WO2023035229A1

WO2023035229A1 - Network nodes, ims node and methods performed in a communication network

Info

Publication number: WO2023035229A1
Application number: PCT/CN2021/117712
Authority: WO
Inventors: Liangliang Guo; Irene Martin Cabello; Chunmiao LIU; Afshin Abtin; Olli Matti Hynoenen; Fuencisla Garcia Azorero; Susana Fernandez Alonso; Sven Gemski
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2021-09-10
Filing date: 2021-09-10
Publication date: 2023-03-16
Anticipated expiration: 2024-03-10
Also published as: EP4399894A4; EP4399894A1

Abstract

Embodiments herein discloses, for example, a method performed by a first network node for handling communication in a communication network. The first network node (13) receives from an IMS node (15), a request indicator in a message, wherein the request indicator indicates a request for NPLI of a UE (10), and wherein the message comprises no information for transmitted user plane data. The first network node further transmits to a second network node (14), a trigger indicator relating to retrieval of the NPLI for a PDU session for the UE.

Description

NETWORK NODES, IMS NODE AND METHODS PERFORMED IN A COMMUNICATION NETWORK

TECHNICAL FIELD

Embodiments herein relate to a first network node, a second network node, an Internet Protocol Multimedia Subsystem (IMS) node and methods performed therein regarding communication in a communication network. Furthermore, a computer program product and a computer-readable storage medium are also provided herein. Especially, embodiments herein relate to retrieve Network Provided Location Information of a user equipment (UE) in the communication network.

BACKGROUND

In a typical communication network, UEs, also known as wireless communication devices, mobile stations, stations (STA) and/or wireless devices, communicate via a Radio access Network (RAN) to one or more core networks (CN) . The RAN covers a geographical area which is divided into service areas or cell areas, with each service area or cell area being served by a radio network node such as an access node e.g. a Wi-Fi access point or a radio base station (RBS) , which in some radio access technologies (RAT) may also be called, for example, a NodeB, an evolved NodeB (eNodeB) and a gNodeB (gNB) . The service area or cell area is a geographical area where radio coverage is provided by the radio network node. The radio network node operates on radio frequencies to communicate over an air interface with the UEs within range of the access node. The radio network node communicates over a downlink (DL) to the UE and the UE communicates over an uplink (UL) to the radio network node. The radio network node may be a distributed node comprising a remote radio unit and a separated baseband unit.

A Universal Mobile Telecommunications System (UMTS) is a third generation telecommunication network, which evolved from the second generation (2G) Global System for Mobile Communications (GSM) . The UMTS terrestrial radio access network (UTRAN) is essentially a RAN using wideband code division multiple access (WCDMA) and/or High-Speed Packet Access (HSPA) for communication with UEs. In a forum known as the Third Generation Partnership Project (3GPP) , telecommunications suppliers propose and agree upon standards for present and future generation networks, and investigate enhanced data rate and radio capacity. In some RANs, e.g. as in UMTS, several radio network nodes may be connected, e.g., by landlines or microwave, to a controller node, such as a radio network controller (RNC) or a base station controller (BSC) , which supervises and coordinates various activities of the plural radio network nodes connected thereto. The RNCs are typically connected to one or more core networks.

Specifications for the Evolved Packet System (EPS) have been completed within the 3 ^rd Generation Partnership Project (3GPP) and also for fifth generation (5G) networks. The EPS comprises the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) , also known as the Long-Term Evolution (LTE) radio access network, and the Evolved Packet Core (EPC) , also known as System Architecture Evolution (SAE) core network. E-UTRAN/LTE is a 3GPP radio access technology wherein the radio network nodes are directly connected to the EPC core network. As such, the Radio Access Network (RAN) of an EPS has an essentially “flat” architecture comprising radio network nodes connected directly to one or more core networks.

With the emerging 5G technologies also known as new radio (NR) , the use of very many transmit-and receive-antenna elements makes it possible to utilize beamforming, such as transmit-side and receive-side beamforming. Furthermore, NR comprises a number of network functions (NF) such as Access and Mobility Management Function (AMF) , session management function (SMF) , policy control function (PCF) etc enabling communication in an efficient manner.

The Internet Protocol (IP) Multimedia Subsystem (IMS) is a well-known Third Generation Partnership Project (3GPP) standard allowing sessions to be set up between two or more parties for a broad variety of services such as voice or video call, interactive messaging sessions or third-party specific applications. A few common enablers are defined by 3GPP for common usage among all these services. Examples of such enablers are capability discovery and subscribing to conference events to be used by for example an ad-hoc voice call conference for clients/devices to identify who leaves and enters the conference.

The signalling protocol chosen by 3GPP is the Session Initiation Protocol (SIP) . SIP is an application layer protocol used for controlling multimedia sessions over IP networks. It is a text-based protocol which uses the request/response model. SIP defines messages sent between endpoints, which govern establishment, termination and other essential elements of a multimedia connection. SIP can be used for creating, modifying and terminating sessions consisting of one or more media streams. It can be both unicast and multicast. Examples of applications which SIP can establish and control are video conferencing, streaming multimedia distribution, instant messaging, presence information, file transfer, fax over IP and online games.

Voice over NR (VoNR) which is the 3GPP solution for Voice over 5GS based on IMS and Voice over LTE (VoLTE) is subject to regulatory requirements in many countries to retrieve the user location which normally is a cell identity but may also be a time zone. This procedure is normally performed by IMS via interaction with 5GC, both when such 5GS UE is on NR or LTE, or for VoLTE with EPC.

Network provided user location information and/or UE time-zone, herein denoted Network Provided Location Information (NPLI) , is required during IMS call establishment, call termination, and also during mid-call. For example, NPLI may be triggered by proxy (P) -Call Session Control Function (CSCF) due to a handover during mid-call, e.g., VoNR to VoLTE handover upon receipt of radio access technology (RAT) type change notification by P-CSCF. NPLI is also required for SMS over IP (SMSoIP) .

The network location (Netloc) reporting today is coupled with policy and charging control (PCC) rules, e.g. certain quality of service (QoS) flow and/or Dedicated Bearer, handling in the N7 interface and also in session management function (SMF) as defined in the 3GPP TS 29.512 v. 16.0.0 section 4.2.6.5.4: When the NetLoc feature is supported, if the application function (AF) requests the policy control function (PCF) to report the access network information, the PCF shall perform the PCC rule provisioning procedure as defined in subclause 4.2.6.2.1 and additionally provide the requested access network information indication, such as user location and/or UE time zone information i.e. NPLI, to the SMF as follows:

● it shall include the "lastReqRuleData" attribute to contain the "reqData" attribute with the value (s) MS_TIME_ZONE and/or USER_LOC_INFO and the "refPccRuleIds" attribute to contain the related installed/modified/removed PCC rule identifier (s) .

● it shall provide the AN_INFO policy control request trigger within the "policyCtrlReqTriggers" attribute (if not yet set) .

In the 4G, the NPLI query is also coupled with PCC rules handling for EPS bearer as indicated in TS 29.212 v 16.0.0:

4.5.22 reporting Access Network Information

When the NetLoc feature is supported, if the AF requests the Policy Control and charging Rules Function (PCRF) to report the access network information and if the PCRF cannot determine that access network information cannot be provided as described in subclause 4.4.6.7 of3GPP TS 29.214 [10] , the PCRF shall provide the requested access network information indication, e.g. user location and/or user time zone information, to the packet data network gateway-control plane (PGW-C) as follows:

-If the PCRF is installing or modifying a PCC rule, the PCRF shall include the Required-Access-Info attribute value pair (AVP) within the Charging-Rule-Definition A VP of an appropriate installed or modified PCC rule;

- Otherwise, if the PCRF is removing PCC rules based on the AF requests, the PCRF shall include the Required-Access-Info AVP within the Charging-Rule-Remove AVP associated with the corresponding PCC rules being removed.

The Netloc reporting which is coupled with Dynamic PCC rules can be used to fetch NPLI during IMS call establishment and call termination but not for the other use cases mentioned above.

SUMMARY

As a part of developing embodiments herein a problem was first identified and will be discussed herein. The Netloc support is not aligned in the 3GPP in stage 3 implementation, it is coupled with PCC rules operations, corresponding to QoS flow in 5GC, and EPS bearer in 4G.

There are use cases where NPLI reporting without dedicated QoS flow operations and/or dedicated bearers in 4G may be requested, such as mid-call during RAT type change where no changes of media component of 5G QoS Identifier (5QI) or QoS class indicator (QCI) for video/voice etc. In the 5GC, the standard behavior for NPLI report request requires PCC rules operations, such as QoS flow operation, in the same procedure. A PCC rule is a set of information enabling the detection of a service data flow and providing parameters for policy control, charging control and other possible control or support information. In order to create a dynamic PCC rule, the PCF needs to derive the related service information and associated control information. However, in, e.g., mid-call NPLI triggered by IP-connectivity access network (CAN) Type change notification and NPLI for SMS over IP, the P-CSCF does not provide service information nor related QoS demands so that the SMF can initiate the related QoS flow operation and get the NPLI as requested by the P-CSCF. Even if the 3GPP specifications allow the P-CSCF to contact the PCF to request NPLI without service information, the procedure on how to get it is not specified which makes the PCF unable to obtain the required information. The right boxes in Fig. 1 describe the problem which points to specific sequence step.

In the 4G EPS, the standard behavior for NPLI report request is coupled with PCC rule operations, i.e., EPS bearer operations, -updating/creating/removing PCC rules in the same procedure. Same applies in 5GS interworking with 4G EPS, as shown in the Fig. 2. In the Fig. 2, dual core SMF/PGW-C and N7 is used.

For pure 4G EPS where Gx is used between SPAC and PGW, the P-CSCF sends the NPLI query together with media components, which corresponds to PCC rule in the EPS domain, to PCRF instead of PCF. PCRF must include the request for User Access Location Info and UE time zone in Required-Access-Info AVP together with PCC rule operation in the radio access response (RAR) message. The message is sent to PGW. The reset of procedures is the same. The block diagram in Fig. 2 shows theSmPolicyDecision fields containing the requested UE time zone and user location with the PCC rule operation request.

An object of embodiments herein is to provide a mechanism that efficiently handles sessions in the communication network.

According to an aspect the object is achieved by providing a method performed by a first network node, such as a PCF or a PCRF, for handling communication in a communication network. The first network node receives from an IMS node, a request indicator in a message, wherein the request indicator indicates a request for NPLI of a UE, and wherein the message comprises no information for transmitted user plane data. The first network node further transmits to a second network node, a trigger indicator relating to retrieval of the NPLI for a protocol data unit (PDU) session for the UE.

According to another aspect the object is achieved by providing a method performed by a second network node, such as a SMF or a PGW, for handling communication in a communication network. The second network node receives a trigger indicator from a first network node related to retrieval of NPLI for a PDU session for a UE. The second network node further triggers a retrieval of the NPLI for the UE.

According to yet another aspect the object is achieved by providing a method performed by an IMS node, such as a P-CSCF, for handling communication in a communication network. The IMS node receives a triggering message associated with a UE in the communication network, wherein the triggering message is related to a mobility related event of the UE. In response to receiving the triggering message, the IMS node sends to a first network node, a request indicator in a message, wherein the request indicator indicates a request for NPLI of the UE, and wherein the message comprises no information for transmitted user plane data.

It is furthermore provided herein a computer program product comprising instructions, which, when executed on at least one processor, cause the at least one processor to carry out any of the methods above, as performed by the IMS node, the first network node and the second network node, respectively. It is additionally provided herein a computer-readable storage medium, having stored thereon a computer program product comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to any of the methods above, as performed by the IMS node, the first network node and the second network node, respectively.

According to still another aspect the object is achieved by providing a first network node, such as a PCF or a PCRF, for handling communication in a communication network. The first network node is configured to receive from an IMS node, a request indicator in a message, wherein the request indicator indicates a request for NPLI of a UE, and wherein the message comprises no information for transmitted user plane data. The first network node is further configured to transmit to a second network node, a trigger indicator relating to retrieval of the NPLI for a PDU session for the UE.

According to yet still another aspect the object is achieved by providing a second network node, such as a SMF or a PGW, for handling communication in a communication network. The second network node is configured to receive a trigger indicator from a first network node related to retrieval of NPLI for a PDU session for a UE. The second network node is further configured to trigger a retrieval of the NPLI for the UE.

According to another aspect the object is achieved by providing an IMS node, such as a P-CSCF, for handling communication in a communication network. The IMS node is configured to receive a triggering message associated with a UE in the communication network, wherein the triggering message is related to a mobility related event of the UE. In response to receiving the triggering message, the IMS node is further configured to send to a first network node, a request indicator in a message, wherein the request indicator indicates a request for NPLI of the UE, and wherein the message comprises no information for transmitted user plane data.

Embodiments herein propose to de-couple NPLI and PCC Rules, for a QoS flow or EPS bearer, since the message comprises no information for transmitted user plane data. The IMS node, as an application function (AF) , is thus able to perform NPLI query without involving operations triggered by the PCC rule provisioning.

The IMS node sends the NPLI query without information for transmitted user plane data, for example, without media-components. The first network node such as a node controlling charging and/or policies, for example, a PCF, sends the NPLI query at the PDU session level to the second network node, for example, by providing the Access Network Report policy control request trigger, if not provided yet, and a new indicator such as a flag or value, to indicate that the NPLI query is for the PDU session. The second network node such as a node controlling a session for example, a SMF or a PGW-C, performs NPLI retrieval from access network if it does not have the latest NPLI by requesting location info to radio network node such as a AMD if the PDU session is in 5GS, or by initiating the update of the default bearer towards the mobility management entity (MME) , if the PDU session is in EPC. Or if it has the NPLI, it simply reports the NPLI to the IMS node via the first network node. Same procedure applies in a pure EPC deployment, where the PCF is replaced by the PCRF.

Embodiments herein provide one or more of the following advantages:

● Support all NPLI query use cases when no media component is being added, changed or removed. For example, in a mid-call request, for example, when a RAT is changed during a call and NPLI is required in the new RAT.

● Avoid unnecessary fake PCC rule operations which requires extra configuration or complexity in the PCF/PCRF and possible wrong use of resources in the network. This is confusing and is presently needed during NPLI query in theaddressed scenarios.

● The unnecessary PCC rule operation coupled with NPLI query consumes extra capacity in SMF/PGW-C/user plane function (UPF) , the new solution improves SMF/PGW-C/UPF performance and simplified the procedure.

Hence, embodiments herein provide a solution that handles sessions efficiently in the communication network thereby improving communication in the communication network.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments will now be described in more detail in relation to the enclosed drawings, in which:

Fig. 1 shows a schematic signalling scheme describing existing 5G procedures according to prior art.

Fig. 2 show a block diagram describing fields of SmPolicydecision according to prior art.

Fig. 3 shows a schematic overview depicting a communication network according to embodiments herein.

Fig. 4 shows a combined signalling scheme and flowchart according to embodiments herein.

Fig. 5 shows a method performed by a first network node according to embodiments herein.

Fig. 6 shows a method performed by a second network node according to embodiments herein.

Fig. 7 shows a signalling scheme according to embodiments herein.

Fig. 8 show a block diagram describing fields of updated SmPolicydecision according to embodiments herein.

Fig. 9 shows a signalling scheme according to embodiments herein.

Fig. 10 shows a method performed by an IMS node according to embodiments herein.

Fig. 11 shows a block diagram depicting first network nodes according to embodiments herein.

Fig. 12 shows a block diagram depicting second network nodes according to embodiments herein.

Fig. 13 shows a block diagram depicting IMS nodes according to embodiments herein.

DETAILED DESCRIPTION

Embodiments herein are described in the context of 5G/NR and LTE but the same concept can also be applied to other wireless communication system such as 4G/LTE and UMTS. Embodiments herein may be described within the context of 3GPP NR radio technology, e.g. using gNB as the radio network node. It is understood, that the problems and solutions described herein are equally applicable to wireless access networks and user equipments (UE) implementing other access technologies and standards. NR is used as an example technology where embodiments are suitable, and using NR in the description therefore is particularly useful for understanding the problem and solutions solving the problem. In particular, embodiments are applicable also to 3GPP LTE, or 3GPP LTE and NR integration, also denoted as non-standalone NR.

Embodiments herein relate to communication networks in general. Fig. 3 is a schematic overview depicting a communication network 1. The communication network 1 comprises one or more RANs and one or more CNs. The communication network 1 may use one or a number of different technologies. Embodiments herein relate to recent technology trends that are of particular interest in a New Radio (NR) context, however, embodiments are also applicable in further development of existing wireless communications systems such as e.g. LTE or Wideband Code Division Multiple Access (WCDMA) .

In the communication network 1, a user equipment (UE) 10, exemplified herein as a wireless device such as a mobile station, a non-access point (non-AP) station (STA) , a STA and/or a wireless terminal, is comprised communicating via e.g. one or more Access Networks (AN) , e.g. radio access network (RAN) , to one or more core networks (CN) . It should be understood by the skilled in the art that “UE” is a non-limiting term which means any terminal, wireless communications terminal, user equipment, narrowband internet of things (NB-IoT) device, Machine Type Communication (MTC) device, Device to Device (D2D) terminal, or node e.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets or even a small base station capable of communicating using radio communication with a radio network node within an area served by the radio network node.

The communication network 1 comprises a radio network node 12 providing radio coverage over a geographical area, a first service area 11 or first cell, of a first radio access technology (RAT) , such as NR, LTE, or similar. The radio network node 12 may be a transmission and reception point such as an access node, an access controller, a base station, e.g. a radio base station such as a gNodeB (gNB) , an evolved Node B (eNB, eNode B) , a NodeB, a base transceiver station, a radio remote unit, an Access Point Base Station, a base station router, a Wireless Local Area Network (WLAN) access point or an Access Point Station (AP STA) , a transmission arrangement of a radio base station, a stand-alone access point or any other network unit or node capable of communicating with a wireless device within the area served by the radio network node depending e.g. on the first radio access technology and terminology used. The radio network node may be referred to as a serving radio network node wherein the service area may be referred to as a serving cell, and the serving network node communicates with the UE in form of DL transmissions to the UE and UL transmissions from the UE. It should be noted that a service area may be denoted as cell, beam, beam group or similar to define an area of radio coverage.

The communication network provides IMS services, such as voice over LTE (VoLTE) , voice over NR (VoNR) , or similar, and comprises a first IMS node 15 and a second IMS node 16 of an IMS. The first IMS node 15, IMS node for short, may be a Call Session Control Function (CSCF) node such as a P-CSCF. The Call session control function, e.g., facilitates Session Internet Protocol (SIP) setup and teardown and an home subscriber server (HSS) plays the role of a location server in IMS, in addition to acting as an authentication, authorization, accounting (AAA) server. The CSCF may comprise one or more of distributed functions, e.g., a proxy CSCF node (P-CSCF) , an Interrogating CSCF (I-CSCF) node, and a Serving CSCF (S-CSCF) node. The P-CSCF acts as the entry point in the IMS network. The second IMS node 16 may be an application server provided by an IMS provider or a Home Subscriber Server (HSS) .

As stated above the communication network comprises a number of core network nodes providing network functions (NF) , such as a first network node 13 for example an PCF or an PCRF and a second network node 14 such as a PGW, an SMF or similar, and a third network node 17 such as an AMF or similar, or any other network function in the communication network 1. The PCF supports the unified policy framework that governs network behaviour. In so doing, it provides policy rules to control plane function (s) to enforce them. In order to facilitate this the subscription information is gathered from a Unified Data Management (UDM) function.

Embodiments herein de-couple an NPLI query, during for example a RAT change in a mid-call, and PCC Rules handling in network nodes such as PCF/SMF in 5GC, PCF/SMF+PGW-C (dual mode 5GC) and or PCRF/PGW in EPS. Thus, embodiments herein provide a solution that handles sessions efficiently in the communication network thereby improving communication in the communication network.

Fig. 4 is a combined signalling scheme and flowchart according to embodiments herein. In this example the UE is connected to the first cell.

Action 401. The first IMS node 15, such as a P-CSCF, receives a triggering message such as a SIP-message and/or a message indicating change of cell or RAT.

Action 402. The first IMS node 15 then sends an NPLI request. For example, the P-CSCF performs an NPLI query which can be triggered by but not limited to terminating, originating SMS request or UE mobility notification between 5G and 4G etc. Thus, the first IMS node 15 requests for the NPLI from the first network node 13. For example, the P-CSCF requests, from, for example, the PCF or PCRF, the NPLI report in Rx interface or Npcf_PolicyAuthorization service using existing parameters with no media-component provided.

Action 403. The first network node 13 then transmits an explicit indicator indicating request for NPLI to the second network node 14 such as SMF or a PGW-C. Thus, when receiving the NPLI report request without media-components or enough service information, the PCF may set subscription for access network information report, same as in the AN_INFO policyCtrlReqTriggers, if not done before and add the request for NPLI, such as user location info and/or UE time zone, in PDU session level.

Action 404. The second network node 14 triggers a retrieval action for reporting the NPLI to the first network node. Thus, when receiving the new PDU session level NPLI report request, since there is no related PCC rule installed and/or bound to the NPLI report request, the second network node 14 won’t perform QoS flow handling (PCC rule operations) . The second network node 14 such as the SMF may directly report the NPLI to PCF if NPLI from other network node, such as AMF/gNB, is not needed, see action 405. In case location retrieval is needed, actions 4041-4044 are triggered.

4041. [Optional] SMF queries the AMF for NPLI.

4042. [Optional] AMF requests user location from gNB

4043. [Optional] gNB reports user location to AMF.

4044. [Optional] AMF sends user location and/or time zone to SMF in Namf_EventExposure_Notify.

Action 405. The second network node 14 may then report the NPLI to the first network node. For example, based on the new trigger, SMF reports NPLI to PCF in Npcf_SMPolicyControl_Update (UserLocation Report) , and PCF sends the NPLI to the P-CSCF. The P-CSCF may send the NPLI to IMS e.g. by sending an appropriate SIP message or a charging report.

4051. SMF reports NPLI (User Access Network Information and or Timezone) to PCF in Npcf_SMPolicyControl_Update (UserLocation Report)

4052. PCF responses the receipt of the NPLI and sends the NPLI to the P-CSCF.

The method actions performed by the first network node, such as a PCF or PCRF, for handling communication in the communication network 1 according to embodiments will now be described with reference to a flowchart depicted in Fig. 5. The actions do not have to be taken in the order stated below, but may be taken in any suitable order. Actions performed in some embodiments are marked with dashed boxes.

Action 501. The first network node 13 receives from the IMS node 15, a request indicator in a message, wherein the request indicator indicates a request for NPLI of a UE 10. The message comprises no information for transmitted user plane data. For example, no media component in the message, wherein a media component is a descriptor for the data transmitted, and/or PCC rules for establishing QoS flow and/or EPS bearer.

Action 502. The first network node 13 further transmits to the second network node 14, a trigger indicator relating to retrieval of the NPLI for a PDU session for the UE such as an IMS PDU session. The trigger indicator may comprise an explicit indicator in a trigger message that may be denoted as an SMpolicycontrol_updatenotify_request. The trigger message may lack any policy or charging information, for example, does not comprise a PCC rule related to the request. The first network node 13 may, upon reception of the request indicator, initiate a subscription for access network information and add the trigger indicator in a message triggering the subscription such as the trigger message. The NPLI comprises location information of the UE 10 and/or time zone of the UE 10, and the trigger indicator may comprise at least two sub-indicators, one sub-indicator for retrieval of the location information of the UE 10 and one sub-indicator for retrieval of the time zone of the UE 10.

Action 503. The first network node 13 may then receive the NPLI or an indication of the NPLI from the second network node 14. For example, receive a value or an index of the any of the location information of the UE and/or the time zone of the UE 10. This NPLI may then be forwarded to the IMS node 15 requesting the NPLI.

The method actions performed by the second network node 14 for handling communication, such as sessions, in the communication network according to embodiments will now be described with reference to a flowchart depicted in Fig. 6. The actions do not have to be taken in the order stated below, but may be taken in any suitable order. Actions performed in some embodiments are marked with dashed boxes.

Action 601. The second network node 14 receives the trigger indicator from the first network node related to retrieval of NPLI for the PDU session for the UE. The trigger indicator may comprise the explicit indicator in the trigger message, such as the SMpolicycontrol_updatenotify_request. The trigger message may lack any policy or charging information. The NPLI may comprise location information of the UE and/or time zone of the UE, and the trigger indicator may comprise at least two sub-indicators, one sub-indicator for retrieval of the location information of the UE and one sub-indicator for retrieval of the time zone of the UE.

Action 602. The second network node 14 triggers a retrieval of the NPLI for the UE 10. The second network node 14 may, for example, receive the triggering indicator in a message triggering a subscription for access network information. The second network node 14 may trigger the retrieval, by retrieving the NPLI internally and reporting the NPLI to the first network node and/or initiating retrieval of the NPLI from another network node.

Fig. 7 is a signalling diagram depicting some embodiments implemented in a%G scenario. In this example, the first network node is a PCF and the second network node is an SMF. The IMS node is exemplified as an P-CSCF.

The P-CSCF performs NPLI query which can be triggered by but not l imited to terminating, originating SMS request or UE mobility notification between 5G and 4G etc.

Note: The underlined texts blew show the changes compared to the existing procedures.

1. The P-CSCF requests the NPLI report in Rx interface or Npcf_PolicyAuthorization service using existing parameters with no media-component provided.

2. When receiving NPLI report request without media-components or enough service information, the PCF sets subscription for access network information report (same as in the AN_INFO policyCtrlReqTriggers) if not done before and add the request for user location info and/or UE time zone in PDU session level (see the data structure below for example) .

3. When receiving the new PUD session level NPLI report request, since there is no related PCC rule installed and/or bound to the NPLI report request, the SMF won’t perform QoS flow handling (PCC rule operations) . SMF directly reports the NPLI to PCF if location retrieval from AMF/gNB is not needed. In case location retrieval is needed, actionas4-7 are triggered.

4. [Optional] SMF queries the AMF for NPLI.

5. [Optional] AMF requests user location from gNB

6. [Optional] gNB reports user location to AMF.

7. [Optional] AMF sends user location and/or time zone to SMF in Namf_EventExposure_Notify

8. SMF reports NPLI (User Access Network Information and or Timezone) to PCF in Npcf_SMPolicyControl_Update (UserLocation Report)

9. PCF responses the receipt of the NPLI with an Npcf_SMPolicyControl_Update Response.

10. Based on the new trigger, SMF reports NPLI (User Access Network Information and or Timezone) to PCF in Npcf_SMPolicyControl_Update (UserLocation Report) .

11. The P-CSCF sends the NPLI to IMS, for example, by using appropriate SIP message.

Fig. 8 is the example data structure for requesting NPLI on session level. 5GS interworking with 4G EPS NPLI query without media components (PCC rules) . A new session level attribute is added where no PCC rule is needed. The existing trigger is reused. When this is set together with the new attribute. SMF only performs NPLI query.

The flow in Fig. 9 will also apply to 5G EPS scenario, by replacing SMF/PGW-C by PGW-C.

The P-CSCF performs NPLI query which can be triggered by but not limited to terminating, originating SMS request or UE mobility between 5G and 4G etc.

Note: The underlined text show the changes compared to the existing procedures.

1. When P-CSCF requests the NPLI report in Rx interface or Npcf_PolicyAuthorization service using existing parameters with no media- components provided.

2. When receiving NPLI report request without media-components, the PCRF sets subscription for access network information report, same as in the AN_INFO policyCtrlReqTriggers, if not done before and add the request for user location info and/or UE time zone in PDU session level, see the data structure below.

3. When receiving the new session level NPLI report request, PGW-C does not perform EPS bearer handling since no PCC Rules are installed and NPLI report request is not bound to any PCC rule. PGW-C directly reports the NPLI to PCRF if location retrieval from SGW/MME is not needed. In case location retrieval from SGW/MME is needed, PGW-C use the default bearer to retrieve user location. Step 4～8 are performed in case NPLI retrieval is needed.

4. [Optional] PGW-C can query the SGW/MME for NPLI by sending Update Bearer Request to SGW with Retrieve Location Indication and default EPS bearer of IMS signaling.

5. [Optional] SGW sends the Update Bearer request to MME.

6. [Optional] MME requests NPLI from eNB. No bearer update really happens.

7. [Optional] MME reports NPLI to SGW.

8. [Optional] SGW reports NPLI to PGW-C.

9. Based on the new trigger, SMF reports NPLI (User Access Network Information and or Timezone) to PCF in Npcf_SMPolicyControl_Update (UserLocation Report)

10. PCF responses the receipt of the NPLI.

11. PCF send the NPLI to the P-CSCF.

12. The P-CSCF can then send the NPLI to IMS using appropriate SIP message.

Same procedure as above is applied in a pure EPC deployment, where the PCF is replaced by the PCRF and the SMF/PGW-C by PGW-C:

- When receiving NPLI report request without media-components, the PCRF requests access network information report (sending the

ACCESS_NETWORK_INFO_REPORT event trigger) if not done before and add the request for user location info and/or UE time zone in Gx RAR message towards PGW-C.

Below is the example data structure for requesting NPLI on Gx RAR level

Message Format:

The method actions performed by the IMS node 15 for handling communication, such as sessions, in the communication network according to embodiments will now be described with reference to a flowchart depicted in Fig. 10.

Action 1001. The IMS node 15 receives a triggering message associated with the UE 10 in the communication network. The triggering message is related to a mobility related event of the UE. The triggering message for the UE 10 and related to the mobility related event is from the 5GC network such as a PCF/PCRF.

Action 1002. The IMS node 15 sends, in response to receiving the triggering message, to the first network node 13, the request indicator in the message, wherein the request indicator indicates the request for NPLI of the UE 10, and wherein the message comprises no information for transmitted user plane data.

Fig. 11 is a block diagram depicting the first network node, in two embodiments, for handling communication in the communication network 1 according to embodiments herein.

The first network node 13 may comprise processing circuitry 1101, e.g. one or more processors, configured to perform the methods herein.

The first network node 13 may comprise a receiving unit 1102, e.g. a receiver, and/or a transceiver. The first network node 13, the processing circuitry 1101, and/or the receiving unit 1102 is configured to receive from the IMS node 15, the request indicator in the message. The request indicator indicates a request for the NPLI of the UE, and the message comprises no information for transmitted user plane data, for example, the message may comprise no media components.

The first network node 13 may comprise a transmitting unit 1103, e.g. a transmitter, and/or a transceiver. The first network node 13, the processing circuitry 1101, and/or the transmitting unit 1103 is configured to transmit to the second network node, the trigger indicator relating to retrieval of the NPLI for the PDU session for the UE. The trigger indicator may comprise an explicit indicator in the trigger message, such as an SMpolicycontrol_updatenotify_request. The trigger message may lack any policy or charging information, for example, PCC related information. The first network node 13, the processing circuitry 1101, and/or the transmitting unit 1103 may be configured to, upon reception of the request indicator, initiate the subscription for access network information, and to add the trigger indicator in the subscription message triggering the subscription. The NPLI may comprise location information of the UE and/or time zone of the UE, and the trigger indicator may comprise at least two sub-indicators, one sub-indicator for retrieval of the location information of the UE and one sub-indicator for retrieval of the time zone of the UE.

The first network node 13 further comprises a memory 1105. The memory comprises one or more units to be used to store data on, such as indications, NPLI, subscription information, trigger message, messages, strengths or qualities, execution conditions, user data, reconfiguration, configurations, applications to perform the methods disclosed herein when being executed, and similar. Thus, the first network node may comprise the processing circuitry and the memory, said memory comprising instructions executable by said processing circuitry whereby said first network node is operative to perform the methods herein. The first network node 13 comprises a communication interface 1108 comprising transmitter, receiver, and/or transceiver.

The methods according to the embodiments described herein for the first network node 13 are respectively implemented by means of e.g. a computer program product 1106 or a computer program product, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the first network node 13. The computer program product 1106 may be stored on a computer-readable storage medium 1107, e.g. a universal serial bus (USB) stick, a disc or similar. The computer-readable storage medium 1107, having stored thereon the computer program product, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the first network node 13. In some embodiments, the computer-readable storage medium may be a non-transitory or transitory computer-readable storage medium.

Fig. 12 is a block diagram depicting the second network node 14, in two embodiments, for handling communication in the communication network 1 according to embodiments herein.

The second network node 14 may comprise processing circuitry 1201, e.g. one or more processors, configured to perform the methods herein.

The second network node 14 may comprise a receiving unit 1202, e.g. a receiver, and/or a transceiver. The second network node 14, the processing circuitry 1201, and/or the receiving unit 1202 is configured to receive the trigger indicator from the first network node 13 related to retrieval of the NPLI for the PDU session for the UE 10. The trigger indicator may comprise an explicit indicator in the trigger message, such as an SMpolicycontrol_updatenotify_request. The trigger message may lack any policy or charging information. The second network node 14, the processing circuitry 1201, and/or the receiving unit 1202 may be configured to receive the trigger indicator in a message triggering the subscription for access network information. The NPLI may comprise location information of the UE 10 and/or time zone of the UE 10, and the trigger indicator may comprise at least two sub-indicators, one sub-indicator for retrieval of the location information of the UE 10 and one sub-indicator for retrieval of the time zone of the UE 10.

The second network node 14 may comprise a triggering unit 1203, e.g. a transmitter, and/or a transceiver. The second network node 14, the processing circuitry 1201, and/or the triggering unit 1203 is configured to trigger the retrieval of the NPLI for the UE. The second network node 14, the processing circuitry 1201, and/or the triggering unit 1203 may be configured to trigger the retrieval by retrieving the NPLI internally and reporting the NPLI to the first network node, and/or by initiating retrieval of the NPLI from another network node, such as an AMF or an MME.

The second network node 14 further comprises a memory 1205. The memory comprises one or more units to be used to store data on, such as indications, NPLI, subscription information, trigger message, messages, strengths or qualities, execution conditions, user data, reconfiguration, configurations, applications to perform the methods disclosed herein when being executed, and similar. Thus, the second network node may comprise the processing circuitry and the memory, said memory comprising instructions executable by said processing circuitry whereby said second network node is operative to perform the methods herein. The second network node 14 comprises a communication interface 1208 comprising transmitter, receiver, and/or transceiver.

The methods according to the embodiments described herein for the second network node 14 are respectively implemented by means of e.g. a computer program product 1206 or a computer program product, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the second network node 14. The computer program product 1206 may be stored on a computer-readable storage medium 1207, e.g. a universal serial bus (USB) stick, a disc or similar. The computer-readable storage medium 1207, having stored thereon the computer program product, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the second network node 14. In some embodiments, the computer-readable storage medium may be a non-transitory or transitory computer-readable storage medium.

Fig. 13 is a block diagram depicting the IMS node, in two embodiments, for handling communication in the communication network 1 according to embodiments herein.

The IMS node 15 may comprise processing circuitry 1301, e.g. one or more processors, configured to perform the methods herein.

The IMS node 15 may comprise a receiving unit 1302, e.g. a receiver, and/or a transceiver. The IMS node 15, the processing circuitry 1301, and/or the receiving unit 1302 is configured to receive the triggering message associated with the UE 10 in the communication network, wherein the triggering message is related to the mobility related event of the UE 10. This may be trigged by the mobility related event, i.e., IPCAN/RAT Type change.

The IMS node 15 may comprise a transmitting unit 1303, e.g. a transmitter, and/or a transceiver. The IMS node 15, the processing circuitry 1301, and/or the transmitting unit 1303 is configured to, in response to receiving the triggering message, send to the first network node 13, the request indicator in the message, wherein the request indicator indicates a request for the NPLI of the UE, and wherein the message comprises no information for transmitted user plane data, such as no media components. This is a control signalling, and a media component is a descriptor for the data transmitted.

The IMS node 15 further comprises a memory 1305. The memory comprises one or more units to be used to store data on, such as indications, NPLI, subscription information, trigger message, messages, strengths or qualities, execution conditions, user data, reconfiguration, configurations, applications to perform the methods disclosed herein when being executed, and similar. Thus, the IMS node may comprise the processing circuitry and the memory, said memory comprising instructions executable by said processing circuitry whereby said IMS node is operative to perform the methods herein. The IMS node 15 comprises a communication interface 1308 comprising transmitter, receiver, and/or transceiver.

The methods according to the embodiments described herein for the IMS node 15 are respectively implemented by means of e.g. a computer program product 1306 or a computer program product, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the IMS node 15. The computer program product 1306 may be stored on a computer-readable storage medium 1307, e.g. a universal serial bus (USB) stick, a disc or similar. The computer-readable storage medium 1307, having stored thereon the computer program product, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the IMS node 15. In some embodiments, the computer-readable storage medium may be a non-transitory or transitory computer-readable storage medium.

In some embodiments a more general term “radio network node” is used and it can correspond to any type of radio network node or any network node, which communicates with a wireless device and/or with another network node. Examples of network nodes are NodeB, Master eNB, Secondary eNB, a network node belonging to Master cell group (MCG) or Secondary Cell Group (SCG) , base station (BS) , multi-standard radio (MSR) radio node such as MSR BS, eNodeB, network controller, radio network controller (RNC) , base station controller (BSC) , relay, donor node controlling relay, base transceiver station (BTS) , access point (AP) , gateways, transmission points, transmission nodes, Remote Radio Unit (RRU) , Remote Radio Head (RRH) , nodes in distributed antenna system (DAS) , core network node e.g. Mobility Switching Centre (MSC) , Mobile Management Entity (MME) etc., Operation and Maintenance (O&M) , Operation Support System (OSS) , Self-Organizing Network (SON) , positioning node e.g. Evolved Serving Mobile Location Centre (E-SMLC) , Minimizing Drive Test (MDT) etc.

In some embodiments the non-limiting term wireless device or user equipment (UE) is used and it refers to any type of wireless device communicating with a network node and/or with another UE in a cellular or mobile communication system. Examples of UE are target device, device-to-device (D2D) UE, proximity capable UE (aka ProSe UE) , machine type UE or UE capable of machine to machine (M2M) communication, PDA, PAD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE) , laptop mounted equipment (LME) , USB dongles etc.

The embodiments are described for 5G. However the embodiments are applicable to any RAT or multi-RAT systems, where the UE receives and/or transmit signals (e.g. data) e.g. LTE, LTE FDD/TDD, WCDMA/HSPA, GSM/GERAN, Wi Fi, WLAN, CDMA2000 etc.

As will be readily understood by those familiar with communications design, that functions means or modules may be implemented using digital logic and/or one or more microcontrollers, microprocessors, or other digital hardware. In some embodiments, several or all of the various functions may be implemented together, such as in a single application-specific integrated circuit (ASIC) , or in two or more separate devices with appropriate hardware and/or software interfaces between them. Several of the functions may be implemented on a processor shared with other functional components of a wireless device or network node, for example.

Alternatively, several of the functional elements of the processing means discussed may be provided through the use of dedicated hardware, while others are provided with hardware for executing software, in association with the appropriate software or firmware. Thus, the term “processor” or “controller” as used herein does not exclusively refer to hardware capable of executing software and may implicitly include, without limitation, digital signal processor (DSP) hardware, read-only memory (ROM) for storing software, random-access memory for storing software and/or program or application data, and non-volatile memory. Other hardware, conventional and/or custom, may also be included. Designers of communications devices will appreciate the cost, performance, and maintenance trade-offs inherent in these design choices.

It will be appreciated that the foregoing description and the accompanying drawings represent non-limiting examples of the methods and apparatus taught herein.

As such, the apparatus and techniques taught herein are not limited by the foregoing description and accompanying drawings. Instead, the embodiments herein are limited only by the following claims and their legal equivalents.

Claims

A method performed by a first network node for handling communication in a communication network, the method comprising

- receiving (501) from an Internet Protocol Multimedia Subsystem, IMS, node, arequest indicator in a message, wherein the request indicator indicates a request for Network Provided Location Information, NPLI, of a user equipment, UE, and wherein the message comprises no information for transmitted user plane data; and

- transmitting (502) to a second network node, atrigger indicator relating to retrieval of the NPLI for a protocol data unit, PDU, session for the UE.
The method according to claim 1, wherein the trigger indicator comprises an explicit indicator in a trigger message.
The method according to claim 2, wherein the trigger message lacks any policy or charging information.
The method according to any of the claims 1-3, upon reception of the request indicator, the first network node initiates a subscription for access network information, and adds the trigger indicator in a message triggering the subscription.
The method according to any of the claims 1-4, wherein the NPLI comprises location information of the UE and/or time zone of the UE, and the trigger indicator comprises at least two sub-indicators, one sub-indicator for retrieval of the location information of the UE and one sub-indicator for retrieval of the time zone of the UE.
A method performed by a second network node for handling communication in a communication network, the method comprising

- receiving (601) atrigger indicator from a first network node related to retrieval of Network Provided Location Information, NPLI, for a protocol data unit, PDU, session for a user equipment, UE; and

- triggering (602) aretrieval of the NPLI for the UE.
The method according to claim 6, wherein the trigger indicator comprises an explicit indicator in a trigger message.
The method according to claim 7, wherein the trigger message lacks any policy or charging information.
The method according to any of the claims 6-8, wherein receiving the trigger indicator comprises receiving the triggering indicator in a message triggering a subscription for access network information.
The method according to any of the claims 6-9, wherein the NPLI comprises location information of the UE and/or time zone of the UE, and the trigger indicator comprises at least two sub-indicators, one sub-indicator for retrieval of the location information of the UE and one sub-indicator for retrieval of the time zone of the UE.
The method according to any of the claims 6-10, wherein triggering the retrieval comprises retrieving the NPLI internally and reporting the NPLI to the first network node, and/or initiating retrieval of the NPLI from another network node.
A method performed by an Internet Protocol Multimedia Subsystem, IMS, node for handling communication in a communication network, comprising

- receiving (1001) atriggering message associated with a user equipment, UE,in the communication network, wherein the triggering message is related to a mobility related event of the UE; and

- , in response to receiving the triggering message, sending (1002) to a first network node, arequest indicator in a message, wherein the request indicator indicates a request for Network Provided Location Information, NPLI, of the UE, and wherein the message comprises no information for transmitted user plane data.
A first network node for handling communication in a communication network, wherein the first network node is configured to

receive from an Internet Protocol Multimedia Subsystem, IMS, node, a request indicator in a message, wherein the request indicator indicates a request for Network Provided Location Information, NPLI, of a user equipment, UE, and wherein the message comprises no information for transmitted user plane data; and

transmit to a second network node, atrigger indicator relating to retrieval of the NPLI for a protocol data unit, PDU, session for the UE.
The first network node according to claim 13, wherein the trigger indicator comprises an explicit indicator in a trigger message.
The first network node according to claim 14, wherein the trigger message lacks any policy or charging information.
The first network node according to any of the claims 12-14, wherein the first network node is configured to, upon reception of the request indicator, initiate a subscription for access network information, and to add the trigger indicator in a subscription message triggering the subscription.
The first network node according to any of the claims 12-16, wherein the NPLI comprises location information of the UE and/or time zone of the UE, and the trigger indicator comprises at least two sub-indicators, one sub-indicator for retrieval of the location information of the UE and one sub-indicator for retrieval of the time zone of the UE.
A second network node for handling communication in a communication network, wherein the second network node is configured to

receive a trigger indicator from a first network node related to retrieval of Network Provided Location Information, NPLI, for a protocol data unit, PDU, session for a user equipment, UE; and

trigger a retrieval of the NPLI for the UE.
The second network node according to claim 18, wherein the trigger indicator comprises an explicit indicator in a trigger message.
The second network node according to claim 19, wherein the trigger message lacks any policy or charging information.
The second network node according to any of the claims 18-20, wherein the second network node is configured to receive the trigger indicator in a message triggering a subscription for access network information.
The second network node according to any of the claims 18-21, wherein the NPLI comprises location information of the UE and/or time zone of the UE, and the trigger indicator comprises at least two sub-indicators, one sub-indicator for retrieval of the location information of the UE and one sub-indicator for retrieval of the time zone of the UE.
The second network node according to any of the claims 18-22, wherein the second network node is configured to trigger the retrieval by retrieving the NPLI internally and reporting the NPLI to the first network node, and/or by initiating retrieval of the NPLI from another network node.
An Internet Protocol Multimedia Subsystem, IMS, node for handling communication in a communication network, wherein the IMS node is configured to

reiceve a triggering message associated with a user equipment, UE, in the communication network, wherein the triggering message is related to a mobility related event of the UE; and

, in response to receiving the triggering message, send to a first network node, arequest indicator in a message, wherein the request indicator indicates a request for Network Provided Location Information, NPLI, of the UE, and wherein the message comprises no information for transmitted user plane data.
A computer program product comprising instructions, which, when executed on at least one processor, cause the at least one processor to carry the method according to any of the claims 1-12, as performed by the IMS node, the first network node and the second network node, respectively.
A computer-readable storage medium, having stored thereon a computer program product comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to any of the claims 1-12, as performed by the IMS node, the first network node and the second network node, respectively.