / or positioning assistance data (e.g., posSIB) when meeting the conditions (e.g., some conditions) (e.g., the RSRP measurement of the target WTRU or the Uu link can be within the preconfigured threshold range).

[0115] In an example, a WTRU may send capabilities / assistance information for supporting relay WTRU-assisted positioning. The WTRU (e.g., a target WTRU and / or a relay WTRU) may send the capabilities / assistance information to one or more of a network (e.g., a gNB or an LMF) or a WTRU to support relay WTRU-assisted positioning when one or more trigger events / conditions as stated herein are detected. The WTRU may send the capabilities / assistance information semi-statically before / after initializing a positioning procedure (e.g., an LPP session) for determining the location of the target WTRU. The WTRU may send the capabilities / assistance information dynamically or on demand at any given time after initializing the positioning procedure. The WTRU may send the capabilities / assistance information to the network in an LPP message (e.g., the LPP may provide capabilities information or the LPP may provide an assistance information message) or in an AS layer send / message (e.g., RRC, MAC CE, uplink control information (UCI), PUSCH). In an example, the relay WTRU may send the capabilities / assistance information to the target WTRU on the SL using a higher layer (e.g., sidelink LTE positioning protocol (SLPP), RSPP) or an AS layer send (e.g., PC5-RRC, MAC CE, SCI), and vice versa.

[0116] Information sent by the target WTRU and / or the relay WTRU as capabilities information (e.g., via an LPP capabilities transfer procedure, an AS layer send / message) or assistance information (e.g., via an LPP assistance data transfer procedure, an AS layer send / message) may include a combination of one or more of the following: positioning techniques; device and timing attributes / parameters; achievable accuracy; transmission measurements / estimates; reference location, reference time instance, trajectory; or information regarding a power saving mode.

[0117] Positioning may include the ability to operate in a WTRU-assisted mode and / or a WTRU-based mode for positioning. In an example, a target WTRU may be located in an OOC and may indicate the ability to support WTRU-based positioning with the assistance of one or more relay WTRUs. In an example, a relay WTRU may indicate the ability to assist a target WTRU to position and / or estimate the location of the target WTRU when operating in a WTRU-based mode or a WTRU-assisted mode. The relay WTRU may indicate the ability to estimate the location of the target WTRU, for example, based on a positioning delegation technique (e.g., the target WTRU location information may be estimated or represented by the relay WTRU location information), with limited PRS / SL-PRS measurements and / or SRSp / SL-PRS transmissions or without performing PRS / SL-PRS measurements and / or SRSp / SL-PRS transmissions. Positioning may include the type of node. In an example, a WTRU may indicate one or more identifiers / information associated with the type of node (e.g., TRP / gNB, PRU, relay WTRU, IAB node) or node attributes (e.g., stationary or mobile) that may be used to perform positioning measurements and / or transmissions. In an example involving positioning, a WTRU may indicate the identifier / information about the positioning that may be used, and the positioning that may be used includes Uu-based, SL-based, and hybrid Uu+SL positioning (e.g., DL-TDOA, UL-TDOA, UL-AOA, multi-RTT, SL-TDOA, SL-RTT, e-CID, etc.).

[0118] Device and timing attributes / parameters may be provided by the WTRU. In an example, the WTRU may provide attributes / parameters including information about the number of antenna elements / panels, the number of radio frequency (RF) front-end chains (e.g., per Uu link and / or SL), antenna configuration information, bandwidth support (e.g., per RF link), and the processing capabilities for transmit / receive for RF transmissions (e.g., PRS, SRSp, CSI-RS, SL transmissions, SL-PRS) for positioning. In an example, the WTRU may provide attributes / parameters including the synchronization source (e.g., gNB, relay WTRU, GNSS) and timing information (e.g., SFN, SFN start offset, direct frame number (DFN), DFN start offset, TA on the Uu link, TA on the SL) supported / applied by the WTRU for data communication and / or positioning. The WTRU may indicate attributes / parameters including priority values and / or preferred values associated with any of the device parameters / attributes (e.g., preference for using the Uu link or SL for communication and / or positioning) and timing information (e.g., priority of the synchronization source, preference for using SFN or DFN).

[0119] The achievable accuracy can include the following. The WTRU may provide one or more positioning accuracy levels that can be achieved when performing positioning using different positioning techniques (e.g., DL-based, UL-based, SL-based). For example, the WTRU may provide positioning accuracy information when using hybrid positioning (e.g., based on the Uu link and SL) with the assistance of one or more relay WTRUs. The WTRU may indicate information regarding timing error groups (TEGs), including, for example, the WTRU Tx TEG ID, the WTRU Rx TEG ID, the WTRU Rx-Tx TEG ID. For example, the WTRU may send the association information between the SRSp resource and the WTRU Tx TEG ID. The WTRU (e.g., the target WTRU or the relay WTRU) may indicate whether measurements and / or transmissions on the Uu link and the SL can be performed simultaneously to meet, for example, the target accuracy value. In an example, the WTRU may indicate the confidence / weight / probability (e.g., between 0 and 1) associated with the Uu link and / or SL-based positioning. The confidence / weight / probability value may be associated with different granularities including positioning, PRS / SRSp / SL-PRS configuration, frequency layer, resource set / resource, beam, etc. The WTRU may indicate a priority value and / or a preference value associated with the accuracy level.

[0120] Transmission measurements / estimations can include the following. In an example, the WTRU may provide information regarding any of the initial measurements (e.g., RSRP, time of arrival (ToA), timestamp, RSTD measurement) made on one or more transmissions including SSB, CSI-RS, PRS, GNSS, SL-PRS, etc. In an example, the WTRU (e.g., the target WTRU or the relay WTRU) may provide information regarding the timing advance / alignment (TA) value associated with the Uu link (e.g., regarding the serving cell) and / or the TA value associated with the SL (e.g., regarding the relay / anchor WTRU). Such measurement / estimation of the TA may be done by the WTRU based on an indication received from the NW / relay WTRU (e.g., in a TA command) or estimated by the WTRU, for example, based on measurements.

[0121] Reference positions, reference time instances, and trajectories can include the following. In an example, a WTRU can provide information (e.g., an identifier) regarding the availability / accessibility of one or more reference positions associated with a positioning reference unit (e.g., a WTRU, a TRP, a gNB, a cell, a relay WTRU, an IAB node, an NTN node, a GNSS satellite) or detectable landmarks in proximity to the WTRU. For example, the WTRU can provide the distance / range to the identified reference positions. In an example, the WTRU can indicate information (e.g., an ID) regarding one or more positioning areas and / or regions associated with the coverage area of one or more cells / TRPs / gNBs / relay WTRUs where the WTRU may have been previously positioned, is currently positioned, and / or is expected to be positioned at different time instances.

[0122] Information regarding power saving modes can include the following. A WTRU (e.g., a target WTRU or a relay WTRU) can provide power saving modes that can be supported and / or configured by the network, including timing information (e.g., a timestamp) of any combination to which the WTRU may have previously transitioned or is expected to transition to RRC connected, RRC inactive, RRC idle, or any other combination of power saving modes. Information regarding power saving modes provided by the WTRU can include one or more configuration information or parameters associated with CDRX / I-DRX / discontinuous reception (DRX) (e.g., cycle time on duration, inactive timer duration). The WTRU can indicate a priority value and / or a preference value associated with the supported power saving mode / status and location / area information and / or timing information regarding where / when such priority / preference values can be applied.

[0123] When a triggering event / condition is detected or when a request message is received, the listed information / indications regarding location can be sent by the target WTRU and / or the relay WTRU to the network or another peer WTRU (e.g., a relay WTRU or a target WTRU). The target WTRU can send assistance information to the relay WTRU and can include (e.g., any of) the above information. For example, the relay WTRU can send (e.g., any of) the above information to the target WTRU or the network. The information / indications sent by the WTRU can be applicable to the positioning described herein.

[0124] PC5 can be established between the target WTRU and the relay WTRU, and the target WTRU can receive information regarding the positioning capabilities of the relay WTRU by sending an explicit request (e.g., PC5-RRC, MAC CE, etc.) to the relay WTRU. The relay WTRU can send / push information to the remote WTRU (e.g., without the need to receive a request from the WTRU).

[0125] If a PC5 connection is not established between the relay WTRU and the target WTRU, the positioning capabilities of the relay WTRU can be conveyed to the target WTRU. The positioning capabilities of the relay WTRU can be included in a relay discovery announcement sent from the relay WTRU. The target WTRU can include a request for the positioning capabilities of the relay WTRU in a relay discovery solicitation message. The relay discovery solicitation message can be a solicitation message that causes the relay WTRU to include their positioning capabilities in a relay discovery response message. The target WTRU can specify one or more positioning capabilities in the solicitation message, and the relay WTRUs that meet the indicated capabilities can respond with a relay discovery response message.

[0126] The WTRU can be configured to perform relay (re)selection taking into account the positioning capabilities of the relay WTRU. In an example, the positioning capabilities of the relay WTRU can be used by the target WTRU to determine a relay selection or reselection mechanism.

[0127] In an example, the target WTRU can be configured to prioritize relay WTRUs that may have one or more positioning capabilities. In an example, the target WTRU (e.g., after determining that a relay WTRU can support certain positioning capabilities) can apply a positive offset to the side link reference signal received power (SL-RSRP) measurements towards the (e.g., involved) relay WTRU (e.g., the relay WTRU that the WTRU is currently connected to, an adjacent relay WTRU, etc.).

[0128] In an example, the target WTRU can be configured to de-prioritize relay WTRUs that may not have one or more positioning capabilities. In an example, after determining that a relay WTRU may not support certain positioning capabilities, the target WTRU can apply a negative offset to the SL-RSRP measurements towards the involved relay WTRU (e.g., a relay WTRU that the WTRU may not currently be connected to, an adjacent relay WTRU, etc.).

[0129] The WTRU can be configured to monitor trigger events / conditions for sending information / indications associated with positioning. In an example, the trigger events / conditions monitored by the WTRU (e.g., the target WTRU and / or the relay WTRU) for sending indications and / or information can include one or more of the following, where the indications and / or information include capability information, assistance information, or requests to initiate, trigger, pause, resume, terminate any positioning technique or relay WTRU-assisted positioning. When the following trigger events / conditions are detected, the WTRU can send information / indications to the network or another peer WTRU (e.g., the relay WTRU or the target WTRU): receiving an indication or request from a higher layer / network; detecting a reference location / time; positioning or ranging information (e.g., distance / direction); positioning information of the WTRU; event-triggered / periodic; or measurements of radio link conditions (e.g., Uu link and / or SL).

[0130] The receiving of an indication or request from a higher layer or network can include the following. In an example, the WTRU can send information / indications when triggered by an LCS client / application in the WTRU (e.g., MO-LR) or by the network (e.g., MT-LR, delayed MT-LR, NI-LR). The LCS client can provide, for example, a reference time for positioning (e.g., scheduled position time) and / or a reference location (e.g., PRU, anchor WTRU, relay WTRU). The WTRU can obtain an indication / request from the LCS client in one or more of the following: LCS messages, LPP messages, AS layer transmissions / channels (e.g., RRC, MAC CE, DCI, data). In an example, the WTRU can send information / indications after receiving an LPP request message from the network. The request message can include an explicit request for capability information, an implicit request for information on measurements, detection of nearby relay WTRUs, the WTRU power saving mode, reference location / time, accuracy attributes, etc., one or more of which. In an example, the target / remote WTRU can send capability / assistance data when receiving an indication / request from a relay / anchor WTRU in a (e.g., any) higher layer transmission (e.g., SLPP, RSPP) and an AS layer transmission (e.g., PC5-RRC, MAC CE, SCI), or vice versa. In an example, the target WTRU can send an indication to the relay WTRU via SL to send capability / assistance information associated with the relay WTRU to the network.

[0131] Detecting a reference location / time can include the following. In an example, the WTRU can send information / indications to the network or another peer WTRU when detecting one or more reference locations (e.g., PRU, positioning area, TRP, anchor WTRU, relay WTRU) and / or at a reference time instance (e.g., scheduled position time).

[0132] Location or ranging information (e.g., distance / direction) may include the following. In an example, when it is determined that the distance to another peer WTRU (e.g., a target WTRU or a relay WTRU) may be above or below one or more distance thresholds, the WTRU (e.g., a relay WTRU or a target WTRU I) may send information / indication. The distance to the peer WTRU may be determined based on the RSRP or RTT measurement of an SL transmission (SL-PRS, discovery, Physical SL Control Channel (PSSCH)), or estimated based on the TA value used for the SL transmission. For example, if the RSRP of the SL-PRS is within the RSRP threshold range, the peer WTRU may be estimated to be within a certain distance. In an example, the WTRU (e.g., a relay WTRU or a target WTRU) may send information / indication when it is determined that the peer WTRU may be located in a specific direction from the WTRU within one or more direction / orientation angle thresholds. For example, the direction of the peer WTRU may be determined based on the Rx beam direction of the SL transmission (e.g., SL-PRS, PSSCH) received by the WTRU from the peer WTRU, the measurement of the power / phase of the SL transmission sent by the peer WTRU when a multi-antenna array is used at the WTRU, or an indication of the direction in which the peer WTRU is sending. The direction of the peer WTRU may be estimated to be within a certain angular range / width (e.g., +10 degrees, -10 degrees) relative to a reference direction (e.g., geographic north, the direction of the WTRU), and for example, the RSRP of the SL transmission received using the Rx beam may be within the RSRP threshold range.

[0133] The location information of the WTRU may include the following. In an example, the WTRU (e.g., a relay WTRU or a target WTRU) may send information / indication to a peer WTRU (e.g., a target WTRU or a relay WTRU) that may be located within or near a pre-configured location area or region. For example, the proximity (ID) to the region may be determined based on whether the WTRU may be within a distance threshold to the expected region, or based on a plurality of regions separating the region where the peer WTRU may be located from the expected region. The location area / region (e.g., any of the location areas / regions) may be associated with one or more location techniques and / or location configurations (e.g., PRS, SRSp, SL-PRS configuration).

[0134] In an example, the WTRU may periodically send information and / or indication, for example, based on one or more periodic values configured by the network or another peer WTRU. In an example, the WTRU may send updated / new capability / assistance information when it detects any change in the capability / assistance information regarding a previous occasion on which information may be sent.

[0135] A WTRU may send measurements of radio link conditions (e.g., Uu link and / or SL conditions). In an example, the WTRU may send information / indication when measuring and / or detecting a change in the radio link / conditions. In an example, the WTRU may be configured to perform measurements on DL-PRS / CSI-RS / SSB received from one or more TRPs / cells (e.g., serving cell and / or neighboring cells) or to estimate the TA value. In an example, the WTRU may be configured to measure SL-PRS / SL-RS / SL-SSB received from one or more relay / anchor WTRUs. The WTRU may send information / indication when the measurement values (e.g., RSRP, received signal strength indicator (RSSI), CBR, TA) may be within one or more thresholds or increase / decrease certain corresponding thresholds.

[0136] The trigger events / conditions described herein (e.g., any of the trigger events / conditions) may be configured and / or monitored by one or more of the target WTRU or relay WTRU for sending (e.g., any) indication / information to one or more of the network (e.g., gNB, LMF) or another peer WTRU. In an example, the relay WTRU may send auxiliary information / indication to the target WTRU or the network based on one or more of the trigger events described herein. The target WTRU may send auxiliary information / indication to the relay WTRU or the network based on one or more of the trigger events described herein.

[0137] The listed trigger events / conditions may apply to the techniques described herein. The indication / information sent by the WTRU when a trigger event / condition is detected may include one or more of the following (e.g., any of them): capability information; a request for auxiliary information; a request for a new / updated SRSp / PRS / SL-PRS configuration; a request to activate / deactivate a pre-configured SRSp / PRS / SL-PRS configuration; an indication of the start of SRSp / SL-PRS transmission or the start of PRS / SL-PRS measurement; a request for one or more relay WTRUs (e.g., alternative / new relay WTRUs); or an indication that a trigger event has been detected.

[0138] The WTRU may send the indication in the RRC connected state, the RRC inactive state, or the RRC idle state. In an example, when the WTRU is in the inactive state, the WTRU may use the SDT random access channel (RACH) or the SDT configured grant (CG) resource to send the indication (e.g., using the RRC Resume Request message or the MAC CE). In an example, when the WTRU is in the idle state, the WTRU may send the indication in one or more of the initial access / RACH messages (e.g., RRC Request, RRC System Information Request, RRC Reconfiguration Request, or RACH / RRC messages associated with positioning). In an example, the WTRU may use the RACH opportunity associated with positioning when in the idle state to send the indication. When sending the indication in the inactive / idle state, the WTRU may include a flag / cause information such that the WTRU may not be transitioned to the connected state. In an example, the WTRU may send the indication to the network after transitioning to the connected state for non-positioning or positioning-related reasons.

[0139] The WTRU may receive auxiliary data / configuration information for supporting relay WTRU-assisted positioning. In an example, the WTRU (e.g., the target WTRU and / or the relay WTRU) may receive auxiliary data and / or configuration information for supporting any positioning technique (e.g., DL-based, UL-based, SL-based, hybrid Uu+SL-based). For example, the auxiliary data and / or configuration information may be received by the WTRU from the LMF, the gNB, and / or a peer WTRU (e.g., the relay WTRU). The auxiliary data may be received by the WTRU in one or more of the following: positioning SIB (posSIB) (e.g., the WTRU may receive the posSIB from the network (e.g., when in coverage) or from the relay WTRU (e.g., when in OOC)); higher layer transmissions (e.g., LPP, SLPP, RSPP, discovery messages); Uu link AS layer transmissions / channels (e.g., RRC, MAC CE, DCI, physical downlink shared channel (PDSCH)); or SL AS layer transmissions (e.g., PC5-RRC, MAC CE, SCI, PSSCH).

[0140] The WTRU may receive the auxiliary data / configuration information associated with relay WTRU-assisted positioning due to one or more of the following triggers (e.g., any one): after sending a request, periodically, or upon detecting a configured event / condition.

[0141] After sending a request, the WTRU can receive auxiliary data / configuration information associated with relay WTRU-assisted positioning. In an example, the WTRU can send a request for auxiliary data (e.g., LPP message on-demand SI, sent at the AS layer) to the network, and the request indicates information / identifiers / configurations / parameters associated with one or more (e.g., any) of the following: a positioning session (e.g., an LPP / SLPP session), a positioning technique (e.g., Uu-link-based, SL-based), an access node (e.g., a TRP, a gNB, a cell), or a relay WTRU. The WTRU can receive the corresponding auxiliary data. In an example, a target WTRU connected to the network via a relay WTRU can send a request for auxiliary data (e.g., an LPP request) by including the ID of the service cell of the relay WTRU and / or the target WTRU / relay WTRU. In an example, the WTRU can receive auxiliary data (e.g., in an LPP message) after sending capability information and / or any other indication / message (e.g., an on-demand request, an LCS message, an LPP message, positioning information / report).

[0142] The WTRU can receive auxiliary data / configuration information associated with relay WTRU-assisted positioning periodically. In an example, the WTRU can be configured by the network to receive auxiliary data from the network or the relay WTRU periodically at a configured periodicity. In an example, the WTRU can request a change in the periodicity for receiving auxiliary data based on detecting one or more events, including a change in link conditions (e.g., an increase / decrease in Uu-link or SL measurements by some threshold), a change in the power saving state of the target / relay WTRU (e.g., when transitioning from connected to inactive), a change in the mobility state of the target WTRU and / or the relay WTRU (e.g., from a stopped state to a moving state), or a change in the accuracy / uncertainty of the relay WTRU location information, etc.

[0143] A WTRU may receive auxiliary data / configuration information associated with relay WTRU-assisted positioning due to the detection of a configured event / condition. In an example, the WTRU may receive one or more auxiliary data associated with a positioning technique (e.g., PRS, SRSp, SL-PRS configuration), an access node (e.g., TRP), or a relay / anchor WTRU. For example, the WTRU may store the auxiliary data and retrieve it for future positioning procedures / sessions (e.g., LPP session). The WTRU may receive validity conditions (e.g., positioning area validity, time validity) and / or events associated with suspending / resuming / releasing the auxiliary data. In an example, the WTRU may use pre-configured auxiliary data as long as the validity conditions can be met and / or the WTRU does not detect an event that invalidates the pre-configured auxiliary data. In an example, when the validity conditions expire and / or an event that invalidates the pre-configured auxiliary data can be detected by the WTRU, the WTRU may receive updated / new auxiliary data. In an example, the updated / new auxiliary data may be received based on an indication sent by the WTRU to the network or another WTRU indicating the expiration of the validity conditions, the detection of an event, and / or a request for new / updated auxiliary data.

[0144] Auxiliary data / configuration received by a WTRU (e.g., a target WTRU and / or a relay WTRU) from the network or another peer WTRU may include one or more of the following: an identifier / index / flag, a positioning configuration, timing information for positioning, location information, positioning measurements / transmission time instances and / or time windows, a priority value, an error and QoS threshold, calibration / compensation information, or a reporting configuration.

[0145] In an example, the auxiliary data / configuration received by the WTRU may include an identifier / index / flag.

[0146] In an example, the target WTRU may receive the ID / index of one or more access nodes (e.g., TRP, cell) and / or relay WTRU / anchor WTRU that may be used for positioning. In an example, a fixed / stationary relay WTRU and a mobile relay WTRU may be indicated with different flags / indexes.

[0147] In an example, a relay WTRU may receive auxiliary data from a network associated with one or more target WTRUs (IDs) that may be connected to the relay WTRU. Such auxiliary data may be received by the relay WTRU based on an indication / request message sent by the relay WTRU to the NW, for example including the ID of the target WTRU. In an example, the relay WTRU may experience different mobility states at different time instances / durations, including moving at a fixed speed, stopping, resuming movement, increasing / decreasing speed, etc. For example, the target WTRU may receive information about the mobility state / condition of the relay WTRU, and the time instance / duration of a mobility state change or an expected change.

[0148] In an example, the auxiliary data / configuration received by the WTRU may include a positioning configuration. In an example, the WTRU may receive one or more PRS, SRSp, and SL-PRS configurations / resources (e.g., IDs) that may be associated with / intended for positioning using one or more relay / anchor WTRUs. In an example, the positioning configuration (e.g., PRS, SRSp, SL-PRS) may be associated with one or more frequency layers, resources, resource sets, beams, TRPs, and / or relay / anchor WTRUs. In an example, one or more positioning configurations associated with the relay WTRU may be used by the target WTRU when connected to the relay WTRU via SL.

[0149] The type of positioning configuration (e.g., PRS, SRSp, SL-PRS) received by the WTRU may include one or more of aperiodic, semi-persistent, and periodic. In an example, the WTRU may receive reference nodes to be used when supporting TDOA-based positioning. The WTRU may receive a reference cell / TRP (ID) to be used when supporting DL-TDOA or a reference anchor WTRU (ID) to be used when supporting SL-TDOA. The indication of the reference node may allow the WTRU to perform RSTD measurements (e.g., the difference between the arrival times of PRS / SL-PRS received from the reference node and another node). In an example, the WTRU may be configured to perform multi-round-trip time (RTT) positioning using one or more TRPs, and the WTRU may receive both PRS configuration and SRSp configuration from the network and / or from the relay WTRU.

[0150] In an example, a WTRU may receive information regarding one or more measurement gap configurations (e.g., IDs) from a network and / or a relay WTRU, which may be associated with a PRS configuration to be used during measurements. For example, such a measurement gap configuration may be aligned with timing information (e.g., SFN, starting offset) provided by the network or relay WTRU to the target WTRU. In an example, a WTRU (e.g., a relay WTRU) may assist a peer WTRU (e.g., a target WTRU) to perform UL-based positioning (e.g., by determining and / or providing SRSp parameters (e.g., bandwidth, density, periodicity, Tx power)) for use during transmission, based on certain conditions, including measurements of SSB / PRS reported by the target WTRU, the relative position of the peer WTRU (e.g., the distance between the relay WTRU and the target WTRU, the positioning area / region where the target WTRU may be located), etc.

[0151] In an example, the assistance data / configurations received by the WTRU may include timing information for positioning. In an example, the target WTRU may receive timing information associated with a positioning configuration, such as a frame number (e.g., SFN), a starting offset time slot, a periodicity, and a stopping offset time slot, from a network or a relay WTRU. In an example, when connected to a relay WTRU, the relay WTRU may provide the SFN information of the serving cell or a timing adjustment / offset (e.g., such that the target WTRU can derive the SFN of the serving cell from the DFN for performing Uu-link-based positioning) to the target WTRU. For example, the timing information that can be used by the target WTRU for positioning may be associated with the relay WTRU and / or the serving cell of the relay WTRU. In an example where the WTRU may be configured with a positioning configuration (e.g., PRS, SRSp), the WTRU may apply certain timing offsets to the positioning configuration based on, for example, the timing information provided by the relay WTRU and / or the serving cell.

[0152] In an example, the assistance data / configurations received by the WTRU may include location information. In an example, the target WTRU may receive location information of one or more relay WTRUs and / or access nodes (e.g., TRPs) that can be used for any positioning mode (e.g., WTRU-based positioning). The location information may be in the form of absolute positioning information (e.g., global coordinates) or relative positioning information (e.g., local coordinates, distance / direction to a reference point). In an example, the location information of the relay WTRU may be directly received from the relay WTRU on the SL (e.g., in an SLPP / RSPP transmission). In an example, the WTRU may receive uncertainty information associated with the location of the access node or relay WTRU used (e.g., for positioning the target WTRU).

[0153] In an example, the assistance data / configuration received by the WTRU may include positioning measurements / transmission time instances and / or time windows. In an example, the target WTRU may receive information of one or more measurement / transmission time instances (e.g., t0, t1, t2, ……, ti) from a relay WTRU or the network, which indicates the time slots / opportunities when the WTRU may perform PRS measurements and / or SRSp transmissions. For example, the time instance may be associated with a start offset time slot (e.g., ti - T1, corresponding to the earliest time slot for starting positioning measurements / transmissions), a duration (e.g., the number of time slots), and a stop offset time slot (e.g., ti + T2, corresponding to the latest time slot for stopping positioning measurements / transmissions). The separation duration between different time instances may be configured to be fixed or variable. When the duration between time instances is fixed, the WTRU may perform positioning measurements / transmissions periodically, e.g., with a fixed periodicity.

[0154] In an example, the WTRU may receive one or more time windows, which indicate the positioning duration when the WTRU may perform PRS measurements and / or SRSp transmissions from / to one or more access nodes / TRPs and / or relay WTRUs. In an example, the duration of the time window may correspond to the maximum waiting time for determining the WTRU location based on PRS measurements and / or SRSp transmissions. For example, the measurement time instance and / or the time window may be identified by an ID / index and / or may be associated with one or more access nodes / TRPs or relay WTRUs used by the WTRU for positioning.

[0155] In an example where the target WTRU may be configured to perform multi-round-trip time (RTT) positioning using one or more access nodes, the WTRU may receive an RTT configuration (e.g., from a relay WTRU) consisting of a set of time instances (e.g., a set of time instances for performing PRS measurements and for performing SRSp transmissions).

[0156] In an example, the assistance data / configuration received by the WTRU may include a priority value. In an example, the WTRU may receive or be configured with a priority value associated with one or more positioning techniques (e.g., DL-based, UL-based, SL-based) to be used when connected to the network via a relay WTRU. Such a priority value may indicate, for example, a preference for using a positioning technique when the WTRU is connected to the relay WTRU.

[0157] The WTRU may receive from a relay WTRU or the network a priority value associated with one or more access nodes (e.g., TRP) and / or relay / anchor WTRU for positioning. Such a priority value may indicate, for example, a preference for selecting / using one or more access nodes and / or relay WTRUs for positioning.

[0158] In an example, the WTRU may receive a priority value from a relay WTRU or the network, indicating a PRS / SRSp configuration to be used when performing positioning with a set of one or more access nodes / TRPs. In an example, the WTRU may select a TRP and / or an associated PRS / SRSp configuration based on the order of priorities. The TRP and / or the associated PRS / SRSp configuration with the highest priority may be used first for positioning measurements, followed by the TRP and / or the associated PRS / SRSp configuration with the next highest priority.

[0159] In an example, the auxiliary data / configurations received by the WTRU may include error and QoS thresholds. In an example, the WTRU may receive one or more error thresholds associated with measurements (e.g., RSRP, RSTD, TOA, RTOA, number of multipaths) and / or positioning QoS (e.g., accuracy, integrity, latency). In an example, the error threshold may be associated with the determination of dilution of precision (DOP). The DOP condition may be determined as follows: For example, given the location of a WTRU, the difference / diversity in the locations of one or more access nodes or relay WTRUs / anchor WTRUs used for positioning may be less than a threshold. In an example, for example, the positioning error may be determined based on whether the calculated / detected DOP condition is above / below the DOP error threshold. For example, when performing measurements of DL or SL transmissions (e.g., PRS, SSB, SL-PRS) received from an access node or a relay / anchor WTRU, the WTRU may use the error threshold to determine whether the positioning measurement may be within the expected error bounds / threshold and / or whether the positioning QoS requirements may be met.

[0160] In an example, the auxiliary data / configurations received by the WTRU may include calibration / compensation information. In an example, the WTRU may receive calibration / compensation information / parameters to apply when performing measurements of DL or SL transmissions (e.g., PRS, SL-PRS) received from a TRP and / or an anchor WTRU / relay WTRU. In an example, the calibration information may include one or more TA values (e.g., cell-specific TA value, reference TA value, and / or WTRU-specific / differential TA value). In an example, the cell-specific TA value and / or the reference TA value may be the TA values used by a relay WTRU when transmitting to the serving cell of the relay WTRU. The WTRU-specific TA value may be related to the TA value applied when the target WTRU transmits any transmission to the relay WTRU on the SL. The TA value used by the target WTRU relative to the network and / or during SRSp transmission in the UL may be determined, for example, based on the cell-specific and WTRU-specific TA values.

[0161] In an example, the target WTRU may receive from the relay WTRU and / or the network TA values (e.g., cell-specific, WTRU-specific) to use when transmitting SRSp to one or more TRPs / cells of a serving cell including the relay WTRU. In an example, the target WTRU may determine the TA value to use when transmitting SRSp to any TRP based on auxiliary data provided by the relay WTRU (e.g., cell-specific TA) and / or RSRP measurements or distance estimates of the WTRU relative to the TRP and / or the relay WTRU. In an example, the target WTRU may be preconfigured by the network or the relay WTRU with one or more TA values to select and use when transmitting SRSp to one or more TRPs. The target WTRU may select the TA value based, for example, on RSRP measurements or estimates of the distance to the TRP and / or the relay WTRU. The WTRU may receive calibration / compensation information / parameters to apply when performing transmission of SRSp to the TRP, measurement of PRS received from the TRP, or transmission of SL-PRS to the relay WTRU.

[0162] In an example, the calibration information may be related to timing / phase errors (e.g., associated with the TRP, PRS configuration), indicating the difference between time instances / phases at which the TRP may generate and transmit the PRS. The calibration information may be related to timing / phase errors (e.g., associated with the WTRU and / or SRSp configuration), indicating, for example, the difference between time instances / phases at which the WTRU may generate and transmit the SRSp.

[0163] In an example, the calibration information received by the WTRU may be related to timing / phase errors expected at different cells, location areas, coverage areas, or reference areas. The WTRU may use the corresponding calibration information when performing measurements of the PRS and / or transmission of the SRSp.

[0164] In an example, the WTRU may receive calibration information / thresholds associated with error sources at the TRP, relay WTRU, and channels / links (e.g., Uu link, SL between the relay WTRU and the target WTRU), including synchronization errors, timing errors (e.g., Tx TEG ID, Tx-Rx TEG ID, Rx TEG ID at the TRP and the relay WTRU), multipath, LOS / NLOS, and errors in the location information of the TRP and / or the relay WTRU. For example, such calibration information may be used by the target WTRU when operating in a WTRU-based mode and where the target WTRU may estimate its location based on PRS and / or SL-PRS measurements.

[0165] In an example, the assistance data / configurations received by the WTRU may include a reporting configuration. In an example, when performing relay WTRU-assisted positioning, the WTRU may receive a reporting configuration to apply when sending positioning measurements. In an example, the reporting configuration may include the ID / index to be used (e.g., LPP / SLPP ID, TRP / cell ID, serving cell ID, relay WTRU ID, positioning technology ID). In an example, the reporting configuration may include whether to report absolute / average / minimum / maximum values related to measurements made on the PRS (e.g., ToA, RSRP, RSTD measurements made on resources / beams / TRPs / cells associated with the PRS).

[0166] In an example, the reporting configuration may include a reporting periodicity (e.g., whether the reporting is to be aligned with measurements / transmissions), an offset regarding the start / end of the measurements, and events that the WTRU may monitor / detect for sending a report to the network via the relay WTRU. In an example, when a change in radio conditions (e.g., RSRP above / below a threshold) is detected and a change in the mobility state of the relay WTRU is detected, the WTRU may send a report regarding positioning measurements / estimations / uncertainties.

[0167] The WTRU may include timing information (e.g., a timestamp) in the report, indicating, for example, the time instance at which the SFN may have been applied and when the measurements may have started / stopped. In an example, when the WTRU may perform prediction / extrapolation / interpolation during time instances when PRS or SL-PRS measurements may not be made or when SL is not available for the relay WTRU, the WTRU may send timing information (e.g., a timestamp) related to the associated start time, duration, and / or stop time. When performing extrapolation / interpolation of measurements, the WTRU may send information regarding one or more of the prediction uncertainty, confidence value, or weight value associated with instances of the extrapolated / interpolated measurement values.

[0168] The target WTRU and / or the relay WTRU may receive the assistance information / indications described herein, for example, when sending a request message or when triggered by an event, from the network or another peer WTRU (e.g., a relay WTRU or a target WTRU).

[0169] The assistance data received by a WTRU can be common across a positioning area (e.g., including multiple cells / TRPs) or specific to one or more cells / TRPs. For example, when the target WTRU receives one or more of the positioning area, TRP, or cell-specific assistance data from a relay WTRU or the network, the WTRU can use the associated assistance data under the coverage of the positioning area / TRP / cell. Similarly, for example, the relay WTRU can provide the target WTRU with the positioning area / TRP / cell-specific assistance data after determining or receiving an indication that the target WTRU can be under the coverage of the associated positioning area / TRP / cell.

[0170] Techniques at the target WTRU can support relay-WTRU-assisted positioning. The WTRU can be configured for WTRU-based and / or WTRU-assisted positioning with the assistance from a relay WTRU. In an example, the WTRU (e.g., the target WTRU) can be configured to perform positioning (e.g., with the assistance and support from one or more relay WTRUs) when using one or more of a WTRU-based positioning mode and a WTRU-assisted (network-based) positioning mode.

[0171] In a WTRU-based positioning mode, the WTRU can perform measurements on PRSs received from an access node (e.g., a TRP). The WTRU can calculate its position based on the measurement and the location information of the access node. In an example, the relay WTRU can support PRS transmission, and the WTRU can perform measurements on PRSs received from the relay WTRU. The WTRU can calculate its position based on the measurement and the location information of the relay WTRU.

[0172] In an example, the WTRU can receive PRSs from one or more access nodes and SL-PRSs from one or more anchor WTRUs (e.g., including relay WTRUs), and the WTRU can perform measurements on the PRSs and SL-PRSs at different time instances. The WTRU can calculate its position based on the PRS and SL-PRS measurements and the location information of the access nodes and the anchor / relay WTRUs.

[0173] Assistance data including one or more of a PRS configuration, an SL-PRS configuration, the location information or correction information of the access nodes and the anchor / relay WTRUs can be configured / received from the relay WTRU directly or indirectly via the relay WTRU from the network, for example. When calculating the WTRU position, for example, the WTRU can apply corrections by considering any errors caused by the relative position of the WTRU with respect to the relay WTRU or the access node.

[0174] In a WTRU-assisted (network-based) positioning mode, the WTRU may perform measurements on the PRS received from an access node and / or the SL-PRS received from an anchor WTRU / relay WTRU, and send a measurement report to the network (e.g., LMF, gNB) for calculating the WTRU location. For example, assistance data including one or more of the PRS configuration and the SL-PRS configuration may be configured / received from the network directly from the relay WTRU or indirectly via the relay WTRU. The measurement report sent to the network via the relay WTRU may include one or more (e.g., any) of the PRS measurement, the SL-PRS measurement, information on the access node and the WTRU for positioning (e.g., TRP ID, anchor / relay WTRU ID), and timing information (e.g., timestamp) for indicating a time instance at which the PRS and the SL-PRS measurements may be made. The timing information (e.g., included in the measurement report by the WTRU) may be indicated as a relative time with respect to a start / reference time (e.g., SFN, DFN), and may be provided by the relay WTRU to the target WTRU.

[0175] In an example, the WTRU may be configured to use one or more PRS configurations and / or PRS parameters (e.g., periodicity, bandwidth) based on the relative position or distance / direction of the target WTRU with respect to the relay WTRU and / or the access node (e.g., TRP). In an example, when the distance to the relay WTRU may be within a first distance threshold range, the WTRU may use a first PRS configuration, and when the distance to the relay WTRU may be within a second distance threshold range, the WTRU may use a second PRS configuration. Such PRS configurations / parameters may be applicable to both WTRU-based and WTRU-assisted modes, and may be used to ensure high-accuracy and reliable PRS measurements when using an access node outside the coverage of the serving cell.

[0176] In an example, if the number of available TRPs with a high RSRP (e.g., the RSRP of a PRS / SSB above the RSRP threshold) is above a threshold, the WTRU may select / determine to use a first PRS configuration (e.g., a first PRS resource set) with one or more of high resource density, high periodicity, high repetition, and / or high bandwidth parameters. For example, if the number of available TRPs with a high RSRP (e.g., the RSRP of a PRS / SSB above the RSRP threshold) is below the threshold, or if the RSRP of the PRS / SSB received from the TRP is below the RSRP threshold, the WTRU may select / determine to use a second PRS configuration (e.g., a second PRS resource set) with one or more of relatively low density, low periodicity, and / or low bandwidth parameters. In an example, the WTRU may determine whether to use the first PRS configuration or the second PRS configuration to perform measurements on the PRS received from the TRP, for example, based on one or more of the determination of the distance / direction to the relay WTRU or based on the RSRP measurement of the SL-PRS / SL transmission received from the relay WTRU.

[0177] In an example, to enable the WTRU to select / determine a suitable PRS or SL-PRS configuration / parameter, the WTRU may be pre-configured with one or more PRS / SL-PRS configuration / parameters, and one or more thresholds associated with relative position, distance / direction, and measurement (e.g., the RSRP of the Uu link transmission, the RSRP of the SL transmission). Such configuration information may be received by the WTRU from the network (e.g., the LMF, gNB) or from the relay WTRU as, for example, auxiliary data.

[0178] The WTRU may select one or more PRS / SL-PRS configuration / parameters for performing measurements on the PRS received from the access node or on the SL-PRS received from the anchor / relay WTRU, for example, based on the auxiliary data. In an example, the WTRU may send an indication (e.g., an on-demand indication via the relay WTRU) to the network (e.g., the LMF, gNB) or the relay WTRU to request, for example, an update, activation, or deactivation of the selected PRS configuration / parameters. In an example, the WTRU may send measurements of transmissions (e.g., PRS, SSB, SL-PRS) received from the access node or other WTRUs to the relay WTRU and / or the network. The WTRU may (e.g., then) receive PRS / SL-PRS configuration / parameters and / or an activation / deactivation indication triggering the use of the PRS / SL-PRS configuration / parameters from the network or the relay WTRU.

[0179] The WTRU may determine the positioning technique to apply when in an OOC or partial coverage scenario. In an example, the WTRU (e.g., the target WTRU) may determine / select one or more positioning techniques (e.g., Uu-link based, SL-based, hybrid Uu+SL-based) based on the criteria described herein. The criteria including one or more parameters / thresholds associated with the positioning technique may be configured by the network (e.g., sent via RRC or LPP) or the relay WTRU. In an example, the Uu-link based positioning technique that may be selected (e.g., by the WTRU) to perform positioning with the assistance of the relay WTRU may include one or more (e.g., any) of DL-TDOA, DL-AOD, UL-TDOA, UL-AOA, or multi-RTT. Similarly, the selectable SL-based positioning techniques may include one or more of, for example, SL-TDOA, SL-AOA, SL-AOA, or SL-RTT. If the WTRU is in an OOC or partial coverage scenario (e.g., the target WTRU may be in OOC and the relay WTRU may be in coverage), the WTRU may be triggered to select a positioning technique for determining the WTRU location after receiving a location request from a higher layer (e.g., MO-LR, MT-LR, NI-LR).

[0180] The WTRU may select / determine positioning based on one or more (e.g., any) of the following: measurements associated with Uu-link and / or SL coverage; an indication from the network or the relay WTRU; positioning QoS; the availability of the relay WTRU; the availability / reliability of resources for SL-based positioning; or priority.

[0181] The WTRU may select / determine positioning based on measurements associated with Uu-link and / or SL coverage. In an example, and (e.g., if) the RSRP measurement of the SSB / PRS / CSI-RS received from the TRP is higher / lower than one or more RSRP thresholds and / or remains higher / lower than the RSRP threshold for a duration (e.g., time duration), the WTRU may determine to use Uu-link based positioning (e.g., DL-based, UL-based, multi-RTT). For example, if the number of TRPs with RSRP above the threshold and / or with LOS condition is higher than the TRP count threshold, the WTRU may determine to use Uu-link positioning.

[0182] In an example, the WTRU may be connected to the serving cell via a relay WTRU. The RSRP of the SSB / PRS / CSI-RS received from the serving cell may be higher / lower than (e.g., some) RSRP thresholds, and when determining to use Uu-link-based positioning, the WTRU may include the serving cell together with other TRPs / cells in the measurement. For example, if the RSRP of the SSB / PRS / CSI-RS received from the serving cell is lower than (e.g., some) RSRP thresholds, the WTRU may include TRPs / cells outside the coverage of the serving cell and exclude the serving cell for Uu-link-based positioning.

[0183] In an example, if the RSRP measurement of the SL transmission (e.g., SL-PRS, discovery message, PSSCH) received from one or more anchor WTRUs (e.g., including / excluding a relay WTRU) is higher / lower than one or more RSRP thresholds (e.g., the RSRP of the SL PRS may be higher than the RSRP threshold), the WTRU may determine to use SL-based positioning (e.g., SL-TDOA). For example, if the RSRP of the SSB / PRS / CSI-RS received from the TRP / gNB is lower than some RSRP thresholds, the WTRU may determine to use SL-based positioning. For example, if the number of anchor WTRUs with an RSRP higher than the threshold and / or with LOS conditions is higher than the anchor WTRU count threshold, the WTRU may determine to use SL-based positioning.

[0184] In an example, if one or more of the following are true, the WTRU may determine to use hybrid Uu+SL-based positioning: the RSRP of the SSB / PRS / CSI-RS received from one or more TRPs is higher / lower than some RSRP thresholds; the RSRP of the SL transmission (e.g., SL-PRS) received from one or more anchor WTRUs is higher / lower than some RSRP thresholds; or the total number consisting of the number of TRPs with an RSRP higher than the threshold and the number of anchor WTRUs with an RSRP higher than the threshold is higher than the node count threshold.

[0185] The WTRU may select / determine a positioning technique based on an indication from the network or a relay WTRU. In an example, the WTRU may use Uu-link-based, SL-based, or hybrid Uu+SL-based positioning based on an indication of positioning received from the network (e.g., in LPP, RRC, MAC CE, DCI) or from a relay WTRU (e.g., in SLPP / RSPP, PC5-RRC, MAC CE, SCI). The WTRU may select / determine positioning based on positioning QoS.

[0186] In an example, when the positioning accuracy can be (e.g., relatively) high (e.g., <1m horizontal / vertical accuracy) and one or more TRPs that can support Uu-link based positioning with a desired accuracy are available, the WTRU may determine / select Uu-link based positioning.

[0187] When determining Uu-link based positioning, when the WTRU can perform positioning with low latency, the WTRU may select UL-TDOA. UL-based positioning can be used to avoid the latency associated with DL-based positioning, which is caused by measurements at the WTRU and sending measurement reports via multi-hop (e.g., via a relay WTRU).

[0188] In an example, if the positioning latency requirement is low (e.g., below a threshold) and one or more anchor WTRUs (e.g., which can support SL-link based positioning with a desired accuracy) are available, the WTRU may determine / select SL-link based positioning.

[0189] In an example, when the positioning accuracy may be (e.g., relatively) high and / or the positioning latency can be less stringent (e.g., not very strict) and the number of TRPs and anchor WTRUs that can be combined for positioning is higher than a threshold, the WTRU may determine / select hybrid Uu+SL-link based positioning.

[0190] The WTRU may select / determine a positioning technique based on the availability of a relay WTRU. In an example, when the WTRU establishes a connection with at least one relay WTRU to receive positioning assistance data / resources from the network, the WTRU may determine to use Uu-based positioning. If no relay WTRU that can assist / support positioning is available / detectable, the WTRU may select to use SL-based positioning.

[0191] The WTRU may select / determine a positioning technique based on the availability / reliability of resources for SL-based positioning. In an example, the WTRU may determine / select to use SL-based positioning after identifying that the availability of resources for SL positioning is above / below a threshold (e.g., a CBR threshold) based on SL-based measurements (e.g., RSRP, RSSI, CBR measurements when operating in mode 2) or an indication from one or more anchor WTRUs and / or after remaining above / below the threshold for a duration. For example, if the resources for SL-based positioning are not available and a TRP for supporting Uu-link based positioning is available, the WTRU may determine to use Uu-based positioning.

[0192] The WTRU may select / determine a positioning technique based on a priority value. In an example, where both Uu-link-based positioning and SL-based positioning are available, when the WTRU has established connectivity on the SL with at least one relay WTRU that can assist / support positioning, the WTRU may determine to use Uu-based positioning with a priority higher than SL-based positioning.

[0193] The WTRU may select (e.g., reselect) a relay WTRU for supporting or assisting positioning. In an example, the WTRU (e.g., the target WTRU) may select (e.g., reselect) one or more relay WTRUs based on a set of one or more events / conditions / criteria to assist and / or support the target WTRU in positioning. For example, the selection criteria may be pre-configured in the WTRU, received from the network (e.g., as assistance data), and / or received on the SL from a peer WTRU (e.g., a non-positioning relay WTRU, an anchor WTRU).

[0194] The WTRU may perform the selection of the relay WTRU for positioning, for example, when triggered by a location request (e.g., MO-LR) and / or when determining the positioning to be applied. After identifying potential relay WTRUs for positioning and / or selecting a relay WTRU, the target WTRU may send a request message to the relay WTRU or to the network (e.g., via the relay WTRU) via the SL (e.g., via PC5-RRC, MAC CE, SCI, PSSCH). For example, when the relay WTRU receives a response message / indication from the relay WTRU or from the network, the relay WTRU may be used for positioning purposes.

[0195] The WTRU may trigger the relay WTRU selection (e.g., reselect) process and / or select (e.g., reselect) a relay WTRU based on one or more of the following events / conditions / criteria: measurements associated with the SL and / or the Uu-link; coverage of posSIB and / or PRS; distance / direction to the relay WTRU; positioning information of the relay WTRU; association with the relay WTRU for data communication; serving cell of the relay WTRU; ability of the relay WTRU for positioning; positioning QoS; priority; or an indication received from the network.

[0196] The WTRU may trigger the selection (e.g., reselection) and / or selection (e.g., reselection) of a relay WTRU based on measurements associated with the SL and / or Uu link. In an example, the WTRU may trigger the selection of a relay WTRU when the RSRP measurement of the Uu link of the serving cell is higher / lower than one or more RSRP thresholds (e.g., lower than a threshold). The WTRU may trigger the selection of a relay WTRU when the RSRP measurement of the Uu link of an adjacent cell is higher / lower than one or more RSRP thresholds (e.g., higher than a threshold). For example, if the RSRP measurement of an SL transmission received from a relay WTRU (e.g., SL-PRS, discovery message, PSSCH) is higher / lower than one or more RSRP thresholds, the WTRU may select a relay WTRU from a set of available candidates.

[0197] The WTRU may trigger the relay WTRU selection (e.g., reselection) process and / or selection (e.g., reselection) of a relay WTRU based on the coverage of posSIB and / or PRS. In an example, the WTRU may trigger the selection of a relay WTRU when determining the coverage of the SIB (e.g., posSIB) received from the serving cell or when the coverage of an adjacent cell (e.g., any one of them) may be lower than the coverage of the PRS. For example, the WTRU may trigger the selection of a relay WTRU when the RSRP of the SSB / posSIB received from an adjacent / serving cell is lower than a first RSRP threshold and the RSRP of the PRS received from the adjacent / serving cell is higher than a second RSRP threshold. For example, the WTRU may trigger the selection of a relay WTRU when the RSRP of the PRS received from the serving cell is lower than an RSRP threshold. For example, the selection and / or use of a relay WTRU may allow the WTRU to receive auxiliary data from the network (e.g., via LPP).

[0198] The WTRU may trigger the relay WTRU selection (e.g., reselection) process and / or select (e.g., reselect) a relay WTRU based on the distance / direction to the relay WTRU. In an example, the WTRU may select a relay WTRU for which the distance to the target WTRU may be above / below one or more distance thresholds. The distance to the relay WTRU may be determined, for example, based on the RSRP or RTT measurements of the SL transmission (SL-PRS, discovery, PSSCH). The distance to the relay WTRU may be estimated based on the TA value (e.g., the TA value for SL transmission (e.g., data transmission)). In an example, the WTRU may select a relay WTRU that may be located in a specific direction from the target WTRU within one or more direction / orientation angle thresholds. For example, the direction to the relay WTRU may be determined based on the Rx beam direction used at the target WTRU or the SL transmission power / phase received from the relay WTRU when a multi-antenna array is used at the target WTRU.

[0199] The WTRU may trigger the relay WTRU selection (e.g., reselection) process and / or select (e.g., reselect) a relay WTRU based on the positioning information of the relay WTRU. In an example, when positioning based on the WTRU is supported, the WTRU may select a relay WTRU for which the location information and attributes (e.g., accuracy, uncertainty, integrity) are provided to / are available for the target WTRU. When multiple candidate relay WTRUs are available, the WTRU may select, for example, the relay WTRU with the highest accuracy and / or the lowest uncertainty. In an example, the WTRU may select a relay WTRU that may be located within or near a positioning area or region associated with one or more TRPs where the WTRU may perform Uu-link based positioning (e.g., DL-based or UL-based).

[0200] The WTRU may trigger the relay WTRU selection (e.g., reselection) process and / or select (e.g., reselect) a relay WTRU based on the association with the relay WTRU used for data communication. In an example, for positioning purposes (e.g., for requesting assistance data or posSIB), the WTRU may be configured or selected to select the same relay WTRU used for data communication. In an example, the WTRU may select and / or use a different relay WTRU for data communication and positioning, for example, if the selected relay WTRU is not overloaded for supporting multiple services and multiple target WTRUs.

[0201] A WTRU may trigger a relay WTRU selection (e.g., reselection) process and / or select (e.g., reselect) a relay WTRU based on the serving cell of the relay WTRU. In an example, the WTRU may select a relay WTRU based on whether the serving cell of the relay WTRU can assist or support the positioning of the target WTRU.

[0202] A WTRU may trigger a relay WTRU selection (e.g., reselection) process and / or select (e.g., reselect) a relay WTRU based on the capabilities of the relay WTRU for positioning. In an example, the WTRU may select a relay that can assist or support the same / similar positioning technology supported by the target WTRU. The WTRU may select a relay WTRU based on the availability of assistance data and / or configuration (e.g., posSIB, PRS configuration, SRSp configuration, SL-PRS configuration) at the relay WTRU associated with the positioning technology, the access node (e.g., TRP), or the anchor WTRU (e.g., used by the target WTRU for positioning). In an example, the WTRU may select a relay WTRU that can provide any one of posSIB, assistance data including PRS configuration, and timing information (e.g., SFN information) associated with the serving cell when determining to use a DL-based positioning technology. When the WTRU determines to use SL-based positioning, the WTRU may select, for example, a relay WTRU that can perform the transmission or measurement of SL-PRS. The WTRU may select a relay WTRU based on whether the relay WTRU can have the ability to perform PRS transmission and / or SRSp measurement, e.g., similar to a TRP.

[0203] A WTRU may trigger a relay WTRU selection (e.g., reselection) process and / or select (e.g., reselect) a relay WTRU based on positioning QoS. In an example, the WTRU may select a relay WTRU that can allow the positioning accuracy requirements to be met by providing a suitable positioning configuration (e.g., PRS configuration, SRSp configuration) to the target WTRU. In an example, the WTRU may select a relay WTRU that can allow the positioning latency requirements to be met based on one or more relay-related attributes such as the number of hops to the network, the load at the relay WTRU, the size of the measurement report, etc. In an example, the WTRU may select a relay that can allow, meet, or extend the validity conditions (e.g., area validity, time validity) associated with a preconfigured PRS / SRSp configuration. For example, the WTRU may select a relay WTRU that can allow the use or extension of the TA timer validity associated with the SRSp configuration that can be provided to the WTRU.

[0204] The WTRU may trigger the relay WTRU selection (e.g., reselection) process and / or select (e.g., reselect) a relay WTRU based on priorities. In an example, when multiple candidate relay WTRUs are available, the WTRU may select the relay WTRU with the lowest load condition, which has a higher priority than other relay WTRUs with high load conditions. The load condition may be associated with the number of remote / target WTRUs served by the relay WTRU, which may be determined by the target WTRU based on, for example, an indication received from the relay WTRU or measurements on the SL. In an example, the WTRU may select a relay WTRU that may be stationary or moving at a low speed with a higher priority than another candidate relay WTRU that may be moving at a high speed. In an example, the WTRU may select a relay WTRU based on the order of priorities configured / indicated by the network.

[0205] The WTRU may trigger the relay WTRU selection (e.g., reselection) and / or select (e.g., reselect) a relay WTRU based on the reception of an indication from the network. In an example, the network (e.g., gNB or LMF) may know the capabilities and attributes associated with positioning or one or more relay WTRUs (e.g., location information of the relay WTRU), and the WTRU may receive information (e.g., ID) associated with the network-selected relay WTRU based on a request message from the target WTRU. In an example, the WTRU may receive auxiliary / supporting information / indication for positioning from the network of the candidate relay WTRUs. For example, the WTRU may select a relay WTRU and indicate the selected relay WTRU (e.g., ID) to the network. The network- or WTRU-selected relay WTRU may be configured by the network to forward any positioning transmissions (e.g., posSIB, LPP message, SRSp configuration) to / from the target WTRU, for example.

[0206] The WTRU may send a positioning-related indication / request message to the relay WTRU. In an example, the WTRU (e.g., target WTRU) may send an indication / request message on the SL to the relay WTRU for indicating one or more of the following: a request for auxiliary data / configuration; a request for posSIB; a request for activating / deactivating positioning configuration; or measurements on the Uu link and / or SL.

[0207] The WTRU may send an indication / request message on the SL to the relay WTRU to indicate a request for assistance data / configuration. In an example, the WTRU may request assistance data that may be associated with Uu-link and SL-based positioning, including one or more (e.g., any) of the following: PRS, SRSp, or SL-PRS configuration and / or parameters of the relay WTRU, location information, location information of the TRP, calibration information, etc. In an example, the WTRU may send a request for region- or positioning area-specific assistance data, which may include cell / TRP IDs, PRS / SRSp configurations associated with (e.g., some) TRPs / cells. For example, a request for new assistance data, a request for updating pre-configured assistance data, a request for switching between different assistance data / configurations, or an on-demand request may be sent.

[0208] The WTRU may send an indication / request message on the SL to the relay WTRU to indicate a request for posSIB. In an example, the WTRU may send a request for posSIB to the relay WTRU by indicating the posSIB ID. In an example, the WTRU may send a request for region-specific posSIB by including the positioning area ID and the posSIB ID. The WTRU may send an explicit or implicit request for timing information (e.g., SFN information, timing offset, offset / adjustment to be applied to the DFN) of the serving cell of the relay WTRU or one or more (e.g., any) neighboring cells (e.g., cell IDs) detected by the WTRU.

[0209] The WTRU may send an indication / request message on the SL to the relay WTRU to indicate a request for activating / deactivating a positioning configuration. In an example, the WTRU may send a request to activate / deactivate any one of the pre-configured SRSp, SL-PRS, and PRS configurations / parameters. The WTRU may send, for example, the ID / index of the configuration / parameter that is requested to be activated / deactivated.

[0210] The WTRU may send an indication / request message on the SL to the relay WTRU to indicate measurements of the Uu-link and / or the SL. In an example, the WTRU may be configured to send a measurement report, including RSRP measurements of SSB / PRS received from the serving cell or neighboring cells, RSRP measurements of SL transmissions (e.g., SL-PRS, discovery message, PSSCH), and CBR measurements of resource pools associated with one or more configurations related to positioning.

[0211] The WTRU may send an indication / request message when detecting any of the following triggering events / conditions: receiving an indication from a higher layer or the NW; receiving an indication / message (e.g., discovery message) from a relay WTRU regarding capabilities for assisting or supporting positioning (e.g., Uu link and / or SL measurements (e.g., when the RSRP measurement of the SSB / PRS received from the serving cell or an adjacent cell is higher / lower than one or more thresholds, the WTRU may be triggered to send a request / indication to the relay WTRU. When the RSRP measurement or CBR measurement of the SL transmission (e.g., SL-PRS) received from any of the anchor WTRU or the relay WTRU is higher / lower than one or more thresholds, the WTRU may send a request / indication)); detecting a change in the movement or location of the target WTRU; or having a periodic triggering event / condition with a configured period. For example, the WTRU may use any of on-demand SI, SLPP / RSPP, PC5-RRC, SL MAC CE, and SCI to send an indication / request message to the relay WTRU. In the example, the WTRU may send a measurement report / location estimate to the relay WTRU and / or the network.

[0212] In the example, the WTRU (e.g., the target WTRU) may send positioning information / report (e.g., location measurement / estimate) to the relay WTRU and / or the network based on one or more of the measurements performed on the PRS received from one or more TRPs or the measurements performed on the SL-PRS received from one or more anchor WTRUs and / or relay WTRUs. In the example, the WTRU may send positioning information based on the reporting configuration received in the assistance data from the relay WTRU or the network. For example, the WTRU may send the positioning information / report after completing the measurements and / or after detecting the triggering events / conditions herein (e.g., receiving a request from the network, periodic reporting, detecting an error, etc.).

[0213] The positioning information / report may be sent by the WTRU periodically or triggered based on an event, in one or more of the following (e.g., any of them): sent by a higher layer (e.g., in LPP, SLPP, RSPP), sent by the AS layer on the SL to the relay WTRU (e.g., in PC5-RRC, MAC CE, SCI, PSSCH), or sent by the AS layer on the Uu link to the network (e.g., in RRC, MAC CE, UCI, PUSCH). The positioning information sent by the WTRU may include one or more of the following: location information / measurement; access node; SL positioning information; timing information; error information; positioning QoS; WTRU mobility / movement information; or prediction / interpolation information.

[0214] In an example, the positioning information sent by the WTRU may include location information / measurements. In an example, the WTRU may send a determined / estimated WTRU location (e.g., coordinates, relative position relative to a reference point / location) and / or measurements that may be used to determine / estimate the WTRU location. For example, the WTRU may send the location information using absolute values ​​(e.g., normal coordinates) or truncated values ​​(e.g., abbreviated coordinates). The location information may be sent along with (e.g., together with) timing information (e.g., a timestamp indicating when the measurement / estimation was performed) and / or an ID / index of a configuration applied during the measurement, the configuration including, for example, one or more of a PRS / SL-PRS configuration, a measurement time instance / window, and a separation criterion. When sending timing information (e.g., a timestamp), the WTRU may report an absolute time (e.g., UTC), a system time (e.g., SFN, DFN), or a differential time (e.g., a time difference relative to a previous / reference time instance / opportunity). In an example, in addition to PRS measurements, the WTRU may also send information about any other measurements and estimates, including measurements of GNSS transmissions (e.g., used to estimate the initial WTRU position), measurements of RRM transmissions (e.g., CSI-RS, SSB), and estimates of the TA.

[0215] In an example, the positioning information sent by the WTRU may include the access node. In an example, the WTRU may send information about the access node / TRP (e.g., ID / index) used during positioning. For example, the WTRU may send timing information (e.g., timestamp) indicating the start / end time of use or switching to one or more (e.g., any) of the access nodes. In an example, the WTRU may send information associated with one or more PRS configurations / parameters (e.g., ID / index) that are used in association with the selection of one or more access nodes. In an example, when a reference unit is used for differential measurement (e.g., RSTD, differential timing / phase), the WTRU may send information (e.g., ID, timing information / timestamp) on any reference unit such as a PRU, a reference point and / or a reference access node / anchor WTRU / TRP.

[0216] In an example, the positioning information sent by the WTRU may include SL positioning information. In an example, when the WTRU is configured with an SL positioning technique (e.g., SL-TDOA, SL-AOD, SL-AOA, SL-RTT) using one or more anchor WTRUs, the WTRU may report one or more of the following: the anchor WTRU ID; the reference time used (e.g., absolute time or relative time), where the time may be based on, for example, one or more of the following: GNSS synchronization time, the SFN provided by the network, the DFN based on which RSTD measurements / calculations can be performed; the reference point used (e.g., the position on the cell / beam sent by the anchor WTRU and / or used by the target WTRU), based on which, for example, position / TA estimation can be performed; the SL-PRS configuration used (e.g., ID), including one or more resource pools / beams (e.g., resource set / resource / beam ID), which may be associated with the anchor WTRU; or ToA, RSRP, and RSTD measurements of the SL-PRS and / or timing information (e.g., timestamp) indicating when measurements can be made.

[0217] In an example, the positioning information sent by the WTRU may include timing information. In an example, the WTRU may indicate the reference timing information or timing / synchronization source (e.g., GNSS, SFN, DFN, timing offset / adjustment with respect to the SFN / DFN) used to perform PRS / SL-PRS measurements.

[0218] In an example, the positioning information sent by the WTRU may include error information. In an example, the WTRU may indicate errors due to time / phase / power measurements (e.g., timing / phase error group ID), and errors related to the position of the access node or anchor WTRU. In an example, the WTRU may report the detection and / or measurement of the error source (e.g., multipath, NLOS).

[0219] In an example, the positioning information sent by the WTRU may include a positioning QoS. In an example, the WTRU may send information associated with the expected and / or achievable positioning QoS (e.g., accuracy, integrity, latency, power savings) regarding the requirements / KPIs received from the network (e.g., LMF, gNB) or the higher layer. The WTRU may report QoS information (e.g., accuracy, waiting time, integrity) for each positioning technique and / or for each access node / anchor WTRU, for example.

[0220] In an example, the positioning information sent by the WTRU may include WTRU mobility / movement information. In an example, the WTRU may send information regarding the mobility state (e.g., stationary, moving at low / high speed), mobility / movement attributes (e.g., speed, direction, distance traveled in a direct / straight path), and / or trajectory information (e.g., a list of positions detected by the WTRU over a duration and / or a list of cells / TRPs / anchor WTRUs (e.g., IDs)).

[0221] In an example, the positioning information sent by the WTRU may include prediction / interpolation information. In an example, the WTRU may send predicted / extrapolated position information / measurements (e.g., for time instances where measurements may not be made or are missed) and / or interpolated position information / measurements (e.g., an estimate between two (2) or more time instances). The WTRU may send timing information (e.g., a timestamp) associated with the prediction / interpolation, indicating, for example, the time instance / window when the WTRU may apply the prediction / interpolation. In an example, the WTRU may indicate a confidence level and / or uncertainty associated with the predicted / interpolated position information / measurements.

[0222] For example, the WTRU may send differential positioning information (e.g., an increment) regarding information sent in a (e.g., previous) reporting instance to minimize the amount of positioning information reported and / or transmitted. In an example, (e.g., different types of) positioning information (e.g., position information determined via measurement / estimation, error information) may be associated with (e.g., different) priority values, where the priority values may be received by the WTRU as side data from a relay WTRU or the network. In such a case, the WTRU may apply (e.g., different) reporting periodicities or urgencies based on the priority associated with the type of information to be reported to send the positioning information. In an example, positioning information including a change value greater than a threshold relative to previously reported information may be sent with a higher periodicity or triggered with a higher urgency. Similarly, for example, the WTRU may send information related to errors and / or changes regarding the expected trajectory of a mobile access node with a higher periodicity and / or a higher urgency.

[0223] A WTRU may support DL-based positioning in an OOC or partial coverage scenario. In an example, location information of a WTRU (e.g., a target WTRU) may be determined, where the WTRU may be in OOC or partial coverage and where at least one or more of the access nodes may be in OOC when using one or more of (e.g., any) DL-based positioning techniques (e.g., DL-TDOA, DL-AOD). The WTRU may have connectivity to a serving cell, for example, via a relay WTRU. The WTRU may be able to receive PRS from the serving cell / TRP and neighboring cell / TRP and use the assistance data received from the network (e.g., via the relay WTRU) to perform measurements of the PRS, regardless of whether the WTRU is able to receive SSB from any cell. The WTRU may receive PRS from one or more (e.g., any) of the cells (e.g., serving cell and neighboring cells) but not receive SSB because the transmission scheme for PRS is used to extend coverage, e.g., the transmission scheme may be different from the transmission scheme for SSB that may limit coverage.

[0224] A target WTRU that may have established connectivity to the network via a relay WTRU may perform one or more of the following when supporting DL-based positioning: a request for assistance data; determination of PRS configuration / parameters; or sending a measurement report / location information.

[0225] For example, a WTRU may request assistance data while supporting DL-based positioning. In an example, the WTRU may send a request for assistance data to an LMF (e.g., in an LPP message). The WTRU may include one or more (e.g., any) of the following in the request: relay WTRU information (e.g., ID of the relay WTRU, relative position / distance), serving cell information (e.g., ID), detectable cell / TRP (e.g., cell / TRP ID, positioning area ID), or initial position of the WTRU (e.g., positioning area ID where the target WTRU may be located). The LMF may provide a suitable PRS configuration related to the relay (e.g., reference cell to be used, TRP / RSU to be used). In an example, the WTRU may send a request for assistance data to a relay WTRU (e.g., in SLPP / RSPP, PC5-RRC, MACCE). The WTRU may include similar information (e.g., detectable TRP / cell, initial position of the WTRU, positioning area) indicated in the request to the LMF in the request to the relay WTRU. In an example, the WTRU may send a request for assistance data to the network or the relay WTRU based on one or more conditions, the one or more conditions including the ability of the relay WTRU to perform positioning, the availability of assistance data at the relay WTRU (e.g., posSIB, area-specific PRS configuration), positioning QoS (e.g., latency, accuracy), etc. The WTRU may determine PRS configuration / parameters when supporting DL-based positioning. In an example, the WTRU may determine / select assistance data and / or PRS configuration / parameters from a candidate set indicated by the relay WTRU / network based on (e.g., some) conditions, the conditions including link conditions (e.g., RSRP measurement) between the WTRU and the cell / TRP transmitting the PRS, positioning QoS (e.g., accuracy), distance to the relay WTRU, priority, etc. The WTRU may perform measurements on PRS received from a TRP outside the coverage of one or more serving cells, for example, based on assistance data provided by the relay WTRU or the network and / or the PRS configuration selected by the WTRU.

[0226] The WTRU may send a measurement report / position information when supporting DL-based positioning. In an example, the WTRU may indicate timing information / timestamp aligned with the SFN of the service of the reference cell in the measurement report / position information sent to the network (e.g., LMF, gNB). In the measurement report to the LMF, a timestamp aligned with the SFN information of the service / reference cell may be included.

[0227] The WTRU may support UL-based positioning in OOC or partial coverage techniques. In an example, when using one or more (e.g., any one) of the UL-based positioning techniques (e.g., UL-TDOA, UL-AOA), the location information of the WTRU (e.g., the target WTRU) may be determined in a technique where the WTRU may be in OOC or partial coverage and at least one or more of the access nodes (e.g., TRP / cell) may be in OOC. The location of the WTRU may be determined based on UL transmissions sent by the WTRU and / or measurements made by one or more access nodes including the serving cell / TRP and neighboring cell / TRP.

[0228] UL transmissions as described herein may include one or more of the following: one or more SRS or SRSp (SRS for positioning) transmissions that may be sent by the WTRU using any one of SRS / SRSp resources, resource sets, beams, frequency layers, and configurations; or one or more RACH preambles, sequences, partitions, and resources that may be sent by the WTRU during a RACH opportunity.

[0229] In an example, the WTRU may establish connectivity with the serving cell via a relay WTRU. For sending UL transmissions for positioning (e.g., SRSp), the WTRU may use resources and / or configurations (e.g., gNB, LMF) that may be received from the network and / or the relay WTRU. The features described herein may assist the access node to perform measurements of UL transmissions (e.g., accurately and reliably) and subsequently determine the location of the WTRU (e.g., at the gNB, LMF), and the WTRU may apply certain adjustments / corrections to the UL transmission based on timing information and / or TA values estimated by the WTRU or indicated by the relay WTRU / NW. A measurement report including the measurements made by the access node may be forwarded to an anchor base station, gNB, BBU, or CU in the RAN or to the AMF or LMF, e.g., for determining the WTRU location.

[0230] The target WTRU may establish connectivity with the network via a relay WTRU. When UL-based positioning is supported, the target WTRU may perform any one of the following: a request for SRSp configuration / parameters; determination of SRSp configuration / parameters to be used during SRSp transmission; or performance of SRSp transmission.

[0231] The target WTRU may request SRSp configuration / parameters when UL-based positioning is supported. In an example, the target WTRU may send a request for SRSp configuration / parameters to the relay WTRU and / or the network (e.g., gNB) when detecting a trigger event / condition as stated herein (e.g., any trigger event / condition). The target WTRU may determine the SRSp configuration / parameters to be used during SRSp transmission when UL-based positioning is supported. In an example, the WTRU may determine / select (e.g., any of those in) the SRSp configuration / parameters from a candidate set indicated by the relay WTRU or the NW based on some conditions including measurements of link conditions between the WTRU and the cell / TRP that can perform SRSp measurements, the distance to the relay WTRU, priorities, etc. In an example, the WTRU may send an indication to the relay WTRU or the network indicating the selected SRSp configuration / parameters.

[0232] The target WTRU may perform SRSp transmission when UL-based positioning is supported. For example, the WTRU may initiate / stop SRSp transmission after receiving an SRSp configuration and / or activation / deactivation indication (e.g., via SL MAC CE, SCI) from the relay WTRU or the network. The WTRU may release / update an existing SRSp configuration after receiving a release / update indication from, e.g., the relay WTRU or the NW.

[0233] The relay WTRU may support relay WTRU-assisted positioning. The WTRU may be configured to support the positioning of the target WTRU(s). In an example, the WTRU (e.g., relay WTRU) may be configured to assist or support the positioning of one or more target WTRUs when using one or more of the following modes: transparent mode or server mode.

[0234] The WTRU may be configured to assist or support the positioning of one or more target WTRUs when using the transparent mode: In an example, the relay WTRU (e.g., L2 relay) may forward positioning transmissions (e.g., LPP messages, RRC messages) (e.g., any of those in) between the target WTRU and the network (e.g., gNB, LMF). The relay WTRU may be configured with an adaptation layer that may allow one or more of the following: mapping data (e.g., mapping the data received from the network on the Uu link to the target WTRU when sending on the SL, or mapping the data received from the target WTRU on the SL to the Uu link when sending the data to the network).

[0235] In an example, a relay WTRU may forward any assistance data and / or positioning configuration received from the network (e.g., PRS, SRSp, SL-PRS configuration) to one or more target WTRUs and / or anchor WTRUs for supporting Uu-link and / or SL-based positioning at the target WTRU. The assistance data and / or positioning configuration may be sent via, for example, broadcast (e.g., posSIB), multicast, or unicast (e.g., LPP, SLPP, RSPP message) transmission modes. The relay WTRU may forward measurement reports received from the target WTRU / anchor WTRU to the NW.

[0236] In an example, the relay WTRU may provide the target WTRU with timing information including the following: the SFN of the serving cell, the offset / adjustment to the DFN, and / or the offset / adjustment to the TA value, such that the target WTRU may (e.g., be able to) perform DL-PRS measurements and / or SRSp transmissions. Such timing information, together with the posSIB / PRS configuration, may be sent periodically at a configured periodicity when one or more of the requests (e.g., on-demand SI request) are received from the target WTRU or when an indication is received from the gNB. The relay WTRU may send the posSIB and / or the timing information periodically at a higher periodicity than the default periodicity when it detects (e.g., via discovery) a certain number of target WTRUs in the vicinity that can perform positioning.

[0237] In an example, the relay WTRU may have the ability to perform SL-based positioning. In this case, the relay WTRU may be configured to perform transmissions of SL-PRS on the SL or perform measurements on the SL-PRS received on the SL. The WTRU may send measurement reports associated with the SL-PRS measurements to the network (e.g., via LPP, RRC transmission). The relay WTRU may perform SL-PR transmissions / measurements, e.g., similar to the anchor WTRU in SL-based positioning. In an example, the relay WTRU may be used to support SL-based positioning in a partial coverage scenario.

[0238] In an example, a relay WTRU may support Uu-based positioning. In an example, the relay WTRU may be configured to perform transmission of PRS to a target WTRU or perform measurements on an SRSp received from the target WTRU. The WTRU may be configured to assist or support positioning of one or more target WTRUs when using the server mode. In an example, the relay WTRU may be configured to operate as a local location server (e.g., local LMF) for supporting positioning of one or more target WTRUs. When operating in the server mode, the functions that may be supported by the relay WTRU may include one or more of the following, for example: initiating / triggering positioning of the target WTRU, determining the positioning technique of the target WTRU (e.g., Uu-link based, SL-based, hybrid Uu+SL-based), configuring positioning resources (e.g., PRS, SRSp, SL-PRS) in the target WTRU, coordinating with one or more anchor WTRUs for positioning of the target WTRU when supporting SL-based positioning, calculating the location of the target WTRU (e.g., based on measurement reports received from the target WTRU and / or anchor WTRUs) and reporting the positioning information (e.g., measurement report / location) of the target WTRU to the network. When operating in the server mode, the relay WTRU may use one or more (e.g., any) of higher layer transmissions (e.g., SLPP, RSPP) or SL AS layer transmissions (e.g., PC5-RRC, MAC CE, SCI, PSSCH) when sending / receiving any transmissions / messages to / from the target WTRU.

[0239] The WTRU may determine the positioning technique and / or assistance information to be provided to the target WTRU. In one aspect, the WTRU (e.g., relay WTRU) may determine / select or assist in determining the positioning of one or more target WTRUs (e.g., Uu-link based, SL-based, hybrid Uu+SL-based) based on criteria as set forth herein. The criteria including one or more parameters / thresholds associated with the positioning technique may be configured by the network (e.g., sent via RRC or LPP). In an example, Uu-link based positioning that may be selected by the target WTRU may include one or more of DL-TDOA, DL-AOD, UL-TDOA, UL-AOA, and multi-RTT. SL-based positioning that may be selected for the target WTRU may include, for example, one or more of SL-TDOA, SL-AOA, SL-AOA, SL-RTT. When receiving a request indication (e.g., positioning request) from the target WTRU, the network, or from a higher layer (e.g., MO-LR, MT-LR, NI-LR), the relay WTRU may be triggered to determine / select the positioning technique for the target WTRU.

[0240] In an example, the relay WTRU may determine assistance data and / or positioning configuration / parameters (e.g., PRS, SRSp, SL-PRS configuration) to provide to a target WTRU to support one or more (e.g., any) of the positioning techniques. In an example, the relay WTRU may determine the assistance data and / or positioning configuration based on the positioning technique determined / selected for the target WTRU. In an example, for instance, the relay WTRU may determine the assistance data and / or positioning configuration after receiving a request indication from the target WTRU.

[0241] In an example, the relay WTRU may retransmit the assistance data / positioning configuration or send an updated assistance data / positioning configuration to the target WTRU when detecting a change in measurements (e.g., Uu link, SL measurements), determining a change in measurements that can be provided by the target WTRU (e.g., RSRP or RTT measurements of SL-PRS are above / below a threshold), receiving an indication from the target WTRU (e.g., movement, detection of a new cell / TRP, detection of a blockage), and receiving an indication from the network (e.g., an update to the PRS, SRSp, SL-PRS configuration).

[0242] In an example, the relay WTRU may not (e.g., decide not to) provide (e.g., any) assistance data or positioning configuration (e.g., PRS, SRSp, SL-PRS configuration) to the target WTRU when detecting one or more (e.g., any) of the following conditions: determining that the distance to the target WTRU is above a distance threshold; a high number of target WTRUs that can be supported for positioning (e.g., above a threshold); data transmission may be prioritized over positioning; handling a high data traffic load (e.g., above a load threshold); low battery life / power; or may not meet the criteria for positioning the target WTRU (e.g., the RSRP measurements of the Uu link and / or SL made by the relay WTRU or reported by the target WTRU may be above / below (e.g., some) RSRP thresholds). When detecting any such condition, the relay WTRU may send a rejection indication or a prohibition indication (e.g., with a prohibition timer) to the target WTRU. For example, the relay WTRU may send an explicit or implicit indication to the target WTRU to receive assistance data, positioning configuration, or posSIB from an adjacent cell (e.g., instead of the serving cell or the relay WTRU) when detecting such a condition.

[0243] In an example, the relay WTRU may send an indication to the network (e.g., gNB, LMF) when determining the positioning for the target WTRU and / or when sending any assistance data and / or positioning configuration / resources to the target WTRU. For example, such an indication may be sent by the relay WTRU to the network in an LPP transmission, RRC, MAC CE, or UCI. In an example, when sending an SRSp configuration and / or an SRSp activation / deactivation indication to the target WTRU, the relay WTRU may send an indication to the network, e.g., for triggering the TRP to perform measurements on the SRSp sent by the target WTRU.

[0244] The criteria configured in the relay WTRU and used by the relay WTRU to determine the positioning technique for the target WTRU and / or the assistance data / positioning configuration provided to the target WTRU may include one or more of the following: measurements associated with the Uu link and / or SL; indications from the network or the target WTRU; ranging information (e.g., distance / direction); positioning information of the target WTRU; positioning QoS; the number of target WTRUs; the availability / reliability of resources for SL-based positioning; or priority.

[0245] In an example, the criteria configured in the relay WTRU may include measurements that may be associated with the Uu link and / or SL. In an example, if the RSRP measurement of the SSB / PRS / CSI-RS received from the TRP at the target WTRU (e.g., including the serving cell / TRP and neighboring cells / TRP) is higher / lower than one or more RSRP thresholds, the relay WTRU may determine to use Uu-link-based positioning for the target WTRU (e.g., DL-based, UL-based, multi-RTT) and / or provide the associated assistance data / configuration. For example, if the number of TRPs with an RSRP higher than the threshold and / or with a LOS condition is higher than the TRP count threshold, the WTRU may determine to use Uu-link positioning. For example, the relay WTRU may decide on the Uu-link-based positioning for the target WTRU based on the measurement report provided by the target WTRU.

[0246] In an example, if the RSRP measurement of an SL transmission (e.g., SL-PRS, discovery message, PSSCH) received from one or more anchor WTRUs (e.g., including / excluding relay WTRUs) by a target WTRU is higher / lower than one or more RSRP thresholds (e.g., the RSRP of the SL PRS is higher than the RSRP threshold), the relay WTRU may determine to use SL-based positioning (e.g., SL-TDOA) for the target WTRU and / or provide associated assistance data / configuration. For example, if the number of anchor WTRUs with RSRP above the threshold and / or with LOS conditions is higher than the anchor WTRU count threshold, the WTRU may determine to use SL-based positioning. For example, the relay WTRU may decide on the SL-based positioning for the target WTRU based on one or more (e.g., any one) of the measurement reports provided by the target WTRU, the measurement reports provided by (e.g., other) anchor WTRUs, and its own measurements of the SL transmission received from the target WTRU. In an example, the relay WTRU may determine to use a hybrid Uu+SL-based positioning for the target WTRU and provide associated assistance data / configuration when one or more of the following occur: the RSRP of the SSB / PRS / CSI-RS received from one or more TRPs at the target WTRU is higher / lower than some RSRP thresholds; the RSRP of the SL transmission (e.g., SL-PRS) received from one or more anchor WTRUs at the target WTRU is higher / lower than (e.g., some) RSRP thresholds (e.g., the second RSRP - the first RSRP is between the thresholds (e.g., two thresholds); or the total number consisting of the number of TRPs with RSRP above the threshold and the number of anchor WTRUs with RSRP above the threshold is higher than the node count threshold. In an example, the criteria configured in the relay WTRU may include an indication from the network or the target WTRU. In an example, the WTRU may use Uu-link-based, SL-based, or hybrid Uu+SL-based positioning and / or forward associated assistance data and / or positioning configuration (e.g.,, PRS, SRSp, SL-PRS configuration) based on an indication of positioning received from the network (e.g., in LPP, RRC, MAC CE, DCI) or from the target WTRU (e.g., in SLPP / RSPP, PC5-RRC, MAC CE, SCI).

[0247] In an example, the criteria configured in the relay WTRU may include ranging information (e.g., distance / direction). In an example, the relay WTRU may send auxiliary data and / or positioning configuration (e.g., for the positioning technique selected for the target WTRU) based on whether the distance to the target WTRU is above / below one or more distance thresholds. The distance to the target WTRU may be determined based on one or more of the RSRP or RTT measurements of the SL transmission (SL-PRS, discovery, PSSCH), or estimated based on the TA value used for the SL transmission. In an example, when it is determined that the distance to the target WTRU is within the first distance threshold range, the relay WTRU may send an SL-PRS configuration to the target WTRU. When it is determined that the distance to the target WTRU is within the second distance threshold range, the relay WTRU may send a PRS configuration or an SRSp configuration to the target WTRU. In an example, the relay WTRU may send appropriate auxiliary data and / or positioning configuration when it is determined that the target WTRU is located in a specific direction from the relay WTRU within one or more direction / orientation angle thresholds. For example, the direction of the target WTRU may be determined based on the Rx beam direction used at the relay WTRU or the SL transmission power / phase received from the target WTRU when a multi-antenna array is used at the WTRU.

[0248] In an example, the criteria configured in the relay WTRU may include the positioning information of the target WTRU. In an example, the relay WTRU may send appropriate auxiliary data and / or positioning configuration to the target WTRU based on the location of the target WTRU (e.g., the target WTRU or the relay WTRU). For example, the location of the target WTRU may be determined at different granularities, including cell, area, or positioning area (e.g., consisting of a list of cells). In an example, when the target WTRU can be estimated to be located in the positioning area / region associated with the PORS configuration / posSIB, the relay WTRU may provide an appropriate PRS configuration or area-specific posSIB to the target WTRU.

[0249] In an example, the relay WTRU may send (e.g., to the target WTRU) a positioning configuration (e.g., SL-PRS, SRSp configuration) associated with the positioning technique selected for the target WTRU and associated with the positioning area / region where the target WTRU may be located. This forwarding of the positioning configuration may be done by the relay WTRU based on an estimate of the initial location of the target WTRU, which uses measurements on the SL (e.g., RSRP measurements of SL transmissions) to determine the region of the target WTRU (e.g., for a 5m x 5m region size resolution). When it is determined that the target WTRU may be located in the area where the relay WTRU is located, the relay WTRU may select a SL-based positioning technique for the target WTRU and forward the SL-PRS configuration for performing SL-RTT transmissions. For example, when it is determined that the target WTRU may be located in a different region from the relay WTRU (e.g., the number of regions between the relay WTRU and the target WTRU may be higher than a region count threshold or the distance between the relay WTRU and the target WTRU may be higher than a distance threshold), the relay WTRU may select a UL-based positioning technique for the target WTRU and forward the SRSp configuration for performing UL-SRSp transmissions (for UL-TDOA).

[0250] In an example, the relay WTRU may determine to provide a subset of the PRS configuration to the target WTRU. In an example, the relay WTRU and the target WTRU may be pre-configured with a PRS configuration (e.g., frequency layer). The relay WTRU may provide a PRS configuration (e.g., TRP, PRS periodicity) associated with the pre-configured PRS configuration. The configuration of the PRS may be based on a PRS hierarchy, and an example of the PRS hierarchy may be shown in FIG. 2. In an example, both the relay WTRU and the target WTRU may be pre-configured with frequency layer #1. Based on conditions, the network WTRU may provide a PRS configuration to the target WTRU, which may be associated with frequency layer #1 (e.g., TRP ID, PRS transmission periodicity). In an example, PRS and SRS or SRSp may be used interchangeably as described herein.

[0251] In an example, the criteria configured in the relay WTRU may include positioning QoS. In an example, the relay WTRU may determine and / or provide a suitable positioning configuration (e.g., PRS, SRSp, SL-PRS) based on the accuracy requirements associated with the positioning of the target WTRU. In an example, the relay WTRU may provide a SRSp configuration (e.g., high density resources) to the target WTRU when the accuracy requirement may be higher than a threshold, and may provide a SRSp configuration (e.g., low density resources) when the accuracy requirement may be lower than a threshold.

[0252] In an example, the criteria configured in the relay WTRU may include the number of target WTRUs. In an example, the relay WTRU may determine the positioning and / or positioning configuration to be provided to the target WTRU based on the number of target WTRUs that may be configured with positioning technology and / or provided with a positioning configuration. In an example, when the number of target WTRUs provided with a PRS configuration is higher than a configured threshold, the relay WTRU may decide to provide the target WTRU with an SL-PRS configuration instead of a PRS configuration.

[0253] In an example, the criteria configured in the relay WTRU may include the availability / reliability of resources for SL-based positioning. In an example, after identifying the availability of resources for SL positioning (e.g., CBR or RSRP may be above / below a threshold) based on measurements on the SL (e.g., RSRP, RSSI, CBR measurements) or an indication from the target WTRU, anchor WTRU, or network, the relay WTRU may (e.g., select) use SL-based positioning for the target WTRU. For example, if sufficient resources or an anchor WTRU for SL-based positioning are not available and a TRP for supporting Uu-link-based positioning is available, the relay WTRU may determine to use Uu-based positioning for the target WTRU.

[0254] In an example, the criteria configured in the relay WTRU may include priorities. In an example, the relay WTRU may be configured with (e.g., some) priority values associated with assisting / supporting the positioning of the target WTRU and / or supporting data traffic relaying. The relay WTRU may decide whether to provide the target WTRU with auxiliary data / positioning configuration (e.g., posSIB) or perform data relaying based on the priority values. In an example, the WTRU may be configured to support the transmission / measurement of SL-PRS, and the relay WTRU may support SL-based positioning when the associated priority may be higher than the priority of data relaying / transmission.

[0255] In an example, the relay WTRU may count the number of events / instances where support for positioning (e.g., providing auxiliary data / positioning configuration, performing SL-PRS transmission / measurement) may be waived in order to support data relaying / transmission due to the lower priority of positioning. When the number of events / instances exceeds a threshold, the relay WTRU may support positioning.

[0256] Figure 2 illustrates an example of a PRS configuration hierarchy. The relay WTRU may provide the target WTRU with a positioning configuration (e.g., SRSp configuration, PRS configuration, posSIB).

[0257] In an example, the relay WTRU may be configured to provide positioning configuration (e.g., SRSp configuration, PRS configuration, posSIB) to a target WTRU based on an estimate of the initial location information of the target WTRU. In an example, the estimate of the initial location information of the target WTRU may be done based on SL measurements (e.g., RSRP of SL-PRS) to identify the region or positioning area of the target WTRU. The relay WTRU may forward to the target WTRU the positioning configuration associated with the region / positioning area where the target WTRU may be located.

[0258] Figure 3 Region-region specific positioning configuration is shown. The relay WTRU may provide region / region specific positioning configuration (e.g., posSIB) to the target WTRU based on an estimate of the region where the target WTRU may be located. In an example, the relay WTRU sends posSIB1 (e.g., Figure 3 to the left side of) to the target WTRU1 located in region 1. The relay WTRU sends posSIB2 (e.g., Figure 3 to the right side of) to the target WTRU2 located in region 2.

[0259] Example techniques applied at the relay WTRU to assist in providing positioning configuration to the target WTRU may include the following. In an example, configuration information may be received from the network. The configuration information may include one or more of the following: one or more RSRP thresholds associated with the distance and / or direction to the target WTRU; the association between the RSRP threshold associated with the distance and / or direction and the region (ID); or one or more positioning configurations (e.g., PRS configuration, SRSp configuration, posSIB) associated with the region (ID).

[0260] In an example, measurements of SL transmissions (e.g., SL-PRS) sent by the target WTRU may be performed. In an example, the relay WTRU may trigger the transmission of SL-PRS in the target WTRU by providing an SL-PRS configuration and / or sending an indication for initiating an SL-PRS transmission.

[0261] In an example, the distance and / or direction of a target WTRU can be determined based on SL measurements (e.g., relative to a reference direction such as the direction of a relay WTRU). In an example, the distance to the target WTRU can be estimated based on the path loss and RSRP measured on an SL transmission (e.g., SL-PRS, PSSCH, CSI-RS, DM-RS) sent by the target WTRU. The distance to the target WTRU can be estimated based on the RTT of the SL-PRS of other SL transmissions sent by the relay WTRU and the target WTRU. For example, if the RSRP of the SL-PRS is within the RSRP threshold range, the target WTRU can be estimated to be within a certain distance. In an example, for instance, the direction of the target WTRU relative to a reference direction (e.g., geographic north, the direction of the relay WTRU) can be estimated based on the Rx beam direction of the relay WTRU for receiving the SL transmission (e.g., SL-PRS, PSSCH) sent by the target WTRU, the measurement of the power / phase of the SL transmission sent by the target WTRU when a multi-antenna array is used at the relay WTRU, or based on an indication of the direction sent by the target WTRU. For example, if the RSRP of the SL transmission received using the Rx beam is within the RSRP threshold range, the direction of the target WTRU can be estimated to be within a certain angular range / width (e.g., +10 degrees, -10 degrees) relative to the reference direction (e.g., geographic north, the direction of the WTRU).

[0262] In an example, the area where the target WTRU may be located (e.g., an ID associated with the area) can be determined. In an example, the relay WTRU can determine the area of the target WTRU based on the determined distance and / or direction of the target WTRU and the association information between the RSRP threshold associated with the distance and / or direction and the area (e.g., an ID associated with the area). In an example, the relay WTRU can determine the area of the target WTRU based on an indication received from the target WTRU indicating the area where the target WTRU can be located.

[0263] In an example, a positioning configuration provided to a target WTRU can be determined based on the region where the target WTRU is located and the association information between the positioning configuration and the region. In an example, the relay WTRU can determine the type of positioning configuration (e.g., PRS configuration, SRSp, posSIB) to be provided to the target WTRU based on a request / indication received from the target WTRU. In an example, the positioning technology to be supported can be determined by the target WTRU and / or the target WTRU can send, in a request / indication (e.g., on-demand SI request), the type (e.g., ID / index) of the positioning configuration associated with the selected positioning technology to the relay WTRU. In an example, when receiving a request (e.g., on-demand SI request) from the target WTRU, the relay WTRU can forward the posSIB associated with the region to the target WTRU based on the region where the target WTRU may be located. In an example, as described herein, the relay WTRU can select the positioning technology for positioning the target WTRU and / or can determine the positioning configuration to be provided to the target WTRU based on one or more (e.g., pre-configured) conditions.

[0264] In an example, the determined positioning configuration can be sent to the target WTRU on the SL. In an example, the relay WTRU can send the positioning configuration to the target WTRU via dedicated transmission (e.g., in SLPP / RSPP, PC5-RRC, MAC CE, SCI) or via broadcast (e.g., in posSIB). In an example, the relay WTRU can send other auxiliary data (e.g., location information of the TRP) and / or timing information (e.g., SFN, offset value to the DFN) to the target WTRU based on the type of the positioning configuration determined to be sent. In an example, the relay WTRU can send an indication (e.g., in RRC, MAC CE, UCI) to the gNB for indicating the transmission of the positioning configuration (ID) to the target WTRU.

[0265] The relay WTRU can assist in triggering the UL-SRSp transmission at the target WTRU. In an example, the relay WTRU can be configured to activate / deactivate the SRSp transmission at the target WTRU based on one or more pre-configured conditions. In an example, the conditions can include the distance between the relay WTRU and the target WTRU and the validity condition (e.g., TA timer associated with the SRSP configuration). Depending on whether these conditions are met, the relay WTRU can send an indication to the target WTRU to activate or deactivate the SRSp transmission.

[0266] Figure 4 An example is shown where the relay WTRU (e.g., the first WTRU) can trigger the activation / deactivation of the SRSp transmission at a target WTRU (e.g., the second WTRU) located out-of-coverage (OOC) (see alsoFigure 6 ). The triggering of SRSp transmission can be done by the relay WTRU based on conditions associated with the validity of the SRSp configuration and / or the relative position of the target WTRU to the relay WTRU. The SRSp sent by the WTRU can be measured by one or more receiving points (RPs) (e.g., transmit and receive point (TRP)) in the network (see Figure 6 ).

[0267] Example features for triggering SRSp transmission at the target WTRU applied at the relay WTRU can include one or more of the following. In an example, configuration information can be received from the network, and the configuration information can include one or more of the following: a first threshold (e.g., SL distance threshold 1), a second threshold (e.g., distance threshold 2); an SRSp configuration; or a validity condition associated with the SRSp configuration (e.g., a TA timer (e.g., a first TA value) at the relay WTRU) (e.g., also see Figure 6 ).

[0268] The relay WTRU can send the SRSp configuration to the target WTRU. In an example, the SRSp configuration sent to the target WTRU can be associated with the area / location area where the target WTRU can be located. For example, the relay WTRU can determine the area / location area of the target WTRU based on the SL measurement of the SL transmission received from the target WTRU and / or the pre-configured association information between the SRSp configuration and the area / location area. In an example, the SRSp configuration can be received from the gNB and sent (e.g., transparently sent) to the target WTRU.

[0269] In an example, measurements on the SL can be performed (e.g., see Figure 6 ; RTT measurement of the RSRP or SL-PRS or SL channel associated with the target WTRU), and the distance to the target WTRU can be determined based on the SL measurement. If the distance to the target WTRU is higher than the SL distance threshold 1, lower than the distance threshold 2, and the validity condition is met (e.g., the TA timer at the relay WTRU is running), the relay WTRU can perform one or more of the following.

[0270] If the distance to the target WTRU is higher than the SL distance threshold 1, lower than the distance threshold 2, and the validity condition is met (e.g., the TA timer at the relay WTRU is running), the relay WTRU can determine a second TA value for use with the SRSp transmission for the target WTRU and send the second TA value to the target WTRU. The determination of the second TA value can be based on the RSRP measurement and the first TA value (e.g., see Figure 6 ).

[0271] If the distance to the target WTRU is higher than the SL distance threshold 1, lower than the distance threshold 2, and the validity condition is met (e.g., the TA timer at the relay WTRU is running), then the relay WTRU may send an indication to the network (e.g., gNB) regarding triggering an SRSp transmission at the target WTRU. In an example, the indication may be sent to the network in a higher layer (e.g., LPP) or AS layer (e.g., RRC, MAC CE, or UCI). In an example, the indication may include one or more of the following: SRSp configuration ID, SRSp trigger reason (e.g., ID of the detected condition), timing information (e.g., timestamp) of when the SRSp transmission is activated / triggered, etc.

[0272] If the distance to the target WTRU is higher than the SL distance threshold 1, lower than the distance threshold 2, and the validity condition is met (e.g., the TA timer at the relay WTRU is running), then an indication of SRSp activation and / or indication of the second TA value (e.g., in PC5 - RRC, SL MAC CE, SCI) may be sent to the target WTRU (e.g., the activation indication may include the second TA value) (e.g., see Figure 6 )

[0273] If the distance to the target WTRU is higher than the SL distance threshold 1, lower than the distance threshold 2, and the validity condition is met (e.g., the TA timer at the relay WTRU is running), and if SRSp was previously activated and the validity condition is not met (e.g., the TA timer at the relay WTRU has expired), then an SRSp de - activation indication (e.g., in PC5 - RRC, SL MAC CE, SCI) may be sent to the target WTRU. In an example, the indication to the gNB may include the SRSp configuration ID, SRSp trigger reason (e.g., ID of the detected condition), timing information (e.g., timestamp) of when the SRSp transmission is de - activated, etc.

[0274] If the distance to the target WTRU is higher than the distance threshold 2, and / or the validity condition is not met (e.g., the TA timer at the relay WTRU has expired), then an indication to release SRSp (e.g., in PC5 - RRC, SL MAC CE, SCI) may be sent by the relay WTRU to the target WTRU (see Figure 6 )

[0275] The relay WTRU may assist in triggering SRSp and SL - PRS transmissions at the target WTRU (e.g., see Figures 4 - 6). In an example, the relay WTRU can be configured to assist in the hybrid positioning (e.g., Uu+SL-based positioning) of a target WTRU when a certain condition (e.g., RSRP measurement of the SSB of the serving cell) for triggering UL-SRS p and SL-PRS transmissions at the target WTRU can be met. Depending on whether the condition can be met, the relay WTRU can send an indication to activate / deactivate SL-PRS and / or UL-SRS p transmissions to the target WTRU.

[0276] Figure 5 An example is shown in which the relay WTRU can assist in hybrid positioning (e.g., Uu+SL) when a certain condition for triggering SRS p and SL-PRS transmissions at the target WTRU can be met. If the condition (e.g., RSRP measurement of the SSB of the serving cell) is met (e.g., Figure 5 the setup shown on the left), the relay WTRU can send an indication to activate SL-PRS transmissions to the target WTRU (e.g., via SL MAC CE). If the condition is not met (e.g., Figure 5 the setup shown on the right), the relay WTRU can provide a UL-SRS p configuration and an indication to activate UL-SRS p and SL-PRS transmissions to trigger hybrid positioning.

[0277] The relay WTRU can send an indication to activate / deactivate SL-PRS and / or UL-SRS p transmissions to the target WTRU as described herein. The relay WTRU can receive configuration information from the network. The configuration information can include one or more of the following: SL-PRS configuration for the target WTRU; SRSp configuration for the target WTRU; or RSRP threshold 1 (upper limit) and threshold 2 (lower limit).

[0278] The relay WTRU can send an SL-PRS configuration to the target WTRU (e.g., via PC5-RRC, MAC CE, SCI). In an example, a measurement report of measurements made by the target WTRU (e.g., including RSRP measurements of the OOC node or the SSB of the serving cell) can be received from the target WTRU (e.g., by the relay WTRU).

[0279] If the RSRP measurement received from the target WTRU is below the RSRP threshold 1 and above the RSRP threshold 2 (e.g., the target WTRU has a poor Uu link with the serving cell), then one or more of the following may occur. An SL-PRS activation indication (e.g., in PC5-RRC, SL MAC CE, SCI) may be sent to the target WTRU. Measurements of the SL-PRS received from the target WTRU may be performed (e.g., RSRP or RTT). A measurement report of the SL-PRS measurement may be sent to the network. The measurement report may include one or more (e.g., any one) of the ID of the target WTRU, arrival time (timestamp), RSRP measurement, RTT measurement of the SL-PRS. The measurement report may be sent at a higher layer (e.g., LPP) or at the AS layer (e.g., RRC, MAC CE, UCI).

[0280] In an example, if the RSRP measurement sent by the target WTRU is below the RSRP threshold 2 (e.g., the target WTRU may not have a Uu link), then one or more of the following may occur. An SRSp configuration may be sent to the target WTRU (e.g., in PC5-RRC, SL MAC CE, SCI). The relay WTRU may send timing information (e.g., SFN, offset value to the DFN) or TA value to be used when sending the SRSp. An indication about triggering SRSp and SL-PRS transmission at the target WTRU may be sent to the network (e.g., gNB). The indication to the network may be sent at a higher layer (e.g., LPP) or at the AS layer (e.g., RRC, MAC CE or UCI). The indication may include one or more of the SRSp configuration ID, SL-PRS / SL-PRS configuration ID, SRSp / SL-PRS trigger reason (e.g., ID of the detected condition), timing information (e.g., timestamp) when the SRSp / SL-PRS transmission can be activated / triggered, etc. An SRSp activation indication and an SL-PRS activation indication (e.g., in PC5-RRC, SL MAC CE, SCI) may be sent to the target WTRU. A measurement report of the SL PRS measurement may be sent to the network. In the example, the measurement report may include one or more of the ID of the target WTRU, arrival time (timestamp), RSRP measurement or RTT measurement of the SL-PRS. In the example, the measurement report may be sent at a high (e.g., higher) layer (e.g., LPP) or at the AS layer (e.g., RRC, MAC CE, UCI).

[0281] Figure 6An example is shown in which a relay WTRU can assist a target WTRU in SRSp transmission. The relay WTRU can receive configuration information for the target WTRU (e.g., one or more of SRSp configuration, a first threshold (e.g., threshold 1), and a second threshold (e.g., threshold 2)) and a reference TA value (e.g., a first TA value) for the relay WTRU from a serving gNB (e.g., a first network node). The relay WTRU can receive a first RSRP measurement made by the target WTRU on an RS (e.g., path loss RS, SSB) received, for example, from an out-of-coverage (OOC) TRP. For example, the first RSRP measurement received from the target WTRU can be associated with the RSRP measurement made by the target WTRU on the RS received from each TRP according to each TRP.

[0282] The relay WTRU can determine an initial TA value and send the initial TA value to the target WTRU to which, for example, SRSp is to be applied. The relay WTRU can send the SRSp configuration to the target WTRU. The relay WTRU can receive a second RSRP measurement made by the target WTRU on the RS received from the TRP. For example, the second RSRP measurement received from the target WTRU can be associated with the RSRP measurement made by the target WTRU on the RS received from each TRP according to each TRP.

[0283] If the difference between the second RSRP measurement and the first RSRP measurement is greater than threshold 1 and less than or equal to threshold 2 (e.g., threshold 2 < second RSRP - first RSRP <= threshold 2), the relay WTRU can determine a new TA value (e.g., a second TA value) and send the new TA value (e.g., the second TA value) to the target WTRU to which SRSp is to be applied. In an example, when multiple measurement reports are received by the relay WTRU from the target WTRU, where each measurement report received in a single or multiple reporting instances can be associated with the RSRP measurement on the RS received from a different TRP, when the RSRP measurement in at least one measurement report meets the condition for updating the TA value (e.g., threshold 2 < second RSRP - first RSRP <= threshold 2), the relay WTRU can send a new TA value (e.g., the second TA value) to the target WTRU.

[0284] If the difference between the second RSRP measurement and the first RSRP measurement is greater than a threshold 2 (e.g., second RSRP - first RSRP > threshold 2), the relay WTRU may send an indication to release the SRSp configuration to the target WTRU. In an example, when the relay WTRU receives multiple measurement reports from the target WTRU, each measurement report received in a single or multiple reporting occasions may be associated with an RSRP measurement of an RS received from a different TRP. When the RSRP measurements in all measurement reports meet the condition for releasing the SRSp configuration (e.g., second RSRP - first RSRP > threshold 2), the relay WTRU may send an indication to release the SRSp configuration to the target WTRU.

[0285] In an example, the technique may support incremental relay WTRU-assisted positioning. The relay WTRU may be configured as a positioning delegate for the target WTRU. In an example, the relay WTRU may be configured to act as a positioning delegate for the target WTRU. The delegate role may include one or more of the following: providing the (absolute / relative) position of the relay WTRU to the target WTRU according to an explicit request from the target WTRU; providing the position of the relay WTRU (e.g., absolute / relative position) to the target WTRU in a multicast / broadcast manner (e.g., periodically at a configured period); or providing the absolute position of the relay WTRU to the target WTRU via a dedicated transmission (e.g., PC5-RRC) and providing relative / incremental position information via multicast / broadcast (e.g., providing periodically).

[0286] In an example, the positioning delegate registration / association may be controlled by the network (e.g., the network may configure the target WTRU to use the relay WTRU as a positioning delegate via an explicit transmission to the target WTRU and the relay WTRU).

[0287] In an example, the positioning delegate registration / association may be performed peer-to-peer between the target WTRU and the relay WTRU. In an example, the target WTRU may request the relay WTRU to become a positioning delegate and / or the relay WTRU may offer (e.g., proactively offer) to become a positioning delegate for the target WTRU. A configuration from the network (e.g., pre-configuration) may be used to establish such a relationship. The configuration may indicate how the association process may be performed by the relay WTRU and / or the target WTRU.

[0288] In an example, the relay WTRU may be configured with different periodicities for broadcasting relative / absolute position information that may depend on one or more of the following: the current location or location range of the relay WTRU; the current mobility state of the relay WTRU (e.g., speed, direction, acceleration, etc.); the number of target WTRUs using the relay WTRU as a positioning delegate; the SL-RSRP / reference signal received quality (RSRQ) between the relay WTRU and the target WTRU; the CBR / channel occupancy ratio (CR) on the SL between the relay WTRU and the target WTRU; the current time of day; the battery power of the relay WTRU; or a request from the target WTRU (e.g., the target WTRU may request a periodicity, and the relay WTRU may use the average, maximum, minimum, mean, etc. of the requested periodicity to determine the periodicity of the position update frequency towards the target WTRU).

[0289] In an example, the target WTRU may be configured with a periodicity. The target WTRU may request location information (e.g., the location information may be provided by the delegating relay WTRU in a request-response manner or indicate a periodicity preference during delegated registration / association with the delegating relay) or obtain location information (e.g., the frequency of reading location information from the relay WTRU broadcast / multicast), which may depend on one or more of the following: the current location or location range of the target WTRU; the current mobility state of the target WTRU (e.g., speed, direction, acceleration, etc.); the SL-RSRP / RSRQ between the relay WTRU and the target WTRU; the CBR / channel occupancy ratio (CR) on the SL; the current time of day; the active bearer / application type; the traffic level (e.g., buffer status, data rate, etc.); the battery power of the target WTRU; or a request from the target WTRU (e.g., the target WTRU may request a specific periodicity, and the relay WTRU may use the average, maximum, minimum, mean, etc. of the requested periodicity to determine the periodicity of the position update frequency towards the target WTRU).

[0290] In an example, when the target WTRU may be using the relay WTRU as a positioning delegate, the target WTRU may be configured not to perform any positioning-related measurements, measurement reports, and / or positioning determination / calculations on its own. In an example, when the target WTRU is using the relay WTRU as a positioning delegate, the target WTRU may be configured to perform positioning-related measurements and / or positioning determination / calculations in a relaxed manner (e.g., with a configured periodicity).

[0291] In an example, when a target WTRU uses (e.g., starts using) a relay WTRU as a positioning delegate, one or more of the target WTRU or the relay WTRU may send an indication to the network (e.g., the target WTRU sends information about the positioning delegate, such as the relay WTRU identity; the relay WTRU sends information about the target WTRU, such as the target WTRU identity, etc.).

[0292] In an example, when the target WTRU stops using the relay WTRU as a positioning delegate, one or more of the target WTRU or the relay WTRU may send an indication to the network. The target WTRU may be configured to adapt positioning-related behavior based on current WTRU conditions and conditions of the link between the target WTRU and the delegated relay WTRU.

[0293] In an example, the target WTRU may be configured to consider the location of the target WTRU to be the same as the location information provided by the delegated relay WTRU based on one or more of the following: the SL-RSRP towards the relay WTRU may be higher than a certain threshold; or the SL-RTT between the target WTRU and the relay WTRU may be lower than a certain threshold.

[0294] In an example, the target WTRU may be configured to apply an offset / increment on top of the location information provided by the delegated relay WTRU. The offset / increment to be applied may be, for example, one or more of the following: SL-RSRP (e.g., if the SL-RSRP is higher than threshold l, there is no offset, if the SL-RSRP is between threshold 1 and threshold 2, offset l is applied, if the SL-RSRP is between threshold 2 and threshold 3, offset 2 is applied, etc.); or SL-RTT (e.g., if the RTT is lower than threshold l, there is no offset, if the RTT is between threshold 1 and threshold 2, offset 1 is applied, if the RTT is between threshold 2 and threshold 3, offset 2 is applied, etc.).

[0295] In an example, the relay WTRU may be configured with an offset / increment configuration, and the relay WTRU (e.g., based on current SL-RSRP, RTT, etc.) may select an appropriate offset / increment and may send the offset / increment value to the WTRU (e.g., when the location delegation can be provided in a broadcast manner) or (e.g., directly) add the offset / increment value to the location information that the relay WTRU may be sending to the target WTRU (e.g., if the location information may be being delivered to the target WTRU in a dedicated manner).

[0296] In an example, the target WTRU may perform (e.g., start performing) positioning measurements / determinations based on one or more of the SL-RSRP dropping below a certain threshold or the SL-RTT becoming greater than a certain threshold. If the target WTRU is not configured for positioning measurements, the target WTRU may send a positioning measurement configuration request to the network and / or the relay WTRU.

[0297] The target WTRU may intermittently (e.g., based on some configured periodicity) perform positioning measurements / determinations as a reference / checkpoint to see if the location provided by the delegate can be considered valid (e.g., if there is a large difference between the location it determines itself and the location provided by the delegate, or if the difference is not constant at different determination times, the WTRU may stop using the positioning delegate; if the difference is small or the difference is constant at different determination times, the WTRU may use the difference as an increment / offset to apply to the location provided by the delegate to find the location of the WTRU). In an example, the target WTRU may intermittently or continuously perform positioning measurements / determinations and determine its own location (e.g., the location of the target WTRU) as a combination (e.g., weighted average) of the location it has determined itself and the location provided by the delegate.

[0298] In an example, the target WTRU may be configured to stop considering the relay WTRU as a positioning delegate if the SL-RSRP drops below a certain threshold.

[0299] In an example, the target WTRU may be configured to stop considering the relay WTRU as a positioning delegate if the SL-RTT is higher than a certain threshold.

[0300] In an example, after determining to stop using the positioning delegate of the relay WTRU, the target WTRU may send an indication to the relay WTRU.

[0301] In an example, the relay WTRU may determine that it (e.g., the relay WTRU) may not be used as a positioning delegate for the target WTRU (e.g., via monitoring of the SL-RSRP, SL-RTT, etc. and comparing them to thresholds).

[0302] In an example, the target WTRU may intermittently perform a positioning determination and compare the location it (e.g., the target WTRU) may have determined with the location that may have been provided by the delegate relay, and if there is a large difference (e.g., greater than a configured threshold), the target WTRU may stop using the positioning delegate.

[0303] In an example, after determining that the relay WTRU may no longer be a positioning delegate (e.g., based on RSRP / RTT thresholds), the target WTRU may start performing positioning measurements for the target WTRU (e.g., based on Uu PRS, based on SL PRS, etc.). If the target WTRU is not configured for positioning measurements, the target WTRU may send a positioning measurement configuration request to the network and / or the relay WTRU.

[0304] In an example, when the relay WTRU determines that it may no longer be suitable for positioning delegation for the target WTRU (e.g., based on its own determination, based on an indication from the target WTRU, etc.), the relay WTRU may send a positioning reference transmission configuration to the target WTRU and / or start sending positioning reference transmissions to the WTRU and / or indicate to the network to send positioning reference transmissions to the target WTRU.

[0305] In an example, one or more of the parameters for dynamic positioning behavior (e.g., SL-RSRP threshold, SL-RTT threshold, offset / increment values to be applied, parameters for weighted average calculation of the position determined by the WTRU itself and the position provided by the delegate, etc.) may be different for different positioning techniques used (e.g., a set of parameters for e-CID based positioning determination, a set of parameters for PRS based positioning determination, etc.).

[0306] Although the features and elements described above are described in specific combinations, each feature or element may be used alone without the other features and elements of the preferred embodiment, or in various combinations with or without other features and elements.

[0307] Although the embodiments described herein may consider 3GPP specific protocols, it should be understood that the embodiments described herein are not limited to this scenario and may be applicable to other wireless systems. For example, although the technical solutions described herein consider LTE, LTE-A, New Radio (NR) or 5G specific protocols, it should be understood that the technical solutions described herein are not limited to this scenario and are also applicable to other wireless systems.

[0308] The above process can be implemented in a computer program, software, and / or firmware combined in a computer-readable medium for execution by a computer and / or a processor. Examples of computer-readable media include, but are not limited to, electronic transmissions (sent 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 / or optical media such as compact disc (CD)-ROM disks and / or digital versatile disc (DVD). A processor associated with software can be used to implement a radio frequency transceiver for a WTRU, a terminal, a base station, an RNC, and / or any host computer.

Claims

1. The first wireless transmit / receive unit WTRU, comprising: A processor, configured to: Receive configuration information from a network node, the configuration information indicating a sounding reference signal SRSp configuration for positioning associated with a second WTRU, a reference timing advance TA value associated with the first WTRU, a first threshold, and a second threshold; Receive a first RSRP measurement from the second WTRU; Determine a first TA value associated with the second WTRU, wherein the determination of the first TA value is based on the first RSRP measurement, the reference TA value, and measurements associated with the network node; And Send the SRSp configuration and the first TA value for the second WTRU to the second WTRU.

2. The first WTRU according to claim 1, wherein the processor is further configured to: Receive a second RSRP measurement from the second WTRU; and Send an indication to the second WTRU based on the first RSRP measurement and the second RSRP measurement.

3. The first WTRU according to claim 2, wherein If the difference between the first RSRP measurement and the second RSRP measurement is between the first threshold and the second threshold, the processor is further configured to: Determine a second TA value for the second WTRU to be used in association with SRSp transmission, wherein the determination of the second TA value is based at least on the first RSRP measurement, the second RSRP measurement, and the first TA value; And Send the indication to the second WTRU, wherein the indication indicates the second TA value.

4. The first WTRU according to claim 2, wherein if the difference between the first RSRP measurement and the second RSRP measurement is higher than the second threshold, the processor is further configured to: Send the indication to the second WTRU, wherein the indication indicates releasing the SRSp configuration.

5. The first WTRU according to claim 2, wherein the first RSRP measurement is associated with a transmission reference point TRP, and wherein the second RSRP measurement is associated with the TRP.

6. The first WTRU according to claim 1, wherein the first TA value indicates a timing advance associated with SRSp transmission with the second WTRU.

7. The first WTRU according to claim 1, wherein the first WTRU includes a relay WTRU, and wherein the second WTRU includes a target WTRU.

8. A method for a first wireless transmit / receive unit WTRU, comprising: Receive configuration information from a network node, the configuration information indicating a sounding reference signal SRSp configuration for positioning associated with a second WTRU, a reference timing advance TA value associated with the first WTRU, a first threshold, and a second threshold; Receive a first RSRP measurement from the second WTRU; Determine a first TA value associated with the second WTRU, wherein the determination of the first TA value is based on the first RSRP measurement, the reference TA value, and measurements associated with the network node; And Send the SRSp configuration and the first TA value for the second WTRU to the second WTRU.

9. The method according to claim 8, wherein the method further comprises: Receive a second RSRP measurement from the second WTRU; And Send an indication to the second WTRU based on the first RSRP measurement and the second RSRP measurement.

10. The method according to claim 9, wherein, If the difference between the first RSRP measurement and the second RSRP measurement is between the first threshold and the second threshold, the method further includes: Determine a second TA value for the second WTRU to be used in association with SRSp transmission, wherein the determination of the second TA value is based at least on the first RSRP measurement, the second RSRP measurement, and the first TA value; and Send the indication to the second WTRU, wherein the indication indicates the second TA value.

11. The method according to claim 9, wherein if the difference between the first RSRP measurement and the second RSRP measurement is higher than the second threshold, the method further comprises: Send the indication to the second WTRU, wherein the indication indicates the release of the SRSp configuration.

12. The method according to claim 9, wherein the first RSRP measurement is associated with a transmission reference point (TRP), and wherein the second RSRP measurement is associated with the TRP.

13. The method according to claim 8, wherein the first TA value indicates a timing advance associated with an SRSp transmission performed with the second WTRU.

14. The method according to claim 8, wherein the first WTRU comprises a relay WTRU, and wherein the second WTRU comprises a target WTRU.

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