WO2022013593A1

WO2022013593A1 - User identification based on location information from a third party

Info

Publication number: WO2022013593A1
Application number: PCT/IB2020/056559
Authority: WO
Inventors: Miguel Angel PUENTE PESTAÑA
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2020-07-13
Filing date: 2020-07-13
Publication date: 2022-01-20
Also published as: EP4179757A1

Abstract

Systems and methods for user identification using a cellular communications system are disclosed. In one embodiment, a method for user identification comprises, at a Network Exposure Function (NEF), receiving a user identification request from an Application Function (AF) comprising information that indicates a location(s) of a user for which identification is requested and sending the user identification request to a Network Data Analytics Function (NWDAF). The method further comprises, at the NWDAF, receiving the user identification request, obtaining a User Equipment (UE) identity of a UE for which a location(s) of the UE match the location(s) of the user, obtaining subscription data for the UE, and sending a user identification response comprising the UE identity and/or at least some of the subscription data for the UE. The method further comprises, at the NEF, receiving the user identification response and sending the user identification response to the AF.

Description

USER IDENTIFICA TION BASED ON LOCA TION INFORMA TION FROM A THIRD

PARTY

Technical Field

[0001] The present disclosure relates to resolving a user identification request in a cellular communications system from a third party.

Background

[0002] Closed-Circuit Television (CCTV), also known as video surveillance, is the use of video cameras to transmit a signal to a specific place on a limited set of monitors.

The signal is not openly transmitted, though it may employ Point-to-Point (P2P), Point- to-Multipoint (P2MP), or mesh wired or wireless links. The term is most often applied to those used for surveillance in areas that may need monitoring such as banks, stores, and other areas where security is needed. Some example uses of CCTV are crime prevention, crime solving, body worn cameras, traffic flow monitoring, vehicle traffic monitoring, pedestrian traffic monitoring, public transport monitoring (e.g., for increasing safety and security), monitoring at sporting events, employee monitoring, monitoring in schools, monitoring in private planes, and monitoring in homes.

[0003] Using video content analysis, computer-controlled cameras can identify, track, and categorize objects in their field of view. Video content analysis, also referred to as video analytics, is the capability of automatically analyzing video to detect and determine temporal events not based on a single image, but rather based on object classification. Video content analysis can also be used to detect unusual patterns in an environment. The system can be set to detect anomalies in a crowd, for instance a person moving in the opposite direction in which they are normally expected (e.g., debarking from a plane at an airport or exiting through an entrance in a subway).

There are different approaches to implementing video content analysis technology.

Data may be processed on the camera itself (i.e., edge processing) or by a centralized server.

[0004] Video content analysis enables detection and categorization of objects, such as people, within the field of view of the cameras. However, in addition to detecting that a person is within the field of view, there is a need to also identify that person. [0005] Systems and methods are disclosed herein for identification of a person (referred to herein as a "user") using collaboration between a content service provider (e.g., a video surveillance system) and a network service provider (e.g., a cellular communications system). In one embodiment, a method for user identification using a cellular communications system comprises, at a Network Exposure Function (NEF), receiving a user identification request from an Application Function (AF) where the user identification request comprises information that indicates one or more locations of a user for which identification is requested, and sending the user identification request to a Network Data Analytics Function (NWDAF). The method further comprises, at the NWDAF, receiving the user identification request from the NEF, obtaining a User Equipment (UE) identity of a UE for which one or more locations of the UE match the one or more locations of the user indicated by the information comprised in the user identification request, obtaining subscription data for the UE having the obtained UE identity, and sending a user identification response to the NEF, where the user identification response comprises the UE identity of the UE, at least some of the subscription data for the UE, or both the UE identity of the UE and at least some of the subscription data for the UE. The method further comprises, at the NEF, receiving the user identification response from the NWDAF and sending the user identification response to the AF. This user identification procedure enables collaboration between a cellular communications system of a network service provider and a third party AF to provide user identification.

[0006] In one embodiment, obtaining the UE identity of the UE for which the one or more locations of the UE match the one or more locations of the user indicated by the information comprised in the user identification request comprises sending a UE identity request to an Access and Mobility Management Function (AMF) where the UE identity request comprises information that indicates the one or more locations of the user, and receiving the UE identity from the AMF in response to the UE identity request.

[0007] In one embodiment, the one or more locations of the user indicated by the information comprised in the user identification request consist of a current location of the user.

[0008] In one embodiment, the method further comprises, at the NWDAF, collecting UE location data for a plurality of UEs in the cellular communications system. Further, obtaining the UE identity of the UE for which the one or more locations of the UE match the one or more locations of the user indicated by the information comprised in the user identification request comprises analyzing the collected UE location data to determine the UE identity of the UE for which the one or more locations of the UE match the one or more locations of the user indicated by the information comprised in the user identification request.

[0009] In one embodiment, the one or more locations of the user indicated by the information comprised in the user identification request comprise a plurality of locations of the user, and the user identification request further comprises a plurality of timestamps for the plurality of locations of the user, respectively, that indicate times at which the user was located at the plurality of locations. In one embodiment, the plurality of locations of the user and the plurality of timestamps define a mobility pattern of the user, and the method further comprises, at the NWDAF, collecting UE location data for a plurality of UEs in the cellular communications system. Further, obtaining the UE identity of the UE comprises obtaining the UE identity of the UE for which a mobility pattern of the UE as defined by the collected UE location data matches the mobility pattern of the user as defined by the plurality of locations and the plurality of timestamps from the user identification request.

[0010] In one embodiment, the user identification request comprises an unknown user identity that is assigned to the user to be identified and is specific to the user to be identified. In one embodiment, the user identification response further comprises the unknown user identity of the user.

[0011] In one embodiment, the user identification request further comprises an unknown user identity associated with the one or more locations of the user for which identification is requested, and the method further comprises, at the NEF, receiving a prior user identification request from the AF, the prior user identification request comprising information that indicates one or more prior locations of the user for which identification is requested and the unknown user identity of the user being associated to the one or more prior locations of the user for which identification is requested. The method further comprises, at the NEF, sending the prior user identification request to the NWDAF. The method further comprises, at the NWDAF, obtaining UE location data for a plurality of UEs in the cellular communications system and receiving the prior user identification request from the NEF. Further, obtaining the UE identity of the UE comprises analyzing the collected UE location data to determine the UE identity of the UE for which locations of the UE match the locations associated with the unknown user identity indicated by the information comprised in both the prior user identification request and the user identification request. In one embodiment, the user identification response further comprises the unknown user identity of the user.

[0012] In one embodiment, a method of operation of a NWDAF in a core network of a cellular communications system comprises receiving a user identification request from an AF via a NEF where the user identification request comprises information that indicates one or more locations of a user for which identification is requested by the AF, and obtaining a UE identity of a UE for which one or more locations of the UE match the one or more locations of the user indicated by the information comprised in the user identification request. The method further comprises obtaining subscription data for the UE having the obtained UE identity and sending a user identification response to the AF via the NEF, where the user identification response comprises the UE identity of the UE, at least some of the subscription data for the UE, or both the UE identity of the UE and at least some of the subscription data for the UE.

[0013] In one embodiment, obtaining the UE identity of the UE for which the one or more locations of the UE match the one or more locations of the user indicated by the information comprised in the user identification request comprises sending a UE identity request to an AMF where the UE identity request comprises information that indicates the one or more locations of the user, and receiving the UE identity from the AMF in response to the UE identity request.

[0014] In one embodiment, the one or more locations of the user indicated by the information comprised in the user identification request consist of a current location of the user.

[0015] In one embodiment, the method further comprises collecting UE location data for a plurality of UEs in the cellular communications system. Further, obtaining the UE identity of the UE for which the one or more locations of the UE match the one or more locations of the user indicated by the information comprised in the user identification request comprises analyzing the collected UE location data to determine the UE identity of the UE for which the one or more locations of the UE match the one or more locations of the user indicated by the information comprised in the user identification request. [0016] In one embodiment, the one or more locations of the user indicated by the information comprised in the user identification request comprise a plurality of locations of the user, and the user identification request further comprises a plurality of timestamps for the plurality of locations of the user, respectively, that indicate times at which the user was located at the plurality of locations. In one embodiment, the plurality of locations of the user and the plurality of timestamps define a mobility pattern of the user, and the method further comprises collecting UE location data for a plurality of UEs in the cellular communications system. Further, obtaining the UE identity of the UE comprises obtaining the UE identity of the UE for which a mobility pattern of the UE as defined by the collected UE location data matches the mobility pattern of the user as defined by the plurality of locations and the plurality of timestamps from the user identification request.

[0017] In one embodiment, the user identification request comprises an unknown user identity that is assigned to the user to be identified and is specific to the user to be identified. In one embodiment, the user identification response further comprises the unknown user identity of the user.

[0018] In one embodiment, the user identification request further comprises an unknown user identity associated with the one or more locations of the user for which identification is requested, and the method further comprises obtaining UE location data for a plurality of UEs in the cellular communications system and receiving a prior user identification request from the AF via the NEF, the prior user identification request comprising information that indicates one or more prior locations of the user for which identification is requested, the unknown user identity of the user being associated to the one or more prior locations of the user for which identification is requested. Further, obtaining the UE identity of the UE comprises analyzing the collected UE location data to determine the UE identity of the UE for which locations of the UE match the locations associated with the unknown user identity indicated by the information comprised in both the prior user identification request and the user identification request. In one embodiment, the user identification response further comprises the unknown user identity of the user.

[0019] Corresponding embodiments of an NWDAF for a core network of a cellular communications system are also disclosed. In one embodiment, the NWDAF is adapted to receive a user identification request from an AF via a NEF, the user identification request comprising information that indicates one or more locations of a user for which identification is requested by the AF. The NWDAF is further adapted to obtain a UE identity of a UE for which one or more locations of the UE match the one or more locations of the user indicated by the information comprised in the user identification request, obtain subscription data for the UE having the obtained UE identity, and send a user identification response to the AF via the NEF, the user identification response comprising the UE identity of the UE, at least some of the subscription data for the UE, or both the UE identity of the UE and at least some of the subscription data for the UE. [0020] In one embodiment, a network node that implements an NWDAF for a core network of a cellular communications system comprises a network interface and processing circuitry associated with the network interface. The processing circuitry is configured to cause the network node to receive a user identification request from an AF via a NEF, the user identification request comprising information that indicates one or more locations of a user for which identification is requested by the AF. The processing circuitry is further configured to cause the network node to obtain a UE identity of a UE for which one or more locations of the UE match the one or more locations of the user indicated by the information comprised in the user identification request, obtain subscription data for the UE having the obtained UE identity, and send a user identification response to the AF via the NEF, the user identification response comprising the UE identity of the UE, at least some of the subscription data for the UE, or both the UE identity of the UE and at least some of the subscription data for the UE.

Brief Description of the Drawings

[0021] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0022] Figure 1 illustrates one example of a cellular communications system according to some embodiments of the present disclosure;

[0023] Figures 2 and 3 illustrate example embodiments in which the cellular communications system of Figure 1 is a Fifth Generation (5G) System (5GS);

[0024] Figures 4, 5, 6A, 6B, and 7 illustrate embodiments for user identification in accordance with various embodiments of the present disclosure; [0025] Figure 8 is a schematic block diagram of a network node according to some embodiments of the present disclosure;

[0026] Figure 9 is a schematic block diagram that illustrates a virtualized embodiment of the network node of Figure 8 according to some embodiments of the present disclosure; and

[0027] Figure 10 is a schematic block diagram of the network node of Figure 8 according to some other embodiments of the present disclosure.

[0028] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0029] Radio Node: As used herein, a "radio node" is either a radio access node or a wireless communication device.

[0030] Radio Access Node: As used herein, a "radio access node" or "radio network node" or "radio access network node" is any node in a Radio Access Network (RAN) of a cellular communications network that operates to wirelessly transmit and/or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., a New Radio (NR) base station (gNB) in a Third Generation Partnership Project (3GPP) Fifth Generation (5G) NR network or an enhanced or evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network), a high-power or macro base station, a low-power base station (e.g., a micro base station, a pico base station, a home eNB, or the like), a relay node, a network node that implements part of the functionality of a base station or a network node that implements a gNB Distributed Unit (gNB-DU)) or a network node that implements part of the functionality of some other type of radio access node.

[0031] Core Network Node: As used herein, a "core network node" is any type of node in a core network or any node that implements a core network function. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a Packet Data Network Gateway (P-GW), a Service Capability Exposure Function (SCEF), a Flome Subscriber Server (HSS), or the like. Some other examples of a core network node include a node implementing a Access and Mobility Management Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), or the like.

[0032] Communication Device: As used herein, a "communication device" is any type of device that has access to an access network. Some examples of a communication device include, but are not limited to: mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or Personal Computer (PC). The communication device may be a portable, hand-held, computer-comprised, or vehicle- mounted mobile device, enabled to communicate voice and/or data via a wireless or wireline connection.

[0033] Wireless Communication Device: One type of communication device is a wireless communication device, which may be any type of wireless device that has access to (i.e., is served by) a wireless network (e.g., a cellular network). Some examples of a wireless communication device include, but are not limited to: a User Equipment device (UE) in a 3GPP network, a Machine Type Communication (MTC) device, and an Internet of Things (IoT) device. Such wireless communication devices may be, or may be integrated into, a mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or PC. The wireless communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data via a wireless connection.

[0034] Network Node: As used herein, a "network node" is any node that is either part of the RAN or the core network of a cellular communications network/system. [0035] Note that the description given herein focuses on a 3GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system.

[0036] Note that, in the description herein, reference may be made to the term "cell"; however, particularly with respect to 5G NR concepts, beams may be used instead of cells and, as such, it is important to note that the concepts described herein are equally applicable to both cells and beams.

[0037] One issue related to video surveillance is the identification of a person (referred to herein as a "user") detected within the field of view of the camera(s) of the video surveillance system. Using video content analysis, it is possible to detect a person in a certain location (i.e., detect that a person is present in a certain location), and sometimes also the person's identity if the face of that person can be observed and contrasted with a facial identification database. However, this approach does not always work since the face-based identification may be inaccurate, the face of the person is not visible, or the person is not in the facial identification database.

[0038] Systems and methods are disclosed herein that address the aforementioned problem with video surveillance systems. The solution proposed herein is based on collaboration between a Content Service Provider (CSP) (e.g., a video surveillance system) and a Network Service Provider (NSP) (e.g., a cellular communications system) to identify a person(s) whose presence in a certain location is detected by a video surveillance system.

[0039] In one embodiment, the solution comprises the following features. A video surveillance system, acting as an Application Function (AF), sends a user identification request to a NEF. The user identification request includes information that indicates a location(s) in which the person was detected. The information that indicates the location(s) may include:

• information that indicates a real-time location of the person (e.g., for an attempt to try to identify the person instantaneously);

• information that indicates a non-real-time location of the person, including also a timestamp that indicates a time at which the person was detected;

• a set of periodic location real-time reports over time, to try to identify the person as soon as the network is able to recognize the mobility pattern of the person: o as discussed below, for this purpose, in one embodiment, the AF may use an unknown-user-identity (ID) to identify the unknown person and the person's reported locations;

• information that indicates a mobility pattern of the person (e.g., a set of locations detected over different times, or in any other form, which defines the movement of the detected person over a certain timespan).

[0040] The NEF forwards the user identification request to a Network Data Analytics Function (NWDAF). Then, the NWDAF determines a UE ID of a UE that matches the location(s) indicated in the user identification request or a set of UE-IDs of a set of UEs that match the location(s) indicated in the user identification request, based on UE location data available at the NWDAF and collected in the cellular communications system. The UE(s) identified by the UE-ID(s) is(are) a UE(s) of a person(s) that potentially corresponds to the person detected at the location(s) by the video surveillance system. In addition or alternatively, the NWDAF may send a request to an AMF for a UE-ID(s) of the UE(s) whose location (known to the AMF) matches the location(s) indicated in the user identification request from the AF. The AMF responds to NWDAF with the matching UE-ID(s). The response from the AMF may also include the location(s) of the UE(s) corresponding to the provided UE-ID(s) for further analysis in the NWDAF. Alternatively, the NWDAF may subscribe to the AMF for the UE-ID(s) of the UE(s) whose location matches the location(s) provided by the AF. Then, the AMF sends notifications to the NWDAF including information on the UE-ID(s) of the UE(s) at the location(s) provided by the AF.

[0041] Based on the above information, the NWDAF sends, to a NEF, the UE-ID that potentially corresponds to the person detected in the location(s) provided by the AF. Optionally, the NWDAF may also include subscription information for the UE-ID, where this subscription information is retrieved from a Uniform Data Repository (UDR) and may include information such as, e.g., the person's name, address, mobile number, etc. The NEF relays this information to the AF.

[0042] Embodiments of the solution disclosed herein provide a number of advantages. For example, embodiments of the solution disclosed herein can be extended to any use case that requires user identification based on location. In other words, while the embodiments described herein focus on user identification requests from a video surveillance system, the present disclosure is not limited to user identification requests from a video surveillance system. Rather, the embodiments disclosed herein can be used to process user identification requests from any type of system. For example, a possible use can be for the identification of people that have potentially caused a wildfire, if the time and location where the wildfire started is known. Embodiments of the solution disclosed herein can also be applied to video surveillance systems composed of many surveillance cameras, as the AF may work not only as the system in a single camera, but as a centralized surveillance system using many cameras. Embodiments of the solution proposed herein can also be applied to identify groups of UE-IDs, in case more than one person is in a given location.

[0043] Figure 1 illustrates one example of a cellular communications system 100 in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system 100 is a 5G System (5GS) including a Next Generation RAN (NG-RAN) and a 5G Core (5GC); however, the embodiments disclosed herein are not limited to the 5GS. In this example, the RAN includes base stations 102-1 and 102-2, which in the 5GS includes gNBs and optionally next generation eNBs (ng-eNBs) (e.g., LTE RAN nodes connected to the 5GC), controlling corresponding (macro) cells 104-1 and 104-2. The base stations 102-1 and 102-2 are generally referred to herein collectively as base stations 102 and individually as base station 102. Likewise, the (macro) cells 104-1 and 104-2 are generally referred to herein collectively as (macro) cells 104 and individually as (macro) cell 104. The RAN may also include a number of low power nodes 106-1 through 106-4 controlling corresponding small cells 108-1 through 108-4. The low power nodes 106-1 through 106-4 can be small base stations (such as pico or femto base stations) or Remote Radio Heads (RRHs), or the like. Notably, while not illustrated, one or more of the small cells 108-1 through 108-4 may alternatively be provided by the base stations 102. The low power nodes 106-1 through 106-4 are generally referred to herein collectively as low power nodes 106 and individually as low power node 106. Likewise, the small cells 108- 1 through 108-4 are generally referred to herein collectively as small cells 108 and individually as small cell 108. The cellular communications system 100 also includes a core network 110, which in the 5GS is referred to as the 5GC. The base stations 102 (and optionally the low power nodes 106) are connected to the core network 110. [0044] The base stations 102 and the low power nodes 106 provide service to wireless communication devices 112-1 through 112-5 in the corresponding cells 104 and 108. The wireless communication devices 112-1 through 112-5 are generally referred to herein collectively as wireless communication devices 112 and individually as wireless communication device 112. In the following description, the wireless communication devices 112 are oftentimes UEs, but the present disclosure is not limited thereto. [0045] Figure 2 illustrates a wireless communication system represented as a 5G network architecture composed of core NFs, where interaction between any two NFs is represented by a point-to-point reference point/interface. Figure 2 can be viewed as one particular implementation of the cellular communications system 100 of Figure 1. [0046] Seen from the access side the 5G network architecture shown in Figure 2 comprises a plurality of UEs 112 connected to either a RAN 102 or an Access Network (AN) as well as an AMF 200. Typically, the R(AN) 102 comprises base stations, e.g. such as eNBs or gNBs or similar. Seen from the core network side, the 5GC NFs shown in Figure 2 include a NSSF 202, an AUSF 204, a UDM 206, the AMF 200, a SMF 208, a PCF 210, and an AF 212.

[0047] Reference point representations of the 5G network architecture are used to develop detailed call flows in the normative standardization. The N1 reference point is defined to carry signaling between the UE 112 and AMF 200. The reference points for connecting between the AN 102 and AMF 200 and between the AN 102 and UPF 214 are defined as N2 and N3, respectively. There is a reference point, Nil, between the AMF 200 and SMF 208, which implies that the SMF 208 is at least partly controlled by the AMF 200. N4 is used by the SMF 208 and UPF 214 so that the UPF 214 can be set using the control signal generated by the SMF 208, and the UPF 214 can report its state to the SMF 208. N9 is the reference point for the connection between different UPFs 214, and N14 is the reference point connecting between different AMFs 200, respectively. N15 and N7 are defined since the PCF 210 applies policy to the AMF 200 and SMF 208, respectively. N12 is required for the AMF 200 to perform authentication of the UE 112. N8 and N10 are defined because the subscription data of the UE 112 is required for the AMF 200 and SMF 208.

[0048] The 5GC network aims at separating User Plane (UP) and Control Plane (CP). The UP carries user traffic while the CP carries signaling in the network. In Figure 2, the UPF 214 is in the UP and all other NFs, i.e., the AMF 200, SMF 208, PCF 210, AF 212, NSSF 202, AUSF 204, and UDM 206, are in the CP. Separating the UP and CP guarantees each plane resource to be scaled independently. It also allows UPFs to be deployed separately from CP functions in a distributed fashion. In this architecture,

UPFs may be deployed very close to UEs to shorten the Round Trip Time (RTT) between UEs and the data network for some applications requiring low latency.

[0049] The core 5G network architecture is composed of modularized functions. For example, the AMF 200 and SMF 208 are independent functions in the CP. Separated AMF 200 and SMF 208 allow independent evolution and scaling. Other CP functions like the PCF 210 and AUSF 204 can be separated as shown in Figure 2. Modularized function design enables the 5GC network to support various services flexibly.

[0050] Each NF interacts with another NF directly. It is possible to use intermediate functions to route messages from one NF to another NF. In the CP, a set of interactions between two NFs is defined as service so that its reuse is possible. This service enables support for modularity. The UP supports interactions such as forwarding operations between different UPFs.

[0051] Figure 3 illustrates a 5G network architecture using service-based interfaces between the NFs in the CP, instead of the point-to-point reference points/interfaces used in the 5G network architecture of Figure 2. Flowever, the NFs described above with reference to Figure 2 correspond to the NFs shown in Figure 3. The service(s) etc. that a NF provides to other authorized NFs can be exposed to the authorized NFs through the service-based interface. In Figure 3 the service based interfaces are indicated by the letter "N" followed by the name of the NF, e.g. Namf for the service based interface of the AMF 200 and Nsmf for the service based interface of the SMF 208, etc. The NEF 300, NRF 302, NWDAF 304, and UDR 306 in Figure 3 are not shown in Figure 2 discussed above. Flowever, it should be clarified that all NFs depicted in Figure 2 can interact with the NEF 300, the NRF 302, the NWDAF 304, and the UDR 306 of Figure 3 as necessary, though not explicitly indicated in Figure 2.

[0052] Some properties of the NFs shown in Figures 2 and 3 may be described in the following manner. The AMF 200 provides UE-based authentication, authorization, mobility management, etc. A UE 112 even using multiple access technologies is basically connected to a single AMF 200 because the AMF 200 is independent of the access technologies. The SMF 208 is responsible for session management and allocates Internet Protocol (IP) addresses to UEs. It also selects and controls the UPF 214 for data transfer. If a UE 112 has multiple sessions, different SMFs 208 may be allocated to each session to manage them individually and possibly provide different functionalities per session. The AF 212 provides information on the packet flow to the PCF 210 responsible for policy control in order to support Quality of Service (QoS). Based on the information, the PCF 210 determines policies about mobility and session management to make the AMF 200 and SMF 208 operate properly. The AUSF 204 supports authentication function for UEs or similar and thus stores data for authentication of UEs or similar while the UDM 206 stores subscription data of the UE 112. The Data Network (DN), not part of the 5GC network, provides Internet access or operator services and similar.

[0053] An NF may be implemented either as a network element on a dedicated hardware, as a software instance running on a dedicated hardware, or as a virtualized function instantiated on an appropriate platform, e.g., a cloud infrastructure.

[0054] Now, a description of some example embodiments of the present disclosure will be provided. Figure 4 illustrates the operation of the cellular communications system 100 in accordance with one embodiment of the present disclosure in which user identification is performed instantly. As illustrated, the AF 212, which in this example is an AF of a video surveillance system, sends a user identification request to the NEF 300 (step 400). In this embodiment, the user identification request includes information that indicates a location (e.g., a current location) of a user, or person, of interest (e.g., a location of a person detected by the video surveillance system). As a non-limiting example, the information that indicates the location of the user may be coordinates that represent the location of the user in three-dimensional (3D) space (e.g., latitude, longitude, and altitude). Flowever, other types of information that indicates the location of the user may be used. Further, the location may be an absolute location or a location relative to some reference location (i.e., a relative location). Further, in one embodiment, the location of the user corresponds to a location defined by a field of view of a particular video camera in the video surveillance system. The NEF 300 forwards the user identification request including the information that that indicates the location of the user to the NWDAF 304 (step 402).

[0055] In this embodiment, the NWDAF 304 sends a request to the AMF 200 for a UE-ID of the UE 112 at the location indicated by the user identification request (step 404). Thus, the request includes the information that indicates the location of the user. The AMF 200 sends a response to the NWDAF 304 that includes the UE-ID of the UE 112 at the location indicated by the user identification request (step 406). The NWDAF 304 sends a request to the UDR 306 for subscription data for the UE 112 identified by the UE-ID returned by the AMF 200 (step 408). The UDR 306 sends a response to the NWDAF 304 that includes the requested subscription data, which may include, e.g., name, address, mobile number, etc. of the user associated with the provided UE-ID (step 410).

[0056] The NWDAF 304 sends a user identification response to the NEF 300, where the user identification response includes at least some of the subscription data obtained from the UDR 306 for the obtained UE-ID and/or the UE-ID of the associated UE 112 (step 412). The NEF 300 forwards the user identification response to the AF 212 (step 414).

[0057] Figure 5 illustrates the operation of the cellular communications system 100 in accordance with another embodiment of the present disclosure. As illustrated, the NWDAF 304 collects and stores UE location information, e.g., using a conventional mechanism (step 500). The AF 212, which in this example is an AF of a video surveillance system, sends a user identification request to the NEF 300 (step 502). In this embodiment, the user identification request includes information that indicates a location(s) of a user, or person, of interest (e.g., a location of a person detected by the video surveillance system at some moment in the past) and a timestamp(s) that indicates the time(s) at which the user was detected at the indicated location(s). In other words, the user identification request includes information that indicates a set of locations and a respective set of timestamps that indicate the times at which the user was detected at those locations. In the case that the set of locations includes multiple locations, the set of locations and respective timestamps define a mobility pattern of the detected UE 112.

[0058] As a non-limiting example, the information that indicates the location of the user may be coordinates that represent the location of the user in 3D space (e.g., latitude, longitude, and altitude). Flowever, other types of information that indicates the location of the user may be used. Further, the location may be an absolute location or a location relative to some reference location (i.e., a relative location).

[0059] The NEF 300 forwards the user identification request including the information that that indicates the location of the user and the timestamp to the NWDAF 304 (step 504). In this embodiment, the NWDAF 304 analyzes the collected UE location information and the set of locations and respective timestamps of the detected user indicated in the user identification request and determines the UE-ID of the UE 112 that was located at the location(s) indicated by the user identification request at the time(s) indicated by the respective timestamp(s) (step 506). For instance, in the case where the set of locations included in the user identification request includes multiple locations defining a mobility pattern of the detected user, the NWDAF 304 analyzes the collected location information to determine the UE 112 having a mobility pattern (i.e., a set of locations and respective timestamps) that matches the mobility pattern defined by the set of locations and respective timestamps included in the user identification request.

[0060] The NWDAF 304 sends a request to the UDR 306 for subscription data for the UE 112 identified by the determined UE-ID (step 508). The UDR 306 sends a response to the NWDAF 304 that includes the requested subscription data, which may include, e.g., name, address, mobile number, etc. of the user associated with the provided UE- ID (step 510). The NWDAF 304 sends a user identification response to the NEF 300, where the user identification response includes at least some of the subscription data obtained from the UDR 306 for the obtained UE-ID and/or the UE-ID of the associated UE 112 (step 512). The NEF 300 forwards the user identification response to the AF 212 (step 514).

[0061] Figures 6A and 6B illustrate the operation of the cellular communications system 100 in accordance with another embodiment of the present disclosure. In this embodiment, the AF 212 first activates user identification for a given location. Also, the procedure of Figures 6A and 6B shows an embodiment in which the AF 212 includes an "unknown-user-ID" in the user activation request. The unknown-user-ID enables the AF 212 to submit concurrent user identification requests for different detected persons that may share the same location at a given time. The NWDAF 304 keeps track of the different unknown-user-IDs that are being analyzed and includes the unknown-user-ID in the user identification response sent to the AF 212 so that the AF 212 can properly identify the person to which the user identification response applies.

[0062] More specifically, as illustrated in Figures 6A and 6B, the AF 212 sends, to the NEF 300, a user identification activation request for a particular location(s) (step 600). The particular location(s) are, in this example, a location(s) monitored by one or more video cameras of a video surveillance system. The NEF 300 forwards the user identification activation request, including information that indicates the location(s) for which user identification activation is being requested, to the NWDAF 304 (step 602). Responsive to the user identification activation request, the NWDAF 304 sends a subscription request to the AMF 200 to subscribe to notifications of UE-IDs of UEs 112 whose locations match the location(s) indicated for which user identification activation is requested (step 604) and the AMF 200 acknowledges the user identification activation request (step 606). Responsive to the subscription request, the AMF 200 sends (e.g., periodically), to the NWDAF 304, notifications including information about UE-IDs of UEs 112 that are located at the subscribed location(s) (step 608).

[0063] The AF 212 sends a user identification request to the NEF 300 (step 610). In this embodiment, the user identification request includes an unknown-user-ID assigned to the detected user (i.e., the user to be identified). The unknown-user-ID is specific to the detected user. In addition, the user identification request may include information that indicates a location(s) of the user to be identified. The location is beneficial in cases in which user identification has been activated for multiple locations. Otherwise, if there is only a single location for which user identification is activated, the user identification request may implicitly indicate this single location (i.e., the location may not be explicitly indicated in the user identification request). In addition, the user identification request may include a timestamp(s) that indicates the time(s) at which the user was at the indicated location(s). The NEF 300 forwards the user identification request to the NWDAF 304 (step 612).

[0064] The NWDAF 304 analyzes the locations of the UEs 112 collected via the notifications from the AMF 200 in an attempt to determine the UE-IDs of the UEs 112 that are/were located at the location(s) indicated by the user identification request and, optionally, at the respective time(s) indicated by the user identification request (step 614). In this example, the NWDAF 304 is not able to resolve the user identification request to a particular UETD in step 614.

[0065] The AF 212 sends a second user identification request to the NEF 300 (step 616). In this embodiment, the second user identification request includes the same unknown-user-ID as the user identification request in step 610 (i.e., the second user identification request indicates that it is for the same detected user as the user identification request in step 610). In addition, the user identification request may include information that indicates a location(s) of the user to be identified. Flere, the detected user may have changed locations in which case the location(s) indicated in the second user identification request may include one or more locations that are different than that/those indicated in the user identification request of step 610. In addition, the user identification request may include a timestamp(s) that indicates the time(s) at which the user was at the indicated location(s). The NEF 300 forwards the second user identification request to the NWDAF 304 (step 618).

[0066] In this example, prior to and/or after receiving the second user identification request, the NWDAF 304 may receive additional notifications from the AMF 200, where these notifications include information about UE-IDs of UEs 112 that are located at the subscribed location(s) (step 620). The NWDAF 304 analyzes the locations of the UEs 112 collected via the notifications from the AMF 200 in an attempt to determine the UE- ID of the UE 112 that is/was located at the location(s) indicated by both the user identification request of step 610 and the second user identification request of step 616 and, optionally, at the respective time(s) indicated by those user identification requests (step 622). In other words, the analysis uses the locations for the same unknown-user- ID from multiple user identification requests. In this example, the NWDAF 304 is able to resolve the user identification request to a particular UE-ID in step 622.

[0067] The NWDAF 304 sends a request to the UDR 306 for subscription data for the UE 112 identified by the determined UE-ID from step 622 (step 624). The UDR 306 sends a response to the NWDAF 304 that includes the requested subscription data, which may include, e.g., name, address, mobile number, etc. of the user associated with the provided UE-ID (step 626). The NWDAF 304 sends a user identification response to the NEF 300, where the user identification response includes at least some of the subscription data obtained from the UDR 306 for the obtained UE-ID and/or the UE-ID of the associated UE 112 (step 628). The NEF 300 forwards the user identification response to the AF 212 (step 630).

[0068] To better understand the usage of the unknown-user-ID, let's consider the following example:

1. For each unidentified person, the AF 212 assigns an unknown-user-ID to that unidentified person and transmits (for example) a user identification request to the NEF 300 including:

{

(unknown-user-ID = X, location = A)

(unknown-user-ID = Y, location = A) (unknown-user-ID = W, location = B)

(unknown-user-ID = Z, location = B)

}

2. The NWDAF 304 is not able to resolve the request since there are several users in the same location. Later, both users X and Z change their location to the field covered by another surveillance camera in location C. So, now the AF 212 sends a subsequent request including:

{

(unknown-user-ID = X, location = C)

(unknown-user-ID = Y, location = A)

(unknown-user-ID = W, location = B)

(unknown-user-ID = Z, location = C)

}

3. Now, the NWDAF 304 is able to resolve the request since, although users X and Z share the same location C, they can be tracked using the unknown-user-ID and their previous locations. So, the NWDAF 304 provides a response including the UE-ID mapped to the unknown-user-ID.

{

(unknown-user-ID = X, UE-ID = 23),

(unknown-user-ID = Y, UE-ID = 24),

}

4. The AF 212 is then is able to identify the users previously assigned to those unknown-user-IDs.

[0069] Figure 7 illustrates the operation of the cellular communications system 100 in accordance with another embodiment of the present disclosure. This embodiment is similar to that of Figure 5 but where the user identification request includes multiple locations of the same user and respective timestamps that define a mobility pattern of the user. As illustrated, the NWDAF 304 collects and stores UE location information, e.g., using a conventional mechanism (step 700). The AF 212, which in this example is an AF of a video surveillance system, sends a user identification request to the NEF 300 (step 702). In this embodiment, the user identification request includes a set of locations of a user, or person, of interest (e.g., set of locations of a person detected by the video surveillance system at respective moments in time) and a respective set of timestamps that indicates the times at which the user was detected at the indicated locations. The set of locations and the respective set of timestamps define a mobility pattern of the detected UE 112.

[0070] The NEF 300 forwards the user identification request including the information that that indicates the set of locations of the user and the respective set of timestamps (i.e., the mobility pattern of the user) to the NWDAF 304 (step 704). In this embodiment, the NWDAF 304 analyzes the collected UE location information and the mobility pattern of the detected user indicated in the user identification request and determines the UE-ID of the UE 112 having a matching mobility pattern (step 706). [0071] The NWDAF 304 sends a request to the UDR 306 for subscription data for the UE 112 identified by the determined UE-ID (step 708). The UDR 306 sends a response to the NWDAF 304 that includes the requested subscription data, which may include, e.g., name, address, mobile number, etc. of the user associated with the provided UE- ID (step 710). The NWDAF 304 sends a user identification response to the NEF 300, where the user identification response includes at least some of the subscription data obtained from the UDR 306 for the obtained UE-ID and/or the UE-ID of the associated UE 112 (step 712). The NEF 300 forwards the user identification response to the AF 212 (step 714).

[0072] Figure 8 is a schematic block diagram of a network node 800 according to some embodiments of the present disclosure. Optional features are represented by dashed boxes. The network node 800 may be, for example, network node that implements the AF 212, the NEF 300, the NWDAF 304, the UDR 306, or the AMF 200 having the functionality described herein. As illustrated, the network node 800 includes one or more processors 804 (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or the like), memory 806, and a network interface 808. The one or more processors 804 are also referred to herein as processing circuitry. The one or more processors 804 operate to provide one or more functions of the network node 800 as described herein (e.g., one or more functions of the AF 212, the NEF 300, the NWDAF 304, the UDR 306, or the AMF 200 as described herein, e.g., with respect to Figure 4, Figure 5, Figures 6A and 6B, and/or Figure 7). In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory 806 and executed by the one or more processors 804.

[0073] Figure 9 is a schematic block diagram that illustrates a virtualized embodiment of the network node 800 according to some embodiments of the present disclosure. As used herein, a "virtualized" network node is an implementation of the network node 800 in which at least a portion of the functionality of the network node 800 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the network node 800 includes one or more processing nodes 900 coupled to or included as part of a network(s) 902. Each processing node 900 includes one or more processors 904 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 906, and a network interface 908.

[0074] In this example, functions 910 of the network node 800 described herein (e.g., one or more functions of the AF 212, the NEF 300, the NWDAF 304, the UDR 306, or the AMF 200 as described herein, e.g., with respect to Figure 4, Figure 5, Figures 6A and 6B, and/or Figure 7) are implemented at the one or more processing nodes 900 or distributed across two or more processing nodes 900 in any desired manner. In some particular embodiments, some or all of the functions 910 of the network node 800 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) 900.

[0075] In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the network node 800 or a node (e.g., a processing node 900) implementing one or more of the functions 910 of the network node 800 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

[0076] Figure 10 is a schematic block diagram of the network node 800 according to some other embodiments of the present disclosure. The network node 800 includes one or more modules 1000, each of which is implemented in software. The module(s) 1000 provide the functionality of the network node 800 described herein (e.g., one or more functions of the AF 212, the NEF 300, the NWDAF 304, the UDR 306, or the AMF 200 as described herein, e.g., with respect to Figure 4, Figure 5, Figures 6A and 6B, and/or Figure 7). This discussion is equally applicable to the processing node 900 of Figure 9 where the modules 1000 may be implemented at one of the processing nodes 900 or distributed across multiple processing nodes 900.

[0077] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.

[0078] While processes in the figures may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).

[0079] At least some of the following abbreviations may be used in this disclosure. If there is an inconsistency between abbreviations, preference should be given to how it is used above. If listed multiple times below, the first listing should be preferred over any subsequent listing(s).

• 3D Three-Dimensional

• 3GPP Third Generation Partnership Project

• 5G Fifth Generation • 5GC Fifth Generation Core

• 5GS Fifth Generation System

• AF Application Function

• AMF Access and Mobility Management Function

• AN Access Network

• ASIC Application Specific Integrated Circuit

• AUSF Authentication Server Function

• CCTV Closed-Circuit Television

• CP Control Plane

• CPU Central Processing Unit

• CSP Content Service Provider

• DN Data Network

• DSP Digital Signal Processor

• eNB Enhanced or Evolved Node B

• FPGA Field Programmable Gate Array

• gNB New Radio Base Station

• gNB-DU New Radio Base Station Distributed Unit

• HSS Flome Subscriber Server

• ID Identity

• IoT Internet of Things

• IP Internet Protocol

• LTE Long Term Evolution

• MME Mobility Management Entity

• MTC Machine Type Communication

• NEF Network Exposure Function

• NF Network Function

• ng-eNB Next Generation Enhanced or Evolved Node B

• NG-RAN Next Generation Radio Access Network

• NR New Radio

• NRF Network Function Repository Function

• NSP Network Service Provider

• NSSF Network Slice Selection Function

• NWDAF Network Data Analytics Function • P2MP Point-to-Multi point

• P2P Point-to-Point

• PC Personal Computer

• PCF Policy Control Function

• P-GW Packet Data Network Gateway

• QoS Quality of Service

• RAM Random Access Memory

• RAN Radio Access Network

• ROM Read Only Memory

• RRH Remote Radio Flead

• RTT Round Trip Time

• SCEF Service Capability Exposure Function

• SMF Session Management Function

• UDM Unified Data Management

• UDR Uniform Data Repository

• UE User Equipment

• UP User Plane

• UPF User Plane Function

[0080] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

Claims

What is claimed is:

1. A method for user identification using a cellular communications system (100), the method comprising:

• at a Network Exposure Function, NEF, (300): o receiving (400; 502; 616; 702) a user identification request from an Application Function, AF, (212), the user identification request comprising information that indicates one or more locations of a user for which identification is requested; and o sending (402; 504; 618; 704) the user identification request to a Network Data Analytics Function, NWDAF, (304);

• at the NWDAF (304): o receiving (402; 504; 618; 704) the user identification request from the NEF (300); o obtaining (404-406; 506; 622; 706) a User Equipment, UE, identity of a UE (112) for which one or more locations of the UE (112) match the one or more locations of the user indicated by the information comprised in the user identification request; o obtaining (408-410; 508-510; 624-626; 708-710) subscription data for the UE (112) having the obtained UE identity; and o sending (412; 512; 628; 712) a user identification response to the NEF (300), the user identification response comprising the UE identity of the UE (112), at least some of the subscription data for the UE (112), or both the UE identity of the UE (112) and at least some of the subscription data for the UE (112); and

• at the NEF (300): o receiving (412; 512; 628; 712) the user identification response from the NWDAF (304); and o sending (414; 514; 630; 714) the user identification response to the AF (212).

2. The method of claim 1 wherein obtaining (404-406; 506; 622; 706) the UE identity of the UE (112) for which the one or more locations of the UE (112) match the one or more locations of the user indicated by the information comprised in the user identification request comprises: sending (404) a UE identity request to an Access and Mobility Management Function, AMF, (200), the UE identity request comprising information that indicates the one or more locations of the user; and receiving (406) the UE identity from the AMF (200) in response to the UE identity request.

3. The method of claim 1 or 2 wherein the one or more locations of the user indicated by the information comprised in the user identification request consist of a current location of the user.

4. The method of claim 1 further comprising: at the NWDAF (304), collecting (500) UE location data for a plurality of UEs (112) in the cellular communications system (100); wherein obtaining (404-406; 506; 622; 706) the UE identity of the UE (112) for which the one or more locations of the UE (112) match the one or more locations of the user indicated by the information comprised in the user identification request comprises analyzing (506) the collected UE location data to determine the UE identity of the UE (112) for which the one or more locations of the UE (112) match the one or more locations of the user indicated by the information comprised in the user identification request.

5. The method of claim 1 wherein: the one or more locations of the user indicated by the information comprised in the user identification request comprise a plurality of locations of the user; and the user identification request further comprises a plurality of timestamps for the plurality of locations of the user, respectively, that indicate times at which the user was located at the plurality of locations.

6. The method of claim 5 wherein the plurality of locations of the user and the plurality of timestamps define a mobility pattern of the user, and the method further comprises: at the NWDAF (304), collecting (700) UE location data for a plurality of UEs (112) in the cellular communications system (100); wherein obtaining (404-406; 506; 622; 706) the UE identity of the UE (112) comprises obtaining (706) the UE identity of the UE (112) for which a mobility pattern of the UE (112) as defined by the collected UE location data matches the mobility pattern of the user as defined by the plurality of locations and the plurality of timestamps from the user identification request.

7. The method of any of claims 1 to 6 wherein the user identification request comprises an unknown user identity that is assigned to the user to be identified and is specific to the user to be identified.

8. The method of claim 7 wherein the user identification response further comprises the unknown user identity of the user.

9. The method of claim 1 wherein the user identification request further comprises an unknown user identity associated with the one or more locations of the user for which identification is requested, and the method further comprises:

• at the NEF (300): o receiving (610) a prior user identification request from the AF (212), the prior user identification request comprising:

^■ information that indicates one or more prior locations of the user for which identification is requested; and

^■ the unknown user identity of the user being associated to the one or more prior locations of the user for which identification is requested; and o sending (612) the prior user identification request to the NWDAF (304);

• at the NWDAF (304): o obtaining (604-606; 620) UE location data for a plurality of UEs (112) in the cellular communications system (100); and o receiving (612) the prior user identification request from the NEF (300); o wherein obtaining (622) the UE identity of the UE (112) comprises analyzing (622) the collected UE location data to determine the UE identity of the UE (112) for which locations of the UE (112) match the locations associated with the unknown user identity indicated by the information comprised in both the prior user identification request and the user identification request.

10. The method of claim 9 wherein the user identification response further comprises the unknown user identity of the user.

11. A method of operation of a Network Data Analytics Function, NWDAF, (304) in a core network (110) of a cellular communications system (100), the method comprising: receiving (402; 504; 618; 704) a user identification request from an Application Function, AF, (212) via a Network Exposure Function, NEF, (300), the user identification request comprising information that indicates one or more locations of a user for which identification is requested by the AF (212); obtaining (404-406; 506; 622; 706) a User Equipment, UE, identity of a UE (112) for which one or more locations of the UE (112) match the one or more locations of the user indicated by the information comprised in the user identification request; obtaining (408-410; 508-510; 624-626; 708-710) subscription data for the UE (112) having the obtained UE identity; and sending (412; 512; 628; 712) a user identification response to the AF (212) via the NEF (300), the user identification response comprising the UE identity of the UE (112), at least some of the subscription data for the UE (112), or both the UE identity of the UE (112) and at least some of the subscription data for the UE (112).

12. The method of claim 11 wherein obtaining (404-406; 506; 622; 706) the UE identity of the UE (112) for which the one or more locations of the UE (112) match the one or more locations of the user indicated by the information comprised in the user identification request comprises: sending (404) a UE identity request to an Access and Mobility Management Function, AMF, (200), the UE identity request comprising information that indicates the one or more locations of the user; and receiving (406) the UE identity from the AMF (200) in response to the UE identity request.

13. The method of claim 11 or 12 wherein the one or more locations of the user indicated by the information comprised in the user identification request consist of a current location of the user.

14. The method of claim 11 further comprising: collecting (500) UE location data for a plurality of UEs (112) in the cellular communications system (100); wherein obtaining (404-406; 506; 622; 706) the UE identity of the UE (112) for which the one or more locations of the UE (112) match the one or more locations of the user indicated by the information comprised in the user identification request comprises analyzing (506) the collected UE location data to determine the UE identity of the UE (112) for which the one or more locations of the UE (112) match the one or more locations of the user indicated by the information comprised in the user identification request.

15. The method of claim 11 wherein: the one or more locations of the user indicated by the information comprised in the user identification request comprise a plurality of locations of the user; and the user identification request further comprises a plurality of timestamps for the plurality of locations of the user, respectively, that indicate times at which the user was located at the plurality of locations.

16. The method of claim 15 wherein the plurality of locations of the user and the plurality of timestamps define a mobility pattern of the user, and the method further comprises: collecting (700) UE location data for a plurality of UEs (112) in the cellular communications system (100); wherein obtaining (404-406; 506; 622; 706) the UE identity of the UE (112) comprises obtaining (706) the UE identity of the UE (112) for which a mobility pattern of the UE (112) as defined by the collected UE location data matches the mobility pattern of the user as defined by the plurality of locations and the plurality of timestamps from the user identification request.

17. The method of any of claims 11 to 16 wherein the user identification request comprises an unknown user identity that is assigned to the user to be identified and is specific to the user to be identified.

18. The method of claim 17 wherein the user identification response further comprises the unknown user identity of the user.

19. The method of claim 11 wherein the user identification request further comprises an unknown user identity associated with the one or more locations of the user for which identification is requested, and the method further comprises: obtaining (604-606; 620) UE location data for a plurality of UEs (112) in the cellular communications system (100); and receiving (612) a prior user identification request from the AF (212) via the NEF (300), the prior user identification request comprising: information that indicates one or more prior locations of the user for which identification is requested; and the unknown user identity of the user being associated to the one or more prior locations of the user for which identification is requested; and wherein obtaining (622) the UE identity of the UE (112) comprises analyzing (622) the collected UE location data to determine the UE identity of the UE (112) for which locations of the UE (112) match the locations associated with the unknown user identity indicated by the information comprised in both the prior user identification request and the user identification request.

20. The method of claim 19 wherein the user identification response further comprises the unknown user identity of the user.

21. A Network Data Analytics Function, NWDAF, (304) for a core network (110) of a cellular communications system (100), the NWDAF (304) adapted to: receive (402; 504; 618; 704) a user identification request from an Application Function, AF, (212) via a Network Exposure Function, NEF, (300), the user identification request comprising information that indicates one or more locations of a user for which identification is requested by the AF (212); obtain (404-406; 506; 622; 706) a User Equipment, UE, identity of a UE (112) for which one or more locations of the UE (112) match the one or more locations of the user indicated by the information comprised in the user identification request; obtain (408-410; 508-510; 624-626; 708-710) subscription data for the UE (112) having the obtained UE identity; and send (412; 512; 628; 712) a user identification response to the AF (212) via the NEF (300), the user identification response comprising the UE identity of the UE (112), at least some of the subscription data for the UE (112), or both the UE identity of the UE (112) and at least some of the subscription data for the UE (112).

22. The NWDAF (304) of claim 21 wherein the NWDAF (304) is further adapted to perform the method of any of claims 12 to 20.

23. A network node (800) that implements a Network Data Analytics Function, NWDAF, (304) for a core network (110) of a cellular communications system (100), the network node (800) comprising: a network interface (808; 908); and processing circuitry (804; 904) associated with the network interface (808; 908), the processing circuitry (804; 904) configured to cause the network node (800) to: receive (402; 504; 618; 704) a user identification request from an Application Function, AF, (212) via a Network Exposure Function, NEF, (300), the user identification request comprising information that indicates one or more locations of a user for which identification is requested by the AF (212); obtain (404-406; 506; 622; 706) a User Equipment, UE, identity of a UE (112) for which one or more locations of the UE (112) match the one or more locations of the user indicated by the information comprised in the user identification request; obtain (408-410; 508-510; 624-626; 708-710) subscription data for the UE

(112) having the obtained UE identity; and send (412; 512; 628; 712) a user identification response to the AF (212) via the NEF (300), the user identification response comprising the UE identity of the UE (112), at least some of the subscription data for the UE (112), or both the UE identity of the UE (112) and at least some of the subscription data for the UE

(112).