Patent Publication Number: US-2023156431-A1

Title: Method and apparatus for improvements in and relating to localisation in a wireless communication system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 U.S.C. § 119 to United Kingdom Patent Application No. 2116341.5 filed on Nov. 12, 2021, United Kingdom Patent Application No. 2206513.0 filed on May 4, 2022, and United Kingdom Patent Application No. 2216703.5 filed on Nov. 9, 2022, in the United Kingdom Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     The disclosure relates to localisation in a wireless communication system. Localisation, in this context, refers to the process of the network determining the location of one or more user equipments (UEs) in a wireless communication system. Localisation may also be known as positioning and both terms are used interchangeably in the art. 
     2. Description of Related Art 
     5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in “Sub 6 GHz” bands such as 3.5 GHz, but also in “Above 6 GHz” bands referred to as mmWave including 28 GHz and 39 GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz (THz) bands (for example, 95 GHz to 3 THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies. 
     At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced mobile broadband (eMBB), ultra reliable low latency communications (URLLC), and massive machine-type communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of bandwidth part (BWP), new channel coding methods such as a low density parity check (LDPC) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service. 
     Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as vehicle-to-everything (V2X) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, new radio unlicensed (NR-U) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE power saving, non-terrestrial network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning. 
     Moreover, there has been ongoing standardization in air interface architecture/protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, integrated access and backhaul (IAB) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and dual active protocol stack (DAPS) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture/service regarding a 5G baseline architecture (for example, service-based architecture or service-based interface) for combining network functions virtualization (NFV) and software-defined networking (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE positions. 
     As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with extended reality (XR) for efficiently supporting augmented reality (AR), virtual reality (VR), mixed reality (MR) and the like, 5G performance improvement and complexity reduction by utilizing artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication. 
     Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as full dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources. 
     SUMMARY 
     The present disclosure relates to wireless communication systems and, more specifically, the present disclosure relates to a method and apparatus for improvements in and relating to localisation in a wireless communication system. 
     Embodiments of the present disclosure relate to the use of proximity services (ProSe) based device to device (D2D) localisation, which can be applied for localisation in different scenarios, from in-coverage group, or set, of UEs to range extension in connecting out-of-coverage UEs. A common feature of embodiments of the disclosure is the leveraging and enhancement of fifth generation (5G) ProSe direct communication and 5G ProSe UE-to-Network Relay techniques to support location reporting. Embodiments of the disclosure provide enhanced messaging between different functions to orchestrate this ProSe based localisation. Further, additional embodiments, including the configuration of localisation privacy indication (LPI) are disclosed. 
     3GPP SA2 completed the enhanced location services (eLCS) phase 2 work item in Release 17. There is strong support for both localisation and ProSe topic continuation. D2D based localisation may be prominent in SA2 Release 18, as there is also a strong interest in the RAN counterpart, the NR-sidelink based positioning. 
     A problem in the prior art is that there is currently no means provided to allow ProSe to support the obtaining of location estimates or assistance data for a group or set of UEs. This problem falls between the domains of localisation, ProSe and relaying. 
     It is an aim of embodiments of the present disclosure to address shortcomings in the prior-art and provide an improved localisation solution. 
     According to the present disclosure there is provided an apparatus and method as set below. Other features of the disclosure will be apparent from the description which follows. 
     According to an aspect of the disclosure, a solution is provided whereby ProSe based D2D localisation can be conducted for a group of UEs or set of UEs for the purpose of one or more of: signalling overhead reduction; out-of-coverage localisation; and under range extension. 
     Embodiments of the disclosure provide an architectural arrangement to initiate a 5G ProSe direct communication and a 5G ProSe UE-to-Network relay to share location information between a remote UE and 5G core (5GC) (e.g., a location management function, LMF). 
     Furthermore, a privacy issue may arise in these scenarios, as the UEs may pass their location information through a ProSe-enabled UE (as lead UE or a ProSe UE-to-Network relay) which may want to know such a lead UE before giving privacy consent. Embodiments of the disclosure provide a solution to achieve this LPI and update the 5GC (e.g., the LMF) on this LPI. 
     Embodiments of the disclosure enhance 5G ProSe direct communication and 5G ProSe UE-to-Network relay and associated capabilities for location reporting. In the following, reference is made to a Lead UE and/or a UE-to-Network relay. The skilled person will understand that, depending on the context, the lead UE may act as a UE-to-Network relay. 
     For the purposes of this disclosure, it is worth noting that the functionality of a 5G ProSe UE-to-Network relay (or lead UE) is assumed to be carried out by a so-called Reference UE, so the terms 5G ProSe UE-to-Network relay and a reference UE can be used indistinctly. In addition to the relaying capabilities proposed in this disclosure, a reference UE is understood to determine a reference plane and reference direction when performing ranging or sidelink positioning between two or more UEs, as defined in 3GPP TR 23.700-86. In addition, a UE acting as reference UE to other UEs may also act as positioning reference unit (PRU) to the network, whereby a PRU is defined as a UE with known location to the network that may assist with the enhancement of the positioning performance of other UE(s), as defined in 3GPP TS 38.305. 
     According to an aspect of the present disclosure, there is provided a system of localisation whereby a location management function (LMF) in the network is arranged to access certain other functions in the network to orchestrate this localisation, both in in-coverage and out-of-coverage scenarios. 
     In an embodiment, out-of-coverage localisation and/or under-range extension are achieved by means of configuring the LMF to orchestrate the localisation activity and to have contact with such other network functions as are required. In a preferred embodiment, this contact is direct contact. Details of this contact and the means by which this can be achieved are shown in the accompanying figures. 
     A first aspect provides a method of conducting localisation based on proximity services, ProSe, (e.g., ProSe based D2D localisation) for a set of UEs, in a 5G network comprising the set of UEs, an access and mobility management function (AMF), a location management function (LMF), and a ProSe application server (AS) for example for a purpose of signalling overhead reduction and/or range extension, by initiating a 5G ProSe direct communication, for example between UEs of the set of UEs and a reference UE, for example included in the set of UEs, to share and/or relay location information between and/or from a remote UE, included in the set of UEs, for example via the reference UE and/or a 5G core, 5GC, (e.g., a 5GC entity) for example the LMF. 
     In an embodiment, the method comprises registering, by the set of UEs, ProSe capabilities thereof the AMF, for example with an intention to select a UE from the set of UEs or from outside the set of UEs if the UE is in D2D range, as a reference UE. In one example, the role of the reference UE is fulfilled by a positional reference unit (PRU), as defined in 3GPP Release 18. 
     In an embodiment, registering, by the set of UEs, the ProSe capabilities thereof with the AMF comprises giving, by the set of UEs to the AMF, location privacy indicators (LPIs), for localisation based on ProSe thereof. 
     In an embodiment, the method comprises starting, by the LMF, localisation procedures. 
     In an embodiment, the method comprises identifying, by the LMF, the set of UEs with certain group or collective behaviour. 
     In an embodiment, the method identifying, by the LMF, the set of UEs with certain group or collective behaviour is based on internal logic within the LMF or input data from other Network Functions, NFs. 
     In an embodiment, identifying, by the LMF, the set of UEs with certain group or collective behaviour comprises considering, by the LMF, all UEs within an area of interest for ProSe based localisation, leaving any grouping or pairing to direct discovery protocol of the ProSe. 
     In an embodiment, the method comprises checking, by the LMF, the ProSe capabilities of the set of UEs registered with the AMF. 
     In an embodiment, the method comprises requesting or subscribing, by the LMF, a newly defined service of the ProSe AS to initiate relay for location reporting for the set of UEs; or interacting, by the LMF with a policy control function, PCF, to initiate relay for location reporting for the set of UEs. 
     In an embodiment, the method comprises authorizing and configuring, by the ProSe application server or the PCF, a UE of the set of UEs as the reference UE, through which the other UEs of the set of UEs relay location information to the 5GC and LMF. In one example, the reference UE is outside the set of UEs but still within D2D range or, the reference UE role is fulfilled by a PRU (Positional Reference Unit). 
     In an embodiment, the method comprises configuring or provisioning the reference UE with special relay service codes (RSCs) authorized for location reporting, optionally wherein the special RSCs are provided by the PCF or already provisioned in the Mobile Equipment, ME, or the reference UE, or configured in the universal integrated circuit card (UICC). 
     In an embodiment, the method comprises authorizing, configuring or provisioning, by the ProSe application server or the PCF, the other UEs of the set thereof with special RSCs authorized for location reporting, optionally wherein the special RSCs are provided by the PCF or already provisioned in the ME or configured in the UICC. 
     In an embodiment, the method comprises conducting ProSe relay discovery on the identified set of UEs with special RSCs based on either discovery model A or discovery model B, wherein the discovery model A and the discovery model B are defined in TS 23.303 and TS 23.304, respectively. 
     In an embodiment, the method comprises establishing connections over PC5 between the reference UE and the other UEs of the set thereof, for the discovered set of UEs. 
     In an embodiment, the method comprises responding or notifying, by the ProSe AS or the PCF to the LMF, when the relay configuration is complete. 
     In an embodiment, the method comprises requesting, by the LMF location data from multiple UEs of the set thereof, via the reference UE. 
     In an embodiment, the method comprises initiating, by the reference UE, side-link based positioning for the multiple UEs of the set thereof, optionally including: obtaining, by the reference UE through the side-link, position estimates from the set of UEs; by the reference UE through the side-link, obtaining, by the reference UE through the side-link, which UE of the set of UEs may carry out UE based positioning; obtaining, by the reference UE through the side-link, positioning assistance data from the set of UEs; and/or executing, by the reference UE through the side-link, a side-link based positioning method and gaining position information of the group of UEs. 
     In an embodiment, the method comprises relaying, by the reference UE, location reporting data back to the LMF. 
     In an embodiment, the method is carried out with the support of a positional reference unit (PRU) instead of a reference UE. 
     In an embodiment, the signalling overhead reduction is by means of positioning protocol messages and/or range extension by gaining location information of UEs outside the network coverage area. 
     In an embodiment, the location information is passed onto a location service (LCS) client through the AMF and a gateway mobile location centre (GMLC). 
     A second aspect provides a 5G network comprising a set of UEs, an access and mobility management function (AMF), a location management function, (LMF), and a ProSe application server (AS) configured to implement the method according to the first aspect. 
     Although a few preferred embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the disclosure, as defined in the appended claims. 
     For a better understanding of the disclosure, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example only, to the accompanying diagrammatic drawings in which: 
     Aspects of the present disclosure provide efficient communication methods in a wireless communication system. 
     Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. 
     Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device. 
     Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: 
         FIG.  1    illustrates a representation of a first scenario according to an embodiment of the present disclosure; 
         FIG.  2    illustrates a representation of a second scenario according to an embodiment of the present disclosure; 
         FIG.  3    illustrates a message flow associated with the first scenario according to an embodiment of the present disclosure; 
         FIG.  4    illustrates a message flow associated with the second scenario according to an embodiment of the present disclosure. 
         FIG.  5    illustrates a structure of a UE according to an embodiment of the present disclosure; 
         FIG.  6    illustrates a structure of a base station according to an embodiment of the present disclosure; and 
         FIG.  7    illustrates a structure of a network entity according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS.  1  through  7   , discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device. 
     Accordingly, the embodiment herein is to provide a method of conducting localisation based on ProSe for a set of UEs in a 5G network comprising the set of UEs, an AMF, a LMF, and a ProSe AS by initiating a 5G ProSe direct communication between UEs of the set of UEs and a reference UE, to relay location information from a remote UE, included in the set of UEs, via the reference UE and a 5G core, 5GC, entity for example the LMF. The method includes registering, by the set of UEs, ProSe capabilities thereof with the AMF, for example with an intention to select a UE from the set of JEs or from outside the set of UEs if the UE is in D2D range, as the reference UE; optionally wherein the role of the reference UE is fulfilled by a PRU. Further, the method includes starting, by the LMF, localisation procedures. Further, the method includes identifying, by the LMF, the set of UEs with certain group or collective behaviour. 
     In an embodiment, the method includes registering, by the set of UEs, the ProSe capabilities thereof with the AMF comprises giving, by the set of UEs to the AMF, LPIs for localisation based on ProSe thereof. 
     In an embodiment, the method includes identifying, by the LMF, the set of UEs with certain group or collective behaviour is based on internal logic within the LMF or input data from other NFs. 
     In an embodiment, the method includes identifying, by the LMF, the set of UEs with certain group or collective behaviour comprises considering, by the LMF, all UEs within an area of interest for ProSe based localisation, leaving any grouping or pairing to direct discovery protocol of the ProSe. 
     In an embodiment, the method includes checking, by the LMF, the ProSe capabilities of the set of UEs registered with the AMF. 
     In an embodiment, the method includes comprising requesting or subscribing, by the LMF, a newly defined service of the ProSe AS to initiate relay for location reporting for the set of JEs; or interacting, by the LMF with a Policy Control Function, PCF, to initiate relay for location reporting for the set of UEs. 
     In an embodiment, the method includes authorizing and configuring, by the ProSe application server or the PCF, a UE of the set of UEs as the reference UE, through which the other UEs of the set of UEs relay location information to the 5GC and LMF; optionally wherein the reference UE is outside the set of UEs but still within D2D range or optionally wherein the reference UE role is fulfilled by an PRU. 
     In an embodiment, the method includes configuring or provisioning the reference UE with special RSCs authorized for location reporting, optionally wherein the special RSCs are provided by the PCF or already provisioned in the mobile equipment (ME), or the reference UE, or configured in the UICC. 
     In an embodiment, the method includes authorizing, configuring or provisioning, by the ProSe application server or the PCF, the other UEs of the set thereof with special RSCs authorized for location reporting, optionally wherein the special RSCs are provided by the PCF or already provisioned in the ME or configured in the UICC. 
     In an embodiment, the method includes conducting ProSe relay discovery on the identified set of UEs with special RSCs based on either discovery model A or discovery model B. Further, the method includes establishing connections over PC5 between the reference UE and the other UEs of the set thereof, for the discovered set of UEs. 
     In an embodiment, the method includes responding or notifying, by the ProSe AS or the PCF to the LMF, when the relay configuration is complete. Further, the method includes requesting, by the LMF location data from multiple UEs of the set thereof, via the reference UE. 
     In an embodiment, the method includes initiating, by the reference UE, side-link based positioning for the multiple UEs of the set thereof. Further, the method optionally includes obtaining, by the reference UE through the side-link, position estimates from the set of UEs; by the reference UE through the side-link, obtaining, by the reference UE through the side-link, which UE of the set of UEs may carry out UE based positioning, obtaining, by the reference UE through the side-link, positioning assistance data from the set of UEs, and executing, by the reference UE through the side-link, a side-link based positioning method and gaining position information of the group of UEs. 
     In an embodiment, the method is carried out with the support of a PRU instead of a reference UE. the signalling overhead reduction is by means of positioning protocol messages and/or range extension by gaining location information of UEs outside the network coverage area and the location information is passed onto an LCS client through the AMF and a GMLC. 
     Accordingly, the embodiment herein is to provide A 5G network comprising a set of UEs, an AMF, an LMF, and a ProSe AS. 
     A first embodiment of the present disclosure relates to a first scenario concerned with reducing an overhead associated with location signalling. 
     Many high-volume localisation applications (such as stadium/theme park/train platform entry and shopping mall visitor tracking) show intrinsic group or collective behaviour patterns among the users. These joint patterns can be identified and effectively used in D2D based localisation to reduce the signalling overheads significantly. Architectural support for D2D based localisation has not yet discussed in standardisation meetings, and is likely to be a key topic for a future release. In this scenario, all the UEs may be “in coverage,” i.e., the 5GC (e.g., an LMF) may be able to communicate with the individual UEs directly. 
     The LMF may preferably identify possible UEs to perform localisation in a D2D mode. This also requires interaction with 5GC (e.g., AMF, the ProSe application server, PCF or UDM), as will be outlined below, to check the ProSe capabilities of the UEs and to check the updated LPI status of each UE to share location information through another UE (e.g., a lead or a ProSe UE-to-Network Relay). Even with a sub-set of the initially identified UEs, significant savings in positioning protocol message overheads (e.g., LPP) between the UE and the network can be achieved as shown in 3GPP standard specification. 
       FIG.  1    through  FIG.  7   , discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device. 
       FIG.  1    illustrates a representation of a first scenario according to an embodiment of the present disclosure. 
     A depiction of a location signalling reduction in this scenario  1  is shown in  FIG.  1   , which shows a stadium  101  having a 5G-NR access point  110  having an associated coverage area  111 . Within the coverage area are a plurality of individual users. Some of these users may be considered as one or more identified user groups  120 , as set out above. 
     A second embodiment relates to localisation through non-public network range extension. 
     In this scenario, D2D links are used to extend the range of a network, in particular a private or non-public network (NPN). In this example, the network whose range is extended is an Industry IoT (IIoT) network, where the NPN spans the area of the industry site and is operable to locate all the people and connected devices (lorries, forklifts etc) within the site for reasons such as process efficiency or safety/security. 
       FIG.  2    shows a representation of this scenario. 
       FIG.  2    illustrates a representation of a second scenario according to an embodiment of the present disclosure. 
     A factory or similar environment has an IIoT network which has a coverage area depicted by  200 . Outside this area, there is a PLMN  220 . 
     There may be related people or devices just outside the site (and beyond the NPN full coverage area), where the NPN network may have a legitimate reason or benefit in localizing such devices. As an example, these devices may be lorries  210  carrying supplies to the site, which are waiting in a queue to get clearance to enter. As the NPN APs may have weaker coverage as the queue extends beyond the range of the NPN, the NPN has to rely on the PLMN if this is available at the site. However, extra payments may have to be made to the PLMN to get this service and delays in the service can also occur, both of which are undesirable. 
     An alternative and a cost/time efficient solution is to utilize the D2D (i.e., ProSe) connection capability between the devices (or UEs) of the lorries in this scenario. Such D2D links are shown by the arrows between the lorries  210 . The First lorry in the queue (i.e., the one nearest the factory) may have reasonable coverage from the NPN and can be localized through the NPN APs. The first lorry (or device) can request the use of D2D capability from subsequent lorries in the queue —for them to be localized through D2D. Furthermore, for this localisation process, relaying messages through the lead UE (i.e., the first lorry) can be configured. 
     This example shows a form of range extension of the NPN, achieved through the first device in the queue, which has good connections to the NPN. The range of the NPN is effectively extended by means of the D2D links between the first and subsequent lorries. In this way, a remote lorry which may be unreachable for being beyond the range of the NPN, can still be localised by the NPN via use of the D2D link(s) between the remote lorry and the NPN, possibly via one or more intermediate lorries. 
       FIG.  3    illustrates a message flow associated with the first scenario. 
     Returning to the first embodiment,  FIG.  3    shows a message flow diagram associated with this embodiment. 
     One of the main benefits of identifying intrinsic groups  120  within the plurality of users shown in  FIG.  1    and using ProSe within the group or set of UEs to relay location information back to the 5GC (e.g., LMF) in this scenario is the overhead reduction in positioning protocol messages. It is assumed that there is a periodic localisation request from a LCS client and the initial localisation steps are already conducted, and the LMF has started individual tracking of the UEs. In some applications (e.g., in private networks), the UEs may readily share the location information with any other member UEs, so it can be assumed that the LPI is already granted for ProSe scenarios before the start of the localisation process. The associated call flow is shown In  FIG.  3    and details of the individual steps follow. 
     At step  302 , the ProSe capabilities of the UEs  300 ,  301  may be registered with the AMF  310  beforehand. A new information element (IE) may be registered as part of this step indicating the support for location reporting in addition to other ProSe capabilities. Also, the LPI for ProSe based localisation may be given by the UE&#39;s at this stage, again to the AMF  310 . 
     When the localisation request comes from the LCS  360  client for a high-volume application, the LMF  320  may start the localisation procedures as in a default scenario for periodic location requests, as given by 3GPP standard specification TS23.273. 
     At step  303 , the LMF  320  may identify a set of UEs  300 ,  301  with certain group or collective behaviour and thus can take steps to initiate the ProSe based localisation for these UEs. This can be based on internal logic within LMF or input data from other NFs. Alternatively, the LMF  320  may consider all UEs within an area of interest for ProSe based localisation, leaving any grouping or pairing to the direct discovery protocol of the ProSe. 
     At Step  304 , the LMF  320  may check the ProSe capabilities registered for the UEs (in Step  302 ), with the AMF  310 . 
     At Step  305 , for the UEs supporting ProSe capability (including also location reporting), the LMF  320 , may request or subscribe to a newly defined service of the ProSe application server  330  to initiate Relay for location reporting. As an alternative, the LMF  320  may interact with policy control function (PCF)  330  instead of ProSe application server  330  for step  305 . 
     At Step  306 , the ProSe application server (or the PCF)  330  may authorize and configure a UE as lead UE  301  or a ProSe UE-to-Network relay through which the other UEs  300  can relay location information to the 5GC and LMF  320 . The lead UE  201  is configured or provisioned with special Relay Service Codes (RSCs) authorized for location reporting. This is provided by the PCF  330  or already provisioned in the ME or UE, or configured in the universal integrated circuit card (UICC). 
     At step  307 , the ProSe application server (or the PCF)  330  may authorize, configure or provision other UEs with special RSCs authorized for location reporting. This is provided by the PCF  330  or already provisioned in the ME or configured in the UICC. 
     At Step  308 , the ProSe relay discovery on the UEs identified in Steps  303  to  305 , is conducted with special RSCs based on either model A or model B. The discovery model A and discovery model B are known in the prior art as defined in TS 23.303 and TS 23.304. 
     once discovered, the connections between the lead UE  301  or a ProSe UE-to-Network relay and the other UEs  300  are established over PC5. 
     At step  309  and  311 , the ProSe application server (or PCF)  330  may respond or notify to the LMF  320 , when the relay configuration is complete (e.g., based on a notification received by AMF  310  or SMF (not shown) from the ProSe UE-to-Network relay after completion). It is not necessary to establish any user plane (UP) protocol data unit (PDU) session for such special RSCs between the ProSe UE-to-Network relay and network as such RSCs may not be associated with any specific PDU session parameters. 
     At step  312 , the LMF  220  may request location data from multiple UEs  300 , via the lead UE  301  or ProSe UE-to-Network relay. 
     At step  313 , the lead UE  301  or ProSe UE-to-Network relay may initiate side-link based positioning for the multiple UEs  300  (as instructed by the LMF  320  in step  312 ). This may include obtaining position estimates from the group of UEs  300 , who may carry out UE based positioning, obtaining positioning assistance data from these UEs or even executing a side-link based positioning method (and gaining position information of the group of UEs). Whatever the method used, the lead UE  301  or ProSe UE-to-Network relay may collect this data through the side-link in step  313 . 
     At step  314  to  315 , the UEs  300  may provide this data over PC5 communication session to the lead UE  201  as established in step  308 ,  309 , and  311 . 
     At step  316 , the lead UE  301  or ProSe UE-to-Network relay may relay location reporting data back to the LMF  320 . This can be over NAS MM messages via the AMF  310  or NAS SM messages via SMF (not shown). The signalling overhead reduction comes by means of positioning protocol messages (e.g., LPP) from the lead UE  301  or ProSe UE-to-Network relay to the LMF  320 . If the location information from multiple UEs is concatenated into fewer protocol messages at the lead UE  301  or at the ProSe UE-to-Network relay, then there are significant signalling overhead savings, when compared to prior art techniques where such a direct link between the lead UE  301  and the LMF  320  is not possible. 
     In steps  317  to  319 , the location information is passed onto the LCS client  360 , through the AMF  310  and the GMLC  340 . These steps are not changed from the default location responses in the prior art in TS23.273. 
     The configuration (or provisioning) of the lead UE  301  or other UEs in step  306  or step  307  can be considered as part of ProSe Policy, as one component in UE route selection policy (URSP) or as part of any other side link/ranging policies to be configured (or provisioned) to the sidelink positioning-enabled UEs for this purpose. 
     Special RSCs in steps  306  to  308  (or step  309  and  311 ) can be replaced by any other ProSe identifiers or side link identifiers exchanged as part of discovery operations for sidelink positioning and ranging in order to authorize location reporting. 
     As will be appreciated, the direct messaging between the lead UE  301  and the LMF  320  reduces the signalling overhead significantly. 
     In the previous description, relating to  FIG.  3   , it was assumed that the LPI is provided to the AMF  310  before the ProSe based localisation process begins. However, in some situations, the UEs  300 ,  301  may want to provide or update their LPI (e.g., on the fly or in real time). This is especially true in cases where the networks are more open to subscribers and where the set of UEs, groups and lead UEs are chosen from a wide variety of UEs. 
     In another embodiment of this disclosure, the AMF  310  advises the LMF  320  and/or GMLC  340  of the need for LPI, in step  304 . The LMF  320  and/or GMLC  340  may then indicate the need for LPI to the ProSe application server (or PCF)  330 , in the message in step  305 . The ProSe application server (or PCF)  330 , in steps  306  and  307 , may indicate to the UEs (lead UE  301  or ProSe UE-to-Network relay and other UEs  300 ) to provide the new LPI to the AMF  310 . The UEs (this can be a subset of UEs if all of the UEs do not agree on using ProSe for localisation in this context) may provide the LPI in NAS messaging to the AMF  310  at this stage, and the AMF  310  may record these LPIs in the user data repository (UDR), to be accessed via the unified data management function (UDM)  350 . These steps are additional steps, positioned between steps  307  and  308  in the message flow shown in  FIG.  3   . 
     The LMF  320  and/or GMLC  340  then checks the LPI status with the UDM  350  in a new step, preceding step  312 . 
     Once the LMF  320  and/or the GMLC  340  receives the LPI indications from the UDM  350 , the LMF  320  (or LMF  320  on notification from GMLC  340 ) only selects the UEs who have given a positive LPI. The LMF  320  requests the location information for these UEs from the lead UE  301  or ProSe UE-to-Network relay in step  312 . The remaining steps may follow, as in  FIG.  3   , for this subset of UEs. 
     Referring again to  FIG.  2    and the scenario depicted therein, this embodiment relates to a situation where out-of-coverage UEs can relay their location through an in-coverage UE, for commercial applications. A private NPN is assumed in this illustration, where all UEs (and devices) within and coming into the NPN have given their privacy consent to be localized by the NPN. This range extension situation occurs when some of the UEs of the lorries  210  are just outside the NPN  200 , waiting for entry into the industry premises. However, these UEs or devices may not have given their privacy consent to be localized through another “lead” UE or ProSe UE-to-Network Relay. In this case, explicit LPI is needed to proceed with the ProSe based localisation and then Relaying. This issue is addressed in the following. 
       FIG.  4    illustrates a message flow associated with the second scenario according to an embodiment of the present disclosure. 
       FIG.  4    shows a call flow according to this embodiment of the disclosure. The entities here share reference numerals with similar entities in  FIG.  3   , but it will be appreciated that each may perform different functions depending upon the exact embodiment. The steps are labelled  401  to  419 . 
     At step  401 , the call flow starts registration including new 5G ProSe capabilities. With a multiple UE localisation request by the LCS client  360 . The LMF  320  carries out these localisations as per the default MT-LR procedure detailed in TS 23.273, known in the prior art. 
     At Step  402 , the LMF  320  notices that some of the UEs  300  or devices needing localisation are not within the NPN  100 . 
     At Step  403 , the LMF  320  makes ProSe capability checks for these devices (from Step  402 ) with the AMF  310 . These ProSe capabilities may have been registered with the AMF previously, or even the wider PLMN can be used by the AMF to carry out these capability checks, as part contained in TS 23.700-07. 
     At Step  404 , for the UEs that show ProSe capability, the LMF  320  requests the ProSe Application Server (or PCF)  330  to initiate ProSe configuration, through UE(s) at the cell edge of the NPN. 
     At Steps  405  and  406 , the ProSe authorization, configuration and provisioning is carried out by the ProSe application server (or the PCF)  330 . The lead UE  301  configuration at the cell edge can be done through the NPN, but for the other “remote” UEs, the configuration is done based on parameters already provisioned in the ME or UE or configured in the UICC. 
     At steps  407 , the relay discovery for the special RSC&#39;s used and the establishment of a PC5 communication session are executed. These steps are similar to steps  308  of  FIG.  3    and so are not described again. 
     At Step  408 , the ProSe AS or the PCF  330  respond back to the LMF  320 , indicating the establishment of the Relay links. This step is similar to step  309  and  311  of  FIG.  3   . 
     At Step  409 , the UEs provide LPI through NAS messaging to the AMF  310 . This step is optional, as in some cases, the UE configuration itself can carry this consent for localisation in the relay mode. Physically, these messages are relayed through by the lead UE  301 . The LPI are then recorded in the UDR and managed by UDM  350 , as shown in step  410 . 
     For step  411  and  412 , there are two possible variants. In the first variant (step  411 ), the LMF  320  accesses the AMF  310  to acquire an update of the LPI information. The AMF  310  exchanges messages with the UDM  350  and then the AMF  310  can report back to the LMF  220 . In the second variant (step  412 ), the LMF  320  (either itself or in coordination with the GMLC  340 ) directly accesses the UDM  350  for LPI information for these multiple UEs. Step  411  is the quicker option but requires some changes to the capabilities of LMF  320  to enable this direct access. 
     At Step  413 , for the UEs who provide positive LPI, the LMF  320  may request the lead UE  301  to provide the location information. 
     Steps  414  to  419  are similar to steps  313  to  319  shown in  FIG.  3   , so further description is omitted for brevity. 
     The configuration (or provisioning) of the lead UE  301  or other UEs in step  405  or step  406  can be considered as part of ProSe Policy, as one component in UE Route Selection Policy (URSP) or as part of any other side link/ranging policies to be configured (or provisioned) to the Sidelink Positioning-enabled UEs for this purpose. 
     Special RSCs in steps  405  to  407  can be replaced by any other ProSe identifiers or side link identifiers exchanged as part of discovery operations for Sidelink Positioning and Ranging in order to authorize location reporting. 
       FIG.  5    illustrates a structure of a UE according to an embodiment of the disclosure. Furthermore, the UE may correspond to UE  200 ,  201  of  FIGS.  3  and  4   . 
     As shown in  FIG.  5   , the UE according to an embodiment may include a transceiver  510 , a memory  520 , and a processor  530 . The transceiver  510 , the memory  520 , and the processor  530  of the UE may operate according to a communication method of the UE described above. However, the components of the UE are not limited thereto. For example, the UE may include more or fewer components than those described above. In addition, the processor  530 , the transceiver  510 , and the memory  520  may be implemented as a single chip. Also, the processor  530  may include at least one processor. 
     The transceiver  510  collectively refers to a UE receiver and a UE transmitter, and may transmit/receive a signal to/from a base station or a network entity. The signal transmitted or received to or from the base station or a network entity may include control information and data. The transceiver  510  may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver  510  and components of the transceiver  510  are not limited to the RF transmitter and the RF receiver. 
     Also, the transceiver  510  may receive and output, to the processor  530 , a signal through a wireless channel, and transmit a signal output from the processor  530  through the wireless channel. 
     The memory  520  may store a program and data required for operations of the UE. Also, the memory  520  may store control information or data included in a signal obtained by the UE. The memory  520  may be a storage medium, such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media. 
     The processor  530  may control a series of processes such that the UE operates as described above. For example, the transceiver  510  may receive a data signal including a control signal transmitted by the base station or the network entity, and the processor  530  may determine a result of receiving the control signal and the data signal transmitted by the base station or the network entity. 
       FIG.  6    illustrates a structure of a base station according to an embodiment of the present disclosure. Furthermore, the base station may correspond to base station of  FIG.  2   . 
     As shown in  FIG.  6   , the base station according to an embodiment may include a transceiver  610 , a memory  620 , and a processor  630 . The transceiver  610 , the memory  620 , and the processor  630  of the base station may operate according to a communication method of the base station described above. However, the components of the base station are not limited thereto. For example, the base station may include more or fewer components than those described above. In addition, the processor  630 , the transceiver  610 , and the memory  620  may be implemented as a single chip. Also, the processor  630  may include at least one processor. 
     The transceiver  610  collectively refers to a base station receiver and a base station transmitter, and may transmit/receive a signal to/from a terminal or a network entity. The signal transmitted or received to or from the terminal or a network entity may include control information and data. The transceiver  610  may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver  610  and components of the transceiver  610  are not limited to the RF transmitter and the RF receiver. 
     Also, the transceiver  610  may receive and output, to the processor  630 , a signal through a wireless channel, and transmit a signal output from the processor  630  through the wireless channel. 
     The memory  620  may store a program and data required for operations of the base station. Also, the memory  620  may store control information or data included in a signal obtained by the base station. The memory  620  may be a storage medium, such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media. 
     The processor  630  may control a series of processes such that the base station operates as described above. For example, the transceiver  610  may receive a data signal including a control signal transmitted by the terminal, and the processor  630  may determine a result of receiving the control signal and the data signal transmitted by the terminal. 
       FIG.  7    illustrates a structure of a network entity according to an embodiment of the present disclosure. 
     As shown in  FIG.  7   , the network entity of the present disclosure may include a transceiver  710 , a memory  720 , and a processor  730 . The transceiver  710 , the memory  720 , and the processor  730  of the network entity may operate according to a communication method of the network entity described above. However, the components of the terminal are not limited thereto. For example, the network entity may include more or fewer components than those described above. In addition, the processor  730 , the transceiver  710 , and the memory  720  may be implemented as a single chip. Also, the processor  730  may include at least one processor. 
     The transceiver  710  collectively refers to a network entity receiver and a network entity transmitter, and may transmit/receive a signal to/from a base station or a UE. The signal transmitted or received to or from the base station or the UE may include control information and data. In this regard, the transceiver  710  may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver  710  and components of the transceiver  710  are not limited to the RF transmitter and the RF receiver. 
     Also, the transceiver  710  may receive and output, to the processor  730 , a signal through a wireless channel, and transmit a signal output from the processor  730  through the wireless channel. 
     The memory  720  may store a program and data required for operations of the network entity. Also, the memory  720  may store control information or data included in a signal obtained by the network entity. The memory  720  may be a storage medium, such as ROM, RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. 
     The processor  730  may control a series of processes such that the network entity operates as described above. For example, the transceiver  710  may receive a data signal including a control signal, and the processor  730  may determine a result of receiving the data signal. 
     At least some of the example embodiments described herein may be constructed, partially or wholly, using dedicated special-purpose hardware. Terms such as “component,” “module” or “unit” used herein may include, but are not limited to, a hardware device, such as circuitry in the form of discrete or integrated components, a field programmable gate array (FPGA) or application specific integrated circuit (ASIC), which performs certain tasks or provides the associated functionality. In some embodiments, the described elements may be configured to reside on a tangible, persistent, addressable storage medium and may be configured to execute on one or more processors. These functional elements may in some embodiments include, by way of example, components, such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. Although the example embodiments have been described with reference to the components, modules and units discussed herein, such functional elements may be combined into fewer elements or separated into additional elements. Various combinations of optional features have been described herein, and it will be appreciated that described features may be combined in any suitable combination. In particular, the features of any one example embodiment may be combined with features of any other embodiment, as appropriate, except where such combinations are mutually exclusive. Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of others. 
     Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. 
     All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. 
     Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. 
     The disclosure is not restricted to the details of the foregoing embodiment(s). The disclosure extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. 
     Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.