WO2024114965A1

WO2024114965A1 - Overload handling for sidelink positioning in a wireless communication system

Info

Publication number: WO2024114965A1
Application number: PCT/EP2023/073411
Authority: WO
Inventors: Hyung-Nam Choi; Robin Rajan THOMAS; Dimitrios Karampatsis
Original assignee: Lenovo (Singapore) Pte. Ltd
Priority date: 2023-07-11
Filing date: 2023-08-25
Publication date: 2024-06-06

Abstract

Various aspects of the present disclosure relate to a user equipment for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the user equipment to: determine, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the user equipment; and transmit, to a first apparatus of a wireless communication system, a first message comprising the one or more parameters.

Description

OVERLOAD HANDLING FOR SIDELINK POSITIONING IN A WIRELESS COMMUNICATION SYSTEM

TECHNICAL FIELD

[0001] The subject matter disclosed herein relates generally to the field of implementing overload handling for sidelink positioning in a wireless communication system. This document defines a user equipment (UE), a processor for a UE, and an apparatus for wireless communication. This document also defines methods in a UE, a processor for a UE, and in an apparatus for wireless communication.

BACKGROUND

[0002] A wireless communication system may include one or multiple network communication devices, such as base stations, which may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE), or other suitable terminology. The wireless communication system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers, or the like). Additionally, the wireless communication system may support wireless communications across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) radio access technology, among other suitable radio access technologies beyond 5G (e.g., sixth generation (6G)).

[0003] The 3^rd Generation Partnership Project (3GPP) Work Item Description (WID) RP-231460 introduces Sidelink (SL) positioning target accuracy requirements for Rel-18 New Radio (NR). SL positioning is intended to be applied for a variety of use-cases such as Vehicle-to-Everything (V2X), public safety, Industrial Internet of Things (IIoT) and commercial use cases. The aim of SL positioning is to determine the position of a User Equipment (UE) by using SL positioning methods such as Round Trip Time (RTT)-type solutions using SL, SL-Angle of Arrival (AoA) and SL-Time Difference of Arrival (TDOA). SL positioning will be based on new SL Positioning Reference Signal (PRS) that is transmitted over the PC5 interface and will be supported in all coverage scenarios (i.e. incoverage, partial coverage and out-of-coverage scenarios) and for PC5-only -based and joint PC5-Uu-based operation scenarios. For exchanging the SL positioning related information between UEs over the PC5 interface and between UEs and a Location Management Function (LMF), over the Uu interface, a new protocol denoted as Sidelink Positioning Protocol (SLPP) will be introduced.

SUMMARY

[0004] The present disclosure relates to methods, apparatuses, and systems, that support overload handling for Sidelink positioning in a wireless communication system.

[0005] There is provided a UE for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: determine, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; and transmit, to a first apparatus of a wireless communication system, a first message comprising the one or more parameters.

[0006] There is further provided a method in a UE, comprising: determining, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; and transmitting, to a first apparatus of a wireless communication system, a first message comprising the one or more parameters.

[0007] There is further provided a processor for a UE for wireless communication, comprising: at least one controller coupled with at least one memory and configured to cause the processor to: obtain, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; and output, a first message comprising the one or more parameters.

[0008] There is further provided a method in a processor for a UE, comprising: obtaining, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; and outputting, a first message comprising the one or more parameters. [0009] There is further provided a second UE for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the second UE to: receive, from a second apparatus of a wireless communication system, a third message requesting the transmission of sidelink positioning reference signals to a third apparatus of the wireless communication system; determine, whether a maximum capacity for sidelink positioning reference signal transmission, has been reached by the second UE; and if the determination is that the maximum capacity for sidelink positioning reference signal transmission has been reached: transmit, to the second apparatus, a third response to the third message, wherein the third response comprises one or more parameters indicating that the maximum capacity for sidelink positioning reference signal transmission has been reached.

[0010] There is further provided a method in a second UE, comprising: receiving, from a second apparatus of a wireless communication system, a third message requesting the transmission of sidelink positioning reference signals to a third apparatus of the wireless communication system; determining, whether a maximum capacity for sidelink positioning reference signal transmission, has been reached by the second UE; and if the determination is that the maximum capacity for sidelink positioning reference signal transmission has been reached: transmitting, to the second apparatus, a third response to the third message, wherein the third response comprises one or more parameters indicating that the maximum capacity for sidelink positioning reference signal transmission has been reached.

[0011] There is further provided, an apparatus for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the apparatus to: receive, from a UE, a first message comprising one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; determine, based at least partly on the one or more parameters, a second request for initiating sidelink positioning for the UE; and transmit, to the UE, the second request.

[0012] There is further provided, a method in an apparatus for wireless communication, comprising: receiving, from a UE, a first message comprising one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; determining, based at least partly on the one or more parameters, a second request for initiating sidelink positioning for the UE; and transmitting, to the UE, the second request.

[0013] The invention disclosed herein tends to ensure that an endpoint that initiates or initiated a SL positioning session, knows the maximum number of SL positioning sessions that can be supported by the peer endpoint. Furthermore, the invention disclosed herein tends to ensure that the endpoint knows the reason why SL positioning procedures may be aborted by the peer endpoint. Furthermore, the invention disclosed herein tends to ensure that the endpoint knows why delivered SL positioning assistance data cannot be processed by a peer endpoint and/or that no new SL positioning assistance data can be processed by the peer endpoint.

[0014] An article “a” before an element is unrestricted and understood to refer to “at least one” of those elements or “one or more” of those elements. The terms “a,” “at least one,” “one or more,” and “at least one of one or more” may be interchangeable. As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of’ or “one or more of’ or “one or both of’) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on”. Further, as used herein, including in the claims, a “set” may include one or more elements.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 illustrates an example of a wireless communication system 100 in accordance with aspects of the present disclosure;

[0016] Figure 2 illustrates an example, useful for understanding aspects of the present disclosure, of LPP message transfer 200; [0017] Figure 3 illustrates an example, useful for understanding aspects of the present disclosure, of an LCS architecture 300;

[0018] Figure 4 illustrates an example, useful for understanding aspects of the present disclosure, of a 5GC-MT-LR procedure 400;

[0019] Figure 5 illustrates an example, useful for understanding aspects of the present disclosure, of a 5GC-M0-LR procedure 500;

[0020] Figures 6a-6c illustrate examples, useful for understanding aspects of the present disclosure, of coverage scenarios 610-630;

[0021] Figure 7 illustrates an example 700, useful for understanding aspects of the present disclosure, of the use of identifiers for the transfer of LPP messages;

[0022] Figure 8 illustrates an example 800 of message flows in accordance with aspects of the present disclosure;

[0023] Figure 9 illustrates a further example 900 of messages flows in accordance with aspects of the present disclosure;

[0024] Figure 10 illustrates an even further example 1000 of messages flows in accordance with aspects of the present disclosure;

[0025] Figure 11 illustrates an example of a user equipment (UE) 1100 in accordance with aspects of the present disclosure.

[0026] Figure 12 illustrates an example of a processor 1200 in accordance with aspects of the present disclosure.

[0027] Figure 13 illustrates an example of a network equipment (NE) 1300 in accordance with aspects of the present disclosure.

[0028] Figure 14 illustrates a flowchart of a method 1400 performed by a UE in accordance with aspects of the present disclosure;

[0029] Figure 15 illustrates a flowchart of a method 1500 performed by a processor in accordance with aspects of the present disclosure; [0030] Figure 16 illustrates a flowchart of a method 1600 performed by a second UE in accordance with aspects of the present disclosure; and

[0031] Figure 17 illustrates a flowchart of a method 1700 performed by an apparatus (i.e., an NE) in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

[0032] The 3GPP WID RP-231460 titled “Revised WID on Expanded and Improved NR Positioning”, was introduced to support the target accuracy requirements for SL positioning as listed in Table 1. The reference in Table 1 to “Set A” and “Set B” refers to the categorization of requirements into two sets.

Table 1 [0033] In addition, the following functionalities shall be supported by the new SLPP: SL Positioning Capability Transfer; SL Positioning Assistance Data exchange; SL Location Information Transfer; Error handling; Abort.

[0034] The cast types which are considered for SLPP signaling over the PC5 interface include unicast, groupcast and broadcast, but unicast/one-to-one operation is assumed as baseline for exchange of SLPP signaling between UEs. For exchange of SL positioning capability and SL positioning assistance data information, groupcast and broadcast (in addition to unicast) are assumed to be supported only when the protection of groupcast/broadcast of SL positioning signaling can be ensured.

[0035] The SLPP will support session-based SL positioning operation between two endpoints, e.g. between i) Target UE and LMF; or ii) between Target UE and Server UE, in order to obtain location related measurements or a location estimate or to transfer assistance data. In session-based SL positioning operation a single SLPP session is used to support a single location request (e.g., a Mobile Terminated Location Request (MT-LR), or a Mobile Originated Location Request (MO-LR)). Each SLPP session comprises one or more SLPP transactions, with each SLPP transaction performing a single operation (capability exchange, assistance data transfer, or location information transfer). Furthermore, multiple SLPP sessions can be used between the involved endpoints to support multiple different location requests. As a consequence, each endpoint may be involved in multiple SL positioning sessions. However, considering the fact that each SLPP session requires processing (e.g. for location measurements, location calculations) and memory resources (e.g. for storing location measurements, location estimations, assistance data) and depending on the current load of the UEs (based on the active applications/services and configured Access Stratum (AS) functionalities such as e.g. carrier aggregation, dual connectivity or MIMO), the involved UEs (i.e. Target UE, Anchor UE, Server UE) may be able to support only a limited number of SL positioning sessions. When this limit is reached, then no new SL positioning session can be established. Currently, there are no means for the concerned UEs to indicate properly such overload situations to their peer endpoints. Therefore, solutions for SL positioning session overload handling are needed. [0036] A relatively straightforward solution to handle SL positioning session overload situations, is to simply reject or abort new or existing SL positioning sessions with a cause value that is “undefined”, if such an overload situation happens in the concerned UEs. However, the main drawback of this solution is that the peer endpoints do not know the actual reason for the reject/abort of the affected SL positioning sessions. As a result, the concerned UEs may still receive from the peer endpoints further requests for establishing new SL positioning sessions which then need to be rejected/aborted if the overload situation still exists in the concerned UEs.

[0037] The invention disclosed herein tends to support SL positioning session overload handling. More specifically, the invention disclosed herein introduces a new capability for indicating available resources for SL positioning. The new SL positioning capability may be introduced in the SLPP ProvideCapabilities message, and be denoted “Maximum number of SL positioning sessions that can be supported” with a value range { 1 , .., n} and e.g. n=8, 16, 32 or 64.

[0038] Depending on its current load (i.e., based on the active applications/services and configured AS functionalities such as e.g. carrier aggregation, dual connectivity or MIMO), a SL positioning capable UE may determine the maximum value of the new SL positioning capability element and send this capability in the SLPP ProvideCapabilities message to the peer endpoint, either unsolicited or upon request by the peer endpoint. The maximum value may be determined by the UE using default reference parameters for a SL positioning session such as e.g., processing load of 2% and/or memory size of 4 kB. Alternatively, the determination of the maximum value may be left to UE implementation.

[0039] This new SL positioning capability element can be sent by any UE that may be involved in an SLPP session. Depending on the type of UE, the new capability may be set differently. For instance, if the new capability is sent by a Target UE then it may include only MT-LR SL positioning sessions. The reason is that the initiation of MO-LR SL positioning sessions by the Target UE shall not be affected by this new capability. If the new capability is sent by an Anchor UE or Server UE then it may include all types of SL positioning sessions, e.g. MT-LR, MO-LR, NI-LR. [0040] The invention disclosed herein also introduces new cause values for the SLPP Abort and Error messages of the SLPP.

[0041] The new cause values that are introduced in the SLPP Abort message may include, “Maximum number of SL positioning sessions that can be supported is reached” . If this cause value is set by a UE then the peer endpoint knows that the associated new or an existing SL positioning session is aborted by the UE. This new cause value can be set by any UE that may be involved in an SLPP session. The new cause values that are introduced in the SLPP Abort message may include, “Maximum capacity for SL PRS transmission that can be supported is reached” . If this cause value is set by a UE then the peer endpoint knows that the associated request for SL-PRS transmission is aborted by the UE. This new cause value can be set by any UE that transmits SL PRS.

[0042] The invention disclosed herein also introduces a new cause value in the SLPP Error message for SLPP. This new cause value may be denoted, “Maximum capacity for SL positioning assistance data that can be supported is reached” . If this cause value is set by a UE then the peer endpoint knows that the recently delivered SL positioning assistance data cannot be processed by the UE or no new SL positioning assistance data can be processed by the UE. In addition to the cause value, the UE may indicate the size of assistance data that exceeds the memory size. This new cause value can be set by any UE that may receive SL positioning assistance data during an SLPP session.

[0043] The new cause values may be introduced solely in either the Abort or the Error message, or across both messages.

[0044] The solutions proposed herein offer a number of advantages. Firstly, the endpoint that initiates or initiated a SL positioning knows the maximum number of SL positioning sessions that can be supported by the peer endpoint. Furthermore, the endpoint knows the reason for aborting SL positioning procedures (related to SL positioning sessions or request for SL-PRS transmission) by the peer endpoint. In addition, the endpoint knows the reason why recently delivered SL positioning assistance data cannot be processed by the UE or no new SL positioning assistance data can be processed by the UE. [0045] Aspects of the present disclosure are described in the context of a wireless communication system.

[0046] Figure 1 illustrates an example of a wireless communication system 100 in accordance with aspects of the present disclosure. The wireless communication system 100 may include one or more NE 102, one or more UE 104, and a core network (CN) 106. The wireless communication system 100 may support various radio access technologies. In some implementations, the wireless communication system 100 may be a 4G network, such as an LTE network or an LTE- Advanced (LTE-A) network. In some other implementations, the wireless communication system 100 may be an NR network, such as a 5G network, a 5G-Advanced (5G-A) network, or a 5G ultrawideband (5G-UWB) network. In other implementations, the wireless communication system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20. The wireless communication system 100 may support radio access technologies beyond 5G, for example, 6G. Additionally, the wireless communication system 100 may support technologies, such as time division multiple access (TDMA), frequency division multiple access (FDMA), or code division multiple access (CDMA), etc.

[0047] The one or more NE 102 may be dispersed throughout a geographic region to form the wireless communication system 100. One or more of the NE 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a network function, a network entity, a radio access network (RAN), a NodeB, an eNodeB (eNB), a next-generation NodeB (gNB), or other suitable terminology. An NE 102 and a UE 104 may communicate via a communication link, which may be a wireless or wired connection. For example, an NE 102 and a UE 104 may perform wireless communication (e.g., receive signaling, transmit signaling) over a Uu interface.

[0048] An NE 102 may provide a geographic coverage area for which the NE 102 may support services for one or more UEs 104 within the geographic coverage area. For example, an NE 102 and a UE 104 may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc.) according to one or multiple radio access technologies. In some implementations, an NE 102 may be moveable, for example, a satellite associated with a non-terrestrial network (NTN). In some implementations, different geographic coverage areas associated with the same or different radio access technologies may overlap, but the different geographic coverage areas may be associated with different NE 102.

[0049] The one or more UE 104 may be dispersed throughout a geographic region of the wireless communication system 100. A UE 104 may include or may be referred to as a remote unit, a mobile device, a wireless device, a remote device, a subscriber device, a transmitter device, a receiver device, or some other suitable terminology. In some implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an Internet-of-Things (loT) device, an Internet-of-Everything (loE) device, or machine-type communication (MTC) device, among other examples.

[0050] A UE 104 may be able to support wireless communication directly with other UEs 104 over a communication link. For example, a UE 104 may support wireless communication directly with another UE 104 over a device-to-device (D2D) communication link. In some implementations, such as vehi cl e-to- vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link may be referred to as a sidelink. For example, a UE 104 may support wireless communication directly with another UE 104 over a PC5 interface.

[0051] An NE 102 may support communications with the CN 106, or with another NE 102, or both. For example, an NE 102 may interface with other NE 102 or the CN 106 through one or more backhaul links (e.g., SI, N2, or network interface). In some implementations, the NE 102 may communicate with each other directly. In some other implementations, the NE 102 may communicate with each other indirectly (e.g., via the CN 106. In some implementations, one or more NE 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC). An ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as a radio heads, smart radio heads, or transmission-reception points (TRPs). [0052] The CN 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The CN 106 may be an evolved packet core (EPC), or a 5G core (5GC), which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and a user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a Packet Data Network (PDN) gateway (P-GW), or a user plane function (UPF)). In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g., data bearers, signal bearers, etc.) for the one or more UEs 104 served by the one or more NE 102 associated with the CN 106.

[0053] The CN 106 may communicate with a packet data network over one or more backhaul links (e.g., via an SI, N2, or another network interface). The packet data network may include an application server. In some implementations, one or more UEs 104 may communicate with the application server. A UE 104 may establish a session (e.g., a protocol data unit (PDU) session, or the like) with the CN 106 via an NE 102. The CN 106 may route traffic (e.g., control information, data, and the like) between the UE 104 and the application server using the established session (e.g., the established PDU session). The PDU session may be an example of a logical connection between the UE 104 and the CN 106 (e.g., one or more network functions of the CN 106).

[0054] In the wireless communication system 100, the NEs 102 and the UEs 104 may use resources of the wireless communication system 100 (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communications). In some implementations, the NEs 102 and the UEs 104 may support different resource structures. For example, the NEs 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the NEs 102 and the UEs 104 may support a single frame structure. In some other implementations, such as in 5G and among other suitable radio access technologies, the NEs 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures). The NEs 102 and the UEs 104 may support various frame structures based on one or more numerologies. [0055] One or more numerologies may be supported in the wireless communication system 100, and a numerology may include a subcarrier spacing and a cyclic prefix. A first numerology (e.g., /t=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a normal cyclic prefix. In some implementations, the first numerology (e.g., /t=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one slot per subframe. A second numerology (e.g., //=1) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a normal cyclic prefix. A third numerology (e.g., g=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g., /t=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g., /t=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a normal cyclic prefix.

[0056] A time interval of a resource (e.g., a communication resource) may be organized according to frames (also referred to as radio frames). Each frame may have a duration, for example, a 10 millisecond (ms) duration. In some implementations, each frame may include multiple subframes. For example, each frame may include 10 subframes, and each subframe may have a duration, for example, a 1 ms duration. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

[0057] Additionally or alternatively, a time interval of a resource (e.g., a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g., quantity) of slots. The number of slots in each subframe may also depend on the one or more numerologies supported in the wireless communication system 100. For instance, the first, second, third, fourth, and fifth numerologies (i.e., /t=0, /t=l, =2, jtz=3, =4) associated with respective subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and 16 slots per subframe, respectively. Each slot may include a number (e.g., quantity) of symbols (e.g., OFDM symbols). In some implementations, the number (e.g., quantity) of slots for a subframe may depend on a numerology. For a normal cyclic prefix, a slot may include 14 symbols. For an extended cyclic prefix (e.g., applicable for 60 kHz subcarrier spacing), a slot may include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that reference to a first numerology (e.g., /t=0) associated with a first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and slots.

[0058] In the wireless communication system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, the wireless communication system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz - 7.125 GHz), FR2 (24.25 GHz - 52.6 GHz), FR3 (7.125 GHz - 24.25 GHz), FR4 (52.6 GHz - 114.25 GHz), FR4a or FR4-1 (52.6 GHz - 71 GHz), and FR5 (114.25 GHz - 300 GHz). In some implementations, the NEs 102 and the UEs 104 may perform wireless communications over one or more of the operating frequency bands. In some implementations, FR1 may be used by the NEs 102 and the UEs 104, among other equipment or devices for cellular communications traffic (e.g., control information, data). In some implementations, FR2 may be used by the NEs 102 and the UEs 104, among other equipment or devices for short-range, high data rate capabilities.

[0059] FR1 may be associated with one or multiple numerol ogies (e.g., at least three numerologies). For example, FR1 may be associated with a first numerology (e.g., /t=0), which includes 15 kHz subcarrier spacing; a second numerology (e.g., //=1), which includes 30 kHz subcarrier spacing; and a third numerology (e.g., //=2), which includes 60 kHz subcarrier spacing. FR2 may be associated with one or multiple numerologies (e.g., at least 2 numerologies). For example, FR2 may be associated with a third numerology (e.g., /z=2), which includes 60 kHz subcarrier spacing; and a fourth numerology (e.g., /t=3), which includes 120 kHz subcarrier spacing.

[0060] In 3GPP Rel-15, only Cell-ID and RAT -independent positioning methods (e.g. GNSS) are supported in NR. In order to meet the positioning requirements for regulatory (i.e., emergency services) and commercial use cases (e.g., IIoT), as listed in Table 2 below, RAT-dependent (for both FR1 and FR2) and RAT-independent positioning methods (such as PPP and RTK) have been specified in 3GPP Rel-16. Table 3 shows the list of RAT - dependent positioning methods which were specified in 3GPP Rel-16.

Table 2

Table 3

[0061] In order to meet the higher positioning requirements for commercial use cases and specifically IIoT use cases, as listed in Table 4, further enhancements for NR positioning have been specified in 3GPP Rel-17. These further enhancements include: improvements of positioning accuracy and latency (UL-AoA enhancements, DL-AoD enhancements, Preconfigured measurement gap, Preconfigured PRS processing window etc.); improvements of network efficiency (On-Demand PRS transmission); improvement of device efficiency (Positioning in RRC INACTIVE); providing high integrity and reliability requirements (GNSS integrity); enhancements of A-GNSS positioning.

Table 4

[0062] In the 5GS architecture that is applicable to positioning of a UE, either the UE itself or the location server determines the UE position depending on the applied positioning method. For exchanging the positioning related information (e.g. location related measurements, location estimates, assistance data), LPP as specified in 3GPP TS 37.355 titled “LTE Positioning Protocol (LPP)”, is used point-to-point between the location server and the UE. In LPP the following message types are supported: Request Capabilities; Provide Capabilities; Request Assistance Data; Provide Assistance Data; Request Location Information; Provide Location Information; Abort; and Error.

[0063] Figure 2 illustrates an example, useful for understanding aspects of the present disclosure, of LPP message transfer 200 between an LMF and a UE.

[0064] The figure shows a UE 210, an NG-RAN node 220, an AMF 230 and an LMF 240. The figure also shows the messaging 201-206 between the UE 210, NG-RAN node 220, AMF 230 and LMF 240. LPP messages are shown as being carried as transparent PDUs across intermediate network interfaces using the appropriate protocols.

[0065] In a first step 201, the LMF 240 sends an LPP message to the AMF 230. The LPP message may be the Request Capabilities message to request the UE 210 to send its positioning capabilities.

[0066] In a further step 202, the AMF 230 transports the received LPP message to the NG-RAN node 220 by including the LPP message into the LPP message container of the DL NAS Transport message.

[0067] In a further step 203, the NG-RAN node 220 transports the received LPP message container to the UE 210 by including the LPP message container into the RRC DLInformationTransfer message as specified in 3GPP Technical Specification 38.331 titled “NR Radio Resource Control (RRC) Protocol specification”.

[0068] In a further step 204, upon receiving the Request Capabilities message, the UE 210 generates the Provide Capabilities message as response. The UE 210 sends the Provide Capabilities message to the NG-RAN node 220 by including the LPP message into the RRC ULInformationTransfer message as specified in 3GPP Technical Specification 38.331 titled “NR Radio Resource Control (RRC) Protocol specification.

[0069] In a further step 205, the NG-RAN node 220 transports the LPP message received from the UE 210 to the AMF 230 by including the LPP message into the LPP message container of the UL NAS Transport message.

[0070] In a further step 206, the AMF 230 extracts the LPP message from the received NAS message/LPP message container and sends it to the LMF 240.

[0071] 3GPP includes a Location Services (LCS) feature, that provides the mechanisms to support mobile location services for operators, subscribers and third-party service providers. Examples of location-based services include emergency services, tracking services, location-based information services (navigation, city sightseeing, location dependent content broadcast, mobile yellow pages etc.). The location information may be requested by and reported to a client (application) associated with a UE, or by a client within or attached to the 5GC.

[0072] Figure 3 illustrates an example, useful for understanding aspects of the present disclosure, of an LCS architecture 300 where an external LCS client requests the 5GC for the current location of the Target UE. In the architecture 300, the relation of the LCS entities is shown.

[0073] More specifically, the architecture 300 comprises a target UE 310, a gNB 320, an AMF 330, an LMF 340, a GMLC 350 and an LCS Client 360. The various interactions of these entities will now be briefly described.

[0074] The external LCS Client 360 interacts with the GMLC 350 for the purpose of obtaining location information for one or more (Target) UEs 310. The LCS Client 360 may reside in a UE and may be implemented as hardware (HW) or software (SW) (i.e., an application). Examples for the LCS client 360 include 911 emergency dispatch centre (PSAP), and Google maps.

[0075] The GMLC 350 is the first node an external LCS client 360 accesses in a public land mobile network (PLMN) and works as a location server to an external application, for location information.

[0076] The LMF 340 manages the overall co-ordination and scheduling of resources required for the location of a LE 310 that is registered with or accessing 5GC. It also calculates or verifies a final location and any velocity estimate and may estimate the achieved accuracy. The LMF 340 processes the location services request which may include transferring assistance data to the Target UE 310 to assist with UE-based and/or UE-assisted positioning and/or may include positioning of the Target UE 310. The LMF 340 then returns the position estimate for a UE 310 back to the AMF 330. In the case of a location service requested by an entity other than the AMF 330 (e.g., a GMLC 350 or UE 310), the AMF 330 returns the location result to this entity. In C-plane the LMF 340 works as location server.

[0077] The AMF 330 contains functionality responsible for managing positioning for a Target UE 310 for all types of location request. The AMF 330 receives a request for some location services associated with a particular Target UE 310 from another entity (e.g., GMLC 350 or UE 310) or the AMF 330 itself decides to initiate some location service on behalf of a particular Target UE 310 (e.g., for an emergency call from the UE 310). The AMF 330 then sends a location services request to an LMF 340.

[0078] The NG-RAN node (i.e. gNB) 320 is involved in the handling of various positioning procedures including positioning of a Target UE 310, provision of location related information not associated with a particular Target UE 310 and transfer of positioning messages between an AMF 330 or LMF 340 and a Target UE 310.

[0079] The Target UE 310 is the UE whose position (absolute or relative) is to be obtained by the network or by the UE itself. [0080] NRPPa is the C-plane radio network layer signaling protocol between a NG- RAN node (gNB) 320 and the LMF 340.

[0081] LPP is a point-to-point positioning protocol that supports positioning and location related services for a Target device 310. In C-plane, LPP is terminated between a Target device 310 and an LMF 340.

[0082] 3GPP specifies a number of different types of location requests. The types of location requests will now be briefly introduced.

[0083] A Network Induced Location Request (NLLR) is where a serving AMF for a UE initiates localization of the UE for a regulatory service (e.g. an emergency call from the UE) or for verification of a UE location (country or international area) for NR satellite access.

[0084] A Mobile Terminated Location Request (MT-LR) is where an LCS client external to or internal to a serving PLMN sends a location request to the PLMN for the location of a Target UE.

[0085] A Mobile Originated Location Request (MO-LR) is where a UE sends a request to a serving PLMN for location related information for the UE itself.

[0086] An Immediate Location Request is where an LCS client sends or instigates a location request for a Target UE (or group of Target UEs) and expects to receive a response containing location information for the Target UE (or group of Target UEs) within a short time period which may be specified using LCS QoS. In regulatory cases, one or more responses of the Target UEs location information can be expected. An immediate location request may be used for an NLLR, MT-LR or MO-LR.

[0087] A Deferred Location Request is where an LCS client sends a location request to a PLMN for a Target UE (or group of Target UEs) and expects to receive a response containing the indication of event occurrence and location information if requested for the Target UE (or group of Target UEs) at some future time (or times), which may be associated with specific events associated with the Target UE (or group of Target UEs). Deferred location requests are supported only for an MT-LR. [0088] Figure 4 illustrates an example, useful for understanding aspects of the present disclosure, of a 5GC-MT-LR procedure 400 for the regulatory location service location service for non-roaming scenario as specified in 3GPP Technical Specification 23.273 titled “5G System (5GS) Location Services (LCS)-Stage 2”. In the scenario illustrated in Figure 4, an external LCS client requests the 5GC for the current location of the Target UE. It is assumed that the Target UE is identified using a Subscription Permanent Identifier (SUPI) or a Generic Public Subscription Identifier (GPSI).

[0089] More specifically, Figure 4 illustrates a UE 410, an NG-RAN 420, an AMF 430, an LMF 440, a GMLC 450, and an external client 460. The various message flows 401-409 between these entities will now be described.

[0090] In a first step 401, the external client 460 sends a request to the GMLC 450 for the current location of the Target UE 410. The request includes amongst other the requested LCS Quality of Service (QoS).

[0091] In a further step 402, the GMLC 450 sends a

Namf Location ProvidePositioninglnfo Request to the AMF 430 to request the current location of the UE 410.

[0092] In a further step 403, if the UE 410 is in a CM-IDLE state, the AMF 430 initiates a network triggered Service Request procedure to establish a signaling connection with the UE 410.

[0093] In a further step 404, the AMF 430 selects an LMF 440 based on the available information (e.g. requested LCS QoS, LMF capabilities, LMF load, LMF location) or based on AMF local configuration (if AMF 430 is configured locally with a mapping table of UE identity and LMF address).

[0094] In a further step 405, the AMF 430 sends a Nlmf Location DetermineLocation Request to the selected LMF 440 to request the current location of the UE 410. The request includes amongst other items, the requested LCS QoS and the UE positioning capability, if available. [0095] In a further step 406, the LMF 440 performs positioning procedures and determines the geographical location of the UE 410.

[0096] In a further step 407, the LMF 440 returns the

Nlmf Location DetermineLocation Response towards the AMF 430 to return the current location of the UE 410, i.e. the location estimate and accuracy, and may include information about the positioning method and the timestamp of the location estimate.

[0097] In a further step 408, the AMF 430 returns the Namf Location ProvidePositioninglnfo Response towards the GMLC 450 to return the current location of the UE 410.

[0098] In a further step 409, the GMLC 450 sends the location service response, including the location information of the UE 410, to the external client 460.

[0099] Figure 5 illustrates an example, useful for understanding aspects of the present disclosure, of a 5GC-MO-LR procedure 500 as specified in 3GPP Technical Specification 23.273 titled “5G System (5GS) Location Services (LCS)-Stage 2”, where a UE requests the serving PLMN to obtain the location of itself or just provide positioning assistance data. It is assumed that an LCS client resides in the UE and initiates the MO-LR.

[0100] More specifically, the figure shows a UE 515, an NG-RAN 520, an AMF 530, an LMF 540, a GMLC 550 and an external client 560. The message flows 501-511 between these entities will now be described.

[0101] In a first step 501, if the UE 515 is in a CM-IDLE state, the UE 515 instigates the UE triggered Service Request procedure in order to establish a signaling connection with the AMF 530.

[0102] In a further step 502, the UE 515 sends an MO-LR Request message included in a UL NAS TRANSPORT message to the AMF 530. Different types of location services can be requested i.e., location estimate of the UE 515, location estimate of the UE 515 to be sent to an LCS client 560, or positioning assistance data. If the UE 515 is requesting its own location or that its own location be sent to an LCS client 560 (e.g. for using a locationbased service), this message carries the requested LCS QoS information (e.g. accuracy, response time). If the UE 515 is requesting that its location be sent to an LCS client 560, the message also includes the identity of the LCS client 560 and the address of the GMLC 550 through which the LCS client 560 should be accessed. If the UE 515 is instead requesting positioning assistance data, the embedded LPP message specifies the type of assistance data and the positioning method for which the assistance data applies.

[0103] In a further step 503, the AMF 530 selects an LMF 540 based on the available information (e.g. requested LCS QoS, LMF capabilities, LMF load, LMF location) or based on AMF local configuration (if AMF 530 is configured locally with a mapping table of UE identity and LMF address).

[0104] In a further step 504, the AMF 530 sends a Nlmf Location DetermineLocation Request to the selected LMF 540. The request includes amongst other an indication whether a location estimate, or positioning assistance data is requested.

[0105] In a further step 505, if the UE 515 is requesting its own location, the LMF 540 performs positioning procedures and determines the geographical location of the UE 515. If the UE 515 is instead requesting positioning assistance data, the LMF 540 transfers this data to the UE 515.

[0106] In a further step 506, when a location estimate best satisfying the requested LCS QoS has been obtained or when the requested location assistance data has been transferred to the UE 515, the LMF 540 returns a Nlmf Location DetermineLocation Response towards the AMF 530. The response includes the location estimate, its age and accuracy. If the UE 515 is requesting positioning assistance data, steps 507 to 511 are skipped.

[0107] In a further step 507, if the location estimate was successfully obtained, the AMF 530 sends a Ngmlc Location LocationUpdate Request to the GMLC 550. The request carries the identity of the UE 515, the event causing the location estimate (5GC- MO-LR) and the location estimate, its age and obtained accuracy indication. In addition, the request includes the identity of the LCS Client 560.

[0108] In a further step 508, the GMLC 550 transfers the Location Information message to the LCS client 560, carrying the identity of the UE 515, the event causing the location estimate (5GC-M0 LR) and the location estimate in accordance with the LCS QoS requested by the UE 515.

[0109] In a further step 509, the LCS Client 560 sends the GMLC 550 a Location Information Ack message signaling that the location estimate of the UE 515 has been received successfully.

[0110] In a further step 510, the GMLC 550 sends a Ngmlc Location LocationUpdate Response to AMF 530 to acknowledge the successful reception of the location estimate by the LCS Client 560.

[OHl] In a further step 511, the AMF 530 sends an MO-LR Response message included in a DL NAS TRANSPORT message. If the UE 515 is requesting its own location, the response carries any location estimate requested by the UE 515 and the timestamp of the location estimate (if available) including the indication received from LMF 540 whether the obtained location estimate satisfies the requested accuracy or not, or an indicator whether a location estimate was successfully transferred to the identified LCS client 560.

[0112] The feature of SL communication was introduced in 3 GPP Rel-16 NR to support V2X and non-V2X services. The interface used for SL communication (transmission/reception) between two UEs (UE1 and UE2) in proximity is denoted as PC5. Table 5 defines the different coverage scenarios which are supported for SL communication.

Table 5

[0113] Figures 6a-6c illustrate examples, useful for understanding aspects of the present disclosure, of the coverage scenarios defined in Table 5. More specifically Figure 6a shows a first scenario 610 where a UE1 611 and a UE2 612 are located out-of-coverage (OOC) of a cell 613. Figure 6b shows a further scenario 620 where a UE1 621 and a UE2 622 are located in partial coverage (PC) of a cell 623. Figure 6c shows a further scenario 630 where a UE1 631 and a UE2 632 are located in-coverage (IC) of a cell 633.

[0114] In 3 GPP, the LPP supports session-based positioning operation between two endpoints, i.e., the Target UE and the LMF, in order to obtain location related measurements or a location estimate or to transfer assistance data. Within a “session”, the communication between two devices takes place over a period of time, during which, a series of messages are exchanged. A single LPP session is used to support a single location request (e.g., for a single MT-LR, MO-LR or NI-LR). Multiple LPP sessions can be used between the same endpoints to support multiple different location requests. Each LPP session comprises one or more LPP transactions, with each LPP transaction performing a single operation (capability exchange, assistance data transfer, or location information transfer).

[0115] The session-based positioning operation in LPP is realized by using identifiers for the transfer of LPP messages. Figure 7 illustrates an example 700, useful for understanding aspects of the present disclosure, of the use of identifiers for the transfer of LPP messages in the current Uu-based positioning operation.

[0116] More specifically, the example 700 shows a target UE 710, an NG-RAN node 720, an AMF 730, and an LMF 740.

[0117] The AMF 730 is the central entity that manages the LCS service requests (e.g. MT-LR, MO-LR, NI-LR). In a first step 701, the AMF 730 initiates a location/positioning session for a Target UE 710. In a further step 702 the AMF 730 selects an LMF 740. In these steps 701-702, the AMF 730 assigns a Routing ID/LCS Correlation ID for the LPP message transfer 703-704 between the selected LMF 740 and the Target UE 710. The Routing ID is used for the LPP message transfer 704 between AMF 730 and UE 710 via the DL NAS TRANSPORT/UL NAS TRANSPORT messages. The LCS Correlation ID is used for the LPP message transfer 703 between AMF 730 and LMF 740. In fact the Routing ID and the LCS Correlation ID are identical and according to 3GPP Technical Specification 29.572 (titled, “5G System Location Management Services-Stage 3”) the Routing ID/LCS Correlation ID is a character string of length 1-255 characters. The AMF 730 assigns the IDs to uniquely identify the LMF 740 and the positioning session between the AMF 730 and LMF 740 when a positioning session is being used. That means, if the Target UE 710 may be involved in multiple positioning sessions, different Routing IDs/LCS Correlation IDs are used to distinguish the different sessions. Furthermore, in LPP the different sessions can be distinguished by using transaction identifiers.

[0118] The transmission and reception of user traffic over the PC5 interface is supported for unicast, groupcast and broadcast transmission. The transmission and reception of signaling traffic over the PC5 interface is supported only for unicast transmission. An SL connection over PC5 is defined as a logical connection between two UEs and is identified by a pair of Source and Destination Layer-2 IDs. Source and Destination Layer-2 IDs identify the sender and the target of the SL communication, respectively. And for a cast type a corresponding pair of a Source Layer-2 ID and a Destination Layer-2 ID is used. The SL communication is based on the Proximity-based Services (ProSe) feature.

[0119] In order to enable SL communication between UEs in proximity the SL discovery procedure may need to be performed by the UEs. The SL discovery procedure is used by UE(s) to discover or to be discovered by other UE(s) in proximity. For instance, a UE that wants to discover other UE(s) in proximity transmits a discovery message over PC5. Other UE(s) in proximity monitor the discovery message and if they want to be discovered they respond with a discovery response message. After discovery the UE can establish a SL communication connection with each of the UE(s) which responded. More details to NR sidelink communication and discovery can be found in the 3GPP Technical Specification 23.304 titled, “Proximity based Services (ProSe) in the 5G System (5GS)”.

[0120] Certain terminology, useful for understanding aspects of the disclosure herein, will now be introduced. These terms are used to refer to roles of particular UE/devices participating in a SL positioning session.

[0121] An ‘Initiator device’ initiates a SL positioning/ranging session. It may be a network entity, (e.g., gNB, LMF) or UE/roadside unit (RSU).

[0122] A ‘Responder device’ responds to a SL positioning/ranging session from an initiator device. It may be a network entity, (e.g., gNB, LMF) or UE/roadside unit (RSU). [0123] A ‘Target UE’ is a UE of interest whose position (absolute or relative) is to be obtained by the network or by the UE itself.

[0124] The term ‘ Sidelink positioning’ refers to positioning of a UE using reference signals transmitted over SL, i.e., PC5 interface, to obtain absolute position, relative position, or ranging information.

[0125] The term ‘Ranging’ refers to- the determination of the distance and/or the direction between a UE and another entity, e.g., Anchor UE.

[0126] An ‘Anchor UE’ is a UE supporting positioning of a Target UE, e.g., by transmitting and/or receiving reference signals for positioning, providing positioning- related information, etc., over the PC5 interface (also may be referred to as SL Reference UE).

[0127] An ‘Assistant UE’ is a UE supporting Ranging/Sidelink between a SL Reference UE and a Target UE over PC5, when the direct Ranging/Sidelink positioning between the SL Reference UE/ Anchor UE and the Target UE cannot be supported. The measurement/results of the Ranging/Sidelink Positioning between the Assistant UE and the SL Reference UE, and that between the Assistant UE and the Target UE, are determined and used to derive the Ranging/Sidelink Positioning results between Target UE and SL Reference UE.

[0128] A ‘SL Positioning Server UE’ is a UE offering location calculation, for SL Positioning and Ranging based service. It interacts with other UEs over PC5 as necessary in order to calculate the location of the Target UE. The Target UE or SL Reference UE can act as a SL Positioning Server UE if location calculation is supported.

[0129] A ‘SL Positioning Client UE’ is a third-party UE, other than SL Reference UE and Target UE, which initiates Ranging/Sidelink positioning service request on behalf of the application residing on it.

[0130] Figure 8 illustrates an example 800 of message flow in accordance with aspects of the present disclosure. More specifically, the example 800 represents a joint PC5-Uu- based positioning operation scenario. [0131] Shown in the example 800 is a target UE 810, an anchor UE 815, an NG-RAN node 820, an AMF 830 and an LMF 840. The Target UE 810 and Anchor UE 815 are in network coverage. The Target UE 810 and Anchor UE 815 are already involved in six SL positioning sessions: five for MT-LR and one for MO-LR. The value of the capability “Maximum number of SL positioning sessions that can be supported” is determined by the Target UE 810 using default reference parameters for an MT-LR SL positioning session such as processing load of 1% and memory size of 2 kB. Based on a new location request (MT-LR) from an LCS Client (not shown in Figure 8) the AMF 830 initiates a new SL positioning session (referred to as session #7) to the Target UE 810 (determined by the requested LCS QoS).

[0132] Also shown in the example 800 are various message flows 801-808, which will now be described in greater detail.

[0133] In a first step 801, for a new SL positioning session#?, the LMF 840 sends an SLPP Requestcapability message to the Target UE 810.

[0134] In a further step 802, the Target UE 810 sends its SL positioning capabilities to the LMF 840 via an AMF 830, in an SLPP ProvideCapability message. The SLPP ProvideCapability message includes the new capability “Maximum number of SL positioning sessions that can be supported” set to value 4 according to the current load of the UE 810.

[0135] In a further step 803, based on the received SL positioning capability information, the LMF 840 sends an SLPP RequestLocationlnformation message to the Target UE 810.

[0136] In a further step 804, SL positioning is performed between the Target UE 810, Anchor UE 815 and LMF 840, for the new SL positioning session #7 (this may include SL positioning assistance data transfer, SL PRS transmission, SL PRS measurements, SL positioning measurements/location estimate transfer).

[0137] In a further step 805, the Target UE 810 receives from NG-RAN node 820 an RRCReconfiguration message including the configuration for setup of carrier aggregation and MIMO. [0138] In a further step 806, owing to the additional load for processing the new AS functionalities, the Target UE 810 determines that no resources are available for continuing SL positioning for the SL positioning session #7 (resources are still available for continuing SL positioning for the parallel SL positioning sessions #1 to #6).

[0139] In a further step 807, the Target UE 810 decides to abort the SL positioning session #7 and sends to LMF 840, via AMF 830, the SLPP Abort message for this session. The SLPP abort message includes the new cause value “Maximum number of SL positioning sessions that can be supported is reached”.

[0140] In a further step 808, upon reception of the Abort message, the LMF 840 and AMF 830 abort the SL positioning session #7.

[0141] According to an extended implementation of the example 800, the Target UE 810 may send an indication/notification to the LMF 840 upon completion or release of an existing/ongoing SL positioning session (for instance, for any of the sessions #1 to #6) so that the LMF 840 may be aware of the availability to trigger a new SL positioning session.

[0142] Figure 9 illustrates an example 900 of message flow in accordance with aspects of the present disclosure. More specifically, the example 900 comprises the initial steps 801-804 of the example 800 of Figure 8. However, the subsequent steps are different for the example 900, as will now be described.

[0143] Shown in the example 900 is a target UE 910, an anchor UE 915, an NG-RAN node 920, an AMF 930, and an LMF 940. Following the completion of steps 801-804, in a further step 905, the LMF 940 sends for the SL positioning session #7, new SL positioning assistance data to the Target UE 910. This is illustrated as being sent using an SLPP ProvideAssistanceData message.

[0144] In a further step 906, the new SL positioning assistance data is of large size and results in exceeding the available memory size of the Target UE 910 for storing SL positioning assistance data.

[0145] In a further step 907, in response, the Target UE 910 sends an Error message to the LMF 940 via AMF 930. The SLPP error message includes the new cause value “Maximum capacity for SL positioning assistance data that can be supported is reached”. In addition to the cause value, the Target UE 910 indicates the size of assistance data that exceeds the memory size, e.g. 1 kB.

[0146] In a further step 908, upon reception of the Error message, the LMF 940 knows that the previously transferred SL positioning assistance data for SL positioning session #7 cannot be processed by the UE 910. The LMF 940 decides to reduce the size of the SL positioning assistance data for SL positioning session #7 by the indicated value of 1 kB.

[0147] In a further step 909, the LMF 940 sends for the SL positioning session #7, new reduced SL positioning assistance data (i.e. by reducing the size of the data) to the Target UE 910. This is shown as being provided using an SLPP ProvideAssistanceData message.

[0148] Figure 10 illustrates an example 1000 of message flow in accordance with aspects of the present disclosure. More specifically, the example 1000 represents a PC5- only-based positioning operation scenario.

[0149] The example 1000 shows a target UE1 1011, a target UE2 1012, a target UE3 1013, a target UE4 1014, an anchor UE 1015, and a server UE 1016. The involved UEs (Target UEs 1011-1014, Anchor UE 1015, Server UE 1016) are out-of-coverage. The Anchor UE 1015 is already involved in multiple SL positioning sessions and transmits SL PRS to the Target UE1 1011 to Target UE3 1013. The Anchor UE 1015 transmits the SL PRS specific to each Target UE 1011-1013 with regards to at least the following SL PRS configuration parameters: start time and duration, frequency range (FR1/FR2), resource bandwidth, sequence ID, comb size, number of symbols resource repetition, muting configuration, power control parameters (e.g., SL Pathloss reference, SL Tx power) etc. Based on a new location request (MT-LR) from a Client UE (not shown in Figure 10), the Server UE 1016 wants to initiate a new SL positioning session to the Target UE4 1014.

[0150] In a first step 1001, the Anchor UE 1015 transmits SL PRS specific to the Target UE1 1011 to Target UE3 1013.

[0151] In a further step 1002, the Server UE 1016 sends to the Anchor UE 1015 the SL PRS activation message for requesting the Anchor UE 1015 to transmit SL PRS to the Target UE4 1014 according to the SL PRS configuration that has been included in the message. The SL PRS configuration is specific to the Target UE4 1014.

[0152] In a further step 1003, owing to current load, the Anchor UE 1015 determines that it cannot comply with the request from the Server UE 1016.

[0153] In a further step 1004, as a response, the Anchor UE 1015 sends to the Server UE 1016 an Abort message (SLPP Abort) including the new cause value “Maximum capacity for SL PRS transmission that can be supported is reached”.

[0154] In a further step 1005, upon reception of the Abort message from the Anchor UE 1015, the Server UE 1016 searches for other candidate Anchor UE(s) which are not overloaded and can comply with the request for transmitting SL PRS to the Target UE4 1014. The Server UE 1016 may select other or alternative Anchor UEs which are not overloaded based on a received candidate Anchor UE list, e.g., via higher-layer signaling such as discovery, etc., or alternatively, the Server UE 1016 may generate a candidate Anchor UE list based on certain criteria including UE role information, supported positioning methods, coverage scenario (in-coverage, out-of-coverage, partial coverage), SL PRS / SL PRS RSRP, received LOS/NLOS indication, absolute/relative location information, SLPP capabilities, and PLMN information. In another implementation, the Anchor UEs from the candidate list may also have an associated load status field indicating the latest load of the respective Anchor UE, e.g., with a value indicating the processing load or available memory/storage capacity.

[0155] According to one aspect of the embodiment 1000, upon an unsuccessful search for alternative Anchor UEs, the Server UE 1016 may transmit an Abort LCS message to the Client UE (not shown in Figure 10) indicating that the LCS request cannot be fulfilled. A further indication may be appended to this Abort message indicating that Anchor UEs could not be found due to e.g., all available Anchor UEs being fully loaded, and/or no suitable Anchor UE could be found based on the existing conditions and procedures.

[0156] Accordingly, the disclosure herein provides, a UE for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: determine, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; and transmit, to a first apparatus of a wireless communication system, a first message comprising the one or more parameters.

[0157] In some embodiments, the at least one processor is configured to cause the UE to: receive, from the first apparatus, a second request for initiating sidelink positioning for the UE; and perform, in response to the second request, a sidelink positioning for the UE.

[0158] In some embodiments, the at least one processor is configured to cause the UE to perform the sidelink positioning by causing the UE to: perform, with the first apparatus and/or a second apparatus of the wireless communication system, at least one of: a sidelink positioning assistance data transfer; a sidelink positioning, positioning-reference-signal (PRS) transmission; a sidelink positioning, PRS measurement; a sidelink positioning measurement transfer; and a sidelink positioning, location estimate transfer.

[0159] In some embodiments, the at least one processor is configured to cause the UE to: receive, from the first apparatus, a first request for sidelink positioning capabilities of the UE; and then transmit the first message, in response to the first request.

[0160] In some embodiments, the first request comprises a Sidelink Request Capabilities message; the first message comprises a Sidelink Provide Capabilities message; and/or the second request comprises a Sidelink Request Location Information message.

[0161] In some embodiments, the at least one processor is configured to cause the UE to determine the maximum number of sidelink positioning sessions, based on: a first reference parameter corresponding to a processing load; and/or a second reference parameter corresponding to a memory size.

[0162] In some embodiments, the UE is selected from the list of UEs consisting of: a sidelink target UE; a sidelink anchor UE; and a sidelink server UE.

[0163] In some embodiments, the first apparatus is selected from the list of apparatuses consisting of: a sidelink target UE; a sidelink anchor UE; a sidelink server UE; and a location management function (LMF). [0164] In some embodiments, the at least one processor is configured to cause the UE to: determine whether: the maximum number of sidelink positioning sessions has been reached; and/or a maximum capacity for sidelink positioning assistance data supportable by the UE has been reached; and then if the maximum number of sidelink positioning sessions, and/or, the maximum capacity for sidelink positioning assistance data, is determined to be reached: transmit a second message to the first apparatus, wherein the second message comprises: an indication that the maximum number of sidelink positioning sessions has been reached, and/or, an indication that the maximum capacity for sidelink positioning assistance data, has been reached.

[0165] In some embodiments, the second message comprises a Sidelink Abort message or a Sidelink Error message.

[0166] In some embodiments the second message indicates that a new or existing sidelink positioning session has been terminated by the UE.

[0167] In some embodiments the second apparatus is a sidelink anchor UE.

[0168] There is further provided a method in a UE, comprising: determining, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; and transmitting, to a first apparatus of a wireless communication system, a first message comprising the one or more parameters.

[0169] In some embodiments, the method comprises: receiving, from the first apparatus, a second request for initiating sidelink positioning for the UE; and performing, in response to the second request, a sidelink positioning for the UE.

[0170] In some embodiments, the performing the sidelink positioning comprises: performing, with the first apparatus and/or a second apparatus of the wireless communication system, at least one of: a sidelink positioning assistance data transfer; a sidelink positioning, positioning-reference-signal (PRS) transmission; a sidelink positioning, PRS measurement; a sidelink positioning measurement transfer; and a sidelink positioning, location estimate transfer. [0171] In some embodiments, the method comprises: receiving, from the first apparatus, a first request for sidelink positioning capabilities of the UE; and then transmitting the first message, in response to the first request.

[0172] In some embodiments, the first request comprises a Sidelink Request Capabilities message; the first message comprises a Sidelink Provide Capabilities message; and/or the second request comprises a Sidelink Request Location Information message.

[0173] In some embodiments, the method comprises determining the maximum number of sidelink positioning sessions, based on: a first reference parameter corresponding to a processing load; and/or a second reference parameter corresponding to a memory size.

[0174] In some embodiments, the UE is selected from the list of UEs consisting of: a sidelink target UE; a sidelink anchor UE; and a sidelink server UE.

[0175] In some embodiments, the first apparatus is selected from the list of apparatuses consisting of: a sidelink target UE; a sidelink anchor UE; a sidelink server UE; and an LMF.

[0176] In some embodiments, the method comprises: determining whether: the maximum number of sidelink positioning sessions has been reached; and/or a maximum capacity for sidelink positioning assistance data supportable by the UE has been reached; and then if the maximum number of sidelink positioning sessions, and/or, the maximum capacity for sidelink positioning assistance data, is determined to be reached: transmitting a second message to the first apparatus, wherein the second message comprises: an indication that the maximum number of sidelink positioning sessions has been reached, and/or, an indication that the maximum capacity for sidelink positioning assistance data, has been reached.

[0177] In some embodiments, the second message comprises a Sidelink Abort message or a Sidelink Error message.

[0178] In some embodiments, the second message indicates that a new or existing sidelink positioning session has been terminated by the UE.

[0179] In some embodiments, the second apparatus is a sidelink anchor UE. [0180] There is further provided a processor for a UE for wireless communication, comprising: at least one controller coupled with at least one memory and configured to cause the processor to: obtain, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; and output, a first message comprising the one or more parameters.

[0181] In some embodiments, the controller is configured to cause the processor to: retrieve, a second request for initiating sidelink positioning for the UE; and obtain, in response to obtaining the second request, a sidelink positioning for the UE.

[0182] In some embodiments, the controller is configured to cause the processor to obtain the sidelink positioning by causing the processor to perform at least one of: a sidelink positioning assistance data transfer; a sidelink positioning, positioning-reference- signal ‘PRS’ transmission; a sidelink positioning, PRS measurement; a sidelink positioning measurement transfer; and a sidelink positioning, location estimate transfer.

[0183] In some embodiments, the controller is configured to cause the processor to: retrieve, a first request for sidelink positioning capabilities of the UE; and then output the first message, in response to the first request.

[0184] In some embodiments, the first request comprises a Sidelink Request Capabilities message; the first message comprises a Sidelink Provide Capabilities message; and the second request comprises a Sidelink Request Location Information message.

[0185] In some embodiments, the controller is configured to cause the processor to obtain the maximum number of sidelink positioning sessions, based on: a first reference parameter corresponding to a processing load; and/or a second reference parameter corresponding to a memory size.

[0186] In some embodiments, the UE is selected from the list of UEs consisting of: a sidelink target UE; a sidelink anchor UE; and a sidelink server UE.

[0187] In some embodiments, the controller is configured to cause the processor to: determine whether: the maximum number of sidelink positioning sessions has been reached; and/or a maximum capacity for sidelink positioning assistance data supportable by the UE has been reached; and then if the maximum number of sidelink positioning sessions, and/or, the maximum capacity for sidelink positioning assistance data, is determined to be reached: output a second message, wherein the second message comprises: an indication that the maximum number of sidelink positioning sessions has been reached, and/or, an indication that the maximum capacity for sidelink positioning assistance data, has been reached.

[0188] In some embodiments, the second message comprises a Sidelink Abort message or a Sidelink Error message.

[0189] There is further provided a method in a processor for a UE, comprising: obtaining, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; and outputting, a first message comprising the one or more parameters.

[0190] In some embodiments, the method comprises: retrieving, a second request for initiating sidelink positioning for the UE; and obtaining, in response to obtaining the second request, a sidelink positioning for the UE.

[0191] In some embodiments, the obtaining the sidelink positioning comprises performing at least one of: a sidelink positioning assistance data transfer; a sidelink positioning, positioning-reference-signal ‘PRS’ transmission; a sidelink positioning, PRS measurement; a sidelink positioning measurement transfer; and a sidelink positioning, location estimate transfer.

[0192] In some embodiments, method comprises: retrieving, a first request for sidelink positioning capabilities of the UE; and then outputting the first message, in response to the first request.

[0193] In some embodiments, the first request comprises a Sidelink Request Capabilities message; the first message comprises a Sidelink Provide Capabilities message; and the second request comprises a Sidelink Request Location Information message. [0194] In some embodiments, the method comprises obtaining the maximum number of sidelink positioning sessions, based on: a first reference parameter corresponding to a processing load; and/or a second reference parameter corresponding to a memory size.

[0195] In some embodiments, the UE is selected from the list of UEs consisting of: a sidelink target UE; a sidelink anchor UE; and a sidelink server UE.

[0196] In some embodiments, the method comprises: determining whether: the maximum number of sidelink positioning sessions has been reached; and/or a maximum capacity for sidelink positioning assistance data supportable by the UE has been reached; and then if the maximum number of sidelink positioning sessions, and/or, the maximum capacity for sidelink positioning assistance data, is determined to be reached: outputting a second message, wherein the second message comprises: an indication that the maximum number of sidelink positioning sessions has been reached, and/or, an indication that the maximum capacity for sidelink positioning assistance data, has been reached.

[0197] In some embodiments, the second message comprises a Sidelink Abort message or a Sidelink Error message.

[0198] There is further provided a second UE for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the second UE to: receive, from a second apparatus of a wireless communication system, a third message requesting the transmission of sidelink positioning reference signals to a third apparatus of the wireless communication system; determine, whether a maximum capacity for sidelink positioning reference signal transmission, has been reached by the second UE; and if the determination is that the maximum capacity for sidelink positioning reference signal transmission has been reached: transmit, to the second apparatus, a third response to the third message, wherein the third response comprises one or more parameters indicating that the maximum capacity for sidelink positioning reference signal transmission has been reached.

[0199] In some embodiments, the third response comprises a Sidelink Abort message or a Sidelink Error message. [0200] In some embodiments, the second apparatus is a sidelink target UE, a sidelink anchor UE, a sidelink server UE, or an LMF.

[0201] In some embodiments, the second UE is a sidelink target UE or a sidelink anchor UE.

[0202] In some embodiments, the third apparatus is a sidelink target UE or a sidelink anchor UE.

[0203] There is further provided a method in a second UE, comprising: receiving, from a second apparatus of a wireless communication system, a third message requesting the transmission of sidelink positioning reference signals to a third apparatus of the wireless communication system; determining, whether a maximum capacity for sidelink positioning reference signal transmission, has been reached by the second UE; and if the determination is that the maximum capacity for sidelink positioning reference signal transmission has been reached: transmitting, to the second apparatus, a third response to the third message, wherein the third response comprises one or more parameters indicating that the maximum capacity for sidelink positioning reference signal transmission has been reached.

[0204] In some embodiments, the third response comprises a Sidelink Abort message or a Sidelink Error message.

[0205] In some embodiments, the second apparatus is a sidelink target UE, a sidelink anchor UE, a sidelink server UE, or an LMF.

[0206] In some embodiments, the second UE is a sidelink target UE or a sidelink anchor UE.

[0207] In some embodiments, the third apparatus is a sidelink target UE or a sidelink anchor UE.

[0208] There is further provided, an apparatus for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the apparatus to: receive, from a UE, a first message comprising one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; determine, based at least partly on the one or more parameters, a second request for initiating sidelink positioning for the UE; and transmit, to the UE, the second request.

[0209] In some embodiments, the at least one processor is configured to cause the apparatus to: transmit, to the UE, a first request for sidelink positioning capabilities of the UE.

[0210] In some embodiments, the first request comprises a Sidelink Request Capabilities message; the first message comprises a Sidelink Provide Capabilities message; and/or the second request comprises a Sidelink Request Location Information message.

[0211] In some embodiments, the UE is selected from the list of UEs consisting of: a sidelink target UE; a sidelink anchor UE; and a sidelink server UE.

[0212] In some embodiments, the apparatus is selected from the list of apparatuses consisting of: a sidelink target UE; a sidelink anchor UE; a sidelink server UE; and an LMF.

[0213] In some embodiments, the at least one processor is configured to cause the apparatus to: receive, from the UE, a second message comprising either: an indication that the maximum number of sidelink positioning sessions has been reached; or an indication that a maximum capacity for sidelink positioning assistance data has been reached.

[0214] In some embodiments, the second message comprises a Sidelink Abort message or a Sidelink Error message.

[0215] In some embodiments, the at least one processor is configured to cause the apparatus to either: abort, based on the Sidelink Abort message or Sidelink Error message, a sidelink positioning session; or modify, based on the Sidelink Abort message or Sidelink Error message, a sidelink positioning assistance data for the sidelink positioning session, and then transmit the modified sidelink positioning assistance data to the UE.

[0216] There is further provided, a method in an apparatus for wireless communication, comprising: receiving, from a UE, a first message comprising one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; determining, based at least partly on the one or more parameters, a second request for initiating sidelink positioning for the UE; and transmitting, to the UE, the second request.

[0217] In some embodiments, the method comprises: transmitting, to the UE, a first request for sidelink positioning capabilities of the UE.

[0218] In some embodiments, the first request comprises a Sidelink Request Capabilities message; the first message comprises a Sidelink Provide Capabilities message; and/or the second request comprises a Sidelink Request Location Information message.

[0219] In some embodiments, the UE is selected from the list of UEs consisting of: a sidelink target UE; a sidelink anchor UE; and a sidelink server UE.

[0220] In some embodiments, the apparatus is selected from the list of apparatuses consisting of: a sidelink target UE; a sidelink anchor UE; a sidelink server UE; and an LMF.

[0221] In some embodiments, the method comprises: receiving, from the UE, a second message comprising either: an indication that the maximum number of sidelink positioning sessions has been reached; or an indication that a maximum capacity for sidelink positioning assistance data has been reached.

[0222] In some embodiments, the second message comprises a Sidelink Abort message or a Sidelink Error message.

[0223] In some embodiments, the method comprises: aborting, based on the Sidelink Abort message or Sidelink Error message, a sidelink positioning session; or modifying, based on the Sidelink Abort message or Sidelink Error message, a sidelink positioning assistance data for the sidelink positioning session, and then transmitting the modified sidelink positioning assistance data to the UE.

[0224] In order to support SL positioning session overload handling, novel aspects of the present disclosure relate to a new SL positioning capability that is introduced in the SLPP ProvideCapabilities message for indicating available resources for SL positioning. This may be denoted, “Maximum number of SL positioning sessions that can be supported” with a value range { 1, .., n] and e.g. n=8, 16, 32 or 64. Depending on its (i.e., the UEs) current load (based on the active applications/services and configured AS functionalities such as e.g. carrier aggregation, dual connectivity or MIMO), the maximum value may be determined by the UE using default reference parameters for a SL positioning session such as e.g. processing load of 2% and/or memory size of 4 kB. Alternatively, the determination of the maximum value may be left to UE implementation. If the new capability is sent by a Target UE then it includes only MT-LR SL positioning sessions. The reason is that the initiation of MO-LR SL positioning sessions by the Target UE shall not be affected by this new capability. If the new capability is sent by an Anchor UE or Server UE then it includes all types of SL positioning sessions, e.g. MT-LR, MO-LR, NI-LR.

[0225] The novel aspects of the present disclosure further relate to, new cause values that are introduced in the SLPP Abort message. These may include, “Maximum number of SL positioning sessions that can be supported is reached” . If this cause value is set by a UE then the peer endpoint knows that the associated new or an existing SL positioning session is aborted by the UE. The new cause values may include, “Maximum capacity for SL PRS transmission that can be supported is reached” . If this cause value is set by a UE then the peer endpoint knows that the associated request for SL-PRS transmission is aborted by the UE.

[0226] The novel aspects of the present disclosure further relate to, a new cause value that is introduced in the SLPP Error message. This may include, “Maximum capacity for SL positioning assistance data that can be supported is reached” . If this cause value is set by a UE then the peer endpoint knows that the recently delivered SL positioning assistance data cannot be processed by the UE or no new SL positioning assistance data can be processed by the UE. In addition to the cause value the UE may indicate the size of assistance data that exceeds the memory size.

[0227] There is provided, a method for processing Sidelink positioning sessions in overload situations, the method comprising: transmitting a first message by a first communication device to a second communication device containing the information about the maximum number of Sidelink positioning sessions that can be supported by the first communication device; determining by the second communication device to initiate a Sidelink positioning session for the first communication device in accordance with the received first message; transmitting a second message by the second communication device to the first communication device containing the initiation of a Sidelink positioning session.

[0228] In some embodiments, the information about the maximum number of Sidelink positioning sessions that can be supported by the first communication device is determined by the first communication device using default reference values for processing load and/or memory size.

[0229] In some embodiments, the first message is a Sidelink Provide Capability message.

[0230] In some embodiments, the second message is a Sidelink Request Location Information message.

[0231] In some embodiments, the first communication device is one of a Sidelink Target UE, Sidelink Anchor UE or Sidelink Server UE.

[0232] In some embodiments, the second communication device is one of a Sidelink Target UE, Sidelink Anchor UE, Sidelink Server UE or LMF.

[0233] In some embodiments, the first communication device transmits a third message to the second communication device when the maximum number of Sidelink positioning sessions that can be supported by the first communication device is reached.

[0234] In some embodiments, the third message is one of a Sidelink Abort or Sidelink Error message.

[0235] In some embodiments, the third message indicates to the second communication device that a new or existing Sidelink positioning session is terminated by the first communication device.

[0236] In some embodiments, the first communication device transmits a third message to the second communication device when the maximum capacity for Sidelink positioning assistance data that can be supported by the first communication device is reached.

[0237] In some embodiments, the third message is one of a Sidelink Abort or Sidelink Error message. [0238] There is further provided, a method for processing a request for transmitting Sidelink positioning reference signals in overload situations, the method comprising: transmitting a first message by a first communication device to a second communication device containing the request to transmit Sidelink positioning reference signals to a third communication device; determining by the second communication device to transmit Sidelink positioning reference signals to a third communication device in accordance with the received first message; transmitting a second message by the second communication device to the first communication device when the maximum capacity for SL PRS transmission that can be supported by the second communication device is reached.

[0239] In some embodiments, the second message is one of a Sidelink Abort or Sidelink Error message.

[0240] In some embodiments, the first communication device is one of a Sidelink Target UE, Sidelink Anchor UE, Sidelink Server UE or LMF.

[0241] In some embodiments, the second and third communication device is one of a Sidelink Target UE or Sidelink Anchor UE.

[0242] Figure 11 illustrates an example of a UE 1100 in accordance with aspects of the present disclosure. The UE 1100 may include a processor 1102, a memory 1104, a controller 1106, and a transceiver 1108. The processor 1102, the memory 1104, the controller 1106, or the transceiver 1108, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

[0243] The processor 1102, the memory 1104, the controller 1106, or the transceiver 1108, or various combinations or components thereof may be implemented in hardware (e.g., circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. [0244] The processor 1102 may include an intelligent hardware device (e.g., a general- purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof). In some implementations, the processor 1102 may be configured to operate the memory 1104. In some other implementations, the memory 1104 may be integrated into the processor 1102. The processor 1102 may be configured to execute computer-readable instructions stored in the memory 1104 to cause the UE 1100 to perform various functions of the present disclosure.

[0245] The memory 1104 may include volatile or non-volatile memory. The memory 1104 may store computer-readable, computer-executable code including instructions when executed by the processor 1102 cause the UE 1100 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such the memory 1104 or another type of memory. Computer-readable media includes both non- transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

[0246] In some implementations, the processor 1102 and the memory 1104 coupled with the processor 1102 may be configured to cause the UE 1100 to perform one or more of the functions described herein (e.g., executing, by the processor 1102, instructions stored in the memory 1104). For example, the processor 1102 may support wireless communication at the UE 1100 in accordance with examples as disclosed herein. The UE 1100 may be configured to support a means for performing various aspects of the present disclosure as described herein.

[0247] The controller 1106 may manage input and output signals for the UE 1100. The controller 1106 may also manage peripherals not integrated into the UE 1100. In some implementations, the controller 1106 may utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some implementations, the controller 1106 may be implemented as part of the processor 1102.

[0248] In some implementations, the UE 1100 may include at least one transceiver 1108. In some other implementations, the UE 1100 may have more than one transceiver 1108. The transceiver 1108 may represent a wireless transceiver. The transceiver 1108 may include one or more receiver chains 1110, one or more transmitter chains 1112, or a combination thereof.

[0249] A receiver chain 1110 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 1110 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 1110 may include at least one amplifier (e.g., a low-noise amplifier (LN A)) configured to amplify the received signal. The receiver chain 1110 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 1110 may include at least one decoder for decoding the processing the demodulated signal to receive the transmitted data.

[0250] A transmitter chain 1112 may be configured to generate and transmit signals (e.g., control information, data, packets). The transmitter chain 1112 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmitter chain 1112 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 1112 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

[0251] Figure 12 illustrates an example of a processor 1200 in accordance with aspects of the present disclosure. The processor 1200 may be an example of a processor configured to perform various operations in accordance with examples as described herein. The processor 1200 may include a controller 1202 configured to perform various operations in accordance with examples as described herein. The processor 1200 may optionally include at least one memory 1204, which may be, for example, an L1/L2/L3 cache. Additionally, or alternatively, the processor 1200 may optionally include one or more arithmetic-logic units (ALUs) 1206. One or more of these components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0252] The processor 1200 may be a processor chipset and include a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) in accordance with examples as described herein. The processor chipset may include one or more cores, one or more caches (e.g., memory local to or included in the processor chipset (e.g., the processor 1200) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase change memory (PCM), and others).

[0253] The controller 1202 may be configured to manage and coordinate various operations (e.g., signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of the processor 1200 to cause the processor 1200 to support various operations in accordance with examples as described herein. For example, the controller 1202 may operate as a control unit of the processor 1200, generating control signals that manage the operation of various components of the processor 1200. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating timing of operations.

[0254] The controller 1202 may be configured to fetch (e.g., obtain, retrieve, receive) instructions from the memory 1204 and determine subsequent instruction(s) to be executed to cause the processor 1200 to support various operations in accordance with examples as described herein. The controller 1202 may be configured to track memory address of instructions associated with the memory 1204. The controller 1202 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 1202 may be configured to interpret the instruction and determine control signals to be output to other components of the processor 1200 to cause the processor 1200 to support various operations in accordance with examples as described herein. Additionally, or alternatively, the controller 1202 may be configured to manage flow of data within the processor 1200. The controller 1202 may be configured to control transfer of data between registers, arithmetic logic units (ALUs), and other functional units of the processor 1200.

[0255] The memory 1204 may include one or more caches (e.g., memory local to or included in the processor 1200 or other memory, such RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some implementations, the memory 1204 may reside within or on a processor chipset (e.g., local to the processor 1200). In some other implementations, the memory 1204 may reside external to the processor chipset (e.g., remote to the processor 1200).

[0256] The memory 1204 may store computer-readable, computer-executable code including instructions that, when executed by the processor 1200, cause the processor 1200 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. The controller 1202 and/or the processor 1200 may be configured to execute computer-readable instructions stored in the memory 1204 to cause the processor 1200 to perform various functions. For example, the processor 1200 and/or the controller 1202 may be coupled with or to the memory 1204, the processor 1200, the controller 1202, and the memory 1204 may be configured to perform various functions described herein. In some examples, the processor 1200 may include multiple processors and the memory 1204 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may, individually or collectively, be configured to perform various functions herein.

[0257] The one or more ALUs 1206 may be configured to support various operations in accordance with examples as described herein. In some implementations, the one or more ALUs 1206 may reside within or on a processor chipset (e.g., the processor 1200). In some other implementations, the one or more ALUs 1206 may reside external to the processor chipset (e.g., the processor 1200). One or more ALUs 1206 may perform one or more computations such as addition, subtraction, multiplication, and division on data. For example, one or more ALUs 1206 may receive input operands and an operation code, which determines an operation to be executed. One or more ALUs 1206 be configured with a variety of logical and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation. Additionally, or alternatively, the one or more ALUs 1206 may support logical operations such as AND, OR, exclusive-OR (XOR), not-OR (NOR), and not- AND (NAND), enabling the one or more ALUs 1206 to handle conditional operations, comparisons, and bitwise operations.

[0258] The processor 1200 may support wireless communication in accordance with examples as disclosed herein. The processor 1200 may be configured to or operable to support a means for performing various aspects of the present disclosure as described herein.

[0259] Figure 13 illustrates an example of a NE 1300 in accordance with aspects of the present disclosure. The NE 1300 may include a processor 1302, a memory 1304, a controller 1306, and a transceiver 1308. The processor 1302, the memory 1304, the controller 1306, or the transceiver 1308, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

[0260] The processor 1302, the memory 1304, the controller 1306, or the transceiver 1308, or various combinations or components thereof may be implemented in hardware (e.g., circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

[0261] The processor 1302 may include an intelligent hardware device (e.g., a general- purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof). In some implementations, the processor 1302 may be configured to operate the memory 1304. In some other implementations, the memory 1304 may be integrated into the processor 1302. The processor 1302 may be configured to execute computer-readable instructions stored in the memory 1304 to cause the NE 1300 to perform various functions of the present disclosure.

[0262] The memory 1304 may include volatile or non-volatile memory. The memory 1304 may store computer-readable, computer-executable code including instructions when executed by the processor 1302 cause the NE 1300 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such the memory 1304 or another type of memory. Computer-readable media includes both non- transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

[0263] In some implementations, the processor 1302 and the memory 1304 coupled with the processor 1302 may be configured to cause the NE 1300 to perform one or more of the functions described herein (e.g., executing, by the processor 1302, instructions stored in the memory 1304). For example, the processor 1302 may support wireless communication at the NE 1300 in accordance with examples as disclosed herein. The NE 1300 may be configured to support a means for performing various aspects of the present disclosure as described herein.

[0264] The controller 1306 may manage input and output signals for the NE 1300. The controller 1306 may also manage peripherals not integrated into the NE 1300. In some implementations, the controller 1306 may utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some implementations, the controller 1306 may be implemented as part of the processor 1302.

[0265] In some implementations, the NE 1300 may include at least one transceiver 1308. In some other implementations, the NE 1300 may have more than one transceiver 1308. The transceiver 1308 may represent a wireless transceiver. The transceiver 1308 may include one or more receiver chains 1310, one or more transmitter chains 1312, or a combination thereof. [0266] A receiver chain 1310 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 1310 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 1310 may include at least one amplifier (e.g., a low-noise amplifier (LN A)) configured to amplify the received signal. The receiver chain 1310 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 1310 may include at least one decoder for decoding the processing the demodulated signal to receive the transmitted data.

[0267] A transmitter chain 1312 may be configured to generate and transmit signals (e.g., control information, data, packets). The transmitter chain 1312 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmitter chain 1312 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 1312 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

[0268] Figure 14 illustrates a flowchart of a method in accordance with aspects of the present disclosure. The operations of the method may be implemented by a UE as described herein. In some implementations, the UE may execute a set of instructions to control the function elements of the UE to perform the described functions.

[0269] At 1401, the method may include determining, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE. The operations of 1401 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1401 may be performed by a UE as described with reference to Figure 11.

[0270] At 1402, the method may include transmitting, to a first apparatus of a wireless communication system, a first message comprising the one or more parameters. The operations of 1402 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1402 may be performed by a UE as described with reference to Figure 11.

[0271] It should be noted that the method 1400 described herein describes a possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0272] Figure 15 illustrates a flowchart of a method in accordance with aspects of the present disclosure. The operations of the method may be implemented by a processor in a UE as described herein.

[0273] At 1501, the method may include obtaining, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE. The operations of 1501 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1501 may be performed by a processor as described with reference to Figure 12.

[0274] At 1502, the method may include outputting, a first message comprising the one or more parameters. The operations of 1502 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1502 may be performed by a processor as described with reference to Figure 12.

[0275] It should be noted that the method 1500 described herein describes a possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0276] Figure 16 illustrates a flowchart of a method in a second UE in accordance with aspects of the present disclosure. The operations of the method may be implemented by a UE as described herein. In some implementations, the UE may execute a set of instructions to control the function elements of the UE to perform the described functions.

[0277] At 1601, the method may include receiving, from a second apparatus of a wireless communication system, a third message requesting the transmission of sidelink positioning reference signals to a third apparatus of the wireless communication system. The operations of 1601 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1601 may be performed by a UE as described with reference to Figure 11.

[0278] At 1602, the method may include determining, whether a maximum capacity for sidelink positioning reference signal transmission, has been reached by the second UE. The operations of 1602 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1602 may be performed by a UE as described with reference to Figure 11.

[0279] At 1603, the method may include if the determining is that the maximum capacity for sidelink positioning reference signal transmission has been reached: transmitting, to the second apparatus, a third response to the third message, wherein the third response comprises one or more parameters indicating that the maximum capacity for sidelink positioning reference signal transmission has been reached. The operations of 1603 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1603 may be performed by a UE as described with reference to Figure 11.

[0280] It should be noted that the method 1600 described herein describes a possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0281] Figure 17 illustrates a flowchart of a method in accordance with aspects of the present disclosure. The operations of the method may be implemented by a NE as described herein. In some implementations, the NE may execute a set of instructions to control the function elements of the NE to perform the described functions.

[0282] At 1701, the method may include receiving, from a UE, a first message comprising one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE. The operations of 1701 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1701 may be performed by a NE as described with reference to Figure 13. [0283] At 1702, the method may include determining, based at least partly on the one or more parameters, a second request for initiating sidelink positioning for the UE. The operations of 1702 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1702 may be performed by a NE as described with reference to Figure 13.

[0284] At 1703, the method may include transmitting, to the UE, the second request. The operations of 1703 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1703 may be performed a NE as described with reference to Figure 13.

[0285] It should be noted that the method described herein describes a possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0286] The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

[0287] The following abbreviations are relevant in the field addressed by this document: 3GPP, 3rd Generation Partnership Project; 5GC, 5G Core; 5GS, 5G System; A- GNSS, Assisted GNSS; AMF, Access and Mobility Management Function; AoA, Angle of Arrival; AoD, Angle of Departure; AS, Access Stratum; CM, Connection Management;

DL, Downlink; DL TDOA, Downlink Time Difference of Arrival; E-CID, Enhanced Cell ID; FR, Frequency Range; GMLC, Gateway Mobile Location Centre; GNSS, Global Navigation Satellite System; GPSI, Generic Public Subscription Identifier; HW, Hardware; IC, In-coverage; IIoT, Industrial loT; loT, Internet of Things; KPI, Key Performance Indicator; LCS, Location Services; LMF, Location Management Function; LOS, Line of Sight; LPP, LTE Positioning Protocol; LTE, Long Term Evolution; MIMO, Multiple Input Multiple Output; MO-LR, Mobile-Originated Location request; MT-LR, Mobile- Terminated Location request; Multi-RTT, Multi Round Trip Time; NAS, Non Access Stratum; NG-RAN, Next Generation RAN; NI-LR, Network Induced Location Request; NLOS, Non Line of Sight; NR, New Radio; NRPPa, NR Positioning Protocol A; OOC, Out-of-coverage; PC, Partial coverage; PDU, Protocol Data Unit; PHY, Physical Layer; PLMN, Public Land Mobile Network; PPP, Precise Point Positioning; ProSe, Proximitybased services; PRS, Positioning Reference Signal; PSAP, Public Safety Answering Point; QoS, Quality of Service; RAN, Radio Access Network; RAT, Radio Access Technology; RRC, Radio Resource Control; RSRP, Reference Signal Received Power; RSU, Roadside Unit; RTK, Real-Time Kinematic; SL, Sidelink; SLPP, Sidelink Positioning Protocol; SUPI, Subscription Permanent Identifier; SW, Software; TDOA, Time Difference of Arrival; TTFF, Time To First Fix; UE, User Equipment; UL, Uplink; V2X, Vehicle-to- Everything; and WID, Work Item Description.

Claims

CLAIMS What is claimed is:

1. A UE for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: determine, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; and transmit, to a first apparatus of a wireless communication system, a first message comprising the one or more parameters.

2. The UE of claim 1, wherein the at least one processor is configured to cause the UE to: receive, from the first apparatus, a second request for initiating sidelink positioning for the UE; and perform, in response to the second request, a sidelink positioning for the UE.

3. The UE of claim 2, wherein the at least one processor is configured to cause the UE to perform the sidelink positioning by causing the UE to: perform, with the first apparatus and/or a second apparatus of the wireless communication system, at least one of: a sidelink positioning assistance data transfer; a sidelink positioning, positioning-reference-signal ‘PRS’ transmission; a sidelink positioning, PRS measurement; a sidelink positioning measurement transfer; and a sidelink positioning, location estimate transfer.

4. The UE of any one of claims 2-3, wherein the at least one processor is configured to cause the UE to: receive, from the first apparatus, a first request for sidelink positioning capabilities of the UE; and then transmit the first message, in response to the first request.

5. The UE of claim 4, wherein: the first request comprises a Sidelink Request Capabilities message; the first message comprises a Sidelink Provide Capabilities message; and/or the second request comprises a Sidelink Request Location Information message.

6. The UE of any preceding claim, wherein the at least one processor is configured to cause the UE to determine the maximum number of sidelink positioning sessions, based on: a first reference parameter corresponding to a processing load; and/or a second reference parameter corresponding to a memory size.

7. The UE of any preceding claim, wherein the UE is selected from the list of UEs consisting of: a sidelink target UE; a sidelink anchor UE; and a sidelink server UE.

8. The UE of any preceding claim, wherein the first apparatus is selected from the list of apparatuses consisting of: a sidelink target UE; a sidelink anchor UE; a sidelink server UE; and a location management function ‘LMF’.

9. The UE of any preceding claim, wherein the at least one processor is configured to cause the UE to: determine whether: the maximum number of sidelink positioning sessions has been reached; and/or a maximum capacity for sidelink positioning assistance data supportable by the UE has been reached; and then if the maximum number of sidelink positioning sessions, and/or, the maximum capacity for sidelink positioning assistance data, is determined to be reached: transmit a second message to the first apparatus, wherein the second message comprises: an indication that the maximum number of sidelink positioning sessions has been reached; and/or an indication that the maximum capacity for sidelink positioning assistance data, has been reached.

10. The UE of claim 9, wherein the second message comprises a Sidelink Abort message or a Sidelink Error message.

11. A processor for a UE for wireless communication, comprising: at least one controller coupled with at least one memory and configured to cause the processor to: obtain, one or more parameters indicating a maximum number of sidelink positioning sessions that can be supported by the UE; and output, a first message comprising the one or more parameters.

12. The processor of claim 11, wherein the controller is configured to cause the processor to: retrieve, a second request for initiating sidelink positioning for the UE; and obtain, in response to obtaining the second request, a sidelink positioning for the

UE.

13. The processor of claim 12, wherein the controller is configured to cause the processor to obtain the sidelink positioning by causing the processor to perform at least one of: a sidelink positioning assistance data transfer; a sidelink positioning, positioning-reference-signal ‘PRS’ transmission; a sidelink positioning, PRS measurement; a sidelink positioning measurement transfer; and a sidelink positioning, location estimate transfer.

14. The processor of any one of claims 11-13, wherein the controller is configured to cause the processor to: retrieve, a first request for sidelink positioning capabilities of the UE; and then output the first message, in response to the first request.

15. The processor of claim 14, wherein: the first request comprises a Sidelink Request Capabilities message; the first message comprises a Sidelink Provide Capabilities message; and the second request comprises a Sidelink Request Location Information message.

16. The processor of any one of claims 11-15, wherein the controller is configured to cause the processor to obtain the maximum number of sidelink positioning sessions, based on: a first reference parameter corresponding to a processing load; and/or a second reference parameter corresponding to a memory size.

17. The processor of any one of claims 11-16, wherein the UE is selected from the list of UEs consisting of: a sidelink target UE; a sidelink anchor UE; and a sidelink server UE.

18. The processor of any one of claims 11-17, wherein the controller is configured to cause the processor to: determine whether: the maximum number of sidelink positioning sessions has been reached; and/or a maximum capacity for sidelink positioning assistance data supportable by the UE has been reached; and then if the maximum number of sidelink positioning sessions, and/or, the maximum capacity for sidelink positioning assistance data, is determined to be reached: output a second message, wherein the second message comprises: an indication that the maximum number of sidelink positioning sessions has been reached; and/or an indication that the maximum capacity for sidelink positioning assistance data, has been reached.

19. The processor of claim 18, wherein the second message comprises a Sidelink Abort message or a Sidelink Error message.

20. A second UE for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the second UE to: receive, from a second apparatus of a wireless communication system, a third message requesting the transmission of sidelink positioning reference signals to a third apparatus of the wireless communication system; determine, whether a maximum capacity for sidelink positioning reference signal transmission, has been reached by the second UE; and if the determination is that the maximum capacity for sidelink positioning reference signal transmission, has been reached: transmit, to the second apparatus, a third response to the third message, wherein the third response comprises one or more parameters indicating that the maximum capacity for sidelink positioning reference signal transmission has been reached.