Method and device for positioning in partial coverage scene

Abstract

The embodiment of the invention relates to a method and equipment for positioning in a partial coverage scene. Embodiments of the present application provide a positioning management function (LMF) for a wireless network that includes a transceiver and a processor coupled to the transceiver. The processor is configured to at least one of: transmit, with the transceiver and to each of a set of first user equipments (UEs) within a coverage of the wireless network, a discovery request for discovering a second UE that is outside the coverage of the wireless network and whose location is requested; receiving, with the transceiver and from a third UE, a request to position the third UE, and transmitting, with the transceiver and to the third UE, a positioning result of the third UE in response to the request, where the third UE is within coverage of the wireless network, a sidelink positioning procedure is executed on fourth UE outside the coverage range of the wireless network for obtaining the positioning of the fourth UE; or receiving, with the transceiver and from a fifth UE, a positioning assistance request, and transmitting, with the transceiver and to the fifth UE, a positioning result of a target UE outside of coverage of the wireless network in response to the positioning assistance request, where a computing power of the fifth UE cannot support a positioning service associated with the target UE.

Description

Technical Field

[0001] The present disclosure generally relates to wireless communication, and more particularly to methods and devices for positioning in a partial coverage scenario. Background Art

[0002] In the 18th version of the 3rd Generation Partnership Project (3GPP), it is agreed to support sidelink positioning in In-Coverage (IC), Partial Coverage (PC), and Out-of-Coverage (OOC) scenarios. One of the situations in the PC scenario is that the target User Equipment (UE) is out of the network coverage, and at least one anchor UE is within the network coverage. In this PC scenario, the network can participate in triggering the positioning service or providing assistance to obtain the positioning of the target UE. Currently, corresponding procedures and signaling need to be designed to support network-related positioning of OOC target UEs. Summary of the Invention

[0003] Embodiments of the present application at least provide a technical solution for positioning in a PC scenario.

[0004] Some embodiments of the present disclosure provide a first UE, comprising: a transceiver; and a processor coupled to the transceiver, wherein the first UE is within the coverage of a wireless network, and the processor is configured to: execute a discovery procedure to discover a second UE outside the coverage of the wireless network; and execute a sidelink positioning procedure for the second UE to obtain the positioning of the second UE.

[0005] In some embodiments, the processor is configured to receive, using the transceiver and from a Location Management Function (LMF) of the wireless network, a discovery request for discovering the second UE before executing the discovery procedure.

[0006] In some embodiments, the discovery request includes at least one of the following: one or more Uu Reference Signal Received Power (RSRP) thresholds, a sidelink RSRP threshold, information of the second UE, a first request for positioning capability information of the first UE, a second request for positioning capability information of the second UE, a third request for the positioning and associated uncertainty of the first UE, a first response time for the first UE to send a discovery response to the LMF; or first information to be included in a discovery message to be sent by the first UE.

[0007] In some embodiments, the first UE meets the one or more Uu RSRP thresholds, and the processor is further configured to: broadcast a first discovery message using the transceiver; and receive a second discovery message using the transceiver and from the second UE.

[0008] In some embodiments, in the case where the discovery request includes the second request: the first discovery message includes a request for the positioning capability information of the second UE; and the processor is configured to receive, using the transceiver, the positioning capability information of the second UE from the second UE.

[0009] In some embodiments, the positioning capability information of the second UE is received via the second discovery message.

[0010] In some embodiments, the positioning capability information of the second UE is received via a broadcast message.

[0011] In some embodiments, the positioning capability information of the second UE is received periodically or after a certain period of time since the last broadcast of the positioning capability information of the second UE.

[0012] In some embodiments, the processor is configured to: perform a measurement of the RSRP of the second discovery message; and transmit a discovery response to the LMF using the transceiver before the expiration of the first response time, wherein the RSRP of the second discovery message exceeds the sidelink RSRP threshold.

[0013] In some embodiments, the discovery response includes at least one of the following: the sidelink quality between the first UE and the second UE or the Uu link quality of the first UE.

[0014] In some embodiments, in the case where the discovery request includes the first request, the discovery response includes the positioning capability information of the first UE.

[0015] In some embodiments, in the case where the discovery request includes the second request, the discovery response includes the positioning capability information of the second UE.

[0016] In some embodiments, in the case where the discovery request includes the third request: if the first UE knows the positioning of the first UE, then the discovery response includes the positioning of the first UE and the associated uncertainty, and otherwise, the discovery response indicates an unknown positioning or does not include the positioning information of the first UE.

[0017] In some embodiments, the processor is further configured to receive, using the transceiver, a relay request from the LMF that includes at least one of the following: a first indication indicating the responsibility of forwarding data from the LMF to the second UE; a second indication for establishing a unicast connection with the second UE; or a second piece of information to be transmitted to the second UE.

[0018] In some embodiments, the first indication further indicates the responsibility of forwarding data from the second UE to the LMF.

[0019] In some embodiments, in response to the relay request, the processor is further configured to: establish a unicast connection with the second UE; and after the unicast connection is established, transmit a relay confirmation to the LMF using the transceiver.

[0020] In some embodiments, the processor is configured to forward the second information to the second UE using the transceiver and via the unicast connection, and the relay confirmation is transmitted after the second information is forwarded.

[0021] In some embodiments, the processor is configured to receive, using the transceiver, an indication from the LMF to perform the sidelink positioning procedure with the second UE.

[0022] In some embodiments, the first information includes: a positioning request with quality of service (QoS) requirements, and a second response time for the second UE to send a response to the discovery message.

[0023] In some embodiments, the first UE meets the one or more Uu RSRP thresholds, and the processor is further configured to: broadcast a first discovery message including the first information using the transceiver; and receive a second discovery message from the second UE using the transceiver before the second response time expires, where the second discovery message includes an acknowledgement indicating that the second UE accepts the positioning request and starts the sidelink positioning procedure.

[0024] In some embodiments, the processor is further configured to transmit, using the transceiver, an acknowledgement indicating that the positioning request is accepted by the second UE to the LMF.

[0025] In some embodiments, the processor is configured to: receive, using the transceiver, the relay reselection configuration of the first UE from the LMF, where the relay reselection configuration includes at least one of a first relay sidelink RSRP threshold or a relay Uu RSRP threshold.

[0026] In some embodiments, the processor is configured to transmit a first relay reselection indication to the LMF using the transceiver when at least one of the following occurs: the RSRP of the sidelink signal on the unicast connection between the first UE and the second UE is lower than the first relay sidelink RSRP threshold; the first UE detects a sidelink radio link failure (RLF); the first UE receives an indication from the upper layer of the first UE; or the first UE is about to lose its connection to the wireless network.

[0027] In some embodiments, the processor is configured to: receive, using the transceiver and from the LMF, a release request to release the unicast connection with the second UE; and in response to the release request, release the unicast connection with the second UE and transmit, using the transceiver and to the LMF, a release confirmation.

[0028] In some embodiments, the processor is configured to: transmit, using the transceiver and to the second UE, a relay reselection configuration for the second UE, the relay reselection configuration including a second relay sidelink RSRP threshold.

[0029] In some embodiments, the processor is configured to receive, using the transceiver and from the LMF, the second relay sidelink RSRP threshold.

[0030] In some embodiments, the processor is configured to transmit, using the transceiver and to the second UE, a second relay reselection indication when at least one of the following occurs: the RSRP of the Uu signal received from a base station (BS) is lower than the relay Uu RSRP threshold; the first UE detects Uu RLF; or the first UE receives an indication from an upper layer of the first UE.

[0031] In some embodiments, the processor is configured to transmit, using the transceiver and to the LMF, a request to locate the first UE.

[0032] In some embodiments, the processor is configured to receive, using the transceiver and from the LMF, a positioning result of the first UE in response to the request to locate the first UE.

[0033] In some embodiments, the request to locate the first UE includes at least one of a QoS requirement for a positioning service or a positioning response time, and wherein when the request to locate the first UE includes the positioning response time, the positioning result is received before the expiration of the positioning response time.

[0034] In some embodiments, the request to locate the first UE is transmitted when the first UE receives a relocating request from the second UE, and the processor is configured to transmit, using the transceiver and to the second UE, a relocating response including the positioning result of the first UE.

[0035] In some embodiments, the relocating request includes at least one of a QoS requirement for a positioning service or a relocating response time, and wherein when the relocating request includes the relocating response time, the relocating response is transmitted before the expiration of the relocating response time.

[0036] In some embodiments, the request to locate the first UE is transmitted when a sidelink positioning estimate calculated by the first UE does not meet the accuracy requirements of the positioning service associated with the second UE.

[0037] In some embodiments, the processor is configured to, before receiving the positioning result of the first UE from the LMF in response to the request to locate the first UE, if an ongoing sidelink positioning meets the accuracy requirements, then transmit a relocation cancellation request to cancel the positioning of the first UE using the transceiver and to the LMF.

[0038] In some embodiments, in a case where the first UE does not receive the positioning result of the first UE from the LMF before the positioning response time expires, the processor is configured to: notify an upper layer of the first UE that the accuracy requirements of the positioning service are currently not met, and that the positioning accuracy may potentially be improved after receiving the positioning result of the first UE from the LMF.

[0039] In some embodiments, the processor is configured to: when the computing capabilities of at least one of the first UE or the second UE cannot support the positioning service associated with the second UE, transmit a positioning assistance request to the LMF using the transceiver, where the positioning assistance request includes at least one of the following: an indication of sidelink-only positioning, an indication of the responsibility of the LMF, or information about the second UE.

[0040] In some embodiments, the positioning assistance request is transmitted together with or separately from a measurement report associated with the second UE.

[0041] In some embodiments, the processor is configured to receive the positioning result of the second UE from the LMF using the transceiver in response to the positioning assistance request.

[0042] Some embodiments of the present disclosure provide an LMF for a wireless network, the LMF including: a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to perform at least one of the following: transmitting, using the transceiver, a discovery request to each of a group of first UEs within the coverage of the wireless network to discover a second UE outside the coverage of the wireless network and whose positioning is requested; receiving, using the transceiver, a request to position a third UE from the third UE, and in response to the request, transmitting, using the transceiver, a positioning result of the third UE to the third UE, wherein the third UE is within the coverage of the wireless network and performs a sidelink positioning procedure for a fourth UE outside the coverage of the wireless network to obtain the positioning of the fourth UE; or receiving, using the transceiver, a positioning assistance request from a fifth UE, and in response to the positioning assistance request, transmitting, using the transceiver, a positioning result of a target UE outside the coverage of the wireless network to the fifth UE, wherein the computing power of the fifth UE cannot support the positioning service associated with the target UE.

[0043] In some embodiments, the processor is configured to transmit the discovery request in response to receiving an indication to position the second UE from an access and mobility management function (AMF) of the wireless network.

[0044] In some embodiments, the discovery request transmitted to each first UE includes at least one of the following: one or more Uu RSRP thresholds, a sidelink RSRP threshold, information of the second UE, a first request for positioning capability information of the corresponding first UE, a second request for positioning capability information of the second UE, a third request for positioning and associated uncertainty of the corresponding first UE, a first response time for the corresponding first UE to send a discovery response to the LMF; or first information to be included in a discovery message to be sent by the corresponding first UE, wherein the first information includes: a positioning request with QoS requirements, and a second response time for the second UE to send a response to the discovery message.

[0045] In some embodiments, the processor is configured to receive, using the transceiver, one or more discovery responses from one or more first UEs within the group of first UEs before the expiration of the first response time.

[0046] In some embodiments, the discovery response received from a corresponding first UE includes at least one of the following: the sidelink quality between the corresponding first UE and the second UE or the Uu link quality of the corresponding first UE.

[0047] In some embodiments, when the discovery request sent to each first UE includes the first request, the discovery response received from the corresponding first UE includes the positioning capability information of the corresponding first UE.

[0048] In some embodiments, when the discovery request sent to each first UE includes the second request, the discovery response received from the corresponding first UE includes the positioning capability information of the corresponding first UE.

[0049] In some embodiments, when the discovery request sent to each first UE includes the third request, the discovery response received from the corresponding first UE includes the positioning and associated uncertainty of the corresponding first UE or indicates unknown positioning or does not include positioning information.

[0050] In some embodiments, the processor is configured to select at least one anchor UE from the one or more discovery responses received from the one or more first UEs to obtain the positioning of the second UE from the one or more first UEs.

[0051] In some embodiments, the at least one anchor UE is selected based on at least one of the following: the positioning capability information of the one or more first UEs; the sidelink quality between each of the one or more first UEs and the second UE; the positioning and associated uncertainty of each of the one or more first UEs; or the positioning requirements for positioning the second UE.

[0052] In some embodiments, the processor is configured to: designate an anchor UE among the at least one anchor UE as a relay anchor UE; and use the transceiver to transmit a first relay request to the relay anchor UE, the first relay request including at least one of the following: a first indication indicating the responsibility of forwarding data from the LMF to the second UE, a second indication for establishing a unicast connection between the relay anchor UE and the second UE, or a second piece of information to be transmitted to the second UE.

[0053] In some embodiments, the first indication further indicates the responsibility of forwarding data from the second UE to the LMF.

[0054] In some embodiments, the processor is configured to: use the transceiver to receive a first relay confirmation from the relay anchor UE; and in response to the first relay confirmation, initiate sidelink positioning between the at least one anchor UE and the second UE and interact with the second UE via the relay anchor UE.

[0055] In some embodiments, in a case where the number of the at least one anchor UE is insufficient to obtain the positioning of the second UE or the positioning information of the at least one anchor UE is not received, the processor is further configured to initiate Uu positioning of the at least one anchor UE.

[0056] In some embodiments, each of the at least one anchor UE is designated as a relay anchor UE.

[0057] In some embodiments, the processor is configured to: in response to the discovery request including the first information, use the transceiver and receive, from a first UE among the group of first UEs, an acknowledgment indicating that the positioning request is accepted by the second UE.

[0058] In some embodiments, the processor is configured to abort the discovery procedure of other first UEs among the group of first UEs.

[0059] In some embodiments, in a case where the discovery request includes the first information and an acknowledgment indicating that the positioning request is accepted by the second UE is not received from the group of first UEs during a certain period, the processor is configured to initiate network-controlled sidelink positioning of the second UE.

[0060] In some embodiments, the processor is configured to use the transceiver and transmit, to the relay anchor UE, a relay reselection configuration of the relay anchor UE, the relay reselection configuration including at least one of a first relay sidelink RSRP threshold and a relay Uu RSRP threshold.

[0061] In some embodiments, the relay anchor UE is a first relay anchor UE, and the processor is configured to perform relay anchor UE reselection to select a second relay anchor UE when at least one of the following occurs: the LMF receives a first relay reselection indication from the first relay anchor UE; a Uu measurement report associated with the first relay anchor UE received from the first relay anchor UE or the BS indicates a Uu RSRP lower than the relay Uu RSRP threshold; a sidelink measurement report associated with the first relay anchor UE received from the first relay anchor UE indicates a sidelink RSRP lower than the first relay sidelink RSRP threshold; or no measurement report is received from the first relay anchor UE within a certain period.

[0062] In some embodiments, the processor is configured to: use the transceiver and transmit a second relay request to the second relay anchor UE.

[0063] In some embodiments, the processor is further configured to: receive, with the transceiver and from the second relay anchor UE, a second relay confirmation; in response to receiving the second relay confirmation, transmit, with the transceiver and to the first relay anchor UE, a release request for releasing the unicast connection between the first relay anchor UE and the second UE; and in response to the release request, receive, with the transceiver and from the first relay anchor UE, a release confirmation.

[0064] In some embodiments, the processor is configured to transmit, with the transceiver and to the relay anchor UE, a relay reselection configuration for the second UE, the relay reselection configuration including a second relay side link RSRP threshold for the second UE to perform relay anchor UE reselection.

[0065] In some embodiments, the processor is further configured to receive, with the transceiver and from an anchor UE among the at least one anchor UE different from the relay anchor UE, an indication indicating that the anchor UE is selected as a new relay anchor UE.

[0066] In some embodiments, the request for positioning the third UE includes at least one of a QoS requirement for a positioning service or a positioning response time, and upon receiving the request for positioning the third UE, the processor is configured to: initiate Uu positioning of the third UE.

[0067] In some embodiments, in the case where the request for positioning the third UE includes the positioning response time, the processor is configured to transmit, with the transceiver and to the third UE, a positioning result before the expiration of the positioning response time.

[0068] In some embodiments, the processor is configured to: receive, with the transceiver, a relocation cancellation request for canceling the positioning of the third UE; and in response to the relocation cancellation request, stop the Uu positioning of the third UE.

[0069] In some embodiments, the fifth UE is the target UE, and the positioning assistance request is received via a side link relay UE within the coverage of the wireless network, or the fifth UE is an anchor UE within the coverage of the wireless network for obtaining the positioning of the target UE.

[0070] In some embodiments, the positioning assistance request is received together with or separately from a measurement report associated with the target UE.

[0071] In some embodiments, the positioning assistance request includes at least one of the following: an indication of only side link positioning, an indication indicating the responsibility of the LMF, or information of the target UE.

[0072] Some embodiments of the present disclosure provide a second UE that is outside the coverage of a wireless network and includes: a transceiver; and a processor coupled to the transceiver, where the processor is configured to perform at least one of the following: receive, using the transceiver, a first discovery message from each of one or more first UEs within the coverage of the wireless network, and transmit, using the transceiver, a second discovery message to each of the one or more first UEs; transmit, using the transceiver, a relocation request to one or more anchor UEs for obtaining the location of the second UE; or transmit, using the transceiver, a positioning assistance request to the LMF of the wireless network via a sidelink relay UE within the coverage of the wireless network, and receive, using the transceiver, an assistance result from the LMF via the sidelink relay UE.

[0073] In some embodiments, the first discovery message includes a request for positioning capability information of the second UE, and the second discovery message includes the positioning capability information of the second UE.

[0074] In some embodiments, the first discovery message includes a request for positioning capability information of the second UE, and the processor is configured to broadcast the positioning capability information of the second UE.

[0075] In some embodiments, the positioning capability information of the second UE is broadcast periodically or after a certain period of time since the last broadcast of the positioning capability information of the second UE.

[0076] In some embodiments, the processor is configured to: establish a unicast connection with a designated first UE among the one or more UEs designated by the LMF as a first relay anchor UE; and receive, using the transceiver, information about the anchor UE selected by the LMF from the first relay anchor UE.

[0077] In some embodiments, the processor is configured to: start sidelink positioning after transmitting the second discovery message; and transmit, using the transceiver, a measurement report or a sidelink positioning result to the LMF via a relay UE within the coverage of the wireless network.

[0078] In some embodiments, the second discovery message includes an acknowledgment indicating that the second UE accepts a positioning request with a QoS requirement included in the first discovery message.

[0079] In some embodiments, the processor is configured to: receive, using the transceiver, a relay reselection configuration of the second UE including a relay sidelink RSRP threshold from the first relay anchor UE.

[0080] In some embodiments, the processor is configured to: when the second UE receives a relay reselection indication from the first relay anchor UE, reselect a second relay anchor UE other than the first relay anchor UE, wherein the RSRP of the sidelink signal received from the second relay anchor UE meets the relay sidelink RSRP threshold; and release the unicast connection with the first relay anchor UE.

[0081] In some embodiments, the relocation request is transmitted to the one or more anchor UEs in response to the sidelink positioning estimate calculated by the second UE not meeting the accuracy requirement of the positioning service associated with the second UE.

[0082] In some embodiments, the relocation request includes at least one of the accuracy requirement of the positioning service or the relocation response time.

[0083] In some embodiments, the relocation request is transmitted via broadcast signaling or multicast signaling, or transmitted via unicast signaling to at least one of the one or more anchor UEs.

[0084] In some embodiments, the relocation request is transmitted to each of the one or more anchor UEs, and the relocation request transmitted to the corresponding anchor UE among the one or more UEs includes a coverage request for the network coverage information of the corresponding anchor UE among the one or more anchor UEs.

[0085] In some embodiments, in the case where the accuracy requirement of the positioning service is met by ongoing sidelink positioning before receiving one or more relocation results, the processor is configured to transmit a relocation cancellation request to the LMF via the sidelink relay UE.

[0086] In some embodiments, in the case where no relocation result is received from at least one of the one or more anchor UEs after the relocation request is transmitted and before the relocation response time expires, the processor is configured to notify the upper layer of the second UE that: the accuracy requirement of the positioning service is currently not met and the positioning accuracy may potentially be improved after receiving the relocation result from at least one of the one or more anchor UEs; and in the case where at least one relocation result is received from at least one of the one or more anchor UEs after the relocation request is transmitted and before the relocation response time expires, the processor is configured to transmit the current sidelink positioning estimate to the upper layer of the second UE based on the at least one relocation result received from at least one of the one or more anchor UEs.

[0087] In some embodiments, the processor is configured to transmit the positioning assistance request when the computing power of the second UE cannot support the positioning service associated with the second UE, where the positioning assistance request includes at least one of the following: an indication indicating the responsibility of the LMF, an indication of positioning only over sidelink, or information of the second UE.

[0088] In some embodiments, the positioning assistance request is transmitted together with or separately from a measurement report associated with the second UE.

[0089] Some embodiments of the present disclosure provide a method performed by a first UE within the coverage of a wireless network. The method includes: performing a discovery procedure to discover a second UE outside the coverage of the wireless network; and performing a sidelink positioning procedure on the second UE to obtain the positioning of the second UE.

[0090] Some embodiments of the present disclosure provide a method performed by an LMF of a wireless network. The method includes at least one of the following: transmitting a discovery request to each of a group of first UEs within the coverage of the wireless network to discover a second UE outside the coverage of the wireless network and whose positioning is requested; receiving a request to position a third UE from the third UE, and transmitting a positioning result of the third UE to the third UE in response to the request, where the third UE is within the coverage of the wireless network and performs a sidelink positioning procedure on a fourth UE outside the coverage of the wireless network to obtain the positioning of the fourth UE; or receiving a positioning assistance request from a fifth UE, and transmitting a positioning result of a target UE outside the coverage of the wireless network to the fifth UE in response to the positioning assistance request, where the computing power of the fifth UE cannot support the positioning service associated with the target UE.

[0091] Some embodiments of the present disclosure provide a method performed by a second UE outside the coverage of a wireless network. The method includes at least one of the following: receiving a first discovery message from each of one or more first UEs within the coverage of the wireless network, and transmitting a second discovery message to each of the one or more first UEs; transmitting a relocation request to one or more anchor UEs for obtaining the positioning of the second UE; or transmitting a positioning assistance request to the LMF of the wireless network via a sidelink relay UE within the coverage of the wireless network, and receiving an assistance result from the LMF via the sidelink relay UE. Description of the Drawings

[0092] To describe the manner in which the advantages and features of the present application can be obtained, the description of the present application is presented by reference to specific embodiments of the present application illustrated in the accompanying drawings. These drawings only depict example embodiments of the present application and should not be considered as limiting its scope.

[0093] Figure 1 is a schematic diagram illustrating an exemplary wireless communication system according to some embodiments of the present disclosure.

[0094] Figure 2 is a flowchart illustrating an exemplary method for discovering and positioning an OOC target UE according to some embodiments of the present disclosure.

[0095] Figure 3 is a flowchart illustrating another exemplary method for discovering and positioning an OOC target UE according to some embodiments of the present disclosure.

[0096] Figure 4 is a flowchart illustrating an exemplary method for reselecting a relay anchor UE according to some embodiments of the present disclosure.

[0097] Figure 5 is a flowchart illustrating another exemplary method for reselecting a relay anchor UE according to some embodiments of the present disclosure.

[0098] Figure 6 is a flowchart illustrating an exemplary method for repositioning an IC anchor UE for sidelink positioning according to some embodiments of the present disclosure.

[0099] Figure 7 is a simplified block diagram illustrating an exemplary device for positioning according to some embodiments of the present disclosure. Detailed Description of the Embodiments

[0100] The detailed description of the drawings is intended as a description of the currently preferred embodiments of the present disclosure and is not intended to represent the only form in which the present disclosure can be practiced. It should be understood that the same or equivalent functions can be accomplished by different embodiments that are intended to be covered by the spirit and scope of the present disclosure.

[0101] Although the operations are depicted in the drawings in a specific order, those skilled in the art will readily recognize that such operations need not be performed in the specific order shown or in a sequential order or that all of the illustrated operations are required to achieve the desired result; sometimes one or more operations may be skipped. Additionally, the drawings may schematically depict one or more example processes in the form of a flowchart. However, other operations not depicted may be incorporated into the example processes schematically illustrated. For example, one or more additional operations may be performed before, after, simultaneously, or between any of the illustrated operations. In some cases, multitasking and parallel processing may be advantageous.

[0102] Reference will now be made in detail to some embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. For the sake of promoting understanding, embodiments are provided in the context of specific network architectures and new service scenarios (such as 3GPP Long Term Evolution (LTE), LTE-Advanced, 5G New Radio (NR), 5G-Advanced, 6G, etc.). It is contemplated that as the network architectures and new service scenarios evolve, all embodiments in the present disclosure are also applicable to similar technical problems; and furthermore, the terms cited in the present disclosure may change, which should not affect the principles of the present disclosure.

[0103] Figure 1 is a schematic diagram illustrating an exemplary wireless communication system 100 in accordance with some embodiments of the present disclosure.

[0104] As Figure 1 shown, the wireless communication system 100 includes at least one LMF 101, at least one UE (such as UE 102a and UE 102b), and at least one BS 103. Although for illustrative purposes, Figure 1 one BS, two UEs, and one LMF are depicted, it is contemplated that the wireless communication system 100 may include any number of BSs, UEs, and LMFs.

[0105] The wireless communication system 100 is compatible with any type of network capable of transmitting and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with wireless communication networks, cellular telephone networks, Time Division Multiple Access (TDMA)-based networks, Code Division Multiple Access (CDMA)-based networks, Orthogonal Frequency Division Multiple Access (OFDMA)-based networks, LTE networks, 3GPP-based networks, 3GPP 5G networks, satellite communication networks, high-altitude platform networks, and / or other communication networks.

[0106] The LMF 101 (also referred to as an LMF entity) may refer to a network element or network entity for supporting positioning services, which may be deployed in a core network (CN) or a radio access network (RAN) of the wireless communication system 100. The LMF 101 may communicate with the BS 103 via NR Positioning Protocol A (NRPPa) signaling and may communicate with the UE (such as UE 102a) via LTE Positioning Protocol (LPP) signaling.

[0107] According to some embodiments of the present application, the UE (such as UE 102a or UE 102b) may be a vehicle UE (VUE) or an energy-saving UE (also referred to as a power-sensitive UE). The energy-saving UE may be a vulnerable road user (VRU), a public safety UE (PS-UE), or a commercial side-link UE (CS-UE) sensitive to power consumption. In an embodiment of the present application, the VRU may be a pedestrian UE (P-UE), a cyclist UE, a wheelchair UE, or another UE that requires energy saving compared to the VUE.

[0108] According to some other embodiments of the present application, a UE (such as UE 102a or UE 102b) may be a computing device, such as a desktop computer, a laptop computer, a personal digital assistant (PDA), a tablet computer, a smart TV (such as a TV connected to the Internet), a set-top box, a gaming console, a security system (including security cameras), an in-vehicle computer, a network device (such as a router, a switch, and a modem), or the like.

[0109] According to some other embodiments of the present application, a UE (such as UE 102a or UE 102b) may be a portable wireless communication device, a smart phone, a cellular phone, a flip phone, a device with a subscriber identification module, a personal computer, a pager, or another device capable of sending and receiving communication signals over a wireless network.

[0110] According to some other embodiments of the present application, a UE (such as UE 102a or UE 102b) may be a wearable device, such as a smart watch, a fitness bracelet, an optical head-mounted display, or the like.

[0111] In addition, a UE (such as UE 102a or UE 102b) may be referred to as a subscriber unit, a mobile device, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, a device, or other terms used in the art.

[0112] BS103 may also be referred to as an access point, an access terminal, a base, a macro cell, a radio access network (RAN) node, a next-generation (NG) RAN node, a Node B, an enhanced Node B (eNB), a gNB, a home Node B, a relay node, or a device, or other terms used in the art. BS103 is generally part of a RAN that may include a controller communicatively coupled to BS 103.

[0113] In Figure 1 the example shown, UE 102a is within the coverage of the network (such as within the coverage area of BS103) and may communicate with BS103 via the LTE or NR Uu interface, and UE 102b is outside the coverage of the network (such as not within the coverage area of any BS). UE 102a may be referred to as an IC UE, and UE 102b may be referred to as an OOC UE. UE 102a may communicate with UE 102b via a sidelink (such as via the PC5 interface defined in the 3GPP standard document).

[0114] When a positioning service request associated with a UE is initiated or occurs, the location of the UE (referred to as the target UE or the positioning service (LCS) target UE) needs to be known. If the target UE is within the coverage area of a BS or the network, then Uu positioning can be performed for the target UE, where the target UE can transmit positioning reference signals (PRSs) to the BS and / or neighboring BSs or receive PRSs from the BS and / or neighboring BSs, and the PRSs can be measured by the BS or the target UE to obtain positioning information.

[0115] Sidelink positioning refers to transmitting PRSs over the sidelink, which can operate independently of the network or radio access technology (RAT) coverage. According to various embodiments of the present application, whether within or outside the coverage area, the target UE can select one or more other UEs as anchor UEs, which can participate in sidelink positioning and help the target UE obtain its location, for example, by sending / receiving sidelink PRSs and performing related measurements. According to some other embodiments of the present application, the anchor UEs can be determined by the network (e.g., by the LMF or the BS), rather than being selected by the target UE. In such embodiments, the target UE and the anchor UEs can be within the coverage area of the network. The anchor UEs should have positioning capabilities.

[0116] One or more anchor UEs can be selected to help the target UE obtain its location. When performing sidelink positioning, the target UE and one or more anchor UEs can be in one of the following scenarios: the target UE and all one or more anchor UEs are within the coverage area of the network (i.e., the IC scenario); at least one of the target UE or one or more anchor UEs is within the coverage area of the network, and at least one of the target UE or one or more anchor UEs is outside the coverage area of the network (i.e., the PC scenario); or the target UE and all one or more anchor UEs are outside the coverage area of the network (i.e., the OOC scenario).

[0117] One of the cases of sidelink positioning in the PC scenario is that the target UE is outside the coverage area of the network (i.e., the OOC target UE), while at least one anchor UE is within the coverage area of the network (i.e., the IC anchor UE). In this PC scenario, the network can participate in triggering the positioning service or providing assistance to obtain the location of the OOC target UE. The present disclosure provides various procedures and signaling to support positioning the OOC target UE in this PC scenario.

[0118] According to some embodiments of the present disclosure, when the network or the OOC target UE triggers the positioning of the OOC target UE, an IC UE (e.g., UE 102a) that can be a candidate anchor UE can perform a discovery procedure to discover the OOC target UE. The discovery procedure can be initiated by the IC UE or the OOC target UE. In the case where the IC UE (e.g., by the LMF of the network or the OOC target UE) is selected as an anchor UE, it can perform a sidelink positioning procedure with the OOC target UE to obtain the location of the OOC target UE.

[0119] According to some embodiments of the present disclosure, the network may trigger the positioning of an OOC target UE. For example, the AMF of the network may send an indication to the LMF indicating the positioning of the OOC target UE, where the indication may provide information on a set of IC candidate anchor UEs and information on the OOC target UE (e.g., the identifier (ID) of the OOC target UE). In some embodiments, the AMF may select the set of IC candidate anchor UEs based on the registered UE capabilities, the target area identified by at least one of the cell ID, BSID, or tracking area identifier (TAI), or the last known cell ID of the OOC target UE.

[0120] In response to receiving the indication from the AMF, the LMF may send a discovery request to each of the set of IC candidate anchor UEs to discover the OOC target UE. Subsequently, the set of IC candidate anchor UEs may execute a discovery procedure in response to the discovery request to discover the OOC target UE.

[0121] Figure 2 A flowchart of an exemplary method 200 for discovering and positioning an OOC target UE according to some embodiments of the present disclosure is illustrated, where the discovery and positioning of the OOC target UE is controlled by the network. Figure 2 The method 200 illustrated in may be executed by at least three entities, such as IC candidate anchor UEs (e.g., UE 102a), an OOC target UE (e.g., UE 102b), and the LMF of the network (e.g., LMF 101). Although the method is illustrated at a system level, those skilled in the art should understand that the methods implemented in the three entities may be implemented separately and incorporated into other devices with similar functions. Additionally, although Figure 2 only one IC candidate anchor UE is illustrated in, it is contemplated that there may be other IC candidate anchor UEs participating in method 200, but Figure 2 not shown in, and the other IC candidate anchor UEs may perform operations similar to those performed by the IC candidate anchor UE illustrated in Figure 2 . Additionally, it is also contemplated that method 200 may include additional steps not shown.

[0122] As Figure 2 illustrated in, in step 201, the LMF may send a discovery request to the IC candidate anchor UE to discover the OOC target UE, for example, in response to receiving an indication from the AMF indicating the positioning of the OOC target UE. The IC candidate anchor UE may be included in the set of IC candidate anchor UEs indicated by the AMF. The LMF may send a discovery request to each of the set of IC candidate anchor UEs to discover the OOC target UE.

[0123] The discovery request sent to the IC candidate anchor UE may include configurations for discovering the OOC target UE. For example, the discovery request may include at least one of the following: one or more Uu RSRP thresholds, a sidelink RSRP threshold (e.g., PC5 RSRP threshold), or information of the OOC target UE (e.g., the ID of the OOC target UE).

[0124] One or more Uu RSRP thresholds may be used by the IC candidate anchor UE to determine whether to send a discovery message to the OOC target UE. In an embodiment, one or more Uu RSRP thresholds may include a maximum Uu RSRP threshold, a minimum Uu RSRP threshold, or both. The maximum and minimum Uu RSRP thresholds may be used to filter the IC candidate anchor UE. For example, if the RSRP of the Uu signal received by the IC candidate anchor UE exceeds the maximum Uu RSRP threshold, it means that the IC candidate anchor UE is very close to the BS and may not be able to have a good connection with the OOC target UE. If the RSRP of the Uu signal received by the IC candidate anchor UE is lower than the minimum Uu RSRP threshold, it means that the IC candidate anchor UE does not have a good connection with the network. The IC candidate anchor UE that does not have a good connection with the OOC target UE or the network may not be selected as the anchor UE, and thus it does not need to send a discovery message to the OOC target UE. Since the number of IC candidate anchor UEs may be very large, it is beneficial to filter out the IC candidate anchor UEs that do not have a good connection with the OOC target UE or the network.

[0125] The sidelink RSRP threshold may be used by the IC candidate anchor UE to determine whether it needs to respond to the discovery request after discovering the OOC target UE. How to use the sidelink RSRP threshold will be described later.

[0126] In some embodiments, the discovery request may include a request for positioning capability information of at least one of the IC candidate anchor UE or the OOC target UE. The positioning capability information may include at least one of the supported positioning methods, positioning calculation capabilities, supported bandwidths, etc.

[0127] In some embodiments, the discovery request may include a request for the positioning and associated uncertainty of the IC candidate anchor UE. The positioning and associated uncertainty of each IC candidate anchor UE may be used by the LMF for anchor UE selection and positioning method determination.

[0128] In some embodiments, the discovery request may include the response time for the IC candidate anchor UE to send a discovery response to the LMF. For example, the LMF may ignore the discovery response received after the expiration of the response time.

[0129] Assume Figure 2The IC candidate anchor UE described in [document] meets one or more Uu RSRP thresholds included in the discovery request. For example, in the case where the discovery request includes a maximum Uu RSRP threshold, the RSRP of the Uu signal received by the IC candidate anchor UE is lower than the maximum Uu RSRP threshold; in the case where the discovery request includes a minimum Uu RSRP threshold, the RSRP of the Uu signal received by the IC candidate anchor UE exceeds the minimum Uu RSRP threshold. Then, in step 202, the IC candidate anchor UE can start discovering the OOC target UE by broadcasting a discovery message.

[0130] In some embodiments, in the case where the discovery request from the LMF includes a request for the positioning capability information of the OOC target UE, the discovery message broadcast by the IC candidate anchor UE may include a request for the positioning capability information of the OOC target UE.

[0131] In Figure 2 In the example described in [document], it is assumed that the OOC target UE receives the discovery message from the IC candidate anchor UE. Then, in step 203, it can transmit a discovery message to the IC candidate anchor UE. In some embodiments, in the case where the discovery message from the IC candidate anchor UE includes a request for the positioning capability information of the OOC target UE, the OOC target UE can transmit its positioning capability information to the IC candidate anchor UE. In some embodiments, the OOC target UE may include its positioning capability information in the discovery message transmitted to the IC candidate anchor UE. In some embodiments, the OOC target UE may transmit its positioning capability information in a broadcast message. For example, since there may be multiple IC candidate anchor UEs requesting the positioning capability information of the OOC target UE, the OOC target UE can transmit its positioning capability information periodically, for example, when it receives the first request among the requests from multiple IC candidate anchor UEs. Alternatively, the OOC target UE can broadcast its positioning capability information after a certain period of time since the last broadcast of its positioning capability information. The period can be defined as a prohibited time.

[0132] When receiving the discovery message from the OOC target UE, the IC candidate anchor UE can perform measurements on the RSRP of the discovery message (e.g., sidelink discovery (SD) RSRP measurement). In Figure 2In the example described, it is assumed that the RSRP of the discovery message is found to exceed the sidelink RSRP threshold included in the discovery request from the LMF. Then, in step 204, the IC candidate anchor UE may transmit a discovery response to the LMF. In some embodiments, the IC candidate anchor UE may transmit a discovery response to the LMF before the expiration of the response time included in the discovery request from the LMF. In the case where the RSRP of the discovery message received by the IC candidate anchor UE does not exceed the sidelink RSRP threshold included in the discovery request from the LMF (which means that the IC candidate anchor UE does not have a good connection with the OOC target UE and is not suitable to be selected as an anchor UE), the IC candidate anchor UE may not transmit a discovery response to the LMF.

[0133] In some embodiments, the discovery response transmitted in step 204 may include at least one of the following: the sidelink quality (e.g., SD PSPR) between the IC candidate anchor UE and the OOC target UE or the Uu link quality (e.g., UuRSRP) of the IC candidate anchor UE.

[0134] In some embodiments, in the case where the discovery request from the LMF includes a request for the positioning capability information of the IC candidate anchor UE, the discovery response may include the positioning capability information of the IC candidate anchor UE.

[0135] In some embodiments, in the case where the discovery request from the LMF includes a request for the positioning capability information of the OOC target UE, the discovery response may include the positioning capability information of the OOC target UE.

[0136] In some embodiments, in the case where the discovery request from the LMF includes a request for the positioning and associated uncertainty of the IC candidate anchor UE, if the IC candidate anchor UE knows its position, the discovery response may include the positioning and associated uncertainty; otherwise, the discovery response may indicate an unknown position or not include the positioning information of the IC candidate anchor UE. According to an embodiment of the present disclosure, the uncertainty associated with the positioning of the IC candidate anchor UE may be inferred by the IC candidate anchor UE or obtained together with the positioning of the IC candidate anchor UE.

[0137] In step 205, the LMF may select at least one anchor UE for obtaining the positioning of the OOC target UE according to the discovery responses received from one or more IC candidate anchor UEs included in Figure 2 As described above, the LMF may consider the discovery responses received before the expiration of the response time and ignore the discovery responses received after the expiration of the response time, where the response time may be included in the discovery request transmitted to the IC candidate anchor UE.

[0138] In some embodiments, the LMF may select at least one anchor UE from one or more IC candidate anchor UEs based on at least one of the following:

[0139] ● Location capability information of one or more IC candidate anchor UEs;

[0140] ● Sidelink quality between each of one or more IC candidate anchor UEs and the OOC target UE;

[0141] ● Location and associated uncertainty of each of one or more IC candidate anchor UEs; or

[0142] ● Location requirements for locating the OOC target UE: For example, the number of at least one anchor UE can be determined by the LMF based on the location requirements, such as how many anchor UEs are needed when absolute location of the OOC target UE is required.

[0143] After the LMF selects at least one anchor UE, in some embodiments, the LMF may designate each anchor UE among the at least one anchor UE as a relay anchor UE for forwarding data from the LMF to the OOC target UE and optionally forwarding data from the OOC target UE to the LMF. Each relay anchor point needs to establish a unicast connection with the OOC target UE. In some embodiments, to avoid the signaling overhead caused by the establishment of unicast connections between all anchor UEs and the OOC target UE, the LMF may designate one of the at least one anchor UEs as a relay anchor UE for forwarding data from the LMF to the OOC target UE and optionally forwarding data from the OOC target UE to the LMF. If the sidelink and Uu link quality of the relay anchor UE exceed the configured threshold, then the LMF considers the relay anchor UE to be suitable in terms of radio criteria. Which anchor UE is designated as the relay anchor UE depends on the implementation scheme of the LMF.

[0144] Assume Figure 2 the IC candidate anchor UE described in is selected as an anchor UE and also designated as a relay anchor UE. In step 206, the LMF may transmit a relay request to the relay anchor UE, where the relay request may include at least one of the following:

[0145] ● An indication indicating the responsibility of forwarding data from the LMF to the OOC target UE and optionally forwarding data from the OOC target UE to the LMF,

[0146] ● An indication for establishing a unicast connection between the relay anchor UE and the OOC target UE, or

[0147] ● Information to be transmitted to the OOC target UE (such as information of all selected anchor UEs).

[0148] In step 207, upon receiving a relay request from the LMF, the relay anchor UE may establish a unicast connection with the OOC target UE. The relay anchor UE may forward the information contained in the relay request (e.g., information of all selected anchor UEs) to the OOC target UE after the unicast connection is established.

[0149] In step 208, after the unicast connection is established, the relay anchor UE may transmit a relay confirmation to the LMF. In some embodiments, the relay confirmation is transmitted to the LMF after the information contained in the relay request is forwarded to the OOC target UE.

[0150] In step 209, in response to receiving at least one relay confirmation from at least one relay anchor UE, the LMF may initiate sidelink positioning between the selected anchor UE and the OOC target UE and interact with the OOC target UE via the at least one relay anchor UE. For example, the LMF may instruct the selected anchor UE to perform a sidelink positioning procedure with the OOC target UE. In some embodiments, in the case where the number of anchor UEs is insufficient to obtain the positioning of the OOC target UE or the positioning information of the anchor UE is not received, the LMF may further initiate Uu positioning of the anchor UE.

[0151] Figure 3 A flowchart illustrating an exemplary method 300 for discovering and positioning an OOC target UE according to some embodiments of the present disclosure, where the discovery of the OOC target UE is triggered by the network, but the OOC target UE performs sidelink positioning without network control. Figure 3 The method 300 described in may be executed by at least three entities, such as an IC candidate anchor UE (e.g., UE 102a), an OOC target UE (e.g., UE 102b), and an LMF of the network (e.g., LMF 101). Although the method 300 is described at a system level, those skilled in the art should understand that the methods implemented in the three entities may be implemented separately and incorporated into other devices with similar functions. In addition, although Figure 3 only one IC candidate anchor UE is described in, it is contemplated that there may be other IC candidate anchor UEs participating in the method 300, but Figure 3 not shown in, and the other IC candidate anchor UEs may perform operations similar to those performed by the IC candidate anchor UE described in Figure 3 In addition, it is also contemplated that the method 300 may include additional steps not shown.

[0152] As Figure 3As shown in [description], in step 301, the LMF may, for example, in response to receiving an indication from the AMF indicating the positioning of the OOC target UE, transmit a discovery request to discover the OOC target UE to the IC candidate anchor UE. The IC candidate anchor UE may be included in a set of IC candidate anchor UEs indicated by the AMF. The LMF may transmit a discovery request to discover the OOC target UE to each of the set of IC candidate anchor UEs.

[0153] The discovery request transmitted to the IC candidate anchor UE may include a configuration for discovering the OOC target UE. For example, the discovery request may include at least one of the following: one or more Uu RSRP thresholds or information about the OOC target UE (e.g., the ID of the OOC target UE).

[0154] One or more Uu RSRP thresholds may be used by the IC candidate anchor UE to determine whether to transmit a discovery message to the OOC target UE. In an embodiment, the one or more Uu RSRP thresholds may include a maximum Uu RSRP threshold, a minimum Uu RSRP threshold, or both. The maximum and minimum Uu RSRP thresholds may be used to filter the IC candidate anchor UEs, as described above with respect to Figure 2 description.

[0155] In some embodiments, the discovery request may include information to be included in the discovery message to be sent by the IC candidate anchor UE. For example, the information may include a positioning request with QoS requirements and a response time for the OOC target UE to send a response to the discovery message.

[0156] Assume Figure 3 that the IC candidate anchor UE described in [description] meets one or more Uu RSRP thresholds included in the discovery request. For example, in the case where the discovery request includes a maximum Uu RSRP threshold, the RSRP of the Uu signal received by the IC candidate anchor UE is lower than the maximum Uu RSRP threshold; in the case where the discovery request includes a minimum Uu RSRP threshold, the RSRP of the Uu signal received by the IC candidate anchor UE exceeds the minimum Uu RSRP threshold. Then, in step 302, the IC candidate anchor UE may start discovering the OOC target UE by broadcasting a discovery message. In some embodiments, the discovery message may include the aforementioned information included in the discovery request, such as a positioning request with QoS requirements and a response time for the OOC target UE to send a response to the discovery message.

[0157] In Figure 3In the example described in, it is assumed that the OOC target UE receives a discovery message from the IC candidate anchor UE. Next, in step 303, the OOC target UE may transmit a discovery message to the IC candidate anchor UE. In the case where the discovery message from the IC candidate anchor UE includes a response time, the OOC target UE may transmit the discovery message before the expiration of the response time. The discovery message transmitted by the OOC target UE may include an acknowledgment indicating that the OOC target UE accepts the positioning request included in the discovery message from the IC candidate anchor UE and starts the sidelink positioning procedure.

[0158] In step 304, in response to receiving the discovery message from the OOC target UE, the IC candidate anchor UE may transmit an acknowledgment to the LMF indicating that the OOC target UE accepts the positioning request included in the discovery request from the LMF. Once the LMF receives this acknowledgment from the IC candidate anchor UE, the LMF may abort the discovery procedures for other IC candidate anchor UEs.

[0159] In step 305, after transmitting the discovery message to the IC candidate anchor UE, the OOC target UE may start sidelink positioning by using the IC candidate anchor UE as the anchor UE. In some embodiments, the anchor UE may transmit a measurement report or sidelink positioning result to the LMF. In some embodiments, the OOC target UE may transmit a measurement report or sidelink positioning result to the LMF via an IC UE (which may be an anchor UE or a non-anchor UE).

[0160] In some embodiments, in the case where the LMF does not receive any acknowledgment indicating that the OOC target UE accepts the positioning request included in the discovery request from any IC candidate anchor UE during a certain period, the LMF may initiate network-controlled sidelink positioning of the OOC target UE, for example, by Figure 2 the method 200 described in.

[0161] As described above with respect to Figure 2 For communicating with the OOC target UE, the LMF may specify a relay anchor UE for transmitting data from the LMF to the OOC target UE and optionally from the OOC target UE to the LMF. However, the current relay anchor UE may become unsuitable for use as the OOC target UE for some reason. In such cases, it is necessary to trigger and perform relay anchor UE reselection to select a new relay anchor UE. In different cases, the relay anchor UE reselection may be triggered by the current relay anchor UE or the LMF, and the entity performing the relay anchor UE reselection may be the OOC target UE or the LMF.

[0162] Figure 4 The flowchart illustrates an exemplary method 400 for the LMF to reselect a relay anchor UE according to some embodiments of the present disclosure. Figure 4The method 400 described in [description] can be executed by at least four entities, such as an OOC target UE (e.g., UE 102b), a first relay anchor UE (i.e., the current relay anchor UE), a second relay anchor UE (i.e., the new relay anchor UE), and an LMF (e.g., LMF 101). Although the method 400 is described at a system level, those skilled in the art should understand that the method implemented in the four entities can be implemented separately and incorporated into other devices with similar functions.

[0163] It is also contemplated that the method 400 may include additional steps not shown. For example, before the steps described in [description] (at least before step 402), the LMF may transmit a relay reselection configuration to the first relay anchor UE for the first relay anchor UE to determine whether to trigger relay anchor UE reselection. The relay reselection configuration may include at least one of a relay sidelink RSRP threshold or a relay Uu RSRP threshold. As another example, before the steps described in [description] (at least before step 402), the OOC target UE may transmit a measurement report to the LMF via the first relay anchor UE according to the associated configuration and / or in response to a request for measurement information. Alternatively or additionally, before the steps described in [description] (at least before step 402), the first relay anchor UE may transmit a measurement report to the LMF according to the associated configuration and / or in response to a request for measurement information. Figure 4 It is also contemplated that the method 400 may include additional steps not shown. For example, before the steps described in [description] (at least before step 402), the LMF may transmit a relay reselection configuration to the first relay anchor UE for the first relay anchor UE to determine whether to trigger relay anchor UE reselection. The relay reselection configuration may include at least one of a relay sidelink RSRP threshold or a relay Uu RSRP threshold. As another example, before the steps described in [description] (at least before step 402), the OOC target UE may transmit a measurement report to the LMF via the first relay anchor UE according to the associated configuration and / or in response to a request for measurement information. Alternatively or additionally, before the steps described in [description] (at least before step 402), the first relay anchor UE may transmit a measurement report to the LMF according to the associated configuration and / or in response to a request for measurement information. Figure 4 It is also contemplated that the method 400 may include additional steps not shown. For example, before the steps described in [description] (at least before step 402), the LMF may transmit a relay reselection configuration to the first relay anchor UE for the first relay anchor UE to determine whether to trigger relay anchor UE reselection. The relay reselection configuration may include at least one of a relay sidelink RSRP threshold or a relay Uu RSRP threshold. As another example, before the steps described in [description] (at least before step 402), the OOC target UE may transmit a measurement report to the LMF via the first relay anchor UE according to the associated configuration and / or in response to a request for measurement information. Alternatively or additionally, before the steps described in [description] (at least before step 402), the first relay anchor UE may transmit a measurement report to the LMF according to the associated configuration and / or in response to a request for measurement information. Figure 4 It is also contemplated that the method 400 may include additional steps not shown. For example, before the steps described in [description] (at least before step 402), the LMF may transmit a relay reselection configuration to the first relay anchor UE for the first relay anchor UE to determine whether to trigger relay anchor UE reselection. The relay reselection configuration may include at least one of a relay sidelink RSRP threshold or a relay Uu RSRP threshold. As another example, before the steps described in [description] (at least before step 402), the OOC target UE may transmit a measurement report to the LMF via the first relay anchor UE according to the associated configuration and / or in response to a request for measurement information. Alternatively or additionally, before the steps described in [description] (at least before step 402), the first relay anchor UE may transmit a measurement report to the LMF according to the associated configuration and / or in response to a request for measurement information.

[0164] In some embodiments, the first relay anchor UE may transmit a relay reselection indication to the LMF in step 401 when at least one of the following occurs:

[0165] ● The RSRP of the sidelink on the unicast connection between the first relay anchor UE and the OOC target UE is lower than the relay sidelink RSRP threshold included in the relay reselection configuration;

[0166] ● The first relay anchor UE detects a sidelink RLF;

[0167] ● The first relay anchor UE receives an indication from the upper layer of the first relay anchor UE: For example, the indication may indicate that the relay anchor UE of the OOC target UE is no longer the relay anchor UE due to certain reasons, such as power consumption, workload, etc.; or

[0168] ● The first relay anchor UE is about to lose its connection to the network (e.g., enter a tunnel).

[0169] In step 402, the LMF may perform relay anchor UE reselection to select a new relay anchor UE (e.g., the second relay anchor UE). The LMF may perform relay anchor UE reselection when at least one of the following occurs:

[0170] ● The LMF receives a relay reselection indication from the first relay anchor UE in step 401;

[0171] ● The Uu measurement report associated with the first relay anchor UE received from the first relay anchor UE or the BS indicates a Uu RSRP lower than the relay Uu RSRP threshold included in the relay reselection configuration;

[0172] ● The sidelink measurement report associated with the first relay anchor UE received from the first relay anchor UE indicates a sidelink RSRP lower than the relay sidelink RSRP threshold included in the relay reselection configuration; or

[0173] ● No measurement report is received from the first relay anchor UE within a certain period.

[0174] If the sidelink and Uu link quality of the new relay anchor UE exceed the configured threshold, then the LMF considers the new relay anchor UE to be suitable in terms of radio criteria. Which anchor UE is selected as the new relay anchor UE depends on the implementation of the LMF.

[0175] In step 403, the LMF may send a relay request to the second relay anchor UE selected as the new relay anchor UE. Regarding Figure 2 the definition of the relay request described herein is also applicable here.

[0176] In step 404, after receiving the relay request from the LMF, the second relay anchor UE may establish a unicast connection with the OOC target UE. The second relay anchor UE may forward the information contained in the relay request to the OOC target UE after the unicast connection is established.

[0177] In step 405, after the unicast connection between the OOC target UE and the second relay anchor UE is established, the second relay anchor UE may send a relay confirmation to the LMF. In some embodiments, the relay confirmation is sent to the LMF after the information contained in the relay request is forwarded to the OOC target UE.

[0178] In step 406, in response to receiving the relay confirmation from the second relay anchor UE, the LMF may send a release request to the first relay anchor UE, requesting the first relay anchor UE to release the unicast connection between the first relay anchor UE and the OOC target UE.

[0179] In response to receiving the release request from the LMF, the first relay anchor UE may release the unicast connection between the first relay anchor UE and the OOC target UE, and then send a release confirmation to the LMF in step 407.

[0180] Therefore, the LMF may send data to the OOC target UE via the second relay anchor UE instead of the first relay anchor UE, and optionally receive data from the OOC target UE via the second relay anchor UE.

[0181] Figure 5 Flowchart of an exemplary method 500 for reselecting a relay anchor UE by an OOC target UE according to some embodiments of the present disclosure. Figure 5 The method 500 described in may be performed by at least four entities, such as an OOC target UE (e.g., UE 102b), a first relay anchor UE (i.e., the current relay anchor UE), a second relay anchor UE (i.e., the new relay anchor UE), and an LMF (e.g., LMF 101). Although the method 500 is described at a system level, those skilled in the art should understand that the method implemented in the four entities can be implemented separately and incorporated into other devices with similar functions.

[0182] It is also contemplated that the method 500 may include additional steps not shown. For example, before the steps described in Figure 5 The LMF may transmit a first relay reselection configuration to the first relay anchor UE for the first relay anchor UE to determine whether to trigger relay anchor UE reselection. The first relay reselection configuration may include at least one of a first relay side link RSRP threshold or a relay Uu RSRP threshold. Optionally, the LMF may transmit a second relay reselection configuration of the OOC target UE to the first relay anchor UE. The second relay reselection configuration of the OOC target UE may be used by the OOC target UE for relay anchor UE reselection and may include a second relay side link RSRP threshold for the OOC target UE to reselect a relay anchor UE. As another example, before the steps described in Figure 5 The first relay anchor UE may transmit a relay reselection configuration to the OOC target UE via, for example, dedicated signaling for the OOC target UE to determine whether to trigger relay anchor UE reselection. The relay reselection configuration may include at least one relay side link RSRP threshold. In some embodiments, the relay side link RSRP threshold is the second relay side link RSRP threshold received by the first relay anchor UE from the LMF. In some other embodiments, the relay side link RSRP threshold is determined by the first relay anchor UE.

[0183] In step 501, the first relay anchor UE may transmit a relay reselection indication to the OOC target UE when at least one of the following occurs:

[0184] ● The RSRP of the Uu signal received from the BS is lower than the relay Uu RSRP threshold;

[0185] ● The first relay anchor UE detects Uu RLF; or

[0186] The first relay anchor UE receives an indication from the upper layer of the first relay anchor UE: For example, the indication may indicate that the relay anchor UE is no longer the relay anchor UE of the OOC target UE due to certain reasons, such as power consumption, workload, etc.

[0187] In step 502, in response to receiving the relay reselection indication, the OOC target UE may perform relay anchor UE reselection to select a new relay anchor UE (e.g., a second relay anchor UE). The new relay anchor UE may be selected from the existing anchor UEs other than the first relay anchor UE. If the sidelink quality of the OOC target UE exceeds a configured threshold, then the OOC target UE considers the new relay anchor UE to be suitable in terms of radio criteria. For example, the RSRP of the sidelink signal received from the new relay anchor UE meets (or exceeds) the relay sidelink RSRP threshold included in the relay reselection configuration received from the first relay anchor UE.

[0188] In some embodiments, the OOC target UE may receive from the LMF via the first relay anchor UE the conditions (e.g., sidelink quality (e.g., RSRP) threshold) for triggering relay anchor UE reselection. In such embodiments, when the conditions are met, the OOC target UE may perform relay anchor UE reselection.

[0189] In step 503, the OOC target UE may establish a unicast connection with the second relay anchor UE selected as the new relay anchor UE.

[0190] In step 504a, the second relay anchor UE may transmit to the LMF an indication that the second relay anchor UE is selected to replace the first relay anchor UE. In step 504b, the OOC target UE may release the unicast connection between the first relay anchor UE and the OOC target UE.

[0191] Accordingly, the LMF may transmit data to the OOC target UE via the second relay anchor UE instead of the first relay anchor UE, and optionally receive data from the OOC target UE via the second relay anchor UE.

[0192] According to some embodiments of the present disclosure, the OOC target UE may perform sidelink positioning with at least one IC anchor UE without network participation. However, if the QoS requirements are not met and no other suitable IC anchor UE can be found, then it may be necessary for the LMF to reposition at least one IC anchor UE via Uu positioning in order to eliminate the positioning error caused by the incorrect positioning of the at least one IC anchor UE.

[0193] Figure 6 A flowchart illustrating an exemplary method 600 for repositioning an IC anchor UE for sidelink positioning according to some embodiments of the present disclosure. Figure 6The method 600 described in [reference] can be executed by at least four entities, such as an OOC target UE (e.g., UE 102b), an IC anchor UE (e.g., UE 102a), a BS (e.g., BS 103), and an LMF (e.g., LMF 101). Although method 600 is described at a system level, those skilled in the art should understand that the method implemented in the four entities can be implemented separately and incorporated into other devices with similar functions. Although Figure 6 only one IC anchor UE is described in [reference], it is contemplated that there may be other anchor UEs participating in method 600, and the other anchor UEs may perform operations similar to those performed by the Figure 3 IC anchor UE described in [reference].

[0194] In step 601a, the OOC target UE may perform a positioning estimate of the OOC target UE (e.g., through sidelink positioning between the OOC target UE and the anchor UE) and evaluate whether the positioning estimate of the OOC target UE meets the QoS requirements of the positioning service associated with the OOC target UE. Alternatively or additionally, in step 601b, the IC anchor UE may perform a positioning estimate of the OOC target UE (e.g., through sidelink positioning between the OOC target UE and the IC anchor UE) and evaluate whether the positioning estimate of the OOC target UE meets the QoS requirements of the positioning service.

[0195] In some embodiments, in the case where the OOC target UE determines that the sidelink positioning estimate of the OOC target UE calculated by the OOC target UE does not meet the accuracy requirements of the positioning service associated with the OOC target UE (which may be included in the QoS requirements) (e.g., the sidelink positioning estimate is lower than the accuracy threshold specified in the QoS requirements of the positioning service), the OOC target UE may transmit a relocation request to one or more anchor UEs (including the IC anchor UE) via, for example, a sidelink positioning protocol (SLPP) message in step 602. In some embodiments, the relocation request may include at least one of the QoS requirements of the positioning service or the relocation response time.

[0196] In some embodiments, only unicast between the OOC target UE and the anchor UE is supported. In the case where the OOC target UE knows the network coverage information of its anchor UE (i.e., whether it is within the coverage or outside the coverage), the OOC target UE may transmit a relocation request only to the IC anchor UE via unicast signaling. In the case where the OOC target UE does not know the network coverage information of its anchor UE, the OOC target UE may transmit a relocation request to each anchor UE and include a coverage request for the network coverage information of the anchor UE in the relocation request.

[0197] In some embodiments, the OOC target UE may transmit a relocation request via broadcast signaling or multicast signaling. In some embodiments, in the case where the OOC target UE does not know the network coverage information of its anchor UE, the relocation request may include a coverage request for the network coverage information of each anchor UE in the relocation request.

[0198] In step 603, the IC anchor UE may transmit a request to the LMF to locate the IC anchor UE. In some embodiments, the IC anchor UE may transmit a request to the LMF to locate the IC anchor UE when the IC anchor UE receives a relocation request from the OOC target UE. In some embodiments, the IC anchor UE may transmit a request to the LMF to locate the IC anchor UE when the sidelink positioning estimate of the OOC target UE calculated by the IC anchor UE does not meet the accuracy requirements of the positioning service associated with the OOC target UE. In some embodiments, the request to locate the IC anchor UE may include at least one of the QoS requirements of the positioning service or the positioning response time.

[0199] In step 604, in response to receiving the request to locate the IC anchor UE from the IC anchor UE, the LMF may initiate locating the IC anchor UE using BS Uu.

[0200] In step 605, the LMF may transmit the positioning result of the IC anchor UE to the IC anchor UE after performing the location of the IC anchor UE using BS Uu. In some embodiments, in the case where the request to locate the IC anchor UE includes a positioning response time, the LMF may transmit the positioning result to the IC anchor UE before the expiration of the positioning response time.

[0201] In some embodiments, in the case where the IC anchor UE receives a relocation request from the OOC target UE in step 602, after the IC anchor UE receives the positioning result from the LMF, the IC anchor UE may transmit a relocation response including the positioning result of the IC anchor UE to the OOC target UE in step 606. In some embodiments, in the case where the relocation request includes a relocation response time, the IC anchor UE may transmit the relocation response to the OOC target UE before the expiration of the relocation response time.

[0202] The OOC target UE and its anchor UE can still perform sidelink positioning during the process of repositioning the IC anchor UE. In some embodiments where the OOC target UE initiates the process of repositioning the IC anchor UE (i.e., the OOC target UE sends a repositioning request to the anchor UE), if the accuracy requirement (or QoS requirement) of the positioning service associated with the OOC target UE is met by the ongoing sidelink positioning before receiving one or more repositioning results from one or more IC anchor UEs in response to one or more repositioning requests, the OOC target UE can transmit a repositioning cancellation request to the LMF via a sidelink relay UE (which can be an IC anchor UE or an IC non-anchor UE). Upon receiving the repositioning cancellation request, the LMF can stop the Uu positioning of one or more IC anchor UEs.

[0203] In some embodiments where the IC anchor UE initiates the process of repositioning the IC anchor UE (i.e., the IC anchor UE does not receive a repositioning request from the OOC target UE), if the accuracy requirement (or QoS requirement) is met by the ongoing sidelink positioning before receiving the positioning result of the IC anchor UE from the LMF in response to the request for positioning the IC anchor UE, the IC anchor UE can transmit a repositioning cancellation request to cancel the positioning of the IC anchor UE to the LMF. Upon receiving the repositioning cancellation request, the LMF can stop the Uu positioning of the IC anchor UE.

[0204] In some embodiments, if the OOC target UE transmits a repositioning request before the repositioning response time expires but does not receive any repositioning results, the OOC target UE can notify the upper layer of the OOC target UE that the accuracy requirement of the positioning service is not currently met, and the positioning accuracy can potentially be improved after receiving the repositioning results from at least one IC anchor UE. The upper layer can determine to stop the repositioning process or wait for the repositioning results.

[0205] In some embodiments, if the IC anchor UE transmits a request for positioning the IC anchor UE to the LMF before the positioning response time expires but does not receive any positioning results of the IC anchor UE from the LMF, the IC anchor UE can notify the upper layer of the IC anchor UE that the accuracy requirement of the positioning service is not currently met, and the positioning accuracy can potentially be improved after receiving the positioning results of the IC anchor UE from the LMF. The upper layer can determine to stop the repositioning process or wait for the repositioning results.

[0206] In some embodiments, if the OOC target UE transmits a repositioning request before the repositioning response time expires and receives at least one repositioning result from at least one (not all) IC anchor UEs, then the OOC target UE can transmit a current sidelink positioning estimate to the upper layer of the second UE based on the at least one repositioning result received from the at least one IC anchor UE.

[0207] According to some embodiments of the present disclosure, when the computing capabilities of the OOC target UE or the IC anchor UE cannot support the positioning service associated with the OOC target UE, the OOC target UE or the IC anchor UE may send a positioning assistance request to the LMF to obtain network assistance. For the OOC target UE, the positioning assistance request may be sent to the LMF via a sidelink relay UE (which may be an IC anchor UE or an IC non-anchor UE).

[0208] In some embodiments, in the case where the computing capabilities of the OOC target UE cannot support the positioning service associated with the OOC target UE, the OOC target UE may transmit a positioning assistance request to the LMF via a sidelink relay UE. The OOC target UE may select the sidelink relay UE based on at least one of the Uu RSRP associated with the sidelink relay UE or the sidelink RSRP. For example, at least one of a Uu RSRP threshold or a sidelink RSRP threshold may be configured, pre-configured, or predefined for the OOC target UE for selecting the sidelink relay UE. In some embodiments, the positioning assistance request may include at least one of the following: an indication indicating the responsibility of the LMF (e.g., calculating the positioning of the OOC target UE), an indication of sidelink-only positioning, or information of the OOC target UE. In some embodiments, the positioning assistance request may be transmitted in the same signaling from the OOC target UE to the LMF together with a measurement report associated with the OOC target UE. In some embodiments, the positioning assistance request may be transmitted in different signaling from the OOC target UE to the LMF separately from the measurement report associated with the OOC target UE. In response to receiving the positioning assistance request, the LMF may perform the responsibility indicated in the positioning assistance request and transmit the assistance result of the OOC target UE to the OOC target UE via the SL relay UE.

[0209] In some embodiments, in the case where the computing capabilities of the IC anchor UE cannot support the positioning service associated with the OOC target UE, the IC anchor UE may transmit a positioning assistance request to the LMF. In some embodiments, the positioning assistance request may include at least one of the following: an indication indicating the responsibility of the LMF (e.g., calculating the positioning of the OOC target UE), an indication of sidelink-only positioning, or information of the OOC target UE. In some embodiments, the positioning assistance request may be transmitted in the same signaling from the IC anchor UE to the LMF together with a measurement report associated with the OOC target UE. In some embodiments, the positioning assistance request may be transmitted in different signaling from the IC anchor UE to the LMF separately from the measurement report associated with the OOC target UE. In response to receiving the positioning assistance request, the LMF may perform the responsibility indicated in the positioning assistance request and transmit the assistance result of the OOC target UE to the IC anchor UE.

[0210] Figure 7 A simplified block diagram of an exemplary device 700 according to some embodiments of the present disclosure is illustrated.

[0211] In some embodiments, device 700 may be or include at least a portion of an IC anchor UE (e.g., UE 102a) capable of performing any of the operations performed by an IC anchor UE as described in this disclosure (e.g., in any of the methods described with respect to Figures 2 to 6 ).

[0212] In some embodiments, device 700 may be or include at least a portion of an OOC target UE (e.g., UE 102b) capable of performing any of the operations performed by an OOC target UE as described in this disclosure (e.g., in any of the methods described with respect to Figures 2 to 6 ).

[0213] In some embodiments, device 700 may be or include at least a portion of an LMF (e.g., LMF 101) capable of performing any of the operations performed by an LMF as described in this disclosure (e.g., in any of the methods described with respect to Figures 2 to 6 ).

[0214] As Figure 7 shown, device 700 may include at least one transceiver 710 and at least one processor 720 coupled to transceiver 710. In some embodiments, transceiver 710 may include a transmitter and a receiver integrated together. In some embodiments, transceiver 710 may include a transmitter and a receiver separate from each other. In some embodiments, transceiver 710 may be a wireless transceiver.

[0215] In some embodiments, device 700 may include a non-transitory computer-readable medium 730 storing computer-executable instructions 740 thereon. Non-transitory computer-readable medium 730 may be coupled to processor 720 and transceiver 710, and computer-executable instructions 740 may be configured to be executable by processor 720. In some embodiments, transceiver 710, non-transitory computer-readable medium 730, and processor 720 may be coupled to each other via one or more local buses.

[0216] Although in Figure 7 , elements such as transceiver 710, non-transitory computer-readable medium 730, and processor 720 are described in the singular form, the plural form is contemplated unless explicitly stated to be limited to the singular form. In certain embodiments of this disclosure, device 700 may further include other components for actual use.

[0217] In various example embodiments, the processor 720 may include, but is not limited to, at least one hardware processor, including at least one microprocessor such as a CPU, a part of at least one hardware processor, and any other suitable dedicated processor, such as a dedicated processor developed based on, for example, a field programmable gate array (FPGA) and an application specific integrated circuit (ASIC). In addition, the processor 720 may also include Figure 7 at least one other circuitry or element not shown in

[0218] In various example embodiments, the non-transitory computer-readable medium 730 may include at least one storage medium in various forms, such as volatile memory and / or non-volatile memory. Volatile memory may include, but is not limited to, for example, RAM, cache, etc. Non-volatile memory may include, but is not limited to, for example, ROM, hard disk, flash memory, etc. In addition, the non-transitory computer-readable medium 730 may include, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or apparatuses, or any combination of the foregoing.

[0219] In addition, in various example embodiments, the device 700 may also include at least one other circuitry, element, and interface, such as antenna elements and the like.

[0220] According to some embodiments, the device 700 is a UE within the coverage of a wireless network. The transceiver 710 and the processor 720 may be configured to perform the operations in any of the methods performed by an IC UE described above. For example, the processor 720 may be configured to: execute a discovery procedure to discover a second UE outside the coverage of the wireless network; and perform a sidelink positioning procedure on the second UE to obtain the positioning of the second UE.

[0221] According to some embodiments, the device 700 is an OOC target UE. The transceiver 710 and the processor 720 may be configured to perform the operations in any of the methods performed by an OOC target UE described above. For example, the processor 720 may be configured to perform at least one of the following: receive a first discovery message from each of one or more first UEs within the coverage of the wireless network using the transceiver 710, and transmit a second discovery message to each of the one or more first UEs using the transceiver 710; transmit a relocation request to one or more anchor UEs for obtaining the positioning of a second UE using the transceiver 710; or transmit a positioning assistance request to the LMF of the wireless network via a sidelink relay UE within the coverage of the wireless network using the transceiver 710, and receive an assistance result from the LMF via the sidelink relay UE using the transceiver 710.

[0222] According to some embodiments, the device 700 is an LMF of a wireless network. The transceiver 710 and the processor 720 may be configured to perform operations in any of the methods performed by an LMF described above. For example, the processor 720 may be configured to perform at least one of the following: transmit, using the transceiver 710 and to each of a first set of UEs within the coverage of the wireless network, a discovery request for a second UE that is outside the coverage of the wireless network and whose positioning is requested; receive, using the transceiver 710 and from a third UE, a request to position the third UE, and in response to the request, transmit, using the transceiver 710 and to the third UE, a positioning result of the third UE, where the third UE is within the coverage of the wireless network and performs a sidelink positioning procedure on a fourth UE outside the coverage of the wireless network to obtain the positioning of the fourth UE; or receive, using the transceiver 710 and from a fifth UE, a positioning assistance request, and in response to the positioning assistance request, transmit, using the transceiver 710 and to the fifth UE, a positioning result of a target UE outside the coverage of the wireless network, where the computing power of the fifth UE cannot support the positioning service associated with the target UE.

[0223] In various example embodiments, the circuitry, components, elements, and interfaces in an exemplary device that includes a processor and a non-transitory computer-readable medium may be coupled together in any suitable manner, including but not limited to buses, cross switches, wiring, and / or wireless lines, in any suitable way, such as electrically, magnetically, optically, electromagnetically, and the like.

[0224] The methods of the present disclosure may be implemented on a programmed processor. However, the controller, flowchart, and modules may also be implemented on a general or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit (such as a discrete element circuit), a programmable logic device, or the like. Generally, any device having a finite state machine capable of implementing the flowchart shown in the figures may be used to implement the processing functions of the present disclosure.

[0225] Although the present disclosure has been described in terms of its specific embodiments, it is apparent that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, the various components of an embodiment may be interchanged, added, or substituted in other embodiments. Also, the operations of the disclosed embodiments do not necessarily require all of the elements shown in each figure. For example, those skilled in the art of the disclosed embodiments will be able to make and use the teachings of the present disclosure by simply employing the elements of the independent claims. Therefore, the embodiments of the present disclosure set forth herein are intended to be illustrative and not restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0226] The term "includes", "including", or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements but also other elements not expressly listed or inherent to the process, method, article, or apparatus. An element that begins with "a", "an", or the like does not, without further limitation, preclude the presence of additional, identical elements in the process, method, article, or apparatus that includes the element. Further, the term "another" is defined as at least a second or more. As used herein, the terms "comprises", "has", and the like are defined as "includes". In this disclosure, relational terms such as "first", "second", and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

Claims

1. A first user equipment (UE), wherein the first UE is within the coverage of a wireless network, and the first UE comprises: A transceiver; And A processor, coupled to the transceiver and configured to: Execute a discovery procedure to discover a second UE outside the coverage of the wireless network; and Execute a sidelink positioning procedure on the second UE to obtain the positioning of the second UE.

2. The first UE according to claim 1, wherein the processor is configured to: When the computing power of at least one of the first UE or the second UE cannot support the positioning service associated with the second UE, transmit a positioning assistance request to the LMF using the transceiver, where the positioning assistance request includes at least one of the following: An indication of only sidelink positioning, An indication indicating the responsibility of the LMF, or Information of the second UE.

3. A positioning management function (LMF) of a wireless network, comprising: A transceiver; And A processor, coupled to the transceiver and configured to execute at least one of the following: Transmit, using the transceiver, a discovery request to each of a group of first user equipments (UEs) within the coverage of the wireless network to discover a second UE outside the coverage of the wireless network and whose positioning is requested; Receive, using the transceiver, a request to position a third UE from the third UE, and in response to the request, transmit, using the transceiver, the positioning result of the third UE to the third UE, where the third UE is within the coverage of the wireless network and executes a sidelink positioning procedure on a fourth UE outside the coverage of the wireless network to obtain the positioning of the fourth UE; Or Receive, using the transceiver, a positioning assistance request from a fifth UE, and in response to the positioning assistance request, transmit, using the transceiver, the positioning result of a target UE outside the coverage of the wireless network to the fifth UE, where the computing power of the fifth UE cannot support the positioning service associated with the target UE.

4. The LMF according to claim 3, wherein the processor is configured to transmit the discovery request in response to receiving an indication to position the second UE from the access and mobility management function (AMF) of the wireless network.

5. The discovery request transmitted to each first UE includes at least one of the following: One or more Uu reference signal received power (RSRP) thresholds, Sidelink RSRP threshold, Information of the second UE, A first request for the positioning ability information of the corresponding first UE, A second request for the positioning ability information of the second UE, A third request for the positioning and associated uncertainty of the corresponding first UE, The first response time for the corresponding first UE to send a discovery response to the LMF; or First information to be included in a discovery message to be sent by the corresponding first UE, where the first information includes: A positioning request with quality of service (QoS) requirements, and The second response time for the second UE to send a response to the discovery message.

6. The LMF according to claim 5, wherein the processor is configured to receive, using the transceiver and from one or more first UEs within the group of first UEs, one or more discovery responses before the expiration of the first response time.

7. The LMF according to claim 6, wherein the processor is configured to select, based on the one or more discovery responses received from the one or more first UEs, at least one anchor UE for obtaining the location of the second UE from the one or more first UEs.

8. The LMF according to claim 7, wherein the processor is configured to: designate an anchor UE among the at least one anchor UE as a relay anchor UE; and transmit, using the transceiver and to the relay anchor UE, a first relay request including at least one of the following: a first indication indicating the responsibility of forwarding data from the LMF to the second UE, a second indication for establishing a unicast connection between the relay anchor UE and the second UE, or second information to be transmitted to the second UE.

9. The LMF according to claim 8, wherein the processor is configured to transmit, using the transceiver and to the relay anchor UE, a relay reselection configuration of the relay anchor UE, the relay reselection configuration including at least one of a first relay sidelink RSRP threshold and a relay Uu RSRP threshold.

10. The LMF according to claim 9, wherein the relay anchor UE is a first relay anchor UE, and the processor is configured to perform relay anchor UE reselection to select a second relay anchor UE when at least one of the following occurs: the LMF receives a first relay reselection indication from the first relay anchor UE; a Uu measurement report received from the first relay anchor UE or a base station BS and associated with the first relay anchor UE indicates a Uu RSRP lower than the relay Uu RSRP threshold; a sidelink measurement report received from the first relay anchor UE and associated with the first relay anchor UE indicates a sidelink RSRP lower than the first relay sidelink RSRP threshold; or no measurement report is received from the first relay anchor UE within a certain period.

11. A second user equipment UE, wherein the second UE is outside the coverage of a wireless network, and the second UE includes: a transceiver; and a processor coupled to the transceiver and configured to perform at least one of the following: receive, using the transceiver and from each of one or more first UEs within the coverage of the wireless network, a first discovery message, and transmit, using the transceiver and to each of the one or more first UEs, a second discovery message; transmit, using the transceiver and to one or more anchor UEs for obtaining the location of the second UE, a relocation request; or transmit, using the transceiver and via a sidelink relay UE within the coverage of the wireless network, a positioning assistance request to a positioning management function LMF of the wireless network, and receive, using the transceiver and via the sidelink relay UE, an assistance result from the LMF.

12. The second UE according to claim 11, wherein the first discovery message includes a request for positioning capability information of the second UE, and the processor is configured to broadcast the positioning capability information of the second UE.

13. The second UE according to claim 11, wherein the relocalization request is transmitted to the one or more anchor UEs in response to a sidelink positioning estimate calculated by the second UE not meeting the accuracy requirements of the positioning service associated with the second UE.

14. The second UE according to claim 13, wherein, in a case where the accuracy requirements of the positioning service are met by ongoing sidelink positioning before receiving one or more relocalization results, the processor is configured to transmit a relocalization cancellation request to the LMF via a sidelink relay UE.

15. The second UE according to claim 13, wherein: in a case where no relocalization result is received from at least one of the one or more anchor UEs after the relocalization request is transmitted and before the relocalization response time expires, the processor is configured to notify the upper layer of the second UE that the accuracy requirements of the positioning service are currently not met and that positioning accuracy can potentially be improved after receiving a relocalization result from at least one of the one or more anchor UEs; and in a case where at least one relocalization result is received from at least one anchor UE among the one or more anchor UEs after the relocalization request is transmitted and before the relocalization response time expires, the processor is configured to transmit a current sidelink positioning estimate to the upper layer of the second UE based on the at least one relocalization result received from at least one of the one or more anchor UEs.

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