SL-U channel acquisition with multi-priority windows

Abstract

Apparatuses and techniques are provided for SL-U acquisition with a multi-priority window. An example device (e.g., an anchor wireless transmit / receive unit (WTRU)) may receive configuration information indicating a time at which a second sidelink positioning reference signal (SL-PRS) is transmitted within after receiving the first SL-PRS. The device may receive a first SL-PRS. The device may execute a listen before talk (LBT) procedure associated with a first priority within a first time window. The device may perform a second LBT procedure associated with a second priority in a second time window without the device acquiring a channel occupancy time (COT) based on the first LBT procedure. The device may send a transmission. The content of the transmission may depend on whether the device is able to acquire the COT during the time within which the second SL-PRS is transmitted.

Description

[0001] Cross-reference to related applications This application claims the benefit of U.S. Provisional Application No. 63 / 531,065, filed August 7, 2023, the contents of which are incorporated herein by reference. Background Technology

[0002] Mobile communication using wireless communication continues to evolve. The fifth generation can be called 5G. The previous generation (traditional) mobile communication can be, for example, the fourth generation (4G) Long Term Evolution (LTE). Summary of the Invention

[0003] This article provides devices and techniques for SL-U channel acquisition using multiple priority windows.

[0004] An example device (e.g., a Wireless Transmit / Receive Unit (WTRU)) can receive configuration information indicating the time within which a second SL-PRS is transmitted after receiving a first Side Link Positioning Reference Signal (SL-PRS). The device can receive the first SL-PRS. The device can execute a Listen-After-Speak (LBT) procedure associated with a first priority within a first time window. If the WTRU does not obtain the Channel Occupied Time (COT) based on the first LBT procedure, the device can execute a second LBT procedure associated with a second priority within a second time window. The device can transmit a transmission. The content of the transmission may depend on whether the WTRU is able to obtain the COT during the time it takes to transmit the second SL-PRS.

[0005] The device can determine the duration of the first time window based on the third priority associated with the first SL-PRS. The duration of the first time window can be inversely proportional to the third priority.

[0006] The device can determine at least one of the following based on local side link channel measurements: the duration of a first time window, the duration of a second time window, a first priority, or a second priority.

[0007] Provided that the WTRU is able to acquire the COT during the time it is able to transmit the second SL-PRS, the transmission may include the second SL-PRS and control information indicating the resources associated with the second SL-PRS. The device may optionally transmit the second SL-PRS via sidelink resources. The transmission may include the second SL-PRS. The transmission may be sent to the target WTRU or the server WTRU via sidelink resources.

[0008] If the WTRU is unable to acquire the COT during the period in which it sends the second SL-PRS, the transmission may include an indication that the current session has been terminated and an indication that the current session has been terminated because the WTRU is unable to acquire the COT.

[0009] At least a portion of the first time window and a portion of the second time window may overlap. The configuration information may indicate the offset between the start of the first time window and the start of the second time window.

[0010] The time for transmitting the second SL-PRS within the timeframe can begin at the start of the first time window and end at the end of the second time window. The WTRU acquires the COT during the time frame for transmitting the second SL-PRS by acquiring the resources used to transmit the second SL-PRS before the end of the second time window.

[0011] An example device (e.g., an anchor WTRU) can receive a first sidelink positioning reference signal (SL-PRS). This device can perform Type 1 Listen-Before-Speak (LBT) at a first priority level within a first window to acquire Channel Occupancy Time (COT). If the anchor WTRU does not acquire COT in the first window, the device can perform Type 1 LBT at a second priority level in a second window. The device can then transmit.

[0012] The device can select sidelink resources during the duration of the first SL-PRS. The transmission may include a second SL-PRS. The sidelink resources can be used to send the transmission to the target or server WTRU.

[0013] If the second SL-PRS fails to be transmitted to the target / server WTRU, the device may: terminate the current RTT session; and transmit an abort instruction to the target / server WTRU.

[0014] The device can receive configuration information. This configuration information can indicate the first window, the second window, and the duration. The first window can be initiated when the anchor WTRU receives the first SL-PRS. Attached Figure Description

[0015] Furthermore, similar reference numerals in the figures indicate similar elements.

[0016] Figure 1A This is a system diagram illustrating an example communication system in which one or more of the disclosed embodiments may be implemented.

[0017] Figure 1B The illustration shows a method according to one embodiment. Figure 1A The diagram shows a system diagram of an example wireless transmit / receive unit (WTRU) used in a communication system.

[0018] Figure 1C The illustration shows a method according to one embodiment. Figure 1A The diagram illustrates a system diagram of an example radio access network (RAN) and an example core network (CN) used within a communication system.

[0019] Figure 1D The illustration shows a method according to one embodiment. Figure 1A The diagram shows another example RAN and another example CN used in the communication system.

[0020] Figure 2 An example of WTRU sensing with two non-overlapping windows (e.g., multi-priority windows) is illustrated.

[0021] Figure 3 An example of WTRU sensing with overlapping sensing windows is illustrated.

[0022] Figure 4 An example of overlapping, start-aligned, multi-priority sensing windows is illustrated (e.g., where two windows start at the same time).

[0023] Figure 5 The illustration shows an example of multi-priority channel acquisition for SL-PRS transmission.

[0024] Figure 6 The illustration shows an example shared COT with SL-PRS-based COT busy signal and anchor WTRU ACK / NACK feedback.

[0025] Figure 7 The illustration shows an example shared COT with a COT busy signal based on SL-PRS.

[0026] Figure 8 The illustration shows an example shared COT with an SL-PRS-based COT busy signal (e.g., with anchor WTRU ACK / NACK).

[0027] Figure 9 The illustration shows an example shared COT with a COT busy signal based on SL-PRS.

[0028] Figure 10 The illustration shows an example server WTRU RTT selection procedure (e.g., utilizing target and anchor WTRU channel measurements).

[0029] Figure 11 The illustration shows the WTRU RTT selector for the example server.

[0030] Figure 12 The illustration shows an example of multiple RTTs sharing COT SL-U positioning. Detailed Implementation

[0031] Figure 1A This diagram illustrates an example 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, and broadcasting to multiple wireless users. The communication system 100 enables multiple wireless users to access such content by sharing system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Zero-Tail Unique Word DFT-Spread Spectrum OFDM (ZT UW DTS-s OFDM), Unique Word OFDM (UW-OFDM), Resource Block Filtered OFDM, Filter Bank Multicarrier (FBMC), and so on.

[0032] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, Public Switched Telephone Network (PSTN) 108, Internet 110, and other networks 112. However, it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, and 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, WTRUs 102a, 102b, 102c, and 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, and so on. Any of WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0033] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks, such as CN 106 / 115, the Internet 110, and / or other networks 112. For example, base stations 114a and 114b may be base transceiver stations (BTS), Node-B, eNode B, home node B, home eNode B, gNB, NR NodeB, site controller, access point (AP), wireless router, etc. Although base stations 114a and 114b are each depicted as a single element, it should be understood that base stations 114a and 114b may include any number of interconnected base station and / or network elements.

[0034] 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 radio signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Therefore, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may use multiple transceivers for each sector of the cell. For example, beamforming can be used to transmit and / or receive signals in a desired spatial direction.

[0035] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interface 116. Air interface 116 can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Any suitable radio access technology (RAT) can be used to establish air interface 116.

[0036] More specifically, as described above, the communication system 100 can be a multi-access system and can employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, base stations 114a and WTRUs 102a, 102b, and 102c in RAN 104 / 113 can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which can establish air interfaces 115 / 116 / 117 using Wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or evolved HSPA (HSPA+). HSPA may include High-Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High-Speed ​​UL Packet Access (HSUPA).

[0037] In one embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement radio technologies such as evolved UMTS terrestrial radio access (E-UTRA), which may use Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro) to establish air interface 116.

[0038] In one embodiment, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as NR radio access, which can use New Radio (NR) to establish air interface 116.

[0039] In one embodiment, base station 114a and WTRUs 102a, 102b, and 102c can implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, and 102c can jointly implement LTE radio access and NR radio access, for example, using the dual connectivity (DC) principle. Therefore, the air interface used by WTRUs 102a, 102b, and 102c can be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0040] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as IEEE 802.11 (i.e., Wi-Fi), IEEE 802.16 (i.e., WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rate GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0041] For example, Figure 1A Base station 114b can be a wireless router, home node B, home eNodeB, or access point, and can utilize any suitable RAT to facilitate wireless connectivity in a localized area, such as commercial locations, homes, vehicles, campuses, industrial facilities, air corridors (e.g., for drone use), roads, etc. In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d can utilize cellular-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish picocells or femtocells. Figure 1A As shown, base station 114b can be directly connected to the Internet 110. Therefore, base station 114b may not need to access the Internet 110 via CN 106 / 115.

[0042] RAN 104 / 113 can communicate with CN 106 / 115, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, and 102d. Data can have different Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. CN 106 / 115 can provide call control, billing services, location-based services, prepaid calling, internet connectivity, video distribution, and / or perform advanced security functions such as user authentication. Although in Figure 1AAlthough not shown, it should be understood that RAN104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs that use the same RAT as or a different RAT than RAN 104 / 113. For example, in addition to being connected to RAN 104 / 113, which may utilize NR radio technology, CN106 / 115 can also communicate with another RAN (not shown) that uses GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0043] CN 106 / 115 can also serve as a gateway for WTRU 102a, 102b, 102c, 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing Common Old-Style Telephone Service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) from the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may use the same RAT as RAN 104 / 113 or a different RAT.

[0044] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multi-mode capabilities (e.g., WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example... Figure 1A The WTRU 102c shown can be configured to communicate with base station 114a, which may employ cellular-based radio technology, and to communicate with base station 114b, which may employ IEEE 802 radio technology.

[0045] Figure 1B This is a system diagram illustrating example WTRU 102. (Example:) Figure 1B As shown, among other things, WTRU 102 may include, in particular, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a global positioning system (GPS) chipset 136, and / or other peripheral devices 138, etc. It should be understood that WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with the embodiments.

[0046] Processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. Processor 118 may perform signal encoding, data processing, power control, input / output processing, and / or any other functions that enable WTRU 102 to operate in a wireless environment. Processor 118 may be coupled to transceiver 120, which may be coupled to transmitting / receiving element 122. Although Figure 1B The processor 118 and transceiver 120 are depicted as separate components, but it should be understood that the processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

[0047] Transmitting / receiving element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over air interface 116. For example, in one embodiment, transmitting / receiving element 122 can be an antenna configured to transmit and / or receive RF signals. In one embodiment, transmitting / receiving element 122 can be, for example, a transmitter / detector configured to transmit and / or receive IR, UV, or visible light signals. In yet another embodiment, transmitting / receiving element 122 can be configured to transmit and / or receive both RF and optical signals. It should be understood that transmitting / receiving element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0048] Although the transmitting / receiving element 122 is in Figure 1B While depicted as a single element, WTRU 102 may include any number of transmit / receive elements 122. More specifically, WTRU 102 may employ MIMO technology. Thus, in one embodiment, WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals on air interface 116.

[0049] Transceiver 120 can be configured to modulate signals transmitted by transmitting / receiving element 122 and demodulate signals received by transmitting / receiving element 122. As described above, WTRU 102 can have multi-mode capability. Therefore, for example, transceiver 120 may include multiple transceivers to enable WTRU 102 to communicate via multiple RATs such as NR and IEEE 802.11.

[0050] The processor 118 of WTRU 102 can be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) unit or an organic light-emitting diode (OLED) display unit) and can receive user input data therefrom. The processor 118 can also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. Furthermore, the processor 118 can access and store information from any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. Non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 may include a user identification module (SIM) card, memory stick, secure digital storage (SD) card, etc. In other embodiments, the processor 118 can access and store information from memory that is not physically located on WTRU 102, such as a server or home computer (not shown).

[0051] The processor 118 can receive power from the power supply 134 and can be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 can be any suitable device that powers the WTRU 102. For example, the power supply 134 may include one or more dry cell battery packs (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0052] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) about the current location of the WTRU 102. In addition to, or instead of, information from the GPS chipset 136, the WTRU 102 may receive location information on the air interface 116 from base stations (e.g., base stations 114a, 114b) and / or determine its location based on the timing of signals received from two or more nearby base stations. It should be understood that the WTRU 102 may acquire location information using any suitable location determination method while remaining consistent with the embodiments.

[0053] The processor 118 may be further coupled to other peripheral devices 138, which may include one or more software and / or hardware modules providing additional features, functions, and / or wired or wireless connectivity. For example, peripheral devices 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (for photos and / or videos), Universal Serial Bus (USB) ports, vibration devices, television transceivers, hands-free headsets, Bluetooth® modules, FM radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, and so on. Peripheral devices 138 may include one or more sensors, such as gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geolocation sensors, altimeters, light sensors, touch sensors, magnetometers, barometers, attitude sensors, biosensors, and / or humidity sensors.

[0054] WTRU 102 may include a full-duplex radio for which the transmission and reception of some or all signals (e.g., signals associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference via hardware (e.g., chokes) or via signal processing by a processor (e.g., a separate processor (not shown) or via processor 118). In one embodiment, WTRU 102 may include a half-duplex radio for which the transmission and reception of some or all signals (e.g., signals associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0055] Figure 1C This diagram illustrates a system diagram of RAN 104 and CN 106 according to an embodiment. As described above, RAN 104 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using E-UTRA radio technology. RAN 104 can also communicate with CN 106.

[0056] RAN 104 may include eNode-Bs 160a, 160b, and 160c; however, it should be understood that RAN 104 may include any number of eNode-Bs while remaining consistent with the embodiments. eNode-Bs 160a, 160b, and 160c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c on air interface 116. In one embodiment, eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Therefore, for example, eNode-B 160a may use multiple antennas to transmit and / or receive radio signals from WTRU 102a.

[0057] Each of the eNode-B 160a, 160b, and 160c 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, etc. Figure 1C As shown, eNode-B 160a, 160b, and 160c can communicate with each other on the X2 interface.

[0058] Figure 1C The CN 106 shown may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (or PGW) 166. While each of the foregoing elements is described as part of CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0059] The MME 162 can connect to each of the eNode-Bs 162a, 162b, and 162c in RAN 104 via the S1 interface and can act as a control node. For example, the MME 162 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, bearer activation / deactivation, selecting a specific serving gateway during the initial attachment of WTRUs 102a, 102b, and 102c, etc. The MME 162 can provide control plane functions for handover between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0060] The SGW 164 can connect to each of the eNode Bs 160a, 160b, and 160c in RAN 104 via the S1 interface. The SGW 164 can typically route and forward user data packets to / from WTRUs 102a, 102b, and 102c. The SGW 164 can perform other functions such as anchoring the user plane during inter-eNode B handover, triggering paging when DL data is available for WTRUs 102a, 102b, and 102c, managing and storing the context of WTRUs 102a, 102b, and 102c, etc.

[0061] SGW 164 can connect to PGW 166, which can provide WTRU 102a, 102b, 102c with access to packet-switched networks such as Internet 110, so as to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices.

[0062] CN 106 can facilitate communication with other networks. For example, CN 106 can provide WTRU 102a, 102b, 102c with access to a circuit-switched network such as PSTN 108, facilitating communication between WTRU 102a, 102b, 102c and traditional landline communication equipment. For example, CN 106 may include, or be able to communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 106 and PSTN 108. Furthermore, CN 106 can provide WTRU 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0063] Despite WTRU in Figure 1A-1D While described as a wireless terminal, it is conceivable that, in some representative embodiments, such a terminal may use (e.g., temporarily or permanently) a wired communication interface with a communication network.

[0064] In a representative embodiment, another network 112 may be a WLAN.

[0065] A WLAN in Infrastructure Basic Services Set (BSS) mode 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 distributed system (DS) or another type of wired / wireless network that carries traffic to and / or out of the BSS. Traffic originating outside the BSS destined for a STA can reach and be delivered to the STA via the AP. Traffic originating from a STA destined for an external BSS can be sent to the AP for delivery to the appropriate destination. For example, traffic between STAs within the BSS can be sent via the AP, where the source STA can send traffic to the AP, and the AP can deliver 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 source and destination STAs (e.g., directly between them) using Direct Link Establishment (DLS). In some representative embodiments, the DLS can use 802.11e DLS or 802.11z Tunneled DLS (TDLS). A WLAN using the Standalone BSS (IBSS) mode may not have an access point (AP), and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode is sometimes referred to as the "ad-hoc" communication mode in this document.

[0066] When using 802.11ac infrastructure operating mode or a similar operating mode, the AP can transmit beacons on a fixed channel, such as the primary channel. The primary channel can be of a fixed width (e.g., a 20 MHz bandwidth) or 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, such as in an 802.11 system, Carrier Sense Multiple Access (CSMA / CA) with collision avoidance can be implemented. For CSMA / CA, each STA, including the AP, can sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, that particular STA can back off. A single STA (e.g., only one station) can transmit at any given time within a given BSS.

[0067] High-throughput (HT) STAs can communicate using a 40 MHz wide channel, for example, by combining a primary 20 MHz channel with adjacent or non-adjacent 20 MHz channels.

[0068] Very High Throughput (VHT) STAs 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, after channel coding, the data passes through a segment resolver, which splits the data into two streams. Each stream can be processed separately using Inverse Fast Fourier Transform (IFFT) and time-domain processing. The streams can be mapped onto 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).

[0069] 802.11af and 802.11ah support operating modes below 1 GHz. The channel operating bandwidth and carrier in 802.11af and 802.11ah are reduced compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV whitespace (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah can support metering-type control / machine-type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only) certain and / or limited bandwidths. MTC devices may include batteries with a battery life exceeding a threshold (e.g., to maintain a very long battery life).

[0070] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include a channel that can be designated as the primary channel. The bandwidth of the primary channel can be 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 limited by the STA among all STAs operating in the BSS that supports the minimum bandwidth operating mode. In the example of 802.11ah, for a STA that supports (e.g., only supports) the 1 MHz mode (e.g., an MTC type device), 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 operating modes. Carrier Sense and / or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, because an STA (which only supports the 1 MHz operating mode) is transmitting to the AP, the entire available band can be considered busy, even if most of the band remains idle and can be available.

[0071] In the United States, the available frequency band for 802.11ah is from 902 MHz to 928 MHz. In South 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. The total available bandwidth for 802.11ah is 6 MHz to 26 MHz, depending on the country code.

[0072] Figure 1D This diagram illustrates a system diagram of RAN 113 and CN 115 according to one embodiment. As described above, RAN 113 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using NR radio technology. RAN 113 can also communicate with CN 115.

[0073] RAN 113 may include gNBs 180a, 180b, and 180c; however, it should be understood that RAN 113 may include any number of gNBs while remaining consistent with the embodiments. gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c on air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, and 180c. Therefore, for example, gNB 180a may use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a. In one embodiment, gNB180a, 180b, and 180c can implement carrier aggregation technology. For example, gNB 180a can transmit multiple component carriers (not shown) to WTRU 102a. A subset of these component carriers can be on unlicensed spectrum, while the remaining component carriers can be on licensed spectrum. In one embodiment, gNB180a, 180b, and 180c can implement Coordinated Multipoint (CoMP) technology. For example, WTRU 102a can receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0074] WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using transmissions associated with scalable digitization. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing can differ for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing a variable number of OFDM symbols and / or a continuously variable absolute time).

[0075] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNode-Bs 160a, 160b, and 160c). In standalone configuration, WTRUs 102a, 102b, and 102c can utilize one or more of gNBs 180a, 180b, and 180c as mobility anchors. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using signals in unlicensed frequency bands. In a non-standalone configuration, WTRUs 102a, 102b, and 102c can communicate / connect with gNBs 180a, 180b, and 180c, while also communicating / connecting with another RAN such as eNode-Bs 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c can implement DC principles to communicate substantially simultaneously with one or more gNBs 180a, 180b, and 180c, as well as one or more eNode-Bs 160a, 160b, and 160c. In a non-standalone configuration, eNode-Bs 160a, 160b, and 160c can act as mobility anchors for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c can provide additional coverage and / or throughput for serving WTRUs 102a, 102b, and 102c.

[0076] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, network slicing support, dual connectivity, interoperability between NR and E-UTRA, routing user plane data to User Plane Functions (UPF) 184a and 184b, routing control plane information to Access and Mobility Management Functions (AMF) 182a and 182b, etc. Figure 1D As shown, gNB 180a, 180b, and 180c can communicate with each other on the Xn interface.

[0077] Figure 1DThe CN 115 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0078] AMF 182a and 182b can connect to one or more of gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can act as control nodes. For example, AMF 182a and 182b can be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting specific SMF183a and 183b, managing registration areas, terminating NAS signaling, mobility management, and so on. AMF 182a and 182b can use network slicing to customize CN support for WTRU 102a, 102b, and 102c based on the service types used by WTRU 102a, 102b, and 102c. For example, different network slices can be established for different use cases, such as services relying on Ultra Reliable Low Latency Time (URLLC) access, services relying on Enhanced Massive Mobile Broadband (eMBB) access, services for Machine Type Communication (MTC) access, and / or so on. AMF 162 can provide control plane functions for handover between RAN 113 and other RANs (not shown) employing other radio technologies such as LTE, LTE-A, LTE-A Pro and / or non-3GPP access technologies such as WiFi.

[0079] SMFs 183a and 183b can connect to AMFs 182a and 182b in CN 115 via the N11 interface. SMFs 183a and 183b can also connect to UPFs 184a and 184b in CN 115 via the N4 interface. SMFs 183a and 183b can select and control UPFs 184a and 184b, and configure the routing of services through UPFs 184a and 184b. SMFs 183a and 183b can perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, etc. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0080] UPF 184a and 184b can be connected to one or more gNBs 180a, 180b, and 180c in RAN 113 via the N3 interface. This N3 interface provides WTRU 102a, 102b, and 102c with access to packet-switched networks (such as Internet 110) to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices. UPF 184 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, and so on.

[0081] CN 115 can facilitate communication with other networks. For example, CN 115 may include, or be able to communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 115 and PSTN 108. Furthermore, CN 115 can provide WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRUs 102a, 102b, and 102c may be connected to the local data network (DN) 185a and 185b via the N3 interface to UPFs 184a and 184b and the N6 interface between UPFs 184a and 184b and DNs 185a and 185b.

[0082] Given Figure 1A-1D as well as Figure 1A-1D The corresponding descriptions herein indicate that one or more, or all, of the functions described herein with respect to one or more of the following can be performed by one or more emulation devices (not shown): WTRU 102a-d, Base Station 114a-b, eNode-B160a-c, MME 162, SGW 164, PGW 166, gNB180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN185a-b, and / or one or more other devices described herein. An emulation device can be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, an emulation device can be used to test other devices and / or simulate network and / or WTRU functions.

[0083] Simulation devices can be designed to perform tests on one or more other devices in laboratory and / or carrier network environments. For 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. Simulation devices can be directly coupled to another device for testing purposes and / or can perform tests using over-the-air wireless communication.

[0084] One or more simulation devices may perform one or more functions, including all functions, rather than being implemented / deployed as part of a wired and / or wireless communication network. For example, simulation devices may be used to test test scenarios in laboratory and / or non-deployment (e.g., testing) wired and / or wireless communication networks to implement the testing of one or more components. One or more simulation devices may be test devices. Simulation devices may transmit and / or receive data using direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas).

[0085] This article provides one or more features associated with New Radio (NR) positioning.

[0086] This document provides one or more features associated with NR Uu positioning based on downlink (DL), uplink (UL), and / or DL ​​and UL based positioning.

[0087] This article provides one or more features associated with DL-based localization.

[0088] In DL-based positioning, DL-PRS can be sent from multiple TRPs to the WTRU. The WTRU can observe and / or measure downlink signals from the TRPs. For WTRU-B positioning, the WTRU can calculate its location. For WTRU-A positioning, the WTRU can transmit downlink measurements to the network. For angle-based positioning, the WTRU can report the angle of arrival (AoA) and / or RSRP of the downlink signals from the TRPs. For timing-based positioning, the WTRU can report RSTD. These techniques can use transmission timing synchronization between TRPs. Positioning calculation errors may arise from synchronization errors and / or multipath propagation.

[0089] This article provides one or more features associated with UL-based positioning.

[0090] In uplink positioning, the WTRU can send a UL-PRS configured by the RRC for positioning to the TRP. The network can calculate the WTRU's location (e.g., based on coordination among all TRPs that received the UL-PRS from the WTRU).

[0091] This article provides one or more features associated with UL- and DL-based positioning.

[0092] In UL and DL-based positioning, the WTRU can measure the receive-transmit (Rx-Tx) time difference between the received DL-PRS and the transmitted UL-PRS. The Rx-Tx time difference and / or RSRP can be reported to the network. The network can coordinate the TRP to calculate the WTRU's location.

[0093] This article provides one or more features associated with sidelink (SL) positioning.

[0094] SL positioning can be used (e.g., in RAN1) for SL-based positioning alone and / or a combination of SL-based and Uu-based positioning. SL positioning can include SL-RTT (Round Trip Time), SL-AoA, and / or SL-TDoA (Time Difference of Arrival) (e.g., it can support R18 SL positioning). For SL-TDoA, technologies based on DL-TDoA and UL-TDoA can be considered.

[0095] "Timing / Angle Positioning Method" can refer to a positioning technique that uses a reference signal such as SL-PRS. A WTRU can receive multiple reference signals from one or more WTRUs. The WTRU can measure RSTD, RSRP, and / or AoA. Examples of angle / timing positioning techniques include SL-AoD or SL-TDOA positioning. A WTRU can transmit SL-PRS to one or more WTRUs. The WTRU can receive measurements (e.g., RSTD, AoA, RSRP) used to determine the position of the WTRU that transmitted the SL-PRS.

[0096] "RTT positioning method" can refer to any positioning technique that uses multiple (e.g., two) WTRUs to transmit SL-PRS to each other. Anchor WTRU can transmit SL-PRS to target WTRU. If the target WTRU receives SL-PRS from the anchor WTRU, the target WTRU can transmit SL-PRS to the anchor WTRU. The target WTRU can 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 transmitted from the anchor WTRU). The target WTRU can report the WTRU Tx-Rx time difference to the anchor WTRU / network (e.g., gNB, LMF). In one example, "target WTRU" can refer to the WTRU whose location is to be determined by peer WTRUs (e.g., server WTRU) and / or the network (e.g., LMF, gNB). "Anchor WTRU" can refer to the WTRU that transmits and / or receives SL-PRS to assist peer WTRUs (e.g., target WTRU, server WTRU) in determining the location of the target WTRU. The target WTRU can determine its location based on measurements made on the SL-PRS. The target WTRU can send measurements to the network or peer WTRUs, enabling the network or peer WTRUs to determine the location of the target WTRU.

[0097] "Network" can include AMF, LMF, gNB, or NG-RAN. "Pre-configured" and "configured" are used interchangeably herein. "Non-serving gNB" and "neighboring gNB" are used interchangeably herein. "gNB" and "TRP" are used interchangeably herein. "PRS" or "PRS resource" are used interchangeably herein. "(One or more) PRS" or "(One or more) PRS resources" are used interchangeably herein. The aforementioned "(One or more) PRS" or "(One or more) PRS resources" can belong to different PRS resource sets. "PRS" or "DL-PRS" or "DL PRS" are used interchangeably herein. "Measurement gap" or "measurement gap mode" are used interchangeably herein. "Measurement gap mode" can include parameters (e.g., measurement gap duration, measurement gap repetition period, and / or measurement gap periodicity, etc.).

[0098] A PRU can be a WTRU or TRP whose location (e.g., altitude, latitude, geographic coordinates, or local coordinates) is known to the network (e.g., gNB, LMF). The capabilities of a PRU can be the same as those of a WTRU or TRP (e.g., capable of receiving PRS or transmitting SRS or SRS for positioning, reporting measurements, and / or transmitting PRS). A WTRU acting as a PRU can be used by the network for calibration purposes (e.g., correcting unknown timing offsets, correcting unknown angular offsets).

[0099] LMF is a non-limiting example of a node or entity (e.g., a network node or entity) that can be used to or support location. Another node or entity can be used instead of LMF while still being consistent with the characteristics described herein.

[0100] An SL reference signal (e.g., a new SL reference signal) and an SL-PRS (e.g., for SL positioning measurements dedicated to SL positioning in R18) can be introduced. SL-PRS transmission can use a comb pattern and / or a pseudo-random sequence. SL-PRS transmission can be based on one or more (e.g., two) resource allocation schemes (e.g., Scheme 1 and Scheme 2). In Scheme 1, SL-PRS resource allocation can be performed by the NW. In Scheme 2, the WTRU can perform autonomous SL-PRS resource allocation based on conventional SL mode 2 resource selection (e.g., SL sensing). The WTRU can obtain time and / or (one or more) frequency resources for SL-PRS transmission from the network by sending a buffer state request. The WTRU can be configured to receive resource allocation from the network without sending a buffer state request. The WTRU can receive SL-PRS configuration from the network (e.g., LMF, gNB). The WTRU can receive indications from the network of time and / or (one or more) frequency resources for SL-PRS transmission.

[0101] SL-PRS configuration may include at least one of the following parameters: number of symbols, transmission power, number of SL-PRS resources included in the SL-PRS resource set, SL-PRS silence mode (e.g., the silence mode may be expressed via a bitmap), periodicity, type of SL-PRS (e.g., periodic, semi-persistent, or aperiodic), time slot offset for periodic SL-PRS transmission, vertical shift of SL-PRS mode in the frequency domain, time slot during repetition, repetition factor, RE (resource element) offset, comb pattern, comb size, spatial relationship, QCL information for SL-PRS (e.g., QCL target, QCL source), number of PRUs, number of TRPs, absolute radio frequency channel number (ARFCN), subcarrier spacing, expected RSTD, uncertainty of expected RSTD, starting physical resource block (PRB), bandwidth, BWP ID, number of frequency layers, start / end time of PRS transmission, SL-PRS on / off indicator, TRP ID, SL-PRS ID, cell ID, global cell ID, PRU ID, and / or applicable time window. WTRU can apply SL-PRS configuration provided that the current time is within the applicable time window.

[0102] This article provides one or more features associated with SL-U channel access.

[0103] SL operations can be performed in unlicensed spectrum (e.g., in 3GPP R18). The WTRU can perform Listen-Before-Tell (LBT) based channel access to acquire a channel for SL transmission. Channel access can be Type 1 or Type 2 (e.g., similar to those applying the NR U framework). LBT-based channel access ensures that SL-U operations comply with regulatory requirements in unlicensed spectrum. For example, SL-U transmissions can meet standards (e.g., requirements) regarding maximum channel occupancy time (mCOT), occupied channel bandwidth (OCB), and / or power spectral density (PSD).

[0104] Type 1 channel access can be based on LBT sensing with random backoff and / or variable extended CCA periods. The parameters (e.g., the contention window size for determining the CCA period) can be included in the Channel Access Priority Category (CAPC) configuration. WTRUs can use the CAPC configuration (e.g., based on data QoS requirements) to perform Type 1 channel access.

[0105] The second type of channel access (e.g., type 2 channel access) can be based on LBT sensing within a (pre)configured fixed period (e.g., 25 microseconds (type 2A) or 16 microseconds (type 2B)). For SL transmissions with a duration of less than 482 microseconds, type 2C channel access can be applied to acquire channel access (e.g., no sensing is performed). WTRUs can perform type 2 channel access to share COTs initiated by another WTRU.

[0106] In out-of-coverage scenarios, the WTRU may perform one or more actions prior to sidelink transmissions (e.g., SL-PRS transmissions) via unlicensed carriers. For example, a Tx WTRU may acquire channel access for transmissions via unlicensed carriers (e.g., according to local regulations for the use of shared spectrum, such as Listen Before Talk (LBT)). Type 1 LBT may refer to a random duration LBT. Type 2 LBT may refer to a deterministic duration LBT. Type 2 LBT may be permitted (e.g., only permitted) for short signal transmissions or for sharing channel occupancy initiated by accompanying equipment.

[0107] Tx WTRU can perform SL resource allocation (e.g., following the SL-U process).

[0108] Due to channel access uncertainties on unlicensed carriers, the transmission of one or more Tx and / or Rx segments in the RTT procedure may not be guaranteed for a short period of time. This may lead to performance issues in RTT-based positioning (e.g., measurements may be unsuitable for location determination due to WTRU movement, clock drift at Tx / Rx, etc.).

[0109] RTT transmissions can be maintained within an acceptable and / or (pre)configured time window T used for positioning in the SL-U.

[0110] One or more features associated with SL-U channel acquisition with multiple priority windows.

[0111] A WTRU can be configured with one or more (e.g., two) priority levels. Priority levels can be associated with a positioning configuration on an unlicensed carrier. A WTRU can be configured with one or more (e.g., two) time windows. The WTRU can execute a first LBT procedure (e.g., Type 1 LBT) associated with a first priority level (e.g., within the first time window). If the WTRU can acquire a COT, the WTRU can transmit a PRS (e.g., during the first window). Otherwise (e.g., if the WTRU does not acquire a COT), the WTRU can execute a second LBT procedure (e.g., Type 1 LBT) associated with a second priority level (e.g., during the second time window). The WTRU can determine one or more Type 1 LBT channel access parameters based on the (pre)configured priority levels. In some examples, a priority level (e.g., one priority level) can be associated with a set of Type 1 LBT channel access parameters. This set of pf parameters can include one or more of the following: the number of LBT sensing slots in the contention window, the number of LBT sensing slots in the delay duration, the number of delay durations in the contention window, an energy detection threshold, and / or the maximum channel occupancy duration (mCOT).

[0112] A higher priority level can be associated with a set of Type 1 LBT channel access parameters having a smaller number of sensing slots and / or delay duration and / or a higher ED threshold, allowing the WTRU to acquire the channel more quickly. The WTRU can apply a shorter mCOT, allowing it to release the channel more quickly. In some examples, the WTRU can receive (e.g., explicitly) a priority level associated with a window via semi-static messages (e.g., RRC, LPP, SLPP) from the network (e.g., LMF, gNB) or peer WTRUs (e.g., server WTRU, anchor WTRU). For example, the priority level can be indicated as "high" or "low," or have a numerical value (e.g., 2 corresponds to a high priority level, 1 to a medium priority level, and 0 to a low priority level). The WTRU can select SL resources from the received SL-PRS within a duration T (e.g., during a second window). Duration T can be the time after receiving the first SL-PRS and within which a second SL-PRS is transmitted. The WTRU can use the selected SL resources to transmit SL-PRS and / or SCI.

[0113] In some examples, WTRUs can be configured with priorities (e.g., a single priority). WTRUs can derive (e.g., can be configured to derive) a first priority and a second priority based on the configured priorities. For example, the first priority can be a configured priority, and the second priority can be a priority one level higher than the first priority.

[0114] The anchor WTRU can receive configuration for the RTT procedure. This configuration may include configuration parameters such as, for example, T (e.g., the time to send the second SL-PRS after receiving the first SL-PRS), the first window, and the second window.

[0115] The anchor WTRU can receive SL-PRS transmissions (e.g., the first SL-PRS from the target / server WTRU). The anchor WTRU can perform measurements on the SL-PRS (e.g., based on the determined resources and SL-PRS configuration).

[0116] The anchor WTRU can execute a first LBT procedure (e.g., type 1 LBT) associated with a first priority level and associated LBT parameters (e.g., within a first time window). The first time window can begin upon receiving the PRS from the target WTRU (e.g., upon receiving the first SL-PRS).

[0117] If the anchor WTRU fails to acquire the Channel Occupied Time (COT) based on the first LBT procedure (e.g., if the anchor WTRU cannot acquire the channel / COT within the first window), the anchor WTRU may execute a second LBT procedure associated with a second priority (e.g., a Type 1 LBT with a second priority level in the second window) within a second time window. The anchor WTRU may select an SL resource from the received SL-PRS within a duration T.

[0118] The anchor WTRU can send transmissions. For example, the anchor WTRU can transmit SL-PRS and / or SCI to the target / server WTRU (e.g., via a selected resource). The content of the transmission may depend on whether the WTRU is able to acquire COT during the time it takes to send a second SL-PRS. For example, if the anchor WTRU cannot transmit SL-PRS to the target / server WTRU, the anchor WTRU can abort the current RTT session. The anchor WTRU can transmit an abort indication to the target / server WTRU. The anchor WTRU can be configured with a duration during which, if it fails to acquire COT for PRS transmission, the WTRU will transmit an abort indication. The anchor WTRU can be further configured with LBT parameters (e.g., priority, etc.) to acquire the channel for the transmission abort indication. The priority can be a priority configured / indicated for PRS transmission, a first priority, or a second priority.

[0119] This document provides one or more features associated with target WTRU coordination (e.g., enabling RTT SL-PRS transport to share COT with SL-PRS-based COT busy signal transport).

[0120] The target WTRU and the anchor WTRU can share the COT (Constant Occupancy Time). If the target WTRU determines to use the SL-PRS (Short-Range Per Second) for the COT busy signal, the target WTRU can transmit a first COT busy signal to the anchor WTRU. The target WTRU can receive (e.g., from the anchor WTRU) the SL-PRS in a second COT busy signal. The contents of the received COT busy signal can be indicated in the SCI (Search Engine Control Center). The target WTRU can measure the COT busy signal (e.g., for positioning).

[0121] The target WTRU can transmit (pre)configuration to the anchor WTRU. The (pre)configuration may include one or more of the following: a first SL-PRS resource configuration for transmitting to the anchor WTRU; and / or a second SL-PRS resource configuration for receiving from the anchor WTRU.

[0122] The target WTRU may transmit a first SL-PRS transmission (e.g., with an associated SCI). The SL-PRS may include COT sharing information to the anchor WTRU. For example, the COT sharing information may include a first COT busy signal configuration. The first COT busy signal configuration may include one or more of the following: transmission duration (e.g., number of symbols / slots); type of signal used in the transmission (e.g., SL-PRS configuration, PSSCH, or pre-configured signal); and / or resource allocation for the transmission.

[0123] If the type of the indicated first COT busy signal conforms to the first SL-PRS configuration, the target WTRU may perform one or more of the following operations. For example, the target WTRU may transmit a first COT busy signal transmission (e.g., according to COT sharing information indicated in the transmitted SCI). The target WTRU may receive a second SL-PRS transmission (e.g., according to a (pre)configured second SL-PRS resource configuration). The associated SCI may provide a second COT busy signal configuration. The second COT busy signal configuration may include one or more of the following: SL-PRS configuration; and / or transmission duration.

[0124] The target WTRU can perform SL positioning measurements (e.g., RTT) on the second SL-PRS transport (e.g., based on the second SL-PRS resource configuration).

[0125] The target WTRU can receive a second COT busy signal (e.g., based on the received second COT busy signal indication). The target WTRU can perform SL positioning measurements (e.g., RTT) on the transmission of the second COT busy signal.

[0126] The target WTRU can receive measurement reports from the anchor WTRU. The measurement reports may include measurement (e.g., RTT) results regarding the first SL-PRS transmission and the first COT busy signal transmission.

[0127] If the type of the indicated first COT busy signal does not conform to the first SL-PRS configuration, the target WTRU may perform one or more of the following actions. For example, the target WTRU may transmit a first COT busy signal transmission (e.g., based on the COT sharing information indicated in the transmitted SCI).

[0128] The target WTRU can receive a second SL-PRS transmission (e.g., based on a (pre)configured second SL-PRS resource configuration).

[0129] The target WTRU can perform SL positioning measurements (e.g., RTT) on the second SL-PRS transport (e.g., based on the second SL-PRS resource configuration).

[0130] The WTRU can receive measurement reports (e.g., RTT results included on the first SL-PRS transmission) from the anchor WTRU.

[0131] This document provides one or more features associated with anchor WTRU coordination (e.g., enabling RTT SL-PRS transmissions to share COT with SL-PRS-based COT busy signal transmissions).

[0132] The target WTRU and the anchor WTRU can share the COT. The anchor WTRU can determine the configuration of the SL-PRS for the second COT busy signal to be transmitted (e.g., based on the configuration of the first COT busy signal received from the target WTRU).

[0133] The anchor WTRU can receive (pre)configuration from the target WTRU. The (pre)configuration may include a first SL-PRS resource configuration for receiving from the target WTRU; and / or a second SL-PRS resource configuration for transmitting to the target WTRU.

[0134] The anchor WTRU can receive a first SL-PRS transmission (e.g., with an associated SCI). The SCI may include COT sharing information (e.g., from the target WTRU). The COT sharing information may include a first COT busy signal configuration. The first COT busy signal configuration may include one or more of the following: transmission duration (e.g., number of symbols / slots); type of signal used in the transmission (e.g., SL-PRS configuration, PSSCH, or pre-configured signal); and / or resource allocation for the transmission.

[0135] The anchor WTRU can perform SL positioning measurements (e.g., RTT) on SL-PRS transmissions (e.g., based on the (pre)configured first SL-PRS resource configuration).

[0136] If the type of the indicated first COT busy signal conforms to (e.g., matches) the first SL-PRS configuration, the anchor WTRU may perform one or more of the following operations. For example, the anchor WTRU may receive the first COT busy signal transmission (e.g., based on the COT sharing information indicated in the received SCI). The anchor WTRU may buffer the received first COT busy signal.

[0137] The anchor WTRU can receive a second COT busy signal configuration (e.g., based on the received first COT busy signal). For example, the second COT busy signal configuration may include the same SL-PRS mode; and / or transmission duration (e.g., based on the SL-PRS mode used for the first COT busy signal).

[0138] The anchor WTRU can perform a second SL-PRS transmission (e.g., based on a (pre)configured second SL-PRS resource configuration with associated SCI). The second SL-PRS resource configuration may include at least the determined second COT busy signal configuration.

[0139] The anchor WTRU can transmit a second COT busy signal (e.g., based on a determined second COT busy signal configuration). The anchor WTRU can perform SL positioning measurements (e.g., RTT) on the buffered first COT busy signal transmission. The anchor WTRU can send a measurement report. The measurement report may include measurement (e.g., RTT) results regarding the first SL-PRS transmission and the first COT busy signal transmission.

[0140] If the type of the indicated first COT busy signal does not follow (e.g., does not match) the first SL-PRS configuration, the anchor WTRU may perform one or more of the following operations. For example, the anchor WTRU may determine the second COT busy signal configuration (e.g., based on the (pre)configured signals and / or PSSCH if SL data is present in the buffer).

[0141] The anchor WTRU can perform a second SL-PRS transmission (e.g., configured according to (pre)configured second SL-PRS resources). The anchor WTRU can transmit a second COT busy signal (e.g., configured according to a determined second COT busy signal). The anchor WTRU can send measurement reports (e.g., RTT measurement results) on the first SL-PRS transmission.

[0142] The server WTRU can select the RTT procedure based on channel sensing and anchor WTRU feedback.

[0143] The server WTRU can determine the probability of success for a single or shared COT. For example, the WTRU can determine the probability of success based on channel measurements reported by peer WTRUs (e.g., anchor WTRU and / or target WTRU) and measurements performed by the server WTRU. WTRU capabilities (e.g., SL-PRS measurements / processing) of the anchor WTRU and / or target WTRU can be reported to the server WTRU. The server WTRU can consider WTRU capabilities when determining the probability of success. The WTRU can determine whether to use a shared COT or a single COT for positioning (e.g., based on one or more of the probability of success).

[0144] The server WTRU can send a request to the anchor WTRU (or target WTRU). This request can be for channel measurements and WTRU processing capabilities (e.g., preparation time for transmitting SL-PRS, measurement processing time, etc.).

[0145] The server WTRU can receive anchor WTRU responses regarding channel measurements (e.g., CBR, RSSI, assumed LBT success). Anchor WTRU capabilities may include PRS measurement time, PRS TX preparation time, RTT report processing, etc.

[0146] The server WTRU can determine one or more parameters related to the RTT location procedure. For example, these parameters may include one or more of the following: maximum COT duration, COT initiation priority category, and / or COT-busy signal nature / duration. The server WTRU can determine one or more parameters based on the anchor WTRU's processing capacity.

[0147] The server WTRU can derive one or more of the following metrics (e.g., based on local channel measurements performed by the server WTRU, determined RTT / COT parameters, and / or received anchor WTRU feedback, such as channel measurements): a first success probability associated with initiating a shared COT shared between the target WTRU and the anchor WTRU; and / or a second success probability associated with a separate COT initiating a transmission from the target WTRU.

[0148] If the first success probability is higher than a first (e.g., configured) threshold, the server WTRU can determine a first RTT procedure (e.g., associated with using a shared COT). Otherwise (e.g., if the first success probability is lower than the first threshold), if the second success probability is higher than a second (e.g., configured) threshold, the server WTRU can select a second RTT procedure (e.g., associated with using a separate COT).

[0149] Otherwise (e.g., if the first success probability is below a first threshold and the second success probability is below a second threshold), the server WTRU can choose to perform an RTT failure / abort procedure (e.g., indicate that an unlicensed channel is not suitable for positioning).

[0150] The server WTRU can instruct the determined RTT procedure to the anchor WTRU.

[0151] This article provides one or more features associated with a shared COT multiRTT procedure from a target WTRU.

[0152] A target WTRU can be configured with multiple anchor WTRUs (e.g., M anchor WTRUs) to perform RTT-based localization. The target WTRU can determine the transmission order of the M anchor WTRUs. The WTRU transmits SL-PRS to the M anchor WTRUs (e.g., using SCI indication). The SCI indication can indicate the transmission order of the anchor WTRUs. If the WTRU receives SL-PRS from at least N anchor WTRUs, the target WTRU can report the measurement to the server WTRU (e.g., based on the determined transmission order). Otherwise (e.g., if the WTRU receives SL-PRS from fewer than N anchor WTRUs), the target WTRU can report an error to the network.

[0153] The target WTRU can transmit target assistance information to M anchor WTRUs. The target assistance information can instruct the anchor WTRUs to perform resource selection, potential start time indications (e.g., t0 and window length), and a set of transmission sequences before COT initiation.

[0154] The target WTRU may determine one or more of the following: (one or more) LBT parameters, COT busy type / duration (e.g., COT_Busy_I&II type / duration), the transmission order of PRS and RTT reports for M anchors performing RTT procedures in a shared COT with at least M anchors, the ability of anchor WTRUs to transmit SL-PRS after receiving SL-PRS from the target WTRU, and / or the ability of anchor WTRUs to process measurements to prepare RTT measurement reports.

[0155] The target WTRU can perform LBT (e.g., Type 1 LBT). The target WTRU can perform LBT to obtain channel access for the RTT procedure (e.g., based on the determined LBT parameters).

[0156] The target WTRU can determine one or more SCI parameters. SCI parameters may include at least one of the following: remaining COT duration; channel access priority category (e.g., for COT acquisition); COT_Busy_I and II (e.g., duration and type of COT_Busy_I, duration and type of COT_Busy_II, I before PRS, and II before RTT reporting); transmission order of PRS transmission for the anchor WTRU (e.g., the transmission order may be a dynamic indication of selecting one of the pre-configured transmission orders, such as an index for selecting the pre-configured transmission order); transmission resources for PRS transmission for the anchor WTRU; and transmission resources for RTT reporting for the anchor WTRU.

[0157] The target WTRU can transmit positioning data to the anchor WTRU. The positioning data transmission may include SL-PRS and / or the determined SCI parameters.

[0158] The target WTRU can transmit a COT_Busy_I signal (e.g., to the anchor WTRU). The COT_Busy_I signal may include an extended SL-PRS.

[0159] If the target WTRU detects SL-PRS transmissions from N anchors (e.g., where N is greater than a (pre)configured threshold), the target WTRU may transmit a COT Busy II signal (e.g., where the COT Busy II signal is a pre-configured type).

[0160] Otherwise (e.g., if the target WTRU detects SL-PRS transmissions from fewer than N anchors), the target WTRU can send an abort indication to the anchor WTRUs. The abort indication can abort the current RTT procedure. The target WTRU can also send an abort indication (e.g., with a reason indication) to the server WTRU.

[0161] The target WTRU can receive RTT measurement reports (e.g., in the transmission order indicated in the SCI used for anchor PRS transmission). The target WTRU can transmit local and / or anchor WTRU RTT reports to the server WTRU. The target WTRU can receive location information from the server WTRU.

[0162] This document provides one or more features associated with positioning and ranging. The positioning-related features described herein can also be used for ranging (e.g., without any limitations). Positioning can refer to a technique or scheme for estimating the geographic location of a WTRU. Ranging can refer to a method / scheme for estimating the distance between WTRUs. "WTRU positioning" or "WTRU location information" can be used interchangeably with "distance between WTRUs" (e.g., where the described features are used for ranging).

[0163] The location of a WTRU can include absolute location (e.g., coordinates, area ID) or relative location (e.g., it can include range, distance and / or propagation time, and / or RTT to another node (e.g., another WTRU, RSU, PRU or gNB)).

[0164] The WTRU can determine the signal used for the SL-PRS. The WTRU may use one or more of the following reference signals as the SL-PRS: DMRS of PSSCH and / or PSCCH; SLSS (S-PSS, S-SSS); PTRS; PSFCH; SL-CSI-RS; and / or a new RS for positioning purposes.

[0165] A WTRU can receive one or more SL-PRS configurations. A WTRU can determine the SL-PRS configuration. A WTRU can receive the SL-PRS configuration from another node (e.g., another WTRU or gNB). SL-PRS configuration may include one or more of the following: resource pool (e.g., for SL-PRS transmission, reception, and / or sidelink measurement reporting); SL-PRS resource ID; SL-PRS sequence ID, or other ID used to generate SL-PRS sequences; time frequency of SL-PRS resources; SL-PRS resource element offset; SL-PRS resource 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; silence mode for SL-PRS; silence parameters (e.g., repetition factor, silence option); SL-PRS resource force; 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 used to receive SL-RS, angle of arrival); frequency layer ID; WTRU ID; and / or SL-PRS ID.

[0166] This article provides one or more features associated with WTRU behavior.

[0167] The WTRU can send configuration requests (e.g., PRS configuration, SRS (SRSp) configuration for positioning, etc.) to the network in PUSCH, PUCCH, UCI, MAC-CE, RRC, or LPP messages. Requests from the WTRU may include configurations for measurement gaps, PRS processing windows, or SRS transmission windows. The WTRU can also send acknowledgment messages for authorizations received from the network (e.g., in PUSCH or PUCCH).

[0168] Multiple conditions / criteria can be used in combination. A WTRU can be configured with more than one condition (e.g., and associated WTRU behaviors). A WTRU can determine which behavior to use based on one or more applicable conditions.

[0169] The WTRU can measure DL-PRS (e.g., inside or outside the active BWP). The WTRU can emit SRSp (e.g., inside or outside the active BWP).

[0170] WTRU can be (pre)configured using parameters (e.g., measurement gap, PRS processing window, PRS configuration, SRSp configuration). For example, WTRU can be (pre)configured using parameters via semi-static messages (e.g., LPP, RRC).

[0171] The actions(s) that a WTRU determines to take can be configured by the network. For example, a WTRU can be configured using rules. The WTRU can determine to take associated actions (e.g., based on rules).

[0172] WTRU may include (for example, in addition to measurements performed on PRS) at least one of the following cell-related measurements: SSB RSRP from the serving cell with the corresponding cell ID; SSB RSRP from one or more neighboring cells with the corresponding cell ID; RSRP of CSI-RS with CSI-RS resource ID; and / or RSRS of DM-RS.

[0173] The WTRU can perform LBT-based channel sensing (e.g., to obtain channel occupancy for transmission on an unlicensed carrier). The LBT can follow a Type 1 channel access procedure (e.g., with a contention-window-based random backoff and variable extended CCA period, the size of which is selected based on a Channel Access Priority Class (CAPC) configuration). The WTRU can perform a Type 2 channel access procedure to share the COT. Type 2A and 2B channel access can be performed when the transmission gap is 25 microseconds and 16 microseconds, respectively. If the transmission gap is less than 16 microseconds, Type 2C channel access can be applied (e.g., where transmission occurs immediately after the gap without sensing).

[0174] The WTRU can perform resource allocation for sidelink transmissions (e.g., PSSCH transmissions or SL-PRS transmissions). The WTRU can perform resource allocation based on the channel sensing window and the detected SCI.

[0175] The WTRU can receive resource indications for transmitting PSSCH or SL-PRS. These resource indications can be provided by the WTRU (e.g., another SL-WTRU or gNB).

[0176] As used herein, “network” can include AMF, LMF, gNB, or NG-RAN. “Pre-configured,” “(pre)configured,” and “configured” are used interchangeably herein. The terms “non-serving gNB” and “neighboring gNB” are used interchangeably herein. The terms “gNB” and “TRP” are used interchangeably herein. “PRS,” “SRS,” “SRS for positioning,” and / or “SRS for positioning purposes” are used interchangeably herein. “PRS” or “PRS resource” are used interchangeably herein. “(one or more) PRS” or “(one or more) PRS resources” are used interchangeably herein. The aforementioned “(one or more) PRS” or “(one or more) PRS resources” may belong to different sets of PRS resources. “PRS,” “DL-PRS,” and / or “DL PRS” are used interchangeably herein. “Measurement gap” or “measurement gap pattern” are used interchangeably herein. “Measurement gap pattern” can include parameters such as measurement gap duration, measurement gap repetition period, and / or measurement gap periodicity.

[0177] A PRU can be a WTRU or TRP whose location (e.g., altitude, latitude, geographic coordinates, or local coordinates) is known to the network (e.g., gNB, LMF). The capabilities of a PRU can be the same as those of a WTRU or TRP (e.g., capable of receiving PRS or transmitting SRS or SRS for positioning, reporting measurements, or transmitting PRS). A WTRU acting as a PRU can be used by the network for calibration purposes (e.g., correcting unknown timing offsets, correcting unknown angular offsets).

[0178] LMF is a non-limiting example of a node or entity (e.g., a network node or entity) that can be used to (or support) localization. Any other node or entity can be used in place of LMF and still be consistent with one or more of the features described herein.

[0179] WTRU can receive one or more pre-configured thresholds from the network (e.g., LMF, gNB).

[0180] The LOS indicator can be a hard indicator (e.g., 1 or 0) or a soft indicator (e.g., 0, 0.1, 0.2…1). The LOS indicator can indicate the likelihood of a LOS path existing between a TRP and a WTRU or along a PRS. The LOS indicator can be associated with a TRP or PRS resource ID (e.g., an index). The WTRU can receive LOS indicators from the network (e.g., per TRP or resource ID). The WTRU can determine the LOS indicator (e.g., based on measurements per TRP or resource ID).

[0181] WTRU locations can be expressed by altitude, latitude, geographic coordinates, local coordinates, and / or other parameters.

[0182] This document provides a sample configuration for RS (Radio Signal) for positioning. This document also provides a sample configuration for PRS (Radio Signal System). The configuration described for PRS in this document can be applied to PRS, SL-PRS, or any other signal used in positioning technologies.

[0183] The PRS configuration may include at least one of the following parameters: number of symbols, transmission power, number of PRS resources included in the PRS resource set, PRS silence mode (e.g., the silence mode may be represented via a bitmap), periodicity, PRS type (e.g., periodic, semi-persistent, or aperiodic), time slot offset for periodic PRS transmission, vertical shift of the PRS pattern in the frequency domain, time slot during repetition, repetition factor, resource element (RE) offset, comb pattern, comb size, spatial relationship, QCL information of the PRS (e.g., QCL target, QCL source), number of PRUs, number of TRPs, absolute radio channel number (ARFCN), subcarrier spacing, expected RSTD, uncertainty of expected RSTD, starting physical resource block (PRB), bandwidth, BWPID, number of frequency layers, start / end time of PRS transmission, PRS on / off indicator, TRP ID, PRS ID, cell ID, global cell ID, PRU ID, applicable time window, and / or etc. The WTRU may apply the PRS configuration provided that the current time is within the applicable time window. In this article, “ID” can be used interchangeably with “index”.

[0184] This article provides a sample configuration of SRS for positioning.

[0185] The SRS (SRSp) or SRS configuration used for positioning may include at least one of the following: resource ID; comb offset value, cyclic shift value; starting position in the frequency domain; number of SRSp symbols; shift of the SRSp in the frequency domain; frequency hopping mode; type of SRSp (e.g., aperiodic, semi-persistent, or periodic); sequence ID (e.g., used to generate the SRSp), or other ID used to generate the SRSp sequence; spatial relation information indicating which reference signal (e.g., DLRS, UL RS, CSI-RS, SRS, DM-RS) or SSB (e.g., SSB ID, SSB cell ID) the SRSp is spatially associated with, where the SRSp and DLRS are related. RS can be spatially aligned; QCL information (e.g., QCL relationship between SRSp and other reference signals or SSBs); QCL type (e.g., QCL type A, QCL type B, QCL type C, QCL type D); resource set ID; a list of SRSp resources in the resource set; transmission power related information; path loss reference information that may contain indices of SSB, CSI-RS, or PRS; periodicity of SRSp transmission; and / or spatial information such as spatial direction information of SRSp transmission (e.g., beam information, angle of transmission), spatial direction information of DLRS reception (e.g., beam ID used to receive DL RS, angle of arrival). "ID" can be used interchangeably with "index".

[0186] This article provides a sample SL PRS configuration.

[0187] SL-PRS configuration may include at least one of the following parameters: number of symbols, transmission power, number of SL-PRS resources included in the SL-PRS resource set, SL-PRS silence mode (e.g., the silence mode may be expressed via a bitmap), periodicity, type of SL-PRS (e.g., periodic, semi-persistent, or aperiodic), time slot offset for periodic transmission of SL-PRS, vertical shift of SL-PRS mode in the frequency domain, time slot during repetition, repetition factor, RE offset, comb pattern, comb size, spatial relationship, QCL information of SL-PRS (e.g., QCL target, QCL source), number of PRUs, number of TRPs, ARFCN, subcarrier spacing, expected RSTD, uncertainty of expected RSTD, starting PRB, bandwidth, BWP ID, number of frequency layers, start / end time of PRS transmission, SL-PRS on / off indicator, TRP ID, SL-PRS ID, cell ID, global cell ID, PRU ID, and / or applicable time window. WTRU can apply SL-PRS configuration provided that the current time is within the applicable time window.

[0188] This article provides example measurements.

[0189] The “WTRU Rx-Tx time difference” can refer to the difference between the arrival time of a reference signal received by the first WTRU from the second WTRU and the transmission time of a reference signal transmitted by the first WTRU. The WTRU Rx-Tx time difference can be associated with a PRS resource ID and / or an SRSp resource ID. The received reference signal and the transmitted reference signal can be an SL-PRS.

[0190] RSTD can refer to the time difference of arrival between PRS transmitted from a reference TRP and a target TRP. A WTRU can be configured with a reference TRP index and a target TRP index. A WTRU can be configured for measurement using a PRS resource index. A WTRU can determine the time of arrival from a TRP (e.g., based on one or more PRS resources associated with the TRP). RSTD can refer to the time difference of arrival between a reference PRS transmitted from a TRP and a target PRS transmitted from the TRP.

[0191] The “WTRU Rx-Tx time difference” can refer to the difference between the arrival time of the reference signal transmitted by the TRP and the transmission time of the reference signal transmitted from the WTRU. The WTRU Rx-Tx time difference can be associated with the PRS resource ID and / or the SRSp resource ID.

[0192] This article provides an example server WTRU role.

[0193] The server WTRU role can be implemented at the target device. The server WTRU role can also be implemented at a WTRU that is different from the target WTRU. If the server WTRU role is implemented at the target WTRU, the anchor WTRU can send SL RTT reports to the target / server WTRU.

[0194] If the server WTRU role is implemented at a WTRU different from the target WTRU, the anchor WTRU can send RTT reports to the server WTRU. The target WTRU can (e.g., subsequently) provide the server WTRU with anchor RTT measurement reports (e.g., for location calculation).

[0195] If measurements are taken at both the target WTRU and the anchor WTRU, the server WTRU can perform positioning measurements to determine the location of the target WTRU. The server WTRU can then provide the determined location of the target WTRU to the target WTRU and / or the anchor WTRU.

[0196] The server WTRU can have LMF capability. The server WTRU can provide PRS configuration (e.g., SL-PRS configuration) to the first group of WTRUs (e.g., anchor WTRU) and the second group of WTRUs (e.g., target WTRU).

[0197] Server WTRU may not have LMF capability.

[0198] LMF capabilities may include at least one or more of the following: the ability to provide RS configuration (e.g., SLPRS configuration) to another WTRU; the ability to configure a positioning method (e.g., RTT-based, TDOA-based, AoA, AoD-based positioning method); the ability to schedule time and / or frequency resources for RS transmission or reception of another WTRU; the ability to receive a report from another WTRU, wherein the report consists of measurements (e.g., RSTD, RSRP, WTRU Rx-Tx RTT) and associated SL-PRS information; the ability to process measurements and determine the location of another WTRU based on the measurements; and the ability to receive location information (e.g., WTRU location estimates) from a WTRU and forward it to a Location Client Server (LCS).

[0199] A server WTRU (e.g., with or without LMF capability) can receive a set of SL-PRS configurations from an LMF (e.g., an LMF in the network, a WTRU with LMF capability) or a peer WTRU (e.g., a server WTRU). The set of PRS configurations may include multiple subsets of SL-PRS configurations. The server WTRU may provide the received PRS configurations (e.g., subsets of SL-PRS configurations, sets of SL-PRS configurations) to a first set of WTRUs (e.g., an anchor WTRU) and a second set of WTRUs (e.g., a target WTRU).

[0200] This article provides an example of SL RTT in unlicensed spectrum.

[0201] One or more target WTRUs, server WTRUs, and / or one or more anchor WTRUs can be configured by the network (e.g., LMF, gNB) and / or peer WTRUs (e.g., WTRUs with LMF capability) using a positioning technique (e.g., RTT-based positioning method, SL RTT). WTRUs can receive configuration messages from the network (e.g., via LPP or RRC messages).

[0202] SL RTT procedures in unlicensed spectrum can be executed by a target WTRU, one or more anchor WTRUs, and / or a server WTRU. SL multi-RTT procedures in unlicensed spectrum can be executed by a target WTRU, a set of anchor WTRUs, and / or a server WTRU.

[0203] The server WTRU can determine whether to trigger an SL location session (e.g., to determine the location information of the target WTRU based on an SL RTT procedure). In unlicensed spectrum, the target WTRU and / or anchor WTRU can execute SL RTT procedures as described herein.

[0204] The SL RTT procedure within a single COT can involve one or more actions of the WTRU. For example, the target WTRU can initiate a first COT. The target WTRU can perform a forward SL-PRS transmission to the anchor WTRU in the first COT. The anchor WTRU can perform measurements on the received forward SL-PRS transmission in the first COT. The anchor WTRU can (e.g., subsequently) initiate a second COT. The anchor WTRU can perform a reverse SL-PRS transmission to the target WTRU (e.g., in the second COT). The anchor WTRU can perform a transmission including reporting the measurement results of the forward SL-PRS transmission in the second COT.

[0205] The SL multi-RTT procedure in different COTs can involve one or more actions of the WTRU. For example, the target WTRU can initiate the first COT. The target WTRU can perform a forward SL-PRS transmission to the anchor WTRU in the first COT. The anchor WTRU (e.g., each anchor WTRU) can perform measurements for the forward SL-PRS transmission. The anchor WTRU (e.g., each anchor WTRU) can initiate separate COTs for reverse SL-PRS transmissions and measurement report transmissions.

[0206] The SL RTT procedure in a shared COT can involve one or more actions of the WTRU. For example, the target WTRU can initiate a first COT. The target WTRU can perform a forward SL-PRS transmission to the anchor WTRU in the first COT. The anchor WTRU can perform measurements on the received forward SL-PRS transmission in the first COT. The anchor WTRU can (e.g., subsequently) perform a reverse SL-PRS transmission to the target WTRU in the same COT (e.g., via a shared first COT). The anchor WTRU can perform a transmission including reporting the measurement results of the forward SL-PRS transmission in the first COT.

[0207] The SL multi-RTT procedure in a shared COT can involve one or more actions of WTRUs. For example, a target WTRU can initiate a first COT. The target WTRU can perform a forward SL-PRS transmission to one or more anchor WTRUs in the first COT. Anchor WTRUs (e.g., each anchor WTRU) can perform measurements for the forward SL-PRS transmission. Anchor WTRUs (e.g., each anchor WTRU) can perform a reverse SL-PRS transmission and measurement report transmission in the first COT.

[0208] The anchor WTRU can perform reverse SL-PRS transmissions by sharing a first COT (e.g., a COT initiated by the target WTRU). The anchor WTRU can (e.g., subsequently) initiate a different COT for the transmission of measurement reports received in the first COT for forward SL-PRS transmissions.

[0209] This article provides one or more features associated with SL-U channel acquisition with multiple priority windows.

[0210] This document provides one or more example SL-U multi-priority channel access configurations.

[0211] A WTRU (e.g., an anchor WTRU) can receive a channel access configuration to initiate a COT. COT initiation can be related to a reverse PRS transmission of an RTT procedure. The channel access configuration can include one or more of the following parameters.

[0212] Channel access configuration may include an Rx-Tx time threshold “T” (e.g., the time after receiving a first sidelink positioning reference signal (SL-PRS) within which a second SL-PRS is transmitted). The Rx-Tx time threshold may refer to the time during which the WTRU receiving the first PRS transmission (e.g., a forward SL-PRS transmission) transmits a second PRS transmission (e.g., a reverse SL-PRS transmission) to make the RTT procedure valid. “T” can be specified in milliseconds. T can be specified in subframes, time slots, or symbols. The Rx-Tx time threshold parameter “T” can be provided to the WTRU (e.g., in a field for packet delay budget used for SL communications). If this configuration is used for SL-PRS transmissions in a positioning session, the WTRU may interpret it as T.

[0213] Channel access configuration may include a first window “w1”. This first window can specify a time window. For example, the duration of the window can be expressed in terms of time slots, subframes, frames, symbols, or the number of seconds. In the example configuration, the first window can be configured using a start time and an end time. The first window can be configured using a start time and a duration. The time for transmitting a second SL-PRS within it can begin at the start of the first time window (e.g., the start time of the first window can be defined relative to the WTRU receiving the first SL-PRS transmission). The start time of the first window can be defined relative to the time slot or symbol(s) of the WTRU receiving the SL-PRS transmission (e.g., a forward SL-PRS transmission based on SLRTT positioning). The start of the first window can be an offset from the received SL-PRS transmission (e.g., a configured offset). As part of the configuration, the offset can be configured to the WTRU. The offset can be known through pre-configuration. This offset can be related to the WTRU processing time.

[0214] Channel access configuration may include a first priority for COT initiation. The WTRU may be configured with a first priority (e.g., the WTRU will use this first priority to initiate a COT in the first window w1). The first priority may be the normal priority of an SL-PRS transmission (e.g., a reverse SL-PRS transmission) that the WTRU is configured to transmit. The first priority may be linked to the priority of SL-PRS transmissions (e.g., forward SL-PRS transmissions) received by the WTRU (e.g., before the COT initiation).

[0215] WTRU can receive more than one configuration for the first window and the first priority.

[0216] The channel access configuration may include a second window "w2". This second window can specify a time window. In the example configuration, the second window can be configured using a start time and an end time. The second window can be configured using a start time and a duration. The start time of the second window can be defined relative to the WTRU receiving the first SL-PRS transmission. The start time of the second window can be defined relative to the time slot or one or more symbols of the WTRU receiving the SL-PRS transmission (e.g., a forward SL-PRS transmission based on SL RTT positioning). The start time of the second window can be defined relative to the first window (e.g., the end time of the first window). The time for transmitting the second SL-PRS within it can end when the second time window ends.

[0217] Channel access configuration may include a second priority for COT initiation. The WTRU can be configured with a second priority (e.g., the WTRU can use this second priority to initiate a COT in a second window w2). The second priority can be linked to the priority of SL-PRS transmissions (e.g., forward SL-PRS transmissions) received by the WTRU (e.g., before the COT initiation). The WTRU can determine the second priority based on the first priority. For example, the second priority can be one level higher than the first priority (e.g., one level higher). If a lower value is assigned to a higher priority for indicative purposes, the second priority can be the first priority minus one.

[0218] Channel access configuration may include energy detection (ED) thresholds. For LBT sensing in the first and second windows, the WTRU can be (pre-)configured with different ED thresholds. The target WTRU can indicate one or more ED thresholds to the anchor WTRU (e.g., in the SLU RTT procedure). This indication can be carried in SCI, MAC, and / or RRC signaling.

[0219] WTRU can receive more than one configuration for the second window and the second priority.

[0220] A WTRU (e.g., an anchor WTRU) can be configured with a window (e.g., a single window) for LBT. The WTRU can perform a Type 1 LBT with a first priority and associated LBT parameters within the first window. If the anchor WTRU cannot acquire a channel / COT within the window, the anchor WTRU can perform a Type 1 LBT with a second priority within the window. If the remaining time during the window period is greater than a threshold (e.g., a configured threshold), the WTRU can determine to perform a Type 1 LBT with a second priority. If the elapsed time during the window period is less than a threshold (e.g., a configured threshold), the WTRU can determine to perform a Type 1 LBT with a second priority. The WTRU can select an SL resource from the SL-PRS received within the window for a duration T. The configured window can be used in conjunction with the SL-PRS transmission and / or reception procedures described herein.

[0221] WTRU can receive forward SL-PRS transmissions (e.g., the first SL-PRS).

[0222] A WTRU (e.g., an anchor WTRU) can receive forward SL-PRS transmissions. The WTRU can receive SL-PRS (e.g., along with associated control information, such as SCI). The SCI can indicate one or more of the following: the priority of the SL-PRS transmission; the time and frequency resources used for the SL-PRS transmission; the RTT method indication; and / or multiple priority window selection.

[0223] SCI can provide indication of RTT location based on a single COT. RTT method indication can be implicit (e.g., the WTRU does not receive any COT sharing information in the control information).

[0224] The WTRU can receive instructions to use a multi-priority window (e.g., channel-based sensing based on the previous configuration of the transmission for reverse SL-PRS transmission).

[0225] The WTRU can receive an indication of a first priority window and a first priority (e.g., a first priority window from a configured set of settings). The WTRU can determine a second priority window and a second priority (e.g., based on the indication of the first priority window).

[0226] WTRU can receive instructions for a first priority window and a second priority window (e.g., from a set of configured first priority windows and second priority windows).

[0227] The WTRU can receive (e.g., from a set of pre-configured configurations) an instruction to select a configuration. Each configuration (e.g., each configuration) can identify a first-priority window with a first priority and a second-priority window with a second priority.

[0228] WTRU can determine the first priority of the first window and the second priority of the second window (e.g., priority based on SL-PRS transmission).

[0229] WTRU can determine one or more SL multi-priority parameters.

[0230] A WTRU (e.g., an anchor WTRU) can determine one or more parameters of the channel access procedure for SL-PRS transmission (e.g., forward or reverse SL-PRS transmission of an SL-based RTT procedure on a shared spectrum). The one or more channel access parameters may include the start / duration of a first priority window (e.g., a first time window), the start / duration of a second priority window (e.g., a second time window), and / or the priorities for the first and second windows (e.g., first priority and second priority).

[0231] The WTRU can determine one or more multi-window channel access parameters based on the priority (e.g., associated with) the received forward (e.g., first) SL-PRS transmission. For example, the anchor WTRU can determine the duration of the first window based on a (pre)configured association between the duration of the first window and the SL-PRS priority indicated for forward and / or reverse SL-PRS transmissions from the target WTRU. The duration of the first window can be inversely proportional to the third priority. For example, a higher priority can be associated with a shorter duration. If the channel is busy in the first window, the WTRU can apply the LBT to a higher-priority SL-PRS transmission earlier in the second window.

[0232] The WTRU can determine one or more multi-window channel access parameters based on local channel measurements. Local channel measurements can be correlated with energy measurements on unlicensed carriers. Local channel measurements can include sidelink-sensing-based measurements (e.g., channel busy rate).

[0233] The WTRU can determine one or more multi-window channel access parameters based on an indication received as part of the first SL-PRS transmission. This indication can be an explicit indication of the multi-window channel access parameters. The received indication can select a multi-window configuration from a set of pre-configured configurations.

[0234] The WTRU can determine one or more multi-window channel access parameters based on local channel measurements and indications received as part of the first SL-PRS transmission.

[0235] The WTRU can determine one or more multi-window channel access parameters based on priorities (e.g., priorities configured using a location procedure or location session). In one example, the WTRU can select parameters associated with a first priority (and first window) and a second priority (and second window) based on configured priority values.

[0236] The WTRU can determine one or more first window channel access parameters based on any of the examples described herein. The WTRU can derive one or more second window parameters based on the parameters determined for the first window.

[0237] This article provides a sample SL multi-priority channel access procedure.

[0238] A WTRU (e.g., an anchor WTRU) can initiate a channel access procedure for SL-PRS transmissions (e.g., forward or reverse SL-PRS transmissions for SL-based RTT procedures on a shared spectrum).

[0239] The WTRU can execute a first LBT procedure associated with a first priority within a first time window (e.g., initiating an LBT channel access procedure for the SL-U based on the determined first window and first priority). The type of LBT can be a Type 1 random duration LBT. The WTRU can use the first priority to derive one or more Type 1 LBT parameters. The WTRU can perform channel sensing / LBT on an unlicensed carrier. An unlicensed carrier can be a carrier in which the WTRU receives SL-PRS transmissions (e.g., forward SL-PRS transmissions for a location procedure based on RTT).

[0240] The WTRU may acquire the Channel Occurrence Point (COT) during the time it takes to transmit the second SL-PRS (e.g., by acquiring resources for transmitting the second SL-PRS before the end of the second time window). If the WTRU is able to acquire the channel (e.g., before the end of the first window), the WTRU may transmit the SL-PRS transmission (e.g., a transmission on suitable resources for the acquired COT). In this case, the WTRU may not perform channel sensing in the second window. If the WTRU does not acquire the COT based on the first LBT procedure (e.g., if the WTRU cannot acquire the COT in the first window), the WTRU may perform a second LBT procedure associated with the second priority in the second time window (e.g., channel sensing in the second window). One or more LBT parameters for channel sensing in the second window may be derived from the second priority. The WTRU may apply a second ED threshold to the LBT sensing in the second window. The WTRU may transmit the transmission. For example, if the WTRU is able to acquire the COT in the second window (e.g., upon successful completion of a Type 1 LBT procedure with LBT parameters derived from the second window), the WTRU can transmit (e.g., a second) SL-PRS transmission (e.g., a reverse SL-PRS transmission of an RTT-based SL positioning procedure). Figure 2 An example of WTRU sensing with two non-overlapping windows (e.g., multi-priority windows) is illustrated.

[0241] Figure 3 The illustration shows an example of WTRU sensing with overlapping sensing windows. Figure 3 As shown, at least a portion of the first time window overlaps with a portion of the second time window. Figure 2 and Figure 3 As shown, the time for sending the second SL-PRS within it can begin at the start of the first time window and end at the end of the second time window. Figure 3 In this context, WTRU can process the first LBT and the second LBT procedures in parallel, for example, during the overlap of the first and second windows.

[0242] The WTRU can initiate a first window. The WTRU can perform channel sensing. The WTRU can be configured with a second window start time. The second window start time can be before the first window end time (e.g., to avoid initial delays in COT acquisition at the start of the second window). The WTRU can receive configuration information indicating the offset between the start of the first and second time windows (e.g., this offset can be provided to the WTRU as part of the configuration). The WTRU can generate one or more Type 1 LBT parameters for a second priority linked to the second window. The WTRU can initiate channel sensing for the second window that overlaps with the first window. Figure 3 The figure illustrates channel sensing based on an overlapping sensing window.

[0243] Figure 4 The illustration shows an example of overlapping, start-aligned, multi-priority sensing windows (e.g., where two windows start simultaneously). In this example, the WTRU can generate one or more Type 1 LBT channel sensing parameters for the window based on first and second priorities. The WTRU can perform channel sensing on both windows simultaneously. The WTRU can handle LBT processing for the second window and the second priority such that the WTRU does not allow the second window to complete before the end time of the first window. For example, the WTRU may not decrement the sensing counter in the second window.

[0244] This article provides one or more features associated with reverse SL-PRS transmission.

[0245] A WTRU (e.g., an anchor WTRU) can transmit a transmission. The content of the transmission may depend on whether the WTRU is able to acquire the COT during the time it transmits the second SL-PRS. For example, the WTRU can perform a reverse SL-PRS transmission when channel sensing is successfully performed in the first or second window. For example, provided that the WTRU is able to acquire the COT during the time it transmits the second SL-PRS, the transmission may include the second SL-PRS and control information indicating the resources associated with the second SL-PRS. The WTRU may transmit the SL-PRS along with an SCI. The SCI may indicate the resources used for the reverse SL-PRS transmission.

[0246] The WTRU can optionally send sidelink resources (e.g., including a second / reverse SL-PRS) for transmissions. For example, the WTRU can reserve resources for its RTT report transmissions (e.g., after a reverse SL-PRS transmission). Resources reserved for SL RTT report transmissions can be indicated in the SCI using a reverse SL-PRS transmission. SL-U resource reservations for RTT report transmissions can be based on channel conditions. This transmission can be sent to either the target WTRU or the server WTRU via sidelink resources.

[0247] The sharing of COT between RTT reporting and reverse SL-PRS transmission can be based on the time when the WTRU can access the channel for reverse SL-PRS transmission. The WTRU can reserve and indicate RTT reporting resources (e.g., if the WTRU can select SL-PRS resources within a second window). Selecting SL-PRS transmission resources in the second window may mean that the WTRU has more time to process SL-PRS received in the forward PRS transmission of the RTT procedure. The WTRU can share the reverse SL-PRS transmission COT with the SL RTT reporting resources (e.g., based on the WTRU's processing time). The WTRU can determine the COT sharing between reverse SL-PRS transmission and RTT reporting (e.g., based on the time when the WTRU acquires the channel for its reverse SL-PRS transmission and the WTRU's processing capacity).

[0248] This article provides one or more features associated with LBT failure and RTT session termination.

[0249] If a WTRU (e.g., an anchor WTRU) cannot acquire a COT during the time it takes to send a second SL-PRS (e.g., if the WTRU cannot acquire the channel for a configured duration "T" after receiving a forward SL-PRS transmission of the RTT procedure), the WTRU may terminate the current RTT session. The WTRU may send a transmission to the target WTRU including an indication that the current session has been terminated (e.g., a termination indication) (through which the WTRU receives a PRS transmission, such as a forward SL-PRS transmission). The WTRU may send a termination indication to the server WTRU. The termination indication may identify the RTT session and the reason for termination. The reason for termination may indicate that the termination was initiated because the WTRU could not acquire a COT (e.g., due to channel access failure). The termination indication may be transmitted as a MAC CE or RRC message.

[0250] The WTRU can perform channel sensing to enable the transmission of an abort indication on the SL-U. The SL-WTRU can perform channel access with first priority to obtain the COT for abort indication transmission. The WTRU can wait for a configured duration before initiating channel sensing to transmit the abort indication.

[0251] Figure 5 The illustration shows an example of multi-priority channel acquisition for SL-PRS transmission.

[0252] The WTRU can be configured with one or more (e.g., two) priority levels. The WTRU can be configured for one or more (e.g., two) windows. The WTRU can perform a Type 1 LBT with a first priority level (e.g., within the first window). If the WTRU can acquire a COT, the WTRU can receive a PRS (e.g., during the first window). Otherwise (e.g., if the WTRU does not acquire a COT), the WTRU can perform a Type 1 LBT with a second priority level (e.g., during the second window). The WTRU can select an SL resource from the received SL-PRS within a duration T (e.g., during the second window). The WTRU can use the selected SL resource to transmit SL-PRS and / or SCI.

[0253] The anchor WTRU can receive configuration for the RTT procedure. This configuration can include configuration parameters such as, for example, T, first window, and second window.

[0254] Anchor WTRUs can receive SL-PRS transmissions (e.g., from target / server WTRUs). Anchor WTRUs can perform measurements on the SL-PRS (e.g., based on determined resources and SL-PRS configuration).

[0255] An anchor WTRU can perform a Type 1 LBT with a first priority level and associated LBT parameters (e.g., within a first window). The first window can be initiated when a PRS is received from the target WTRU.

[0256] If the anchor WTRU cannot acquire a channel / COT within the first window, the anchor WTRU may perform a Type 1 LBT with a second priority level (e.g., in the second window). The anchor WTRU may select an SL resource from the received SL-PRS within a duration T.

[0257] The anchor WTRU can send SL-PRS and / or SCI to the target / server WTRU (e.g., via a selected resource). If the anchor WTRU cannot send SL-PRS to the target / server WTRU, the anchor WTRU can abort the current RTT session. The anchor WTRU can send an abort instruction to the target / server WTRU.

[0258] Target WTRU coordination can be used to enable RTT SL-PRS transmissions to share COT with SL-PRS-based COT busy signal transmissions.

[0259] This article provides a sample SL-U shared COT PRS transport configuration.

[0260] A WTRU (e.g., the first WTRU) can send one or more of the following configuration elements to another WTRU (e.g., the second WTRU).

[0261] The configuration element may include a first SL-PRS resource configuration. The first SL-PRS resource configuration may include SL-PRS resource configurations for forward transfers of RTT procedures (e.g., from the first WTRU to the second WTRU).

[0262] The configuration element may include a second SL-PRS resource configuration. The second SL-PRS resource configuration may include SL-PRS resource configurations for reverse transfers of RTT procedures (e.g., from the second WTRU to the first WTRU).

[0263] Configuration elements may include a start time indication. This start time indication may be an indication of the timing for forward SL-PRS transmissions. The first WTRU (e.g., the target WTRU) may transmit according to the indicated timing (e.g., subject to successful channel access). Timing may be indicated by absolute time, relative time with respect to a reference, frame index, subframe index, slot index, and / or time slot index.

[0264] Configuration elements may include a shared COT indication. A WTRU can provide an indication that an SL RTT session will be based on a shared COT. More than one WTRU may use a COT (e.g., a shared COT) to transmit or receive data and / or signals.

[0265] Configuration elements may include ACK / NACK configurations for sharing COT RTT procedures.

[0266] Configuration elements may include COT Busy I configuration. The COT Busy I configuration can provide a set of types that the WTRU can use to maintain COT busy between SL-PRS transmissions (e.g., forward SL-PRS transmissions) and subsequent SL-PRS transmissions (e.g., reverse SL-PRS transmissions). This configuration may indicate one or more of the following types: SL PRS resource configuration; a known or configured sequence or a set of known or configured sequences; a random sequence (e.g., a complex sequence generated by a pseudo-digit generator); and / or shared channel data.

[0267] The COT Busy I configuration may include a first part and a second part of the COT Busy I configuration. In this case, the COT Busy I configuration may include the type and duration for the first and second parts.

[0268] This article provides a sample SL-U channel access procedure for sharing a COT.

[0269] The WTRU can select parameters for channel sensing (e.g., appropriate parameters) (e.g., to obtain COT on the SL-U). The LBT parameters for performing channel sensing can be based on one or more of the following.

[0270] The LBT parameters for performing channel sensing can be based on the priority of SL-PRS transmission (e.g., the WTRU obtains the SL-PRS priority from a higher layer).

[0271] The LBT parameters for performing channel sensing can be based on the length of the COT to complete an RTT session within the same COT. The length of the COT can be selected (e.g., expressed in seconds, time slots, frames, subframes, or symbols) to perform forward SL-PRS transmissions and reverse SL-PRS transmissions within the same COT (e.g., to accommodate measurement and preparation times for SL-PRS transmissions). The length of the COT can be selected to perform forward SL-PRS transmissions, reverse SL-PRS transmissions, and / or RTT reporting within the same COT (e.g., including the WTRU processing time required for each intermediate step).

[0272] This article provides one or more features associated with forward SL-PRS transmission.

[0273] A WTRU (e.g., a target WTRU) may perform a forward SL-PRS transmission (e.g., upon successful COT acquisition via SL-U). The WTRU may transmit the SL-PRS (e.g., along with an SCI). The SCI may indicate any of the following: the priority of the SL-PRS transmission; the time and frequency resources used for the SL-PRS transmission; and / or COT sharing information. The SCI may provide COT sharing information to the receiving WTRU. COT shared information may include one or more of the following elements: a priority value for determining the COT to acquire LBT parameters; the remaining COT duration; resource allocation for reverse SL-PRS transmission (e.g., a WTRU may perform resource allocation for reverse SL-PRS transmission and indicate the resource allocation to an Rx WTRU to be used for reverse SL-PRS transmission, for example, the resource allocation may be an indication of time-frequency resources, time-only resources, or frequency-only resources for reverse SL-PRS transmission); RTT report containing indicators (e.g., COT shared information may include an indication to an SL Rx WTRU whether the same COT can be used for RTT reporting, for example, an Rx WTRU may keep the COT occupied by a second COT busy signal between reverse SL-PRS transmission and RTT report transmission); and / or a first COT busy signal indication.

[0274] The first COT busy signal indication may include the transmission duration. The transmission duration of the first COT busy signal can be provided in absolute time using appropriate units (e.g., milliseconds, microseconds, symbols, time slots, frames, or subframes). The duration of the first COT busy signal can be indicated by the duration of both the time slot and the symbol. Reference time slots and symbols can be used for a given subcarrier interval or for the active subcarrier interval.

[0275] The first COT busy signal indication may include the type of first COT busy signal used in the transmission. For example, the type of first COT busy signal may be SL PRS; a (pre)configured sequence or a set of (pre)configured sequences; a random sequence; shared channel data (e.g., shared channel data may be sent to the same WTRU as the forward PRS transmission, or the WTRU may send shared channel data to an RxWTRU different from the receiver of the forward SL-PRS transmission); and / or resource allocation for the transmission (e.g., time-frequency resources, time-only resources, or frequency-only resources indication for the first COT busy signal transmission).

[0276] The first COT busy signal indication may include a first part of COT Busy I and a second part of COT Busy I. In this case, the COT Busy I indication may provide a type and duration (e.g., for each of the first and second parts).

[0277] This document provides one or more features associated with the first COT busy signal transmission.

[0278] A WTRU (e.g., a target WTRU) may perform the transmission of a first COT busy signal. The first COT busy signal transmission may be initiated with a delay (e.g., a fixed or configured delay) following a forward SL-PRS transmission. The WTRU will transmit a first COT busy signal of this type (e.g., SLPRS, random sequence, shared channel data). The duration of this signal may be indicated in the COT sharing information transmitted along with the forward SL-PRS transmission.

[0279] The WTRU can transmit the first part of the first COT busy signal (e.g., if a configuration has been provided for the first and second parts of the first COT busy signal).

[0280] WTRU can receive ACK / NACK.

[0281] The WTRU (e.g., the target WTRU) can receive feedback from the second WTRU (e.g., a forward SL-PRS transmission following the first portion of the first COT busy signal). The feedback can be positive feedback (e.g., ACK) or negative feedback (e.g., NACK).

[0282] The WTRU can determine to continue sharing the COT RTT procedure (e.g., based on received feedback). If an ACK is determined, the WTRU can continue sharing the COT procedure. If a NACK is determined, the WTRU can stop sharing the COT RTT procedure. The WTRU can revert to a separate COT RTT procedure (e.g., if a NACK is determined). The WTRU can wait to receive a reverse SL-PRS transmission within an RTT time threshold.

[0283] This document provides one or more features associated with the second part of the first COT busy signal transmission.

[0284] A WTRU (e.g., a target WTRU) may perform the transmission of a second portion of a first COT busy signal. The second portion of the first COT busy signal transmission may be initiated after a delay (e.g., a fixed delay following the first portion of the first COT busy signal). The second portion of the first COT busy signal transmission may be initiated after receiving feedback from a second WTRU (e.g., in response to a forward SL-PRS transmission). The WTRU may transmit the second portion of the first COT busy signal (e.g., based on the received feedback). The WTRU may transmit the second portion if (e.g., only if) the received feedback is a positive acknowledgment.

[0285] This article provides one or more features associated with reverse SL-PRS transmission.

[0286] A WTRU (e.g., a target WTRU) can receive reverse SL-PRS transmissions from different WTRUs (e.g., WTRUs that receive SL-PRS from the target WTRU and / or the anchor WTRU). For example, a WTRU can receive a reverse SL-PRS transmission after a forward SL-PRS transmission and / or a first COT busy signal transmission. A WTRU can receive reverse SL-PRS transmissions from different WTRUs (e.g., on time-frequency resources indicated in the SCI of the forward SL-PRS transmission). The SCI of the forward SL-PRS transmission can indicate (e.g., only indicate) time. This time can be absolute time or time with a window within which the WTRU can receive the reverse SL-PRS transmission. A WTRU can receive a reverse SL-PRS transmission in response to its forward SL-PRS transmission. Other WTRUs can perform resource allocation for the reverse SL-PRS transmission.

[0287] An SL-PRS transmission (e.g., a reverse SL-PRS transmission) can indicate the transmission of a second COT busy signal (e.g., after an SL-PRS transmission). The indication of the second COT busy signal can be received in the SCI accompanying the SL-PRS transmission. The indication of the second COT busy signal can include one or more of the following: the duration of the second COT busy signal transmission; the type of the second COT busy signal (e.g., SL PRS; a known sequence or a set of known sequences; a random sequence; and / or shared channel data); and / or resource allocation for transmission. Resource allocation can be an indication of time-frequency resources, time-only resources, or frequency-only resources for the transmission of the second COT busy signal.

[0288] It can receive the second COT busy signal.

[0289] The WTRU can receive an indication of the second COT busy signal in a received SL-PRS transmission (e.g., a reverse SL-PRS transmission). The WTRU can receive the second COT busy signal parameter in an SCI accompanying an SL-PRS transmission (e.g., a reverse SL-PRS transmission of an RTT procedure).

[0290] If the second COT busy signal is determined to be carrying SL-PRS, the WTRU can perform measurements on these signals. These measurements can be used to calculate the RTT measurement results. The measurements can be reported as part of the RTT measurement report.

[0291] Implicit indication of the content of the second COT busy signal can be sent / received.

[0292] The target WTRU can determine that the second COT busy signal includes the same signal (e.g., from the anchor WTRU) as the first COT busy signal (e.g., no explicit indication received, for example, via SCI). For example, the target WTRU can determine to use SL PRS for the first COT busy signal. The target WTRU can determine that the anchor WTRU uses the same sequence (e.g., generated by the same random number generator, the same seed of the random number generator, and the same linear feedback shift register of the random number generator) to transmit SL PRS in the second COT busy signal. The WTRU can receive indications or configurations from the network or peer WTRUs (e.g., WTRUs with LMF capability, server WTRUs) to determine the content of the second COT busy signal (e.g., implicitly).

[0293] It can receive measurement reports.

[0294] The WTRU can receive measurement reports (e.g., after receiving a second COT busy signal). The WTRU can send measurement reports to the LMF and / or peer WTRUs (e.g., server WTRU). The WTRU can send measurement reports via Side Link Positioning Protocol (SLPP), LPP, RRC, MAC-CE, SCI, or UCI.

[0295] The WTRU can receive measurement reports (e.g., accompanying a second SL-PRS transmission) regarding resources for which a reservation indication has been received in the SCI. The WTRU can also receive measurement reports without a prior reservation indication. The WTRU can receive measurement reports based on one or more of the following signal measurements (e.g., measurements performed at a second WTRU (e.g., the anchor WTRU): a first (e.g., forward) SL-PRS transmission; a first COT busy signal; a first portion of the first COT busy signal; a second portion of the first COT busy signal; a second (e.g., reverse) SL-PRS transmission; and / or a second COT busy signal.

[0296] The received measurement report may include Rx-Tx time difference measurements based on signals received from and / or transmitted from the second WTRU (e.g., anchor WTRU).

[0297] This article provides one or more example Rx-Tx time differences.

[0298] An example of Rx-Tx time difference is the difference between the arrival time and the transmission time of the SL-PRS. The arrival time or transmission time can be expressed as one or more of the following: absolute time, reference time with respect to a reference, subframe index, frame index, slot index, and / or symbol index. The arrival time or transmission time can also be expressed according to the timing of the subframe, frame, slot(one or more), or symbol(one or more) of the SL-PRS that is received or transmitted.

[0299] An RTT measurement report can be prepared.

[0300] The WTRU (e.g., the target WTRU) can prepare or generate an Rx-Tx time difference measurement report (e.g., based on a first SL-PRS transmission and a second SL-PRS transmission). The first SL PRS transmission can be a forward SL PRS transmission transmitted by the WTRU. The second SL-PRS transmission can be a reverse transmission received by the SL-WTRU.

[0301] The WTRU can prepare Rx-Tx time difference measurements based on a first SL-PRS transmission, a first COT busy signal, and / or a second SL-PRS transmission. The WTRU can calculate two time difference measurements. The first measurement can be performed between the first and second SL-PRS transmissions. The second measurement can be performed between the first COT busy signal and the second SL-PRS transmission.

[0302] The WTRU can prepare an Rx-Tx time difference measurement based on a first SL-PRS transmission, a first COT busy signal, a second SL-PRS transmission, and / or a second COT busy signal. The WTRU can calculate two time difference measurements. The first measurement can be performed between the first and second SL-PRS transmissions. The second measurement can be performed between the first and second COT busy signals (e.g., Rx-Tx time based on the transmission time of the first COT busy signal and the reception time of the second COT busy signal).

[0303] The WTRU can use the reference time of the first and second COT busy signals (e.g., a suitable reference time) to determine time difference measurements. The start of the time slot for the first / second COT busy signals can be used as a reference transmit / receive time. The start of the symbol time used to transmit the first / second COT busy signals can be used as a reference transmit / receive time. The precise transmit / receive time can be used as a time reference for the first / second COT busy signals (e.g., to determine the RTT time difference).

[0304] WTRU can include in its measurement report an indication of which signal was used to determine the Rx-Tx time difference (e.g., the arrival time or transmission time of the first or second COT busy signal).

[0305] The WTRU can receive information from the network or peer WTRUs (e.g., server WTRU) regarding which signal(s)(e.g., first SL PRS transmission, second SL PRS transmission, COT busy I signal, and / or COT busy II signal, etc.) is being used. Figure 6 (As illustrated) to determine the configuration or indication of the Rx-Tx time difference.

[0306] The WTRU can prepare a measurement report based on one or more of the following: the transmission time of the first (forward) SL-PRS transmission; the transmission time of the first COT busy signal; the transmission time of the first portion of the first COT busy signal; the transmission time of the second portion of the first COT busy signal; the reception time of the second (reverse) SL-PRS transmission; and / or the reception time of the second COT busy signal.

[0307] Measurement reports may include Rx-Tx time difference measurements based on signals received from and / or transmitted from the WTRU (e.g., the target WTRU).

[0308] The WTRU can determine the Rx-Tx time difference using a first SL-PRS, a second SL-PRS, a first COT busy signal, and / or a second COT busy signal (e.g., based on channel conditions). Channel conditions may include a LOS or NLOS indicator associated with the SL-PRS. For example, the WTRU can determine the Rx-Tx time difference using a COT busy signal (e.g., in addition to the SL-PRS) (e.g., if the LOS indicator associated with the received or transmitted SL-PRS is below a configured threshold).

[0309] Channel conditions may include the RSRP or RSRPP of a reference signal (e.g., SL-PRS, SL-SSB, SL-CSI-RS). For example, the WTRU may determine to use the COT busy signal (e.g., in addition to SL-PRS) to determine the RSRP measurement (e.g., if the received SL-PRS is below a configured threshold).

[0310] The target WTRU can coordinate by performing the SL RTT procedure (e.g., utilizing ACK / NACK transmissions from the anchor WTRU).

[0311] The target WTRU can execute SL RTT procedures (e.g., including feedback, such as ACK / NACK transmissions from one or more anchor WTRUs, etc.). Figure 6 (As shown in the diagram) Figure 6 The illustration shows an example shared COT with SL-PRS-based COT busy signal and anchor WTRU ACK / NACK feedback.

[0312] A WTRU (e.g., a target WTRU) may transmit (pre)configuration to an anchor WTRU. The (pre)configuration may include one or more of the following: a first SL-PRS resource configuration for transmission to the anchor WTRU, a second SL-PRS resource configuration for reception from the anchor WTRU, and / or an ACK / NACK configuration for sharing the COT RTT procedure.

[0313] The WTRU may transmit a first SL-PRS transmission (e.g., with an associated SCI) to the anchor WTRU. The SCI may include COT sharing information. The COT sharing information may include one or more of the following: a first COT busy signal configuration (e.g., including a first part and a second part), and the transmission duration for each part (e.g., the number of symbols / slots), the type of signal used in the transmission (e.g., SL-PRS configuration, PSSCH, or pre-configured signal), and / or the resource allocation for the transmission.

[0314] If the type of the indicated first COT busy signal follows the first SL-PRS configuration, the WTRU may transmit the first part of the first COT busy signal transmission (e.g., according to the COT sharing information indicated in the transmitted SCI).

[0315] If the type of the indicated first COT busy signal does not conform to the first SL-PRS configuration, the WTRU may transmit the first part of the first COT busy signal transmission (e.g., according to the COT sharing information indicated in the transmitted SCI).

[0316] The WTRU (e.g., the target WTRU) can receive an ACK from the anchor WTRU. The WTRU can (e.g., upon receiving an ACK) transmit a second part of the first COT busy signal transmission (e.g., according to the COT sharing information indicated in the transmitted SCI).

[0317] The WTRU (e.g., the target WTRU) can receive a NACK from the anchor WTRU. The target WTRU may not transmit the second part of the first COT busy signal (e.g., if the WTRU receives a NACK from the anchor WTRU).

[0318] In the case of NACK reception, the WTRU (e.g., the target WTRU) can receive a second SL-PRS transmission (e.g., a second SL-PRS resource configuration based on a (pre)configured SCI). The SCI can provide a second COT busy signal configuration. The second COT busy signal configuration can include one or more of the following: SL-PRS configuration and / or transmission duration.

[0319] The WTRU (e.g., the target WTRU) can perform SL positioning measurements (e.g., RTT) on the second SL-PRS transport (e.g., based on the second SL-PRS resource configuration).

[0320] The WTRU (e.g., the target WTRU) can receive a second COT busy signal (e.g., based on the received second COT busy signal indication). The WTRU (e.g., the target WTRU) can perform SL positioning measurements (e.g., RTT) on the transmission of the second COT busy signal.

[0321] The WTRU (e.g., the target WTRU) can receive measurement reports from the anchor WTRU. The measurement reports may include measurements (e.g., RTT results) of the first SL-PRS transmission and the first COT busy signal transmission (e.g., the first part and the second part).

[0322] The WTRU (e.g., the target WTRU) can receive measurement reports (e.g., RTT results regarding the first SL-PRS transmission) from the anchor WTRU.

[0323] Figure 7 The illustration shows an example shared COT with a COT busy signal based on SL-PRS.

[0324] The target WTRU and the anchor WTRU can share the COT (Constant Occupancy Time). If the target WTRU determines to use the SL-PRS (Short-Range Per Second) for the COT busy signal, the target WTRU can transmit a first COT busy signal to the anchor WTRU. The target WTRU can receive (e.g., from the anchor WTRU) the SL-PRS in a second COT busy signal. The contents of the received COT busy signal can be indicated in the SCI (Search Engine Control Center). The target WTRU can measure the COT busy signal (e.g., for positioning).

[0325] The target WTRU can transmit (pre)configuration to the anchor WTRU. The (pre)configuration may include one or more of the following: a first SL-PRS resource configuration for transmitting to the anchor WTRU; and / or a second SL-PRS resource configuration for receiving from the anchor WTRU.

[0326] The target WTRU may transmit a first SL-PRS transmission (e.g., with an associated SCI). The SL-PRS may include COT sharing information to the anchor WTRU. For example, the COT sharing information may include a first COT busy signal configuration. The first COT busy signal configuration may include one or more of the following: transmission duration (e.g., number of symbols / slots); type of signal used in the transmission (e.g., SL-PRS configuration, PSSCH, or pre-configured signal); and / or resource allocation for the transmission.

[0327] If the type of the indicated first COT busy signal follows a first SL-PRS configuration, the target WTRU may perform one or more of the following operations. For example, the target WTRU may transmit a first COT busy signal transmission (e.g., according to COT sharing information indicated in the transmitted SCI). The target WTRU may receive a second SL-PRS transmission (e.g., according to a (pre)configured second SL-PRS resource configuration). The associated SCI may provide a second COT busy signal configuration. The second COT busy signal configuration may include one or more of the following: SL-PRS configuration; and / or transmission duration.

[0328] The target WTRU can perform SL positioning measurements (e.g., RTT) on the second SL-PRS transport (e.g., based on the second SL-PRS resource configuration).

[0329] The target WTRU can receive a second COT busy signal (e.g., based on the received second COT busy signal indication). The target WTRU can perform SL positioning measurements (e.g., RTT) on the transmission of the second COT busy signal.

[0330] The target WTRU can receive a measurement report from the anchor WTRU. This measurement report may include measurement (e.g., RTT) results regarding the first SL-PRS transmission and the first COT busy signal transmission.

[0331] If the type of the indicated first COT busy signal does not conform to the first SL-PRS configuration, the target WTRU may perform one or more of the following actions. For example, the target WTRU may transmit a first COT busy signal transmission (e.g., based on the COT sharing information indicated in the transmitted SCI).

[0332] The target WTRU can receive a second SL-PRS transmission (e.g., based on a (pre)configured second SL-PRS resource configuration).

[0333] The target WTRU can perform SL positioning measurements (e.g., RTT) on the second SL-PRS transport (e.g., based on the second SL-PRS resource configuration).

[0334] The WTRU can receive measurement reports (e.g., including RTT results for the first SL-PRS transmission) from the anchor WTRU.

[0335] Anchor WTRU coordination can be used to enable RTT SL-PRS transmissions to share COT with SL-PRS-based COT busy signal transmissions.

[0336] It can receive SL-U shared COT SL-PRS configuration.

[0337] A WTRU (e.g., an anchor WTRU) can receive one or more of the following configuration elements from another device.

[0338] The WTRU can receive the first SL-PRS resource configuration. The first SL-PRS resource configuration may include the SL-PRS resource configuration for the forward transmission of the RTT procedure.

[0339] The WTRU can receive a second SL-PRS resource configuration. The second SL-PRS resource configuration may include the SL-PRS resource configuration for the reverse transmission of the RTT procedure.

[0340] The WTRU can receive a start time indication. This configuration can include an indication of the timing of forward SL-PRS transmissions.

[0341] The WTRU can receive a shared COT indication. The WTRU can receive an indication that the SL RTT session will be based on a shared COT.

[0342] The WTRU can receive ACK / NACK configurations for sharing COT RTT procedures. The WTRU can also receive COT Busy I configurations. These configurations may include a set of types of signals that the WTRU can receive (e.g., signals transmitted between SL-PRS transmissions (e.g., forward SL-PRS transmissions) and subsequent SL-PRS transmissions (e.g., reverse SL-PRS transmissions) to keep COT busy). This configuration may indicate one or more of the following types of COT Busy I signals: SL PRS resource configuration; a known sequence or a set of known sequences; a random sequence; and / or shared channel data.

[0343] The COT Busy I signal may include a first part and a second part of COT Busy I. In this case, the COT Busy I configuration may include the type and duration of the first part and the second part (e.g., each of the first part and the second part).

[0344] It can receive forward SL-PRS transmissions.

[0345] A WTRU (e.g., an anchor WTRU) can receive forward SL-PRS transmissions. A WTRU can receive SL-PRS (e.g., along with an SCI). The SCI can indicate one or more of the following: the priority of the SL-PRS transmission; the time and frequency resources used for the SL-PRS transmission; and / or COT sharing information.

[0346] SCI can provide COT sharing information to WTRU. COT sharing information may include one or more of the following elements: priority values ​​for determining COT to acquire LBT parameters; remaining COT duration; resource allocation for reverse SL-PRS transmission (e.g., resource allocation may be an indication of time-frequency resources, time-only resources, or frequency-only resources for reverse SL-PRS transmission); RTT report containing indicators (e.g., an indication of whether the same COT can be used for RTT reporting; for example, if the same COT is to be used for RTT reporting, the WTRU may keep the COT occupied by a second COT busy signal between the reverse SL-PRS transmission and the RTT report transmission); and / or the first COT busy signal configuration.

[0347] The first COT busy signal configuration may include the transmission duration. The transmission duration of the first COT busy signal can be provided in absolute time using appropriate units (e.g., milliseconds or microseconds). The duration of the first COT busy signal can be indicated by the duration of the time slot and / or symbol. The reference time slot and / or symbol can be used to reference the subcarrier spacing or the active subcarrier spacing.

[0348] The first COT busy signal configuration may include the type of first COT busy signal used in the transmission. The type of first COT busy signal may be an SL PRS configuration; a known sequence or a set of known sequences; a random sequence; shared channel data (e.g., which may be destined for a WTRU receiving forward PRS transmissions, or it may be destined for a different WTRU); and / or resource allocation for the transmission. Resource allocation may be a time-frequency resource, time-only resource, or frequency-only resource indication for the first COT busy signal transmission.

[0349] The WTRU can determine the type of the first COT busy signal based on one or more of the following: the priority of the location procedure / session, reliability specifications, accuracy specifications, QoS specifications associated with the location procedure, received auxiliary information, channel sensing, etc. For example, if the priority of the location procedure / session is higher than (e.g., a configured) threshold, the WTRU can determine that SL-PRS is used as the type of the first COT busy signal. If the priority is lower than the threshold, the WTRU can determine that a random or known sequence is used as the type of the first COT busy signal.

[0350] The first COT busy signal indication may include a first part of COT Busy I and a second part of COT Busy I. In this case, the COT Busy I indication may include the type and duration of the first part and the second part (e.g., each of the first part and the second part).

[0351] It can receive the first COT busy signal.

[0352] A WTRU (e.g., an anchor WTRU) may receive a first COT busy signal transmission. The first COT busy signal transmission may be initiated after a delay (e.g., a fixed delay following a forward SL-PRS transmission). The WTRU may receive the first COT busy signal, the type and duration of which are indicated in the COT sharing information received along with the forward SL-PRS transmission.

[0353] If the first and second parts of the first COT busy signal have been configured, the WTRU can receive the first part of the first COT busy signal.

[0354] If the first COT busy signal or a first portion of the first COT busy signal is identified as carrying an SL-PRS, the WTRU can buffer these signals. The WTRU can measure these signals. This measurement can be used to calculate the RTT measurement result. The measurement can be reported as part of the RTT measurement report.

[0355] It can send ACK / NACK signals to the RTT procedure.

[0356] A WTRU (e.g., an anchor WTRU) may transmit ACK / NACK feedback (e.g., in response to a received first SL-PRS transmission). ACK / NACK feedback can be used for RTT procedures. If the WTRU agrees to continue sharing the COT RTT procedure (e.g., based on the received configuration), the WTRU will transmit ACK. The WTRU may transmit NACK to indicate that the WTRU will not share the COT of the first (e.g., forward) SL-PRS transmission.

[0357] Feedback can have one or more (e.g., more than two) outcomes. For example, an ACK can continue the shared COTRTT procedure. A NACK can indicate a fallback to a separate COT RTT procedure. This feedback can be an abort indication for the RTT procedure. A WTRU may not emit feedback to indicate abort (e.g., if no feedback at a second WTRU (e.g., the target WTRU) would be considered an abort).

[0358] The WTRU can determine appropriate resources for ACK / NACK transmissions. ACK / NACK resources can be determined based on the resources of the first (e.g., forward) SL-PRS transmission. ACK / NACK resources can be based on one or more of the following: resources of the first SL-PRS transmission; resources of the first portion of the first COT busy signal; the WTRU ID of the WTRU (e.g., anchor WTRU); the WTRU ID of the second WTRU (e.g., target WTRU); and / or indications (e.g., explicit indications) in control information received along with the first SL-PRS transmission.

[0359] It can receive the second part of the first COT busy signal.

[0360] A WTRU (e.g., an anchor WTRU) can receive a second portion of the first COT busy signal. The second portion of the first COT busy signal can be initiated after a delay (e.g., a fixed delay after the first portion of the first COT busy signal). The second portion of the first COT busy signal transmission can be initiated after an ACK / NACK transmission. The WTRU can receive the second portion of the first COT busy signal based on the transmitted feedback. The WTRU can receive the second portion if (e.g., only if) the transmitted feedback is a positive acknowledgment (e.g., ACK) of the RTT procedure.

[0361] If the second portion of the first COT busy signal is determined to be carrying SL-PRS, the WTRU can buffer the signal. The WTRU can measure the signal. This measurement can be used to calculate the RTT measurement result. The measurement can be reported as part of the RTT measurement report.

[0362] It can transmit reverse SL-PRS transmissions.

[0363] A WTRU (e.g., an anchor WTRU) can transmit a reverse SL-PRS transmission (e.g., after a first COT busy signal). The WTRU can transmit a reverse SL-PRS transmission on a time-frequency resource (e.g., the time-frequency resource that the WTRU receives in the SCI of a forward SL-PRS transmission). The SCI of the forward SL-PRS transmission can indicate (e.g., only indicate) the time. This time can be absolute time or time with a window within which the WTRU can receive the reverse SL-PRS transmission. The WTRU can perform autonomous resource allocation on the SL resource (e.g., mode 2-based resource allocation) to transmit a reverse SL-PRS transmission (e.g., in response to a received forward SL-PRS transmission).

[0364] SL-PRS transmissions (e.g., reverse SL-PRS transmissions) can indicate the transmission of RTT reports and / or the resources used for RTT report transmissions. RTT report indications can be determined based on indications received (e.g., in the SCI of a forward SL-PRS transmission).

[0365] WTRU can reserve resources for RTT report transmissions. WTRU can indicate reserved resources (e.g., in the SCI of a reverse SL-PRS transmission).

[0366] An SL-PRS transmission (e.g., a reverse SL-PRS transmission) may indicate the transmission of a second COT busy signal (e.g., after an SL-PRS transmission). A WTRU (e.g., an anchor WTRU) may transmit an indication of a second COT busy signal (e.g., in an SCI accompanying an SL-PRS transmission). The indication of a second COT busy signal may include one or more of the following: the duration of the second COT busy signal transmission; the type of the second COT busy signal; the SL PRS configuration; a (pre)configured sequence or a set of (pre)configured sequences; a random sequence; shared channel data; and / or resource allocation for transmission. Resource allocation may be an indication of time-frequency resources, time-only resources, or frequency-only resources for the transmission of the second COT busy signal.

[0367] The WTRU (e.g., the anchor WTRU) can determine the transmission type of the second COT busy signal (e.g., based on the first COT busy signal received from the target WTRU). The WTRU can determine to use a COT busy signal of the same type as the received first COT busy signal.

[0368] The WTRU can determine the transmission duration of the second COT busy signal (e.g., based on the WTRU processing capacity of the target WTRU). The target WTRU and the anchor WTRU can exchange WTRU capacity information (e.g., processing and measurement time required for SL-PRS transmission). The WTRU (e.g., the anchor WTRU) can determine the processing time (e.g., based on the target WTRU's capacity and / or the configuration of the reverse SL-PRS transmission, e.g., SL-PRS mode). The WTRU can determine the duration of the second COT busy signal (e.g., based on the processing time).

[0369] A WTRU (e.g., an anchor WTRU) can determine the frequency resources of a second COT busy signal (e.g., based on an implicit association with the frequency resources of the received first COT busy signal, such as if the two signals are of the same type, for example, using the same SL-PRS sequence). The implicit association can be a frequency offset. For example, if the offset is zero, the same frequency resources can be applied to the second COT busy signal. If the offset is the number of RBs and / or subcarriers (one or more), the WTRU can determine the frequency resources of the second COT signal based on the offset.

[0370] It can transmit a second COT busy signal.

[0371] A WTRU (e.g., an anchor WTRU) may transmit a second COT busy signal (e.g., after transmitting an SL-PRS transmission (e.g., a reverse SL-PRS transmission)). The WTRU may transmit the second COT busy signal based on parameters transmitted in an SCI (e.g., an SCI accompanying an SL-PRS transmission (e.g., a reverse SL-PRS transmission of an RTT procedure)).

[0372] The type of the second COT busy signal can be determined.

[0373] The WTRU (e.g., an anchor WTRU) can determine the type of the second COT busy signal (e.g., based on the first COT busy signal). The WTRU can also select the type of the second COT busy signal SL-PRS (e.g., if the type of the received first COT busy signal is SL-PRS).

[0374] The WTRU can select the type of the second COT busy signal without considering (e.g., independently of) the type of the first COT busy signal. The WTRU can select the type as a known sequence, a sequence from a set of known or configured sequences, or a random sequence.

[0375] A WTRU can perform shared channel data transmission as a second COT busy signal. A WTRU can (e.g., may only) perform data transmission to another WTRU from which it has received a COT sharing indication.

[0376] A WTRU can perform data transfers to WTRUs that are different from the WTRU that provides COT sharing indication. Data transfers to different WTRUs may be subject to conditions (e.g., priority conditions and duration conditions). If the data has a higher priority than the priority used for COT acquisition (e.g., higher than a known / configured / defined offset), the WTRU can transmit to a different WTRU.

[0377] This article provides a sample RTT measurement report.

[0378] The WTRU (e.g., an anchor WTRU) can prepare an Rx-Tx time difference measurement report (e.g., based on a first SL-PRS transmission and / or a second SL-PRS transmission). The first SL PRS transmission can be a forward SL PRS transmission received by the WTRU. The second SL-PRS transmission can be a reverse transmission transmitted by the WTRU (e.g., an SL-WTRU).

[0379] The WTRU can prepare Rx-Tx time difference measurements (e.g., based on a first SL-PRS transmission, a first COT busy signal, and / or a second SL-PRS transmission). The WTRU can calculate one or more (e.g., two) time difference measurements. The first measurement can be performed between the first and second SL-PRS transmissions. The second measurement can be performed between the first COT busy signal and the second SL-PRS transmission.

[0380] The WTRU can prepare Rx-Tx time difference measurements based on a first SL-PRS transmission, a first COT busy signal, a second SL-PRS transmission, and / or a second COT busy signal. The WTRU can calculate one or more (e.g., two) time difference measurements. The first measurement can be performed between the first and second SL-PRS transmissions. The second measurement can be performed between the first and second COT busy signals.

[0381] The WTRU can use the reference time of the first and second COT busy signals (e.g., a suitable reference time) to determine the time difference measurement. For example, the start of the time slot of the first / second COT busy signal can be used as a reference receive / transmit time. The start of the symbol time used to transmit the first / second COT busy signal can be used as a reference receive / transmit time. The precise receive / transmit time can be used as a time reference for the first / second COT busy signal (e.g., to determine the RTT time difference).

[0382] WTRU can prepare RTT measurement reports based on one or more of the following signals: a first (e.g., forward) SL-PRS transmission; a first COT busy signal; a first portion of the first COT busy signal; a second portion of the first COT busy signal; a second (e.g., reverse) SL-PRS transmission; and / or a second COT busy signal.

[0383] RTT measurement reports may include Rx-Tx time difference measurements (e.g., based on one or more of the signals received and transmitted at the WTRU (e.g., anchor WTRU).

[0384] It can send measurement reports.

[0385] The WTRU can transmit measurement reports (e.g., after transmitting a second COT busy signal).

[0386] The WTRU can select the resource for RTT reporting (e.g., before the reverse SL-PRS transmission). In this case, the WTRU can indicate the reporting resource (e.g., in the SCI of the reverse transmission). The WTRU can use this resource to transmit an RTT measurement report (e.g., after transmitting the second COT busy signal).

[0387] WTRU can perform resource allocation for RTT reporting (e.g., after a reverse SL-PRS transmission or after a second COT busy signal transmission).

[0388] The transmission of measurement reports can be performed in the same COT used to perform the second SL-PRS transmission. This could be the case, for example, if a second COT busy signal is transmitted to maintain COT ownership.

[0389] The WTRU can perform channel access procedures (e.g., on an unlicensed SL carrier) to transmit measurement reports. One or more LBT parameters (e.g., based on the priority of SL-PRS transmissions) can be determined for channel sensing.

[0390] Anchor WTRU can execute SL RTT procedures (e.g., using ACK / NACK transmission).

[0391] like Figure 8 As illustrated, the anchor WTRU can execute an SL RTT procedure that includes feedback to the target WTRU (e.g., ACK / NACK transmission).

[0392] The WTRU (e.g., the anchor WTRU) can receive (pre)configuration from the target WTRU. The (pre)configuration may include one or more of the following: a first SL-PRS resource configuration (e.g., for receiving from the target WTRU), a second SL-PRS resource configuration (e.g., for transmitting to the target WTRU), and / or an ACK / NACK configuration for sharing the COT RTT procedure.

[0393] A WTRU (e.g., an anchor WTRU) may receive a first SL-PRS transmission (e.g., with an associated SCI). The SCI may include COT sharing information from a target WTRU. The COT sharing information may include a first COT busy signal configuration. The first COT busy signal configuration may include one or more of the following (e.g., for both the first and second parts): transmission duration (e.g., the number of symbols / slots), signal type used in the transmission (e.g., SL-PRS configuration, PSSCH, or a pre-configured signal), and / or resource allocation for the transmission.

[0394] WTRU (e.g., anchor WTRU) can perform SL positioning measurements (e.g., RTT) on SL-PRS transports (e.g., based on a (pre)configured first SL-PRS resource configuration).

[0395] If the type of the indicated first COT busy signal conforms to the first SL-PRS configuration, the WTRU (e.g., anchor WTRU) may receive a first portion of the first COT busy signal transmission (e.g., based on the COT sharing information indicated in the received SCI). The WTRU may buffer the first portion of the received first COT busy signal.

[0396] WTRU (e.g., anchor WTRU) can send ACK to target WTRU (e.g., according to (pre)configuration).

[0397] A WTRU (e.g., an anchor WTRU) can receive a second portion of the first COT busy signal transmission (e.g., based on COT sharing information). The WTRU can buffer the second portion of the first COT busy signal.

[0398] The WTRU (e.g., anchor WTRU) can determine the second COT busy signal configuration (e.g., based on the received first COT busy signal, for example, the same SL-PRS mode, based on the transmission duration of the SL-PRS mode used for the first COT busy signal).

[0399] WTRU (e.g., anchor WTRU) can determine the second COT busy signal configuration (e.g., based on the (pre)configured signal and / or PSSCH if SL data is present in the buffer).

[0400] The WTRU (e.g., the anchor WTRU) can perform a second SL-PRS transmission (e.g., a second SL-PRS resource configuration based on a (pre)configured SCI). The SCI may include a determined second COT busy signal configuration.

[0401] WTRU (e.g., anchor WTRU) can transmit a second COT busy signal (e.g., configured according to a determined second COT busy signal).

[0402] A WTRU (e.g., an anchor WTRU) can perform SL positioning measurements (e.g., RTT) on a buffered first COT busy signal transmission. The WTRU (e.g., an anchor WTRU) can send a measurement report. The measurement report may include measurement (e.g., RTT) results regarding the first SL-PRS transmission, the second SL-PRS transmission, and / or the first COT busy signal transmission.

[0403] Figure 8 The illustration shows an example shared COT with an SL-PRS-based COT busy signal (e.g., with anchor WTRU ACK / NACK). Figure 9The illustration shows an example shared COT with a COT busy signal based on SL-PRS.

[0404] The target WTRU and the anchor WTRU can share the COT. The anchor WTRU can determine the configuration of the SL-PRS for the second COT busy signal to be transmitted (e.g., based on the configuration of the first COT busy signal received from the target WTRU).

[0405] The anchor WTRU can receive (pre)configuration from the target WTRU. The (pre)configuration may include a first SL-PRS resource configuration for receiving from the target WTRU; and / or a second SL-PRS resource configuration for transmitting to the target WTRU.

[0406] The anchor WTRU can receive a first SL-PRS transmission (e.g., with an associated SCI). The SCI may include COT sharing information (e.g., from the target WTRU). The COT sharing information may include a first COT busy signal configuration. The first COT busy signal configuration may include one or more of the following: transmission duration (e.g., number of symbols / slots); type of signal used in the transmission (e.g., SL-PRS configuration, PSSCH, or pre-configured signal); and / or resource allocation for the transmission.

[0407] The anchor WTRU can perform SL positioning measurements (e.g., RTT) on SL-PRS transmissions (e.g., based on the (pre)configured first SL-PRS resource configuration).

[0408] If the type of the indicated first COT busy signal conforms to (e.g., matches) the first SL-PRS configuration, the anchor WTRU may perform one or more of the following operations. For example, the anchor WTRU may receive the first COT busy signal transmission (e.g., based on the COT sharing information indicated in the received SCI). The anchor WTRU may buffer the received first COT busy signal.

[0409] The anchor WTRU can receive a second COT busy signal configuration (e.g., based on the received first COT busy signal). For example, the second COT busy signal configuration may include the same SL-PRS mode; and / or transmission duration (e.g., based on the SL-PRS mode used for the first COT busy signal).

[0410] The anchor WTRU can perform a second SL-PRS transmission (e.g., based on a (pre)configured second SL-PRS resource configuration with associated SCI). The second SL-PRS resource configuration may include at least the determined second COT busy signal configuration.

[0411] The anchor WTRU can transmit a second COT busy signal (e.g., based on a determined second COT busy signal configuration). The anchor WTRU can perform SL positioning measurements (e.g., RTT) on the buffered first COT busy signal transmission. The anchor WTRU can send a measurement report. The measurement report may include measurement (e.g., RTT) results regarding the first SL-PRS transmission and the first COT busy signal transmission.

[0412] If the type of the indicated first COT busy signal does not follow (e.g., does not match) the first SL-PRS configuration, the anchor WTRU may perform one or more of the following operations. For example, the anchor WTRU may determine the second COT busy signal configuration (e.g., based on the (pre)configured signals and / or PSSCH if SL data is present in the buffer).

[0413] The anchor WTRU can perform a second SL-PRS transmission (e.g., configured according to (pre)configured second SL-PRS resources). The anchor WTRU can transmit a second COT busy signal (e.g., configured according to a determined second COT busy signal). The anchor WTRU can send measurement reports (e.g., RTT measurement results) on the first SL-PRS transmission.

[0414] The server WTRU can select an RTT procedure (e.g., based on channel measurements and / or anchor WTRU feedback).

[0415] This article provides one or more features associated with channel measurement and WTRU capability requests.

[0416] A WTRU (e.g., a server WTRU) may send a request to a second WTRU. This request may request feedback regarding channel measurements and / or other WTRU capabilities. The second WTRU may be an anchor WTRU. The second WTRU may be a target WTRU. A WTRU may send this request to a second WTRU (e.g., an anchor WTRU). A WTRU may send requests to both a second WTRU (e.g., an anchor WTRU) and a third WTRU (e.g., a target WTRU). The second WTRU and / or the third WTRU may represent a second WTRU group and a third WTRU group, respectively.

[0417] A WTRU may transmit a channel measurement request to a second and / or third WTRU (e.g., each WTRU), for example, individually as a unicast transmission. A WTRU may also transmit the request as a multicast transmission (e.g., to a group of WTRUs). For example, a WTRU may transmit a multicast channel measurement request to a second group. This request may include a destination WTRU ID specified for the second group. A WTRU may also transmit a multicast channel measurement request to a third group. This request may include a destination WTRU ID specified for the third group.

[0418] Channel measurements may include channel sensing for unlicensed carrier operation. Channel measurements may include channel sensing for sidelink resource allocation (e.g., mode 2-based resource allocation).

[0419] A measurement request can specify one or more measurement configuration parameters. WTRU can request different types of channel measurements for second and / or third groups. One or more measurement configuration parameters can include measurement type, measurement start time (e.g., absolute or relative), measurement duration, minimum measurement duration, antenna configuration to be used, etc.

[0420] The requested parameters for channel measurement may include one or more of the following: Channel Busy Rate (CBR) of a set (or multiple sets) of SL resource pools; CO (Channel Occupancy) rate; a set of RSSI values ​​(e.g., for a set of SL resource pools, with appropriate time-frequency granularity for calculating these values); future resources (e.g., SL resource reservations already detected for other WTRUs); the assumed success rate of LBT at the second WTRU, anchor WTRU, and / or third WTRU (e.g., target WTRU); and / or preferred RTT procedure and / or COT type. The second WTRU and / or third WTRU may be (pre)configured to determine the preferred RTT procedure and / or COT type (e.g., based on local channel measurements). The WTRU may indicate the preferred RTT procedure in a shared COT (e.g., if the channel is busy).

[0421] The requested parameters for WTRU capability may include one or more of the following: PRS measurement time (e.g., SL-PRS measurement time); SL-PRS transmission preparation time; and / or RTT report processing time.

[0422] It can receive feedback on channel measurements and / or WTRU capabilities.

[0423] A WTRU (e.g., a server WTRU) can receive feedback regarding channel measurements and / or WTRU capabilities. This feedback can be a response to a request from the WTRU.

[0424] A WTRU can receive feedback from a second WTRU (e.g., an anchor WTRU). A WTRU can receive feedback from a second WTRU (e.g., an anchor WTRU) and / or a third WTRU (e.g., a target WTRU). The second WTRU and the third WTRU can represent a group of second WTRUs and a group of third WTRUs, respectively.

[0425] This article provides an example of local channel measurement.

[0426] WTRU (e.g., server WTRU) can perform local channel measurements.

[0427] A WTRU can perform local channel measurements (e.g., before transmitting a feedback request to other WTRUs). A WTRU can perform local channel measurements after transmitting a feedback request. A WTRU can perform local channel measurements after receiving feedback on the channel measurements from one or more other WTRUs.

[0428] The configuration parameters used to perform local channel measurements can be the same as those provided to one or more other WTRUs in the WTRU request for feedback. Configuration parameters used to perform local channel measurements can be selected (e.g., independent of feedback request parameters).

[0429] Local channel measurements can include channel sensing for unlicensed carrier operation. Local channel measurements can also include channel sensing for sidelink resource allocation (e.g., mode 2-based resource allocation).

[0430] The estimated parameters for channel measurements may include one or more of the following: the CBR of a set (or multiple sets) of SL resource pools; a set of RSSI values ​​(e.g., for a set of SL resource pools, with appropriate time-frequency granularity for calculating these values); future resources (e.g., SL resource reservations that have been detected for other WTRUs); and / or the assumed success rate of LBT at the second WTRU.

[0431] One or more RTT program parameters can be determined.

[0432] A WTRU (e.g., a server WTRU) can determine one or more parameters (e.g., via an SL-U carrier) related to an RTT-based positioning method. The WTRU can use COT-based (e.g., COT-based individual SL-PRS forward / reverse transmissions) to determine parameters for RTT-based positioning. The WTRU can also use COT-based SL-PRS forward / reverse transmissions to determine RTT-based positioning parameters. The WTRU can determine RTT-based positioning parameters for both COT-based and COT-based positioning procedures.

[0433] This determination can be made for one or more of the following parameters of the RTT procedure: maximum COT duration, priority category of COT initiation, first COT busy signal type / duration (e.g., the first COT busy signal may include a first part and a second part), and / or second COT busy signal type / duration.

[0434] The determination of one or more parameters of the RTT procedure may be based on one or more of the following: WTRU processing capacity (e.g., as received in feedback); the number of first group WTRUs in the procedure (e.g., anchor WTRUs); the number of second group WTRUs in the procedure (e.g., target WTRUs); one or more reverse SL-PRS transmissions sharing COT with forward SL-PRS transmissions, RTT reports sharing COT with one or more SL-PRS transmissions, and / or ACK / NAK transmissions from the first group WTRUs (e.g., anchor WTRUs).

[0435] You can export one or more RTT program selection metrics.

[0436] WTRUs (e.g., server WTRUs) can derive metrics (e.g., relevant metrics) to select the appropriate RTT procedure. For example, a WTRU can derive metrics using SL RTT procedures in different COTs or SL RTT procedures in a shared COT.

[0437] The WTRU can derive one or more of the following metrics from local channel measurements, determined RTT / COT parameters, and / or feedback (e.g., channel measurements) received from one or more anchor and / or target WTRUs.

[0438] The metrics(s) may include one or more of the following: a first success probability of initiating an RTT procedure based on a shared COT (e.g., where forward, reverse SL-PRS transmissions and RTT reports share the same COT); a second success probability of initiating an RTT procedure based on a shared COT (e.g., where forward and reverse SL-PRS transmissions share the same COT); and / or a third success probability of initiating a separate COT for SL-PRS transmissions (e.g., forward SL-PRS transmissions).

[0439] The success probability can be determined based on a combination of one or more of the following: (one or more) local measurements; measurements received in the feedback of the target WTRU (e.g., according to the requested parameters); measurements received in the feedback of the anchor WTRU (e.g., according to the requested parameters); the received WTRU capability of the target WTRU (e.g., according to the requested parameters); and / or the received WTRU capability of the anchor WTRU (e.g., according to the requested parameters).

[0440] Success probability calculation can be defined as initiating a hypothetical test of the COT using a given set of parameters (e.g., duration and / or priority). The success probability calculation can be defined as initiating a hypothetical test of the COT using a given set of parameters based on channel measurement / sensing results, received feedback, and / or locally performed channel measurements. The WTRU can initiate N hypothetical tests on the COT (e.g., to calculate the success probability). N can be a configured parameter.

[0441] The RTT program can be identified.

[0442] The WTRU (e.g., the server WTRU) can determine the SL RTT location procedure (e.g., based on the derived success probability). The RTT location method determination may include the RTT method and / or the COT type to be used for the RTT method. For example, the WTRU can determine whether a different COT or a shared COT (e.g., and the corresponding SL RTT parameters) is used for the SL RTT location procedure.

[0443] The WTRU can determine the RTT positioning method (e.g., a suitable RTT positioning method) based on the success probability (e.g., the success probability determined using channel measurements / sensing). If a first success probability is higher than a first (e.g., configured) threshold, the WTRU can determine a first RTT procedure (e.g., a SHARED COT for forward / reverse SL-PRS transmission and RTT reporting). Otherwise (e.g., if the first success probability is not higher than the first threshold), if a second success probability is higher than a second (e.g., configured) threshold, the WTRU can select a second RTT procedure (e.g., a SHARED COT for forward / reverse SL-PRS transmission). Otherwise (e.g., if the first success probability is not higher than the first threshold and the second success probability is not higher than the second threshold), if a third success probability is higher than a third (e.g., configured) threshold, the WTRU can select a second RTT procedure (e.g., a separate COT). Otherwise (e.g., if none of the success probabilities are higher than their respective thresholds), the WTRU can select RTT failure / abortion (e.g., implying that an unlicensed channel is currently unsuitable for positioning procedures).

[0444] The WTRU can determine the RTT positioning method (e.g., a suitable RTT positioning method) based on (e.g., directly based on) channel sensing measurements. The WTRU can use one or more of the following measurements to perform the RTT procedure determination: channel measurements performed at a second set of WTRUs (e.g., anchor WTRU); channel measurements performed at a third set of WTRUs (e.g., target WTRU); and / or local channel measurements performed at a WTRU (e.g., server WTRU).

[0445] A WTRU (e.g., a server WTRU) can determine its RTT procedure based on instructions from a second set of WTRUs (e.g., an anchor WTRU) regarding a (preferred) RTT method. A WTRU can also determine its RTT procedure based on instructions from both a second set of WTRUs and a third set of WTRUs regarding (preferred) RTT methods.

[0446] This article provides example instructions for the determined RTT procedure.

[0447] A WTRU (e.g., a server WTRU) can provide an indication of the determined RTT procedure. This indication may include the determined procedure and / or parameters associated with it. These parameters may relate to SL-PRS configuration, channel acquisition for unlicensed carriers (e.g., priority category, COT sharing information, COT busy signals I and II with type / duration), etc.

[0448] WTRUs (e.g., server WTRUs) can determine the SL-PRS configurations of a second group of WTRUs (e.g., anchor WTRUs) and a third group of WTRUs (e.g., target WTRUs) based, for example, on the COT type and the determined RTT procedure. WTRUs can determine a first SL-PRS configuration for a first COT type (e.g., shared COT) and a second SL-PRS configuration for a second COT type (e.g., individual COT).

[0449] A WTRU (e.g., a server WTRU) may receive a set of SL-PRS configurations (e.g., from an LMF). The WTRU may distribute the configurations received (e.g., from the LMF) to a second group of WTRUs (e.g., an anchor WTRU) and / or a third group of WTRUs (e.g., a target WTRU). The configurations received (e.g., from the LMF) may be configurations for different COT types and / or for different RTT procedures (e.g., independent configurations). In this case, the WTRU (e.g., the server WTRU) may select an SL-PRS configuration (e.g., a suitable SL-PRS configuration) for the second group of WTRUs and / or the third group of WTRUs based on the determined RTT procedure and / or COT type.

[0450] A WTRU can provide instructions on the selected RTT procedure to a second group of WTRUs (e.g., an anchor WTRU). A WTRU can provide instructions on the selected RTT procedure to a third group of WTRUs (e.g., a target WTRU).

[0451] WTRU can transmit defined procedural instructions (e.g., as PHY, MAC, or RRC-based signaling).

[0452] The SL RTT procedure can be based on channel measurements (e.g., from the target WTRU and / or the anchor WTRU).

[0453] WTRUs can determine SL RTT procedures based on channel measurements of the target WTRU and / or (one or more) anchor WTRUs (e.g., as...). Figure 10 (As shown in the illustration).

[0454] WTRUs (e.g., WTRU servers) can send requests for channel measurements and / or WTRU processing capabilities to target and / or anchor WTRUs.

[0455] The WTRU (e.g., WTRU server) can receive feedback from the target / anchor WTRU regarding channel measurements (e.g., CBR, RSSI, assumed LBT success) and / or feedback regarding the processing capabilities of the target / anchor WTRU (e.g., PRS measurement time, PRS TX time, RTT report processing, etc.).

[0456] A WTRU (e.g., a server WTRU) can determine one or more RTT positioning parameters (e.g., RTT positioning method-related parameters). One or more RTT positioning parameters may include the maximum COT duration, the priority category of the COT initiation, and / or the nature / duration of the COT-busy signal (e.g., based on the anchor WTRU's processing capacity).

[0457] A WTRU (e.g., a server WTRU) can derive one or more of the following metrics (e.g., based on local channel sensing, determined RTT / COT parameters, and / or received target / anchor feedback): a first success probability of initiating a shared COT (e.g., to be shared between target and / or anchor WTRUs), and / or a second success probability of initiating a separate COT (e.g., for target WTRU transmissions).

[0458] If the first success probability is higher than a first (e.g., a configured) threshold, the WTRU (e.g., the server WTRU) can determine a first RTT procedure (e.g., SHARED COT). Otherwise (e.g., if the first success probability is not higher than the first threshold), if the second success probability is higher than a second configured threshold, the server WTRU can select a second RTT procedure (e.g., COT alone). Otherwise (e.g., if neither the first nor the second success probability is higher than their respective thresholds), the server WTRU can select RTT failure / abortion (e.g., an unlicensed channel is unsuitable for positioning).

[0459] WTRU (e.g., server WTRU) can instruct the determined RTT procedure to the target and / or anchor WTRU.

[0460] Figure 10 The illustration shows an example server WTRU RTT selection procedure (e.g., utilizing target and anchor WTRU channel measurements). Figure 11 The illustration shows the WTRU RTT selector for the example server.

[0461] The server WTRU can select the RTT procedure based on channel sensing and anchor WTRU feedback.

[0462] The server WTRU can determine the probability of success for a single or shared COT. For example, the WTRU can determine the probability of success based on channel measurements reported by peer WTRUs (e.g., anchor WTRU and / or target WTRU) and measurements performed by the server WTRU. WTRU capabilities (e.g., SL-PRS measurements / processing) of the anchor WTRU and / or target WTRU can be reported to the server WTRU. The server WTRU can consider WTRU capabilities when determining the probability of success. The WTRU can determine whether to use a shared COT or a single COT for localization (e.g., based on one or more of the probability of success).

[0463] The server WTRU can send a request to the anchor WTRU (or target WTRU). This request can be for channel measurements and WTRU processing capabilities (e.g., preparation time for transmitting SL-PRS, measurement processing time, etc.).

[0464] The server WTRU can receive anchor WTRU responses regarding channel measurements (e.g., CBR, RSSI, assumed LBT success). Anchor WTRU capabilities may include PRS measurement time, PRS TX preparation time, RTT report processing, etc.

[0465] The server WTRU can determine one or more parameters related to the RTT location procedure. For example, these parameters may include one or more of the following: maximum COT duration, COT initiation priority category, and / or COT-busy signal nature / duration. The server WTRU can determine one or more parameters based on the anchor WTRU's processing capacity.

[0466] The server WTRU may (e.g., based on local channel measurements performed by the server WTRU, determined RTT / COT parameters, and / or received anchor WTRU feedback, such as channel measurements) derive one or more of the following metrics: a first success probability associated with initiating a shared COT shared between the target WTRU and the anchor WTRU; and / or a second success probability associated with an individual COT initiating a transmission from the target WTRU.

[0467] If the first success probability is higher than a first (e.g., configured) threshold, the server WTRU can determine a first RTT procedure (e.g., associated with using a shared COT). Otherwise (e.g., if the first success probability is lower than the first threshold), if the second success probability is higher than a second (e.g., configured) threshold, the server WTRU can select a second RTT procedure (e.g., associated with using a separate COT).

[0468] Otherwise (e.g., if the first success probability is below a first threshold and the second success probability is below a second threshold), the server WTRU can choose to perform an RTT failure / abort procedure (e.g., indicate that an unlicensed channel is not suitable for positioning).

[0469] The server WTRU can instruct the determined RTT procedure to the anchor WTRU.

[0470] This article provides one or more features associated with a shared COT multiRTT procedure from a target WTRU.

[0471] This article provides a sample SL-U shared COT PRS transport configuration.

[0472] A WTRU (e.g., a target WTRU) can emit one or more of the following configuration elements.

[0473] Configuration elements may include auxiliary information for the first group of WTRUs (e.g., anchor WTRUs). This auxiliary information may instruct the first group of WTRUs to perform resource selection (e.g., prior to the initiation of a COT to perform an SL-PRS transmission). WTRUs may indicate a potential start time for the first SL-PRS transmission (e.g., a forward SL-PRS transmission). WTRUs may provide an estimated start time for the forward SL-PRS transmission, or a start time with a window / duration within which the first group of WTRUs can receive the forward SL-PRS transmission.

[0474] Configuration elements may include a set of transmission sequences for the first group of WTRUs (e.g., anchor WTRUs) for their transmission in a shared COT-based RTT procedure.

[0475] Configuration elements may include a mapping from the first group (e.g., anchor) WTRU identifiers to the second group identifiers (e.g., the WTRU can use this mapping to indicate the transmission order of the first group of anchor WTRUs).

[0476] The configuration element may include a first SL-PRS resource configuration. The first SL-PRS resource configuration may include SL-PRS resource configurations for forward transmission of RTT procedures.

[0477] Configuration elements may include a second SL-PRS resource configuration. The second SL-PRS resource configuration may include SL-PRS resource configurations for reverse transmissions of the RTT procedure (e.g., from one or more WTRU receivers of the first / forward SL-PRS transmission).

[0478] Configuration elements may include a shared COT indication. The WTRU can provide an indication that the SL RTT session will be based on a shared COT. This indication may include information about the transmissions of the shared COT (e.g., forward SL-PRS transmissions, reverse SL-PRS transmissions, and / or RTT measurement reports).

[0479] Configuration elements may include COT busy configuration. This configuration can provide a set of types that the WTRU can use (e.g., to maintain COT busy between SL-PRS transmissions (e.g., forward SL-PRS transmissions) and / or subsequent SL-PRS transmissions (e.g., reverse SL-PRS transmissions)). This configuration may indicate one or more of the following types: SL PRS resource configuration; known sequence or a set of known sequences; random sequence; and / or shared channel data.

[0480] The COT Busy I signal may include a first part and a second part of the COT Busy I signal. In this case, the COT Busy I configuration may include the type and duration of the first part and the second part (e.g., each of the first part and the second part).

[0481] Configuration elements may include COT Busy II configuration. This configuration may include a set of types that the WTRU can use (e.g., to maintain COT busy between a set of SL-PRS transmissions (e.g., reverse SL-PRS transmissions and / or subsequent RTT reports)). This configuration may indicate one or more of the following types: SL PRS resource configuration; known sequence or a set of known sequences; random sequence; and / or shared channel data.

[0482] One or more RTT program parameters can be determined.

[0483] A WTRU (e.g., a target WTRU) can determine one or more RTT procedure parameters. For example, one or more RTT procedure parameters may include one or more of the following: LBT parameters for COT acquisition (e.g., priority, COT duration); a first COT busy signal (e.g., type / duration); a second COT busy signal (e.g., type / duration); the transmission order of the first set of WTRUs (e.g., anchor WTRUs) for PRS transmission; and / or the transmission order of the first set of WTRUs (e.g., anchor WTRUs) for RTT report transmission.

[0484] One or more parameters can instruct the WTRU to perform RTT procedures in a shared COT (e.g., at least the number of anchors M and the capabilities of the anchor WTRU, such as the preparation time for launching SL-PRS, measurement processing time, etc.).

[0485] The RTT procedure parameters can be determined based on one or more of the following: the number of first-group WTRUs (e.g., anchor WTRUs); the capabilities of the first-group WTRUs (e.g., anchor WTRUs) (e.g., preparation time for transmitting SL-PRS, measurement processing time, etc.); the capabilities of WTRUs (e.g., target WTRUs) (e.g., preparation time for transmitting SL-PRS, measurement processing time, etc.; the priority of SL-PRS transmissions); the length of the COT (e.g., the length required to complete an RTT session in the same COT; for example, the length of the COT can be selected to perform forward SL-PRS transmissions and / or reverse SL-PRS transmissions in the same COT to accommodate the measurement and preparation times of SL-PRS transmissions, or the length of the COT can be selected to perform forward SL-PRS transmissions, reverse SL-PRS transmissions, and / or RTT reporting in the same COT, including the WTRU processing time required for each intermediate step); the channel conditions at the first WTRU (e.g., target WTRU); and / or the channel conditions at the second WTRU (e.g., anchor WTRU).

[0486] This article provides a sample SL-U channel access procedure for sharing a COT.

[0487] A WTRU (e.g., a target WTRU) can perform LBT-based channel sensing (e.g., acquiring the COT of the RTT procedure). The WTRU can perform LBT-based channel sensing based on the determined LBT(one or more) parameters(s).

[0488] This article provides an example of forward SL-PRS transmission.

[0489] A WTRU (e.g., a target WTRU) can perform a forward SL-PRS transmission (e.g., based on a successful COT acquisition on the SL-U). The WTRU can transmit the SL-PRS (e.g., along with accompanying control information). The control information can be transmitted in the SCI. The control information can indicate one or more of the following: the priority of the SL-PRS transmission; the time and frequency resources used for the SL-PRS transmission; the priority value used to determine the LBT parameters for COT acquisition; and / or the remaining COT duration.

[0490] Control information may include the transmission order for PRS transmissions of the anchor WTRU. This transmission order may be an indication (e.g., a dynamic indication). The transmission order can be selected from one of (indicating) a (pre)configured transmission order (e.g., selecting an index of the (pre)configured transmission order). The transmission order can be a static or semi-static transmission order. In this case, an indication of the transmission order (e.g., a dynamic indication) may not be transmitted. The transmission order can be a static or semi-static order. The WTRU (e.g., the target WTRU) can override the semi-static order (e.g., by providing a dynamic indication in the SCI).

[0491] WTRU can determine dynamic indications (e.g., indications in SCI).

[0492] Dynamic indicators can be explicit. WTRUs can indicate a sequential order of WTRU IDs (e.g., in an SCI indicator). For example, an SCI indicator can include N bit positions. Bit positions (e.g., each bit position) can be indicated by a WTRU ID. The length of a bit position can be determined by the number of anchor WTRUs in a multi-RTT procedure. WTRU IDs can be based on anchor WTRU group IDs (e.g., pre-configured by server WTRUs and / or LMFs). WTRU IDs can also be based on WTRU IDs specified by the network.

[0493] Dynamic indications can be implicit. A set of transmission orders in an anchor WTRU group can be (pre)configured. The transmission order (e.g., each transmission order) can be represented by a corresponding index. WTRUs can indicate the transmission order using indexes (e.g., in SCI).

[0494] Control information may include resource allocation for reverse SL-PRS transmissions. A WTRU can perform resource allocation for a reverse SL-PRS transmission. A WTRU may indicate to one or more receiver WTRUs (e.g., anchor WTRUs) the resource allocation to be used for its one or more reverse SL-PRS transmissions. Resource allocation may be (e.g., time-frequency resource, time-only resource, or frequency-only resource indication for a reverse SL-PRS transmission).

[0495] Control information may include an RTT report inclusion indicator. COT sharing information may include an indication of whether the same COT can be used for RTT reporting (e.g., for an SL Rx WTRU). If RTT reports can be transmitted in different COTs, a WTRU (e.g., a target WTRU) may initiate a second COT for RTT reporting. The WTRU may indicate that the second COT for RTT reporting will be initiated by a second WTRU (e.g., an anchor WTRU).

[0496] Control information may include the transmission order of RTT report transmissions for the anchor WTRU. This transmission order may be a dynamic indication (e.g., selecting one of a (pre)configured transmission order, such as selecting an index of a (pre)configured transmission order). The transmission order may be static or semi-static. In this case, a dynamic indication of the transmission order may not be transmitted. The transmission order may be static or semi-static. The WTRU (e.g., the target WTRU) may control a semi-static order (e.g., by providing a dynamic indication in the SCI).

[0497] Control information may include resource allocation for RTT measurement reporting. A WTRU can perform resource allocation for RTT report transmission. A WTRU can indicate resource allocation to a receiving WTRU (e.g., an anchor WTRU). Resource allocation can be (e.g., for RTT report transmission) time-frequency resources, time-only resources, or frequency-only resources.

[0498] Control information may include a first COT busy signal indication. The first COT busy signal indication may include one or more of the following.

[0499] The first COT busy signal indication may include the transmission duration. The transmission duration of the first COT busy signal can be provided in absolute time using appropriate units (e.g., milliseconds or microseconds). The duration of the first COT busy signal can be indicated by time slot and / or symbol duration. Reference time slots and / or symbols can be used for a given subcarrier interval or active subcarrier interval.

[0500] The first COT busy signal indication may include the type of first COT busy signal used in the transmission. The type of first COT busy signal may be an SL PRS configuration, a known sequence or a set of known sequences, a random sequence, shared channel data (e.g., the shared channel data may be destined for one or more of the first set of WTRUs, such as the anchor WTRU, the receiver of the forward PRS transmission, or the WTRU may send the shared channel data to a different WTRU than the receiver of the forward SL-PRS transmission), and / or resource allocation for the transmission. Resource allocation may be an indication of time-frequency resources, time-only resources, or frequency-only resources for the first COT busy signal transmission.

[0501] Control information may include a second COT busy signal indication. The second COT busy signal indication may include one or more of the following.

[0502] The second COT busy signal indication may include the transmission duration. The transmission duration of the second COT busy signal may be provided in absolute time in an appropriate unit (e.g., milliseconds or microseconds). The duration of the first COT busy signal may be indicated by the time slot and / or symbol duration. The reference time slot and / or symbol may be used for a given subcarrier interval or active subcarrier interval.

[0503] The second COT busy signal indication may include the type of second COT busy signal used in the transmission. The type of second COT busy signal may include one or more of the following: SL PRS configuration; a known sequence or a set of known sequences; a random sequence; shared channel data (e.g., the shared channel data may be destined for one or more of the first set of WTRUs, such as the anchor WTRU, the receiver of the forward PRS transmission, or the WTRU may send the shared channel data to a WTRU different from the receiver of the forward SL-PRS transmission); and / or resource allocation for the transmission. Resource allocation may be an indication of time-frequency resources, time-only resources, or frequency-only resources for the second COT busy signal transmission.

[0504] This document provides one or more features associated with the first COT busy signal transmission.

[0505] A WTRU (e.g., a target WTRU) may perform the transmission of a first COT busy signal. The first COT busy signal transmission may be initiated after a delay (e.g., a fixed delay following a forward SL-PRS transmission). The WTRU may transmit the first COT busy signal (e.g., an SCI transmitted along with a forward SL-PRS transmission) for the type and / or duration indicated in the control information.

[0506] This article provides one or more characteristics associated with the receiver of a reverse SL-PRS transmission.

[0507] For example, after a forward SL-PRS transmission and / or a first COT busy signal transmission, a WTRU (e.g., a target WTRU) can receive a reverse SL-PRS transmission from a first group of WTRUs (e.g., an anchor WTRU). The WTRU can receive the reverse SL-PRS transmission on a time-frequency resource (e.g., the time-frequency resource transmitted in the SCI of the forward SL-PRS transmission). The SCI of the forward SL-PRS transmission can indicate (e.g., only indicate) a time. This time can be an absolute time or a time with a window within which the WTRU can reverse the SL-PRS transmission. In response to a forward SL-PRS transmission, a WTRU can receive a reverse SL-PRS transmission (e.g., where another WTRU performs resource allocation for the reverse SL-PRS transmission).

[0508] A WTRU (e.g., a target WTRU) can receive reverse SL-PRS transmissions from a first group of WTRUs (e.g., an anchor WTRU) in a known transmission order. The transmission order of the reverse SL-PRS transmissions can be semi-static. The WTRUs may have already indicated a dynamic transmission order in the SCI of the forward SL-PRS transmissions.

[0509] This article provides one or more features associated with determining that sufficient PRS transmissions have been received for multi-RTT effectiveness.

[0510] The WTRU (e.g., the target WTRU) can determine whether the WTRU has received enough SL-PRS transmissions for a valid multi-RTT procedure.

[0511] If a WTRU (e.g., the target WTRU) successfully receives SL-PRS transmissions from N anchors (e.g., where N is greater than a (pre)configured threshold), the WTRU can determine that the current RTT session has received sufficient measurements. If the WTRU is able to successfully decode the SCI of the SL-PRS transmission, the WTRU can consider the SL-PRS transmission reception successful. If the RSRP of the received SL-PRS transmission is greater than (e.g., a configured) threshold, the WTRU can consider the SL-PRS transmission reception successful.

[0512] If the WTRU determines that it has received sufficient SL-PRS transmissions, it can determine to transmit a second COT busy signal. Otherwise (e.g., if the WTRU has not yet received sufficient SL-PRS transmissions), the WTRU (e.g., the target WTRU) can abort the ongoing RTT session. In this case, the WTRU can transmit an abort indication to the first group of WTRUs (e.g., the anchor WTRU). For the first group of WTRUs in a session for which an abort indication has been received, the first group of WTRUs may not transmit a measurement report (e.g., based on the receipt of the abort indication).

[0513] WTRU can indicate to the server WTRU the termination of the current RTT session (e.g., with a reason indication).

[0514] It can transmit a second COT busy signal.

[0515] If the WTRU determines to transmit a second COT busy signal (e.g., when a multi-RTT procedure is active), the WTRU may transmit a second COT busy signal. The transmission of the second COT busy signal may follow one or more parameters indicated in the SCI transmitted in the forward SL-PRS.

[0516] The WTRU may not transmit a second COT busy signal. This could be the case if an RTT measurement report is transmitted from a COT separate from the COT used for SL-PRS transmission.

[0517] This article provides a sample SL-U channel access procedure for RTT reporting.

[0518] A WTRU (e.g., a target WTRU) can determine one or more LBT parameters to initiate a COT for an RTT report from a second set of WTRUs (e.g., an anchor WTRU).

[0519] A WTRU (e.g., a target WTRU) can perform LBT-based channel sensing (e.g., obtaining COT reports for RTT). The WTRU can perform LBT-based channel sensing based on the determined LBT(one) or more LBT(parameters).

[0520] This article provides a sample request for an RTT report.

[0521] A WTRU (e.g., a target WTRU) may transmit a request to a second group of WTRUs (e.g., an anchor WTRU) to receive RTT measurement reports. This request may be transmitted as PHY, MAC, or RRC signaling. Associated control information may indicate one or more of the following: transmission priority; time and frequency resources used to request the transmission; priority values ​​used to determine the COT acquisition of LBT parameters; the remaining COT duration; the transmission order of the anchor WTRU's RTT report transmissions; and / or resource allocation for RTT measurement reports.

[0522] The transmission order can be a dynamic indication of selecting one of a (pre)configured transmission order (e.g., an index for selecting a preconfigured transmission order). The transmission order can be static or semi-static. In this case, a dynamic indication of the transmission order may not be transmitted. The transmission order can be static or semi-static. A WTRU (e.g., a target WTRU) can override a semi-static order (e.g., by providing a dynamic indication in the SCI).

[0523] The WTRU can perform resource allocation for RTT report transmissions. The WTRU can indicate resource allocation to the receiving WTRU (e.g., the anchor WTRU). Resource allocation can be an indication of time-frequency resources, time-only resources, or frequency-only resources for RTT measurement reports.

[0524] A WTRU (e.g., an anchor WTRU) can determine the transmission timing of a received forward SL-PRS transmission of a measurement report (e.g., an explicit indication based on the transmission order). The WTRU can receive this indication (e.g., in a request transmission from a target WTRU and / or in an SCI associated with a forward SL-PRS transmission from a target WTRU).

[0525] A WTRU (e.g., an anchor WTRU) can determine the transmission timing of measurement reports received from forward SL-PRS transmissions (e.g., based on the transmission order of reverse SL-PRS transmissions received in a COT initiated by a target WTRU). The WTRU can apply the same reverse SL-PRS transmission order to measurement report transmissions.

[0526] It can receive measurement reports.

[0527] The WTRU can receive measurement reports from a group of WTRUs (e.g., anchor WTRUs, such as the anchor WTRU after transmitting the second COT busy signal).

[0528] The WTRU can receive measurement reports on resources for which reservation indications have been transmitted (e.g., in an SCI accompanying a forward SL-PRS transmission).

[0529] WTRU can receive measurement reports without prior reservations.

[0530] A WTRU (e.g., a target WTRU) can receive RTT reports from a set of WTRUs (e.g., anchor WTRUs) in a (e.g., known) transmission order. The transmission order used for RTT report transmissions can be a semi-static order. WTRUs may have already indicated a dynamic transmission order (e.g., in the SCI of a forward SL-PRS transmission).

[0531] This article provides a sample RTT measurement report.

[0532] A WTRU (e.g., a target WTRU) can prepare an Rx-Tx time difference measurement report (e.g., based on a first SL-PRS transmission and / or (one or more) reverse SL-PRS transmissions). The first SL-PRS transmission can be a forward SL-PRS transmission transmitted by the WTRU. (one or more) second SL-PRS transmissions can be (one or more) transmissions received by the WTRU (e.g., an SL-WTRU).

[0533] The WTRU can prepare Rx-Tx time difference measurements (e.g., based on forward SL-PRS transmissions, a first COT busy signal, and / or (one or more) reverse SL-PRS transmissions). The WTRU can calculate one or more sets (e.g., two sets) of time difference measurements. The first set of measurements can be performed between forward and reverse SL-PRS transmissions. The second set of measurements can be performed between the first COT busy signal and the reverse SL-PRS transmission.

[0534] The WTRU can use the reference time of the first COT busy signal (e.g., a suitable reference time) (e.g., to determine time difference measurements). The start of the timeslot of the first COT busy signal can be used as a reference transmit / receive time. The start of the symbol time used to transmit the first COT busy signal can be used as a reference transmit / receive time. The precise transmit / receive time can be used as a time reference for the first COT busy signal (e.g., to determine the RTT time difference).

[0535] Figure 12 The illustration shows an example of multiple RTTs sharing COT SL-U positioning.

[0536] A target WTRU can be configured with multiple anchor WTRUs (e.g., M anchor WTRUs) to perform RTT-based localization. The target WTRU can determine the transmission order of the M anchor WTRUs. The WTRU transmits SL-PRS to the M anchor WTRUs (e.g., using SCI indication). The SCI indication can indicate the transmission order of the anchor WTRUs. If the WTRU receives SL-PRS from at least N anchor WTRUs, the target WTRU can report the measurement to the server WTRU (e.g., based on the determined transmission order). Otherwise (e.g., if the WTRU receives SL-PRS from fewer than N anchor WTRUs), the target WTRU can report an error to the network.

[0537] The target WTRU can transmit target assistance information to M anchor WTRUs. This target assistance information can instruct the anchor WTRUs to perform resource selection, potential start time indications (e.g., t0 and window length), and a set of transmission sequences before COT initiation.

[0538] The target WTRU may determine one or more of the following: (one or more) LBT parameters, COT busy type / duration (e.g., COT_Busy_I&II type / duration), the transmission order of PRS and RTT reports for M anchors performing RTT procedures in a shared COT using at least M anchors, the ability of the anchor WTRU to transmit SL-PRS after receiving SL-PRS from the target WTRU, and / or the ability of the anchor WTRU to process measurements to prepare RTT measurement reports.

[0539] The target WTRU can perform LBT (e.g., Type 1 LBT). The target WTRU can perform LBT to obtain channel access for the RTT procedure (e.g., based on the determined LBT parameters).

[0540] The target WTRU can determine one or more SCI parameters. The SCI parameters may include at least one of the following: remaining COT duration; channel access priority category (e.g., for COT acquisition); COT_Busy_I and II (e.g., duration and type for I, duration for II, I before PRS, and II before RTT reporting); transmission order of PRS transmissions for the anchor WTRU (e.g., the transmission order may be a dynamic indication of selecting one of a pre-configured transmission order, such as an index for selecting a pre-configured transmission order); transmission resources for PRS transmissions for the anchor WTRU; and transmission resources for RTT reporting for the anchor WTRU.

[0541] The target WTRU can transmit positioning data to the anchor WTRU. The positioning data transmission may include SL-PRS and / or the determined SCI parameters.

[0542] The target WTRU can transmit a COT_Busy_I signal (e.g., to the anchor WTRU). The COT_Busy_I signal may include an extended SL-PRS.

[0543] If the target WTRU detects SL-PRS transmissions from N anchors (e.g., where N is greater than a (pre)configured threshold), the target WTRU may transmit a COT Busy II signal (e.g., where the COT Busy II signal is a pre-configured type).

[0544] Otherwise (e.g., if the target WTRU detects SL-PRS transmissions from fewer than N anchors), the target WTRU can send an abort indication to the anchor WTRUs. The abort indication can abort the current RTT procedure. The target WTRU can also send an abort indication (e.g., with a reason indication) to the server WTRU.

[0545] The target WTRU can receive RTT measurement reports (e.g., in the transmission order indicated in the SCI used for anchor PRS transmission). The target WTRU can transmit local and / or anchor WTRU RTT reports to the server WTRU. The target WTRU can receive location information from the server WTRU.

[0546] Although the above features and elements are described in specific combinations, each feature or element may be used alone without other features and elements of the preferred embodiment, or in various combinations with or without other features and elements.

[0547] While the implementations described herein may take into account 3GPP-specific protocols, it should be understood that the implementations described herein are not limited to this scenario and can be applied to other wireless systems. For example, although the solutions described herein take into account LTE, LTE-A, New Radio (NR), or 5G-specific protocols, it should be understood that the solutions described herein are not limited to this scenario and can also be applied to other wireless systems.

[0548] The above processes can be implemented incorporating computer programs, software, and / or firmware in a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted via wired and / or wireless connections) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor storage devices, magnetic media (such as, but not limited to, internal hard disks and removable disks), magneto-optical media, and / or optical media (such as optical disc (CD)-ROMs and / or digital versatile discs (DVDs)). The processor associated with the software can be used to implement a radio frequency transceiver used in WTRUs, terminals, base stations, RNCs, and / or any host computer.

[0549] It should be understood that the entity performing the processes described herein can be a logical entity, which can be implemented in the form of software (e.g., computer-executable instructions) stored in the memory of a mobile device, network node, or computer system and executed on the processor of that mobile device, network node, or computer system. That is, the processes can be implemented in the form of software (e.g., computer-executable instructions) stored in the memory of a mobile device and / or network node (such as a node or computer system), which execute the processes discussed when executed by the node's processor. It should also be understood that any transmit and receive processes illustrated in the figures can be executed by the node's communication circuitry under the control of the node's processor and the computer-executable instructions (e.g., software) it executes.

[0550] The various techniques described herein can be implemented in combination with hardware or software, or, where appropriate, with a combination of both. Therefore, implementation schemes and apparatuses of the subject matter described herein, or certain aspects or portions thereof, can take the form of program code (e.g., instructions) embodied in a tangible medium including any other machine-readable storage medium, wherein when the program code is loaded and executed by a machine such as a computer, that machine becomes an apparatus for practicing the subject matter described herein. In the case where the program code is stored on a medium, this may be the case where the program code in question is stored on one or more media that collectively perform the actions in question; that is, one or more media together contain the code for performing the actions. However, in the case where more than one single medium exists, it is not required that any particular portion of the code be stored on any particular medium. In the case of program code execution on a programmable device, the computing device typically includes a processor, processor-readable storage media (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device. One or more programs can be implemented, for example, by using APIs, reusable controls, etc., or utilize the processes described in conjunction with the subject matter described herein. Such programs are preferably implemented in a high-level program or an object-oriented programming language to communicate with a computer system. However, if needed, one or more programs can be implemented in assembly language or machine language. In any case, the language can be a compiled or interpreted language, and it can be combined with a hardware implementation scheme.

[0551] While the example embodiments may relate to utilizing aspects of the subject matter described herein within the context of one or more independent computing systems, the subject matter described herein is not limited thereto, but can be implemented in conjunction with any computing environment, such as a networked or distributed computing environment. Furthermore, aspects of the subject matter described herein can be implemented in or across multiple processing chips or devices, and storage can similarly be implemented across multiple devices. Such devices may include personal computers, web servers, handheld devices, supercomputers, or computers integrated into other systems, such as automobiles and aircraft.

[0552] In describing preferred embodiments of the subject matter of this disclosure, as illustrated in the figures, specific terminology has been used for clarity. However, the claimed subject matter is not intended to be limited to the specific terminology chosen so far, and it should be understood that each specific element includes all technical equivalents that operate in a similar manner to achieve a similar purpose.

Claims

1. A wireless transmit / receive unit (WTRU), comprising: The processor is configured as follows: Receive configuration information, the configuration information indicating the time after receiving the first side link positioning reference signal (SL-PRS), and send the second SL-PRS within the time specified in the configuration information; Receive the first SL-PRS; Execute the first listen-before-speak (LBT) procedure associated with the first priority within the first time window; If the WTRU does not obtain the Channel Occupancy Time (COT) based on the first LBT procedure, a second LBT procedure associated with the second priority is executed in the second time window; as well as A transmission is sent, wherein the content of the transmission depends on whether the WTRU is able to acquire the COT during the time period in which the second SL-PRS is sent.

2. The WTRU according to claim 1, wherein, The processor is further configured to determine the duration of the first time window based on a third priority associated with the first SL-PRS, wherein the duration of the first time window is inversely proportional to the third priority.

3. The WTRU according to claim 1, wherein, The processor is further configured to determine at least one of the following based on local sidelink channel measurements: the duration of the first time window, the duration of the second time window, the first priority, or the second priority.

4. The WTRU according to claim 1, wherein, Provided that the WTRU is able to acquire the COT during the time it is able to transmit the second SL-PRS, the transmission includes the second SL-PRS and control information indicating the resources associated with the second SL-PRS.

5. The WTRU according to claim 4, wherein, The processor is further configured to select a sidelink resource, in which the second SL-PRS is transmitted, and wherein: The transmission includes the second SL-PRS, and The transmission is sent to the target WTRU or server WTRU via the sidelink resource.

6. The WTRU according to claim 1, wherein, If the WTRU is unable to acquire the COT during the time period in which it transmits the second SL-PRS, the transmission includes an indication that the current session has been terminated and an indication that the current session has been terminated because the WTRU is unable to acquire the COT.

7. The WTRU according to claim 1, wherein, At least a portion of the first time window overlaps with a portion of the second time window, and the configuration information further indicates the offset between the start of the first time window and the start of the second time window.

8. The WTRU according to claim 1, wherein, The time during which the second SL-PRS is transmitted begins at the beginning of the first time window and ends at the end of the second time window, and the WTRU is able to acquire the COT during the time during which the second SL-PRS is transmitted, including the WTRU acquiring resources before the end of the second time window and transmitting the second SL-PRS in those resources.

9. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: Receive configuration information, the configuration information indicating the time after receiving the first side link positioning reference signal (SL-PRS), and send the second SL-PRS within the time specified in the configuration information; Receive the first SL-PRS; Execute the first listen-before-speak (LBT) procedure associated with the first priority within the first time window; If the WTRU does not obtain the Channel Occupancy Time (COT) based on the first LBT procedure, a second LBT procedure associated with the second priority is executed in the second time window; as well as A transmission is sent, wherein the content of the transmission depends on whether the WTRU is able to acquire the COT during the time period in which the second SL-PRS is sent.

10. The method according to claim 9, wherein, The method further includes determining the duration of the first time window based on a third priority associated with the first SL-PRS, wherein the duration of the first time window is inversely proportional to the third priority.

11. The method according to claim 9, wherein, The method further includes determining at least one of the following based on local side link channel measurements: the duration of the first time window, the duration of the second time window, the first priority, or the second priority.

12. The method according to claim 9, wherein, Provided that the WTRU is able to acquire the COT during the time it is able to transmit the second SL-PRS, the transmission includes the second SL-PRS and control information indicating the resources associated with the second SL-PRS.

13. The WTRU of claim 12, wherein, The method further includes selecting a sidelink resource, transmitting the second SL-PRS in the sidelink resource, and wherein: The transmission includes the second SL-PRS, and The transmission is sent to the target WTRU or server WTRU via the sidelink resource.

14. The method according to claim 9, wherein, If the WTRU is unable to acquire the COT during the time period in which it transmits the second SL-PRS, the transmission includes an indication that the current session has been terminated and an indication that the current session has been terminated because the WTRU is unable to acquire the COT.

15. The method according to claim 9, wherein, At least a portion of the first time window overlaps with a portion of the second time window, and the configuration information further indicates the offset between the start of the first time window and the start of the second time window.

16. The method according to claim 9, wherein, The time during which the second SL-PRS is transmitted begins at the beginning of the first time window and ends at the end of the second time window, and the WTRU is able to acquire the COT during the time during which the second SL-PRS is transmitted, including the WTRU acquiring resources before the end of the second time window and transmitting the second SL-PRS in those resources.

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