WO2023184130A1

WO2023184130A1 - Location service user plane function address information obtainment

Info

Publication number: WO2023184130A1
Application number: PCT/CN2022/083565
Authority: WO
Inventors: Mao Cai
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2022-03-29
Filing date: 2022-03-29
Publication date: 2023-10-05

Abstract

Embodiments of the present disclosure relate to devices, methods, apparatuses and computer readable storage media for user plane function address information obtainment. According to embodiments of the present disclosure, the network device is caused to provision a location management function (LMF) domain name sever (DNS) behind an Edge Application Server Discovery Function (EASDF) instance through a network exposure function interface; receive a DNS query message for querying an IP address of a location user plane (LCUP) function instance from the EASDF instance; determine whether to respond to the DNS query message based on a predetermined responding rule; obtain an IP address of a LCUP instance associated with the LMF in accordance with the determination; and transmit the IP address of the LCUP instance to the EASDF instance. In such a way, the UE could be provided IP address of the LCUP associated with the LMF serving the terminal device, thereby enabling CP location service enhancement based on UP location function.

Description

LOCATION SERVICE USER PLANE FUNCTION ADDRESS INFORMATION OBTAINMENT

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of telecommunications, and in particular, to devices, methods, apparatuses and computer readable media for location service user plane function address information obtainment.

BACKGROUND

Some communication systems, such as New radio (NR) , support location service. The location service can be provided through a control plane protocol such as LTE Positioning Protocol. In addition, a user plane positioning was proposed as a location service enhancement solution.

The key target of architectural enhancement is to identify the 3rd Generation Partnership Project (3GPP) location services (LCS) features and enhancements required to support user plane positioning.

SUMMARY

In general, example embodiments of the present disclosure provide devices, methods, apparatuses and computer readable media for location service user plane function address information obtainment.

In a first aspect, there is provided a network device. The network device can be for example a location management function (LMF) instance. The network device comprises at least one processor; and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the network device to provision a location management function (LMF) domain name sever (DNS) behind an Edge Application Server Discovery Function (EASDF) instance through a network exposure function interface; receive a DNS query message for querying an IP address of a location user plane (LCUP) function instance from the EASDF instance; determine whether to respond to the DNS query message based on a predetermined responding rule; obtain an IP address of a LCUP instance associated with the LMF in accordance with the determination; and transmit the IP address of the LCUP instance to the EASDF instance.

In a second aspect, there is provided another network device. The network device comprises at least one processor; and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the network device to forward a domain name sever (DNS) query message for querying an IP address of a location user plane (LCUP) function instance to at least one Location Management Function (LMF) DNS servers based on a provisioned DNS message handling rule; receive the IP address of the LCUP instance from one of at least one LMF DNS server that serves a terminal device; transmit the IP address of the LCUP instance to the terminal device.

In a third aspect, there is provided a further network device. The network device comprises at least one processor; and at least one memory including computer program code; where the at least one memory and the computer program code are configured to, with the at least one processor, cause the network device to subscribe the network device to a network exposure function instance; receive a notification of location management function (LMF) domain name sever (DNS) provision from the network exposure function instance; and provision an Edge Application Server Discovery Function (EASDF) instance with a DNS message handling rule.

In a fourth aspect, there is provided a method. The method comprises provisioning a location management function (LMF) domain name sever (DNS) behind an Edge Application Server Discovery Function (EASDF) instance through a network exposure function interface; receiving a DNS query message for querying an IP address of a location user plane (LCUP) function instance from the EASDF instance; determining whether to respond to the DNS query message based on a predetermined responding rule; obtaining an IP address of a LCUP instance associated with the LMF in accordance with the determination; and transmitting the IP address of the LCUP instance to the EASDF instance.

In a fifth aspect, there is provided a method. The method comprises forwarding a domain name sever (DNS) query message for querying an IP address of a location user plane (LCUP) function instance to at least one Location Management Function (LMF) DNS servers based on a provisioned DNS message handling rule; receiving the IP address of the LCUP instance from one of at least one LMF DNS server that serves a terminal device; and transmitting the IP address of the LCUP instance to the terminal device.

In a sixth aspect, there is provided a method. The method comprises subscribing the network device to a network exposure function instance; receiving a notification of location management function (LMF) domain name sever (DNS) provision from the network exposure function instance; and provisioning an Edge Application Server Discovery Function (EASDF) instance with a DNS message handling rule.

In a seventh aspect, there is provided an apparatus. The apparatus comprises means for provisioning a location management function (LMF) domain name sever (DNS) behind an Edge Application Server Discovery Function (EASDF) instance through a network exposure function interface; means for receiving a DNS query message for querying an IP address of a location user plane (LCUP) function instance from the EASDF instance; means for determining whether to respond to the DNS query message based on a predetermined responding rule; means for obtaining an IP address of a LCUP instance associated with the LMF in accordance with the determination; and means for transmitting the IP address of the LCUP instance to the EASDF instance.

In an eighth aspect, there is provided another apparatus. The apparatus comprises means for forwarding a domain name sever (DNS) query message for querying an IP address of a location user plane (LCUP) function instance to at least one Location Management Function (LMF) DNS servers based on a provisioned DNS message handling rule; means for receiving the IP address of the LCUP instance from one of at least one LMF DNS server that serves a terminal device; means for transmitting the IP address of the LCUP instance to the terminal device.

In a ninth aspect, there is provided a further apparatus. The apparatus comprises means for subscribing the network device to a network exposure function instance; means for receiving a notification of location management function (LMF) domain name sever (DNS) provision from the network exposure function instance; means for provisioning an Edge Application Server Discovery Function (EASDF) instance with a DNS message handling rule.

In a tenth aspect, there is a computer readable storage medium comprising program instructions stored thereon. The instructions, when executed by an apparatus, cause the apparatus to perform the method according to the above fourth, fifth or sixth aspect.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some example embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

Fig. 1 illustrates an example system in which example embodiments of the present disclosure may be implemented;

Fig. 2 illustrates a flowchart of an example method according to some example embodiments of the present disclosure;

Fig. 3 illustrates a flowchart of an example method according to some example embodiments of the present disclosure;

Fig. 4 illustrates a flowchart of an example method according to some example embodiments of the present disclosure;

Fig. 5a illustrates a signalling chart illustrating an example process according to some example embodiments of the present disclosure;

Fig. 5b illustrates a signalling chart illustrating an example process according to some example embodiments of the present disclosure;

Fig. 5c illustrates a signalling chart illustrating an example process according to some example embodiments of the present disclosure;

Fig. 6 illustrates a signaling chart illustrating an example process according to some example embodiments of the present disclosure;

Fig. 7 illustrates a signaling chart illustrating an example process according to some example embodiments of the present disclosure;

Fig. 8 illustrates a simplified block diagram of a device that is suitable for implementing embodiments of the present disclosure; and

Fig. 9 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an example embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) , New Radio (NR) and so on. Furthermore, the communications between User Equipment (UE) and a network device or communications between network devices in the communication network may be performed according to any suitable communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future such as the future sixth generation (6G) . Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which UE accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a remote radio unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology. In the following description, the terms “network device” , “BS” , and “node” may be used interchangeably.

The term “UE” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, UE may also be referred to as a communication device, terminal device, a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The UE may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , Universal Serial Bus (USB) dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , UE-type rode side unit (RSU) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably. Some communication systems, such as New radio (NR) , support location service. The location service can be provided through a control plane protocol such as LTE Positioning Protocol. In addition, a user plane positioning was further proposed as a location service enhancement solution. Therefore, architectural enhancement is required to support the user plane positioning.

The term “network element” refers to elements, functions or devices in the network system. For the 3GPP 5G system, the network may include, for example, an Access Network AN, Radio AN (RAN) , New Generation AN (NF-RAN) , Access and Mobility Management Function (AMF) , Session Management Function (SMF) 106, user plane function (UPF) , Location Management Function (LMF) , location service user plane (LCUP) function (a new element proposed in the present disclosure) , Unified Data Management (UDM) function, Network Exposure function (NEF) , Binding Support Function (BSF) , and other existing or future NF in the core network.

The user plane positioning was already proposed as a location service enhancement solution. The key target of architectural enhancement is to identify the 3GPP location service (LCS) features and enhancements required to use user plane interface between the UE and the network to improve positioning, for example, to reduce the signaling load induced by a CP initiated positioning procedure. It is to address architectural changes allowing usage of user plane interface between the UE and the network, including central deployment or deployment at the edge, e.g.

- Discovery of user plane capability and configuration and selection of PDU Sessions (if needed) to be used for the communication between UE and user plane positioning interface termination.

- Whether and how to enhance existing 5GS LCS architecture or related procedures to support Mobile Originating Location Request (MO-LR) , Mobile Terminal-Location Request (MT-LR) , Deferred MT-LR and regulatory-related positioning procedures when user plane positioning is involved.

- Interaction with legacy LCS call flows and security aspect .

- Requirements on transport protocol e.g., if reliable transport and in sequence delivery is required.

- Interaction (if any) between user plane and existing control plane solution.

- User plane as a possible enhancement to control plane.

Embodiments of the present disclosure are directed to user plane discovery and enhancements to control plane enhancement. Discovery of User Plane positioning interface termination is a procedure by which UE discovers (Internet Protocol) IP address (es) of a suitable User Plane Server (s) (or Service Location Protocol (SLP) as Open Mobile Alliance (OMA) terminology) using Domain Name System (DNS) .

3GPP TS 23.273 defines the current LCS architecture which involves a LMF (Location Management Function) , which is the entity responsible of making the necessary computation to determine the UE location. For the purpose of UE location, it needs to obtain measurements from the New Generation (NG) Radio Access Network (RAN) and from the UE.

According to Section 4.3.1 of 3GPP TS 38.305, the standard user plane (UP) from OMA, Secure User Plane Location (SUPL) supports only part of positioning methods, as given in Table 1:

Table 1 Positioning methods or protocols supported by SUPL

In the above table, a number of positioning methods or protocols are given, wherein A-GNSS denotes a positioning method based on Assisted Global Navigation Satellite System; OTDOA denotes a positioning method based on Observed Time Difference Of Arrival; E-CID denotes enhanced Cell ID; sensor denotes a positioning method based on sensors; WLAN denotes a positioning method based on Wireless Local Area Network; Bluetooth denotes a positioning method based on Bluetooth; DL-TDOA denotes a positioning method based on Downlink time difference of arrival; DL-AoD denotes a positioning method based on Downlink Angle of Departure, Multi-RTT denotes a positioning method based on multi-cell round trip time; UL-TDOA denotes a positioning method based on Uplink time difference of arrival; and UL-AoA denotes a positioning method based on Uplink angle-of-arrival. From the above table, it can be seen that the SUPL can only provide partial measurements for the Multi-RTT method.

For User Plane LCS, the SLP instance is defined by Open Mobile Alliance (OMA) SLP FQDN spec, reference can be made to

- For emergency, it is in Section 6.1.5.1 in OMA-TS-ULP-V2_0_6-20200804-A(industry vendors mostly follow this approved spec)

- For non-emergency, it is not well defined in approved OMA spec, but candidate spec of 3.0 has Section 6.4 of OMA-TS-ULP-V3_0-20181213-C

Both approaches mentioned above use H-SLP (non-emergency) or E-SLP (for emergency) FQDN to locate the SLP server.

Embodiments of the present disclosure propose assuming architecture where the LMF can use a mixture of CP (Control Plane) and UP (User Plane) interactions for a single LCS request. The LMF uses CP interaction to interact with the NG RAN to e.g. require an NG RAN to send signals to the UE or to measure some signals from the UE, and uses UP interactions with UE after a short CP interaction with the UE to require the UE to send signals to the NG RAN or to report measurements made on some signals from the NG RAN.

Embodiments of the present disclosure are to provide enhancement to legacy 3GPP Control Plane (CP) specifications to integrate in 3GPP R18 UP communication between the UE and the LCS functionalities in the network.

Example Environments

Fig. 1 shows an example system 100 of the present disclosure in which example embodiments can be implemented. As illustrated in Fig. 1, the system 100 includes a terminal device such as User Equipment (UE) 101. UE 101 is an example of terminal device but the present disclosure is not limited thereto; instead, it could be any type of terminal device such as a vehicle, etc. and the system 100 could include any numbers of UE.

UE 101 is commutatively connected to an Access Network or Radio Access Network RAN 102. RAN 102 can be for example, a Next-Generation Radio Access Network (NG-RAN) which is an access network of the 3GPP 5G System.

UE 101 is further commutatively connected with Access and Mobility Management Function (AMF) 105. AMF 105 is a portal for the RAN 102 to access the core network of the 3GPP 5G system. The AMF can provide access control and mobility management function and communicate with other network elements in the core network through interface Nanf. AMF 105 is also communicatively connected to RAN 102 through interfaces N2.

RAN 102 is further commutatively connected with User Plane Function UPF 103 through interface N3. As an important element in the core network of the 3GPP 5G system, a user plane function (UPF) 103 is responsible for data packet routing and forwarding on the user plane. UPF 102 is communicatively connected with Session Management Function (SMF) 106 and a Data Network (DN) 104 through interfaces N4 and N6.

SMF 105 is a network element in the core network for session management, particularly responsible for interacting with the user plane, creating, updating, deleting sessions and managing session context with UPF 103. Meanwhile, SMF 105 can be communicated with other network elements through Nsmf.

DN 104 is a network for providing network data service to UE, which can be for example, an Operator Network, Internet, a third party service network, etc.

Location Management Function (LMF) 1 107a and LMF2 107b are two location management functions on the control plane in the core network. They coordinate and schedule resources required for managing UE’s locations and provide location and speed computation and verification. LMF1 107a and LMF2 107b can receive a location request for UE from AMF through interface Nlmf, communicate with UE on the control plane to exchange location information suitable for a UE assisted or UE based positioning method and interact with other network element such as NF-RAN, Non-3GPP InterWorking Function, etc. to obtain location information.

Specially, embodiments of the present disclosure propose arranging one or more associated or matched LCS user plane (LCUP) function for each of LMF; for example LMF1 107a may be associated with LCUP1-0 108a and LCUP1-1 108c while LMF2 107b may be associated with LCUP2 108b. The term “LCUP” used herein means a network element or a network function for location service on the user plane, which may e.g. correspond to user plane part of the LMF or to an SUPL location platform defined OMA specification.

The LCUP function handles location operations on the user plane and can be used with the associated LMF to enhance location service on the control plane. The LMF and the associated LCUP can be located within the same region, for example, co-located with each other or may communicate via an interface. Additional or alternatively, the LMF and the associated LCUP can also support similar positioning methods so that they can match each other. However, embodiments of the present disclosure are not limited thereto; it is possible to be associated with each other based on other factors. In addition, it is to be noted that LMF1 107a and LMF2 107b are given only for illustration purposes, the system 100 can include more numbers of LMFs. In addition, an LMF can be associated with one LCUP, and it is possible to be associated with more than on LCUPs. Or alternatively, an LCUP is also possible to be associated with more than one LMF, dependent on specific system implementations. Additionally, each LCUP can be communicatively connected with the DN 104.

The system 100 also comprises a Network Repository Function (NRF) 109 which functions as a centralized repository for all network functions (NFs) in the operator network and provides a record of all NFs together with the profile thereof and supported services.

Unified Data Management (UDM) function 111 provides a data management on network user data in a centralized way and particularly manages data for access authorization, user registration, and data network profiles. The UDM provides service through Nudm to AMF, SMF, and other NFs such as Network Exposure function (NEF) , and Binding Support Function (BSF) . The NEF is located between the 5G core network and external third-party application functionaries, and responsible for managing the external open network data, and all external applications that want to access the internal data of the 5G core must pass through the NEF. The BSF is mainly responsible for binding various sessions that originate on different interfaces in the network but share common criteria, for example sessions belonging to the same subscriber.

Edge Application Server Discovery Function (EASDF) 112 acts as a Domain Name System (DNS) resolver to the UE and can complement the DNS queries with UE location-related information, which enables the DNS system to resolve to application servers close to the UE location. The EASDF can communicate with other NFs through Neasdf interface.

In addition, the system also includes other NFs such NEF, Policy Charging Function (PCF) , Application Function (AF) , etc., and they all can communicate with other network elements in the core network through their respective interfaces. It is to be noted that these other NF (s) are not depicted in Figure 1 just for simplification purposes.

Example embodiments of the present disclosure relate to User Plane communication between UE being localized by a

LMF

107a, 107b and the

LMF

107a, 107b via a LCUP entity determined by the LMF, in order to enhance the CP positioning. One of objectives of the present disclosure is to enable that the UE will contact over the UP an LCUP that corresponds to the User Plane termination of the LMF serving a terminal device.

To this end, embodiments of the present disclosure propose provisioning a LMF DNS server, forwarding a DNS query message to one or more LMF DNS server, by which address information of the matched LCUP could be provided.

Embodiments of the present disclosure can be implemented within system 100 as illustrated in Fig. 1; however, it is to be understood that Fig. 1 is given merely for illustrative purposes without suggesting any limitation to the protection scope. Instead, embodiments of the present disclosure can be implemented in other communication systems with similar CP location service enhancement requirements.

Hereinafter, some example embodiments will be detailed with reference to Figs. 2 to 9.

Example processes

Fig. 2 illustrates a flowchart of an example method 200 of an example method for LCUP address information obtainment according to some example embodiments of the present disclosure. The method could be implemented at a network device, such as LMF instance, or any other appropriate network element in the network.

As illustrated in Fig. 2, the network device, such as LMF instance or entity, provisions 210 a location management function (LMF) domain name sever (DNS) behind an Edge Application Server Discovery Function (EASDF) instance through a network exposure function interface. It is to be noted that LMF is an example embodiments of the present disclosure and the present disclosure is not limited thereto.

In some example embodiments, the LMF instance can provision itself as the LMF DNS server to serve a DNS query from a terminal device. In some example embodiments, the LMF DNS server can be another entity, element or function embedded in the LMF instance or capable of referring to the LMF. Thus, the LMF DNS server can be communicated with the LMF instance to require the LMF instance to handle the DNS query.

The provision operation is a pre-configuration operation and a detailed description on some example embodiments for provision process will be made hereinafter with reference to Figs. 5a-5c and 6.

In response to a CP location service request initiated by a terminal device or a network, a serving LMF shall be selected. In some embodiments of the present disclosure, if a geographic criteria of a single local LMF matches the geographic area of a local data network of EAS, the single local LMF device could be chosen as the serving LMF device.

In order to match the service entry of LMF device and its location user plane (LCUP) function instance, the same local EAS discovery process may apply to the local LCUP discovery to select a matched, or associated LCUP for the serving LMF. The LMF will trigger a UP location service by for example sending a capability request message to the terminal. The capability request message is only an example and it is also possible to trigger UE to start a UP location operation in any appropriate way.

In response to such a trigger, the terminal device can send a DNS query message to get the address information of the LCUP. In some embodiments of the present disclosure, the terminal device could send the DNS query message as did in the prior art, for example using the domain name embedded in the terminal device or pre-configured by the network. The network will be responsible for guiding the UE to contact the proper LCUP as to be described hereinafter.

The DNS query message will be received by an EASDF instance. Due to the provisioned LMF DNS server, the EASDF will forward the DNS query message to the LMF DNS server. When the LMF DNS server is embedded in the LMF instance, or refers to the LMF instance, the LMF DNS server will further send the DNS message to the LMF. Thus, the network device such as LMF then receives 220 a DNS query message for querying an IP address of a LCUP function instance from the EASDF instance.

Upon receipt of the DNS query message, the network device determines 230 whether to respond to the DNS query message based on a predetermined responding rule. For example, if the LMF determines that there is a correlation between the terminal device and

In some example embodiments, the determining comprises determining whether to respond to the DNS query message based on cell identifier. In other words, a location-based rule can be applied.

The cell identifier may be obtained in different ways. In some embodiments, it can be obtained from any of SIP header in a SIP invite message. For example; for an emergency request, Location Retrieval Function (LRF) /Routing Determination Function (RDF) may receive Session Initiation Protocol (SIP) INVITE from Emergency –Call Session Control Function (E-CSCF) . By co-locating with a Gateway Mobile Location Centre (GMLC) and/or LRF/RDF, or by obtaining a GMLC instance address in Access and Mobility Management Function (AMF) request (hgmlcCallBackURI) , LMF device may obtain the contents of the SIP INVITE. Then the location of User equipment (UE) can be located in serving cell identity in P-Access-Network-Info SIP Header. As another example, the core network maintain all cell identifiers of the terminal devices in the network, and thus the LMF can learn the cell ID of the cell serving the UE from the cell network.

Thus, based on the cell identifier, the LMF device can decide whether it is located in the same region and thus whether its associated LCUP should be serving the UE or not. If yes, the LMF device can respond to the IP address of the LMF for the DNS query; if no, it will make no reply.

In some example embodiments, such determination can be made based on the IP address of the terminal device. In some cases, the DNS query message forwarded from the EASDF contains an IP address of the terminal device, and in such a case, it can be determined whether an IP address of any terminal device that the LMF is serving matches the IP address contained within the forwarded DNS query message. If so the LMF could determine to respond; otherwise make no reply.

In some example embodiments, the IP address of the terminal device may be obtained from an SIP Header in SIP invite message. For example, in an emergency request, Location Retrieval Function (LRF) /Routing Determination Function (RDF) may receive SIP INVITE from E-CSCF. By co-locating with a GMLC and/or LRF/RDF, or by obtaining a GMLC instance address in AMF request, the LMF device may obtain contents of the SIP INVITE. Thus, the LMF can extract the location of UE from SIP Header to determine whether it matches the UE IP address in a DNS query. So that the LMF device can decide whether the DNS query shall be served by itself.

In some example embodiments, the IP address of the terminal device may be obtained by extracting the terminal device’s identity from input parameters from Nlmf_Location_DetermineLocation Request, and querying BSF to get the IP address matching the terminal device’s identity through a DNS query.

In some example embodiments, there are a group of network devices. The network devices can be organized in different manners. For example, there may be a facade network device in the group of network devices, and a facade network device can be communicatively connected with each of other network devices. In some example embodiments, a group of network devices may be communicatively connected in a cascade manner.

The network device obtains 240 an IP address of a LCUP instance associated with the LMF in accordance with the determination. Particularly, the LMF maintains the information on the associated LCUP. Therefore, the LMF could obtain an IP address of the LCUP associated with the LMF. When there are more than one LCUP associated with LMF, the LMF could select one of them in a predetermined rule.

Thereafter, the LMF transmits 250 the IP address of the LCUP instance back to the EASDF instance. In cases where the LMF itself is not the LMF DNS server, the LMF will provide the IP address of the LCUP instance to the LMF DNS server and the LMF DNS server provides in turn the IP address to the EASDF. The EASDF will send the received the IP address to the terminal device as a response to the DNS query message.

Fig. 3 illustrates a flowchart of an example method 300 of an example method for LCUP address information obtainment according to some example embodiments of the present disclosure. The method could be implemented at a network device, such as EASDF instance, or any other appropriate network element in the network.

As described above, when a LMF device is invoked by 3GPP MT-LR/NI-LR/MO-LR, as per TR 23.700-71, the LCUP of the LMF device can be activated for the location service. LMF device can activate the UE to use its paired/expected LCUP instance. After the UP location service is triggered by the network, the UE could send a DNS query message to obtain the IP address of the LCUP to establish a UP connection.

Upon receipt of the DNS query message, the network device forwards 310 the DNS query message for querying an IP address of a location user plane (LCUP) function instance to at least one Location Management Function (LMF) DNS servers based on a provisioned DNS message handling rule.

Before activing a LCUP session by either OMA (Orthogonal Multiple Access) push mechanisms or other means, the LMF device will apply any of the following EASDF DNS message handling rules before UP activation to the UE.

In some embodiments of the present disclosure, if the DNS message type is a “DNS query” , then the DNS message can be forwarded. This could ensure only DNS query to be forwarded to LMFs.

In some example embodiments, forwarding a DNS query message may comprise determining whether a source IP address contained within a DNS query message matches an IP address of the terminal device allocated by a network; and transmitting a DNS query message to at least one LMF DNS server in accordance with the determination. In other words, the EASDF may determine whether the IP address of the UE sending the DNS query is the same as the UE establishing the session. If yes, it means the UE sending the DNS query message has the right to use the session, and the EASDF may decide to forward the DNS query message.

In some embodiments of the present disclosure, alternatively, or additionally, if the domain name contained within the DNS query message complies with any predetermined rule of LCUP domain names, the EASDF may decide to forward the DNS query message. For example, the EASDF could determine whether the FQDN in a DNS Query matches the FQDN (s) specified by OMA SLP FQDN or any other existing rule of LCUP FQDN by operator network,

It is to be noted that the above DNS message handling rule can be used separately or collectively and there is also possible to use other proper DNS message handling rules.

In some embodiments, EASDF then may forward a DNS message (s) to the LMF DNS server/resolver (s) with IP address of UE attached through Extension Mechanisms for DNS Client Subnet. In such a way, the LMF may use the UE IP address to determine whether to respond to the DNS query message to provide the IP address of its matched LCUP.

In some example embodiments, wherein at least one LMF DNS server may comprise a group of LMF DNS servers including a facade LMF DNS server communicatively connected with each of other LMF DNS servers. Thus, the EASDF may forward a DNS query message to the facade network device and meanwhile the EASDF will receive the IP address of the LCUP instance from the facade network device, no matter which one of the LMF DNS provide the IP address.

In some example embodiments, wherein at least one LMF DNS server may comprise a group of LMF DNS servers communicatively connected in a cascade manner. Accordingly, the EASDF may forward a DNS query message to the group of LMF DNS servers one by one until receiving the IP address of the LCUP instance.

The network device such EASDF receives 320 the IP address of the LCUP instance from one of at least one LMF DNS server that serves a terminal device and transmits 330 the IP address of the LCUP instance to the terminal device. Thus, the UE could get the IP address of the LUCH which enables a UP connection between the UE and the LCUP associated with the serving LMF.

Fig. 4 illustrates a flowchart of an example method 400 for LCUP address information obtainment according to some example embodiments of the present disclosure. The method could be implemented at a network device, such as SMF instance, or any other appropriate network element in the network.

As illustrated in Fig. 4, the network device such as SMF subscribes 410 itself to a network exposure function (NEF) instance. In such a way, when any LMF provisions an LMF DNS server, the SMF will receive 420 a notification of LMF DNS provision from the NEF instance due to the subscription in advance. In response to the notification, the SMF provisions 430 an Edge Application Server Discovery Function (EASDF) instance with the DNS message handling rule.

Fig. 5a illustrates a signalling chart illustrating an example process 500 according to some example embodiments of the present disclosure. The process can be performed amongst for example LMF, NEF and UDR.

When a network device such as LMF device and its paired/expected/matched LCUP instance is setup, the LMF may provision a LMF DNS server behind the EASDF through NEF. The LMF itself could be provisioned as the LMF DNS server or the LMF could provision its embedded/referenced entity as a DNS server. The DNS server may perform a single task to resolve the Fully Qualified Domain Name (FQDN) of its paired/expected LCUP instance.

The LMF may transmit 510a a Nnef_EASDeployment_Create request to network exposure function (NEF) interface 502 to provision for example itself as a server. The request can contain a DNS message handling rule.

Upon the receipt of Nnef_EASDeployment_Create request, the NEF may proceed with NEF handling 502a. The NEF may obtain the information in Nnef_EASDeployment_Create request and transmit 503a a Nudr_DM_Create request to Unified Data Repository (UDR) to store the DNS message handling rule in the UDR.

Upon receipt of the Nudr_DM_Create request, the UDR may store the handling rule and transmit 504a a Nudr_DM_Create response to the NEF. Upon reception of Nudr_DM_Create response, the NEF may forward 550a the Nudr_DM_Create response to the LMF.

Fig. 5b illustrates a signalling chart illustrating an example process according to some example embodiments of the present disclosure. The process can be performed amongst for example LMF, NEF and UDR.

When the first device, such as LMF device desires to update the LMF DNS server provision it may transmit 510b a Nnef_EASDeployment_Update request to NEF 502 to register as a server. The request can contain for example updated DNS message handling rule. Upon the receipt of Nnef_EASDeployment_Update request, the NEF may proceed with NEF handling 502b and transmit 503b Nudr_DM_Update request to Unified Data Repository (UDR) to store updated DNS message handling rule in the UDR.

Upon receipt of the Nudr_DM_Upadate request, the UDR may transmit 504b Nudr_DM_Upadate response to the NEF. The NEF may further forward 550b the Nudr_DM_Upadate response to LMF.

Fig. 5c illustrates a signalling chart illustrating an example process according to some example embodiments of the present disclosure. The process can be performed amongst for example LMF, NEF and UDR.

When the network device, such as LMF device decide to delete a LMF DNS server provision behind the EASDF. The LMF may transmit 510c Nnef_EASDeployment_Delete request to network exposure function (NEF) interface 502 to cancel a DNS server provision.

Upon the receipt of Nnef_EASDeployment_Delete request, the NEF may proceed with NEF handling 502c. The NEF may transmit 503c a Nudr_DM_Delete request to Unified Data Repository (UDR) to for example delete DNS message handling rule in the UDR.

Upon receipt of the Nudr_DM_Delete request, the UDR may delete a DNS message handling rule and transmit 504c Nudr_DM_Delete response to the NEF. The NEF may forward 550c the Nudr_DM_Delete response to the LMF to notify the compete of the DNS server provision deletion.

Fig. 6 illustrates another signaling chart illustrating an example process according to some example embodiments of the present disclosure. The process can be performed between for example SMF and NEF.

The example process is performed to enable a DNS server provision could be notified by NEF so that the SMF could obtain the DNS message handling rule and apply the rule to the EASDF.

As illustrated, the SMF device 601 could transmit 610 to NEF 602 a Nnef_EASDeployment_Subscribe request to require subscribe itself to the NEF.

Upon receipt of the Nnef_EASDeployment_Subscribe request, the NEF 602 may record the subscription so that any LMF DNS server provision could be notified to the SMF.

After the NEF handling, the NEF may transmit 620 Nnef_EASDeployment_Subscribe responses to the SMF device 601 to notify for example a successful subscription.

After having subscribed to the NEF, the NEF 602 may transmit 630 Nnef_EASDeployment_Notify request to SMF device 601 whenever there is a LMF DNS server provision. The SMF device 601 may obtain the DNS message handling rules and apply the rules to the EASDF, for example through Neasdf_DNSContext service operations. The SMF device 601 may further transmit 640 a Nnef_EASDeployment_Notify response to the NEF 602 to for example acknowledge the reception of the notification.

Fig. 7 illustrates a further signaling chart illustrating an example process according to some example embodiments of the present disclosure;

UE 701 transmits 710 a domain name sever (DNS) query message to EASDF instance 704.

As illustrated, upon receipt of the DNS query message from the UE, the EASDF forwards 720 the DNS query message for querying an IP address of a location user plane (LCUP) function instance to at least one Location Management Function (LMF) DNS servers 703 based on a provisioned DNS message handling rule.

Upon the receipt of the DNS query message, the LMF DNS servers 703 determine 730 whether to respond to the DNS query message based on a predetermined responding rule and obtain 730 an IP address of a LCUP instance associated with the LMF in accordance with the determination. LMF DNS servers 703 then transmit 740 the IP address of the LCUP instance to the EASDF instance. The EASDF instance 704 then transmits the IP address of the LCUP instance to the terminal device as a response to the DNS query message.

Detailed operations at UE, LMF and the EASDF are already described with reference to Fig 2 to 6 and therefore will not be elaborated herein.

Fig. 8 is a simplified block diagram of a device 800 that is suitable for implementing embodiments of the present disclosure. For example, the terminal device, LMF, SMF, NEF and EASDF, shown in Figs. 1 to 7 may be implemented by the device 800. As shown, the device 800 includes one or more processors 810, one or more memories 820 coupled to the processor 7810, and one or more communication modules 840 coupled to the processor 810.

The communication module 840 is for directional communications. The communication module 840 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 810 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 800 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 820 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 824, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital versatile disc (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 822 and other volatile memories that will not last in the power-down duration.

A computer program 830 includes computer executable instructions that are executed by the associated processor 810. The program 830 may be stored in the ROM 824. The processor 810 may perform any suitable actions and processing by loading the program 830 into the RAM 822.

The embodiments of the present disclosure may be implemented by means of the program 830 so that the device 800 may perform any process of the disclosure as discussed with reference to Figs. 2-7. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some example embodiments, the program 830 may be tangibly contained in a computer readable medium which may be included in the device 800 (such as in the memory 820) or other storage devices that are accessible by the device 800. The device 800 may load the program 830 from the computer readable medium to the RAM 822 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like.

Fig. 9 shows an example of the computer readable medium 900 in form of CD or DVD. The computer readable medium has the program 930 stored thereon.

It should be appreciated that future networks may utilize network functions virtualization (NFV) which is a network architecture concept that proposes virtualizing network node functions into “building blocks” or entities that may be operationally connected or linked together to provide services. A virtualized network function (VNF) may comprise one or more virtual machines running computer program codes using standard or general type servers instead of customized hardware. Cloud computing or data storage may also be utilized. In radio communications, this may mean node operations to be carried out, at least partly, in a central/centralized unit, CU, (e.g. server, host or node) operationally coupled to distributed unit, DU, (e.g. a radio head/node) . It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. It should also be understood that the distribution of labour between core network operations and base station operations may vary depending on implementation.

In an embodiment, the server may generate a virtual network through which the server communicates with the distributed unit. In general, virtual networking may involve a process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Such virtual network may provide flexible distribution of operations between the server and the radio head/node. In practice, any digital signal processing task may be performed in either the CU or the DU and the boundary where the responsibility is shifted between the CU and the DU may be selected according to implementation.

Therefore, in an embodiment, a CU-DU architecture is implemented. In such case the device 900 may be comprised in a central unit (e.g. a control unit, an edge cloud server, a server) operatively coupled (e.g. via a wireless or wired network) to a distributed unit (e.g. a remote radio head/node) . That is, the central unit (e.g. an edge cloud server) and the distributed unit may be stand-alone apparatuses communicating with each other via a radio path or via a wired connection. Alternatively, they may be in a same entity communicating via a wired connection, etc. The edge cloud or edge cloud server may serve a plurality of distributed units or a radio access networks. In an embodiment, at least some of the described processes may be performed by the central unit. In another embodiment, the device 900 may be instead comprised in the distributed unit, and at least some of the described processes may be performed by the distributed unit.

In an embodiment, the execution of at least some of the functionalities of the device 900 may be shared between two physically separate devices (DU and CU) forming one operational entity. Therefore, the apparatus may be seen to depict the operational entity comprising one or more physically separate devices for executing at least some of the described processes. In an embodiment, such CU-DU architecture may provide flexible distribution of operations between the CU and the DU. In practice, any digital signal processing task may be performed in either the CU or the DU and the boundary where the responsibility is shifted between the CU and the DU may be selected according to implementation. In an embodiment, the device 900 controls the execution of the processes, regardless of the location of the apparatus and regardless of where the processes/functions are carried out.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the

method

200, 300, and 400, and any of processes 500 to 700 as described above with reference to Figs. 2-7. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A network device, comprising

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device to:

provision a location management function (LMF) domain name sever (DNS) behind an Edge Application Server Discovery Function (EASDF) instance through a network exposure function interface;

receive a DNS query message for querying an IP address of a location user plane (LCUP) function instance from the EASDF instance;

determine whether to respond to the DNS query message based on a predetermined responding rule;

obtain an IP address of a LCUP instance associated with the LMF in accordance with the determination; and

transmit the IP address of the LCUP instance to the EASDF instance.
The network device of Claim 1, wherein the determining whether to respond to the DNS query message comprises determine whether to respond to the DNS query message based on cell identifier.
The network device of Claim 2, wherein the cell identifier is obtained from any of SIP header in a SIP invite message or from a core network.
The network device of any of Claims 1 to 3, wherein the DNS query message from the EASDF contains an IP address of the terminal device; and

wherein the determining whether to respond to the DNS query message comprises determining whether to respond to the DNS query message based on the IP address of the terminal device.
The network device of Claim 4, wherein the IP address of the terminal device is obtained from an SIP Header in SIP invite message.
The network device of Claim 4, wherein the IP address of the terminal device is obtained by extracting the terminal device’s identity from input parameters from Nlmf_Location_DetermineLocation Request, and querying Binding Support Function (BSF) to get the IP address matching the terminal device’s identity through a DNS query.
The network device of any of Claims 1 to 6, wherein the network device is one of a group of network devices including a facade network device communicatively connected with each of other network devices.
The network device of Claim 7, wherein the network device is one of a group of network devices communicatively connected in a cascade manner.
The network device of any of Claims 1 to 8, wherein the network device comprises an LMF instance and the LMF instance itself is provisioned as the LMF DNS server.
The network device of any of Claims 1 to 8, wherein the network device comprises an LMF instance and the LMF DNS server can be communicated with the LMF instance.
A network device, comprising

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, and cause the network device to:

forward a domain name sever (DNS) query message for querying an IP address of a location user plane (LCUP) function instance to at least one Location Management Function (LMF) DNS server based on a provisioned DNS message handling rule;

receive the IP address of the LCUP instance from one of at least one LMF DNS server that serves a terminal device; and

transmit the IP address of the LCUP instance to the terminal device.
The network device of Claim 11, wherein the forwarding a DNS query message comprises

determining whether a source IP address contained within a DNS query message matches an IP address of the terminal device allocated by a network; and

transmitting a DNS query message to the at least one LMF DNS server in accordance with the determination.
The network device of Claim 11, wherein the forwarding a DNS query message further comprises:

determining whether the domain name contained within the DNS query message complies with any predetermined rule of LCUP domain names; and

transmitting a DNS query message to the at least one LMF DNS server in accordance with the determination.
The network device of Claim 11, wherein the forwarding a DNS query message comprises

determining whether a source IP address of a DNS query message matches an IP address of the terminal device allocated by a network and whether the domain name contained within complies with any predetermined rule of UPF domain names;

transmitting a DNS query message to the at least one LMF DNS server in accordance with the determinations.
The network device of any of Claims 11 to 14, wherein the forwarding a DNS query message further comprises:

forwarding a DNS query message with an IP address of the terminal device attached through Extension Mechanisms for DNS Client Subnet.
The network device of any of Claims 11 to 15, wherein at least one LMF DNS server comprises a group of LMF DNS servers including a facade LMF DNS server communicatively connected with each of other LMF DNS servers,

wherein the forwarding a DNS query message comprises forwarding a DNS query message to the facade LMF DNS servers, and

wherein the receiving the IP address of the LCUP instance comprises receiving the IP address of the LCUP instance from the facade LMF DNS server.
The network device of any of Claims 11 to 15, wherein at least one LMF DNS server comprises a group of LMF DNS servers communicatively connected in a cascade manner, and

wherein the forwarding a DNS query message comprises forwarding a DNS query message to the group of LMF DNS servers one by one until receiving the IP address of the LCUP instance.
The network device of any of Claims 11 to 17, wherein the network device comprises an edge Application Server Discovery Function (EASDF) instance.
A network device, comprising:

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, and cause the network device to:

subscribe the network device to a network exposure function instance;

receive a notification of location management function (LMF) domain name sever (DNS) provision from the network exposure function instance; and

provision an Edge Application Server Discovery Function (EASDF) instance with a DNS message handling rule.
The network device of Claim 19, wherein the network device comprises Session Management Function (SMF) instance.
A method, comprising

provisioning a location management function (LMF) domain name sever (DNS) behind an Edge Application Server Discovery Function (EASDF) instance through a network exposure function interface;

receiving a DNS query message for querying an IP address of a location user plane (LCUP) function instance from the EASDF instance;

determining whether to respond to the DNS query message a predetermined responding rule;

obtaining an IP address of a LCUP instance associated with the LMF in accordance with the determination; and

transmitting the IP address of the LCUP instance to the EASDF instance.
A method, comprising

forwarding a domain name sever (DNS) query message for querying an IP address of a location user plane (LCUP) function instance to at least one Location Management Function (LMF) DNS servers based on a provisioned DNS message handling rule;

receiving the Internet Protocol (IP) address of the LCUP instance from one of at least one LMF DNS server that serves a terminal device; and

transmitting the IP address of the LCUP instance to the terminal device.
A method, comprising:

subscribing the network device to a network exposure function instance;

receiving a notification of location management function (LMF) domain name sever (DNS) provision from the network exposure function instance; and

provisioning an Edge Application Server Discovery Function (EASDF) instance with a DNS message handling rule.
An apparatus, comprising

means for provisioning a location management function (LMF) domain name sever (DNS) behind an Edge Application Server Discovery Function (EASDF) instance through a network exposure function interface;

means for receiving a DNS query message for querying an IP address of a location user plane (LCUP) function instance from the EASDF instance;

means for determining whether to respond to the DNS query message a predetermined responding rule;

means for obtaining an IP address of a LCUP instance associated with the LMF in accordance with the determination; and

means for transmitting the IP address of the LCUP instance to the EASDF instance.
An apparatus, comprising

means for forwarding a domain name server (DNS) query message for querying an IP address of a location user plane (LCUP) function instance to at least one Location Management Function (LMF) DNS servers based on a provisioned DNS message handling rule;

means for receiving the Internet Protocol (IP) address of the LCUP instance from one of at least one LMF DNS server that serves a terminal device; and

means for transmitting the IP address of the LCUP instance to the terminal device.
An apparatus, comprising

means for subscribing the network device to a network exposure function instance;

means for receiving a notification of location management function (LMF) domain name sever (DNS) provision from the network exposure function instance; and

means for provisioning an Edge Application Server Discovery Function (EASDF) instance with a DNS message handling rule.
A computer readable medium comprising program instructions for causing an apparatus to perform at least the method of any of Claims 21 to 23.