WO2022042606A1 - Procédé et appareil de gestion de services - Google Patents

Procédé et appareil de gestion de services Download PDF

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Publication number
WO2022042606A1
WO2022042606A1 PCT/CN2021/114540 CN2021114540W WO2022042606A1 WO 2022042606 A1 WO2022042606 A1 WO 2022042606A1 CN 2021114540 W CN2021114540 W CN 2021114540W WO 2022042606 A1 WO2022042606 A1 WO 2022042606A1
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Prior art keywords
entity
terminal device
gateway
user plane
control entity
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PCT/CN2021/114540
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English (en)
Inventor
Juan Xu
Chunmiao LIU
Yingjiao HE
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Telefonaktiebolaget Lm Ericsson (Publ)
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Publication of WO2022042606A1 publication Critical patent/WO2022042606A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/20—Manipulation of established connections
    • H04W76/25—Maintenance of established connections
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/02—Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
    • H04W36/023—Buffering or recovering information during reselection

Definitions

  • the present disclosure generally relates to communication networks, and more specifically, to methods and apparatuses for service management.
  • LTE long-term evolution
  • 4G fourth generation
  • NR new radio
  • 5G fifth generation
  • 3GPP 3rd generation partnership project
  • IP Multimedia subsystem The Internet protocol (IP) Multimedia subsystem (IMS) is specified in 3GPP TS 23.228 V16.3.0, the disclosure of which is incorporated by reference herein in their entirety.
  • IP multimedia core network (IM CN) subsystem enables operators to offer their subscribers multimedia services.
  • the IM CN subsystem may enable the convergence of, and access to, voice, video, messaging, data and web-based technologies for the wireless and wireline user.
  • the complete solution for the support of IP multimedia applications may include terminals, IP-Connectivity Access Networks (IP-CAN) , and the specific functional elements of the IM CN subsystem as described in 3GPP TS 23.228 V16.3.0.
  • IP-Connectivity Access Network examples include the GPRS (General Packet Radio Service) core network with GERAN (GSM (Global System for Mobile communications) EDGE (Enhanced Data rates for GSM Evolution) Radio Access Network) and/or UTRAN (Universal Terrestrial Radio Access Network) radio access networks; and EPC (Evolved Packet Core) core network and E-UTRAN (Evolved UTRAN) radio access network; and 5GS (5G system) access network.
  • GSM Global System for Mobile communications
  • EDGE Enhanced Data rates for GSM Evolution Radio Access Network
  • UTRAN Universal Terrestrial Radio Access Network
  • EPC Evolved Packet Core
  • E-UTRAN Evolved UTRAN
  • forwarding tunnel such as direct forwarding tunnel, indirect forwarding tunnel, etc.
  • forwarding tunnel may cause downlink data lost.
  • SIP signaling lost may impact the voice traffic.
  • a terminal device such as user equipment (UE) camped on a next generation-radio access network (NG-RAN) may have one or more ongoing protocol data unit (PDU) sessions each including one or more quality of service (QoS) flows.
  • PDU protocol data unit
  • QoS quality of service
  • PLMN public land mobile network
  • AMF mobility management function
  • the NG-RAN may be configured to support evolved packet system (EPS) fallback for IMS voice and decide to trigger fallback to EPS, considering the UE’s capabilities, the indication from the AMF that “Redirection for EPS fallback for voice is possible” , the network configuration and radio conditions, etc.
  • Source NG-RAN responds indicating rejection of the PDU session modification to setup QoS flow for IMS voice by PDU session response message towards the SMF via AMF with an indication that mobility due to fallback for IMS voice is ongoing.
  • EPS evolved packet system
  • a packet gateway control plane function (PGW-C) combined with a session management function (SMF) PGW-C+SMF
  • PGW-C+SMF session management function
  • the NG-RAN may initiate either handover (HO) or access network (AN) release via inter-system redirection to the EPS.
  • HO handover
  • AN access network
  • SIP session initiation protocol
  • the NG-RAN may be configured to support RAT (Radio Access Technology) fallback for IMS voice and decide to trigger RAT fallback, taking into account on UE capabilities, network configuration and radio conditions, etc.
  • Source NG-RAN responds indicating rejection of the PDU session modification to setup QoS flow for IMS voice by PDU session response message towards the SMF via AMF with an indication that mobility due to fallback for IMS voice is ongoing.
  • the SMF maintains the PCC (Policy and Charging Control) rule (s) associated with the QoS flow (s) .
  • PCC Policy and Charging Control
  • Source NG-RAN initiates Xn based Inter NG-RAN handover or N2 based inter NG-RAN handover, or redirection to E-UTRA (Evolved Universal Terrestrial Radio Access) connected to 5GC.
  • the SMF reports change of the RAT type if subscribed by PCF (Policy Control Function) .
  • PCF Policy Control Function
  • the SIP signaling exchange between the UE and the IMS network may be still ongoing, but the default QoS flow/default bearer for IMS signaling transferred may not be available for data transfer for a short period of time.
  • IMS domain In a network where EPS fallback or inter-RAT fallback is deployed for IMS service such as voice call, when NG-RAN rejects the QoS flow setup for voice call, the IMS domain does not have enough knowledge of whether there will be some data connectivity or service interruption in the network. Therefore the IMS domain could not take proper and accurate actions to optimize the signaling handling. For example, IMS domain may try to continue to send SIP (Session Initiated Protocol) signaling to the UE even there is service interruption, which will result in SIP signaling loss and increase the call setup time. Alternatively, the IMS domain may try to buffer SIP signaling even when there is no service interruption, which will increase the call setup time.
  • SIP Session Initiated Protocol
  • P-CSCF proxy call session control function
  • the NG-RAN may additionally include the fallback information and send it to the PGW-C+SMF.
  • the fallback information may indicate whether redirection, or handover with direct data forwarding or handover without direct data forwarding is used.
  • PGW-C+SMF knows (e.g. by local configuration) that indirect data forwarding is not available, PGW-C+SMF could trigger UPF to buffer DL (downlink) packets.
  • the UPF buffering can’t be triggered at the right time point and it could cause SIP signaling lost or transferring delay.
  • indirect forwarding or direct forward function is used to avoiding the data loss, but indirect forwarding function is complicated and costly and needs quite some interworking nodes (NR Node, AMF, PGW-C+SMF, MME, SGW-C, eNodeB) supporting this function.
  • Direct forwarding requires that both the the source RAN (such as NR node) and target RAN (such as eNodeB) have the direct communication channel, and this is very costly way to support.
  • the embodiments of the present disclosure propose an improved solution of service management, which can optimize the signaling handling such as avoiding signaling loss and/or decreasing the call setup time.
  • a method performed by a gateway session management entity comprises receiving, from an access and mobility management entity, information indicating that a data forwarding tunnel is not available for a handover procedure of a terminal device.
  • the method further comprises, based on the received information, performing at least one of sending a message for triggering downlink data buffering for the terminal device in a gateway user plane entity to the gateway user plane entity; or sending a connect path interruption event of the terminal device to a policy control entity.
  • the information is included in an Nsmf_PDUSession_UpdateSMContext Request.
  • the data forwarding tunnel comprises at least one of an indirect forwarding tunnel and a direct forwarding tunnel.
  • the information is received from the access and mobility management entity via an Intermediate Session Management Function (I-SMF) or a visited Session Management Function (V-SMF) .
  • I-SMF Intermediate Session Management Function
  • V-SMF visited Session Management Function
  • the method when the message for triggering downlink data buffering for the terminal device in the gateway user plane entity is sent to the gateway user plane entity, the method further comprises receiving a modify bearer request relate to the terminal device from a serving gateway, wherein the modify bearer request comprises at least one serving gateway address for user plane and at least one tunnel endpoint identifier.
  • the method further comprises, based on the modify bearer request, sending, to the gateway user plane entity, a request for stopping the downlink data buffering for the terminal device in the gateway user plane entity and forwarding buffered downlink data of the terminal device to the serving gateway.
  • the serving gateway is a serving gateway control plane (SGW-C) and the buffered downlink data of the terminal device is requested to be forwarded to a serving gateway user plane (SGW-U) .
  • SGW-C serving gateway control plane
  • SGW-U serving gateway user plane
  • the method when the connect path interruption event of the terminal device is sent to the policy control entity, the method further comprises receiving a modify bearer request relate to the terminal device from a serving gateway, wherein the modify bearer request comprises at least one serving gateway address for user plane and at least one tunnel endpoint identifier.
  • the method further comprises: based on the modify bearer request, sending a radio access type change event of the terminal device to the policy control entity.
  • the radio access type change event of the terminal device is sent to the policy control entity, in response to a subscription of the radio access type change event by the policy control entity.
  • the handover procedure is fifth generation system (5GS) to evolved packet system (EPS) handover using N26 interface.
  • 5GS fifth generation system
  • EPS evolved packet system
  • the gateway session management entity is a packet data network gateway (PGW) control plane (PGW-C) combined with a session management function (SMF)
  • the access and mobility management entity is an access and mobility management function (AMF)
  • the gateway user plane entity is a PGW user plane (PGW-U) combined with a user plane function (UPF)
  • the policy control entity is a policy control function (PCF) .
  • a method performed by a policy control entity.
  • the method comprises receiving a connect path interruption event of a terminal device from a gateway session management entity.
  • the method further comprises reporting the connect path interruption event of the terminal device to a call control entity.
  • the method further comprises receiving a radio access type change event of the terminal device from the gateway session management entity.
  • the method further comprises reporting the radio access type change event of the terminal device to the call control entity.
  • the radio access type change event of the terminal device is reported to the call control entity, in response to a subscription of the radio access type change event by the call control entity.
  • the connect path interruption event of the terminal device is reported to the call control entity, in response to a subscription of the connect path interruption event by the call control entity.
  • the gateway session management entity is a packet data network gateway (PGW) control plane (PGW-C) combined with a session management function (SMF)
  • PGW-C packet data network gateway
  • SMF session management function
  • P-CSCF proxy call session control function
  • PCF policy control function
  • a method performed by a call control entity comprises receiving a connect path interruption event of a terminal device from a policy control entity.
  • the method further comprises buffering at least one signaling related to the terminal device in the call control entity based at least in part on the connect path interruption event of the terminal device.
  • the connect path interruption event of the terminal device is received from the policy control entity, in response to a subscription of the data connectivity temporary interruption event by the call control entity.
  • the at least one signaling related to the terminal device comprises call setup signaling.
  • the method further comprises receiving a radio access type change event of the terminal device from a policy control entity.
  • the method further comprises resuming the at least one signaling related to the terminal device based at least in part on the radio access type change event of the terminal device.
  • the radio access type change event of the terminal device is received from the policy control entity, in response to a subscription of the radio access type change event by the call control entity.
  • the connect path interruption event of the terminal device is received from the policy control entity, in response to a subscription of the connect path interruption event by the call control entity.
  • the call control entity is a proxy call session control function (P-CSCF)
  • the policy control entity is a policy control function (PCF) .
  • a method performed by an access and mobility management entity.
  • the method comprises determining that a data forwarding tunnel is not available for a handover procedure of a terminal device.
  • the method further comprises sending information indicating that the data forwarding tunnel is not available for the handover procedure of the terminal device to a gateway session management entity.
  • the information is included in an Nsmf_PDUSession_UpdateSMContext Request.
  • the data forwarding tunnel comprises at least one of an indirect forwarding tunnel and a direct forwarding tunnel.
  • the information is sent to the access and mobility management entity via an Intermediate Session Management Function (I-SMF) or a visited Session Management Function (V-SMF) .
  • I-SMF Intermediate Session Management Function
  • V-SMF visited Session Management Function
  • the gateway session management entity is a packet data network gateway (PGW) control plane (PGW-C) combined with a session management function (SMF) and the access and mobility management entity is an access and mobility management function (AMF) .
  • PGW packet data network gateway
  • PGW-C packet data network gateway
  • SMF session management function
  • AMF access and mobility management function
  • a method performed by a gateway user plane entity comprises receiving a message for triggering downlink data buffering of a terminal device in the gateway user plane entity from a gateway session management entity.
  • the method further comprises triggering downlink data buffering for the terminal device in the gateway user plane entity.
  • the method further comprises receiving, from the gateway session management entity, a request for stopping the downlink data buffering for the terminal device in the gateway user plane entity and forwarding buffered downlink data of the terminal device to a serving gateway.
  • the method further comprises stopping the downlink data buffering for the terminal device in the gateway user plane entity.
  • the method further comprises forwarding buffered downlink data of the terminal device to the serving gateway.
  • the serving gateway is a serving gateway control plane (SGW-C) and the buffered downlink data of the terminal device is forwarded to a serving gateway user plane (SGW-U) .
  • SGW-C serving gateway control plane
  • SGW-U serving gateway user plane
  • the gateway session management entity is a packet data network gateway (PGW) control plane (PGW-C) combined with a session management function (SMF) and the gateway user plane entity is a PGW user plane (PGW-U) combined with a user plane function (UPF) .
  • PGW packet data network gateway
  • SMF session management function
  • PGW-U PGW user plane
  • UPF user plane function
  • a gateway session management entity comprises one or more processors and one or more memories storing computer program codes.
  • the one or more memories and the computer program codes may be configured to, with the one or more processors, cause the gateway session management entity at least to perform any step of the method according to the first aspect of the present disclosure.
  • a policy control entity comprises one or more processors and one or more memories storing computer program codes.
  • the one or more memories and the computer program codes may be configured to, with the one or more processors, cause the policy control entity at least to perform any step of the method according to the second aspect of the present disclosure.
  • a call control entity comprises one or more processors and one or more memories storing computer program codes.
  • the one or more memories and the computer program codes may be configured to, with the one or more processors, cause the call control entity at least to perform any step of the method according to the third aspect of the present disclosure.
  • an access and mobility management entity comprises one or more processors and one or more memories storing computer program codes.
  • the one or more memories and the computer program codes may be configured to, with the one or more processors, cause the access and mobility management entity at least to perform any step of the method according to the fourth aspect of the present disclosure.
  • a gateway user plane entity comprises one or more processors and one or more memories storing computer program codes.
  • the one or more memories and the computer program codes may be configured to, with the one or more processors, cause the gateway user plane entity at least to perform any step of the method according to the fifth aspect of the present disclosure.
  • a gateway session management entity comprises a receiving module and a performing module.
  • the receiving module may be configured to receive, from an access and mobility management entity, information indicating that a data forwarding tunnel is not available for a handover procedure of a terminal device.
  • the performing module may be configured to, based on the received information, perform at least one of sending a message for triggering downlink data buffering for the terminal device in a gateway user plane entity to the gateway user plane entity or sending a connect path interruption event of the terminal device to a policy control entity.
  • the policy control entity comprises a receiving module and a reporting module.
  • the receiving module may be configured to receive a connect path interruption event of a terminal device from a gateway session management entity.
  • the reporting module may be configured to report the connect path interruption event of the terminal device to a call control entity.
  • a call control entity comprises a receiving module and a buffering module.
  • the receiving module may be configured to receive a connect path interruption event of a terminal device from a policy control entity.
  • the buffering module may be configured to buffer at least one signaling related to the terminal device in the call control entity based at least in part on the connect path interruption event of the terminal device.
  • an access and mobility management entity comprises a determining module and a sending module.
  • the determining module may be configured to determine that a data forwarding tunnel is not available for a handover procedure of a terminal device.
  • the sending module may be configured to send information indicating that the data forwarding tunnel is not available for the handover procedure of the terminal device to a gateway session management entity.
  • a gateway user plane entity comprises a receiving module and a triggering module.
  • the receiving module may be configured to receive a message for triggering downlink data buffering of a terminal device in the gateway user plane entity from a gateway session management entity.
  • the triggering module may be configured to trigger downlink data buffering for the terminal device in the gateway user plane entity.
  • a computer-readable medium having computer program codes embodied thereon which, when executed on a computer, cause the computer to perform any step of the methods according to the first to the fifth aspects of the present disclosure.
  • a computer program product comprising instructions which when executed by at least one processor, cause the at least one processor to perform any step of the methods according to the first to the fifth aspects of the present disclosure.
  • Embodiments herein afford many advantages, of which a non-exhaustive list of examples follows.
  • the proposed solution according to some exemplary embodiments can solve signaling and/or data loss in handover, for example, the SIP signaling loss issue in EPS fallback with handover.
  • the gateway session management entity such as PGW-C+SMF may report “connect path interruption event” to the policy control entity such as PCF, in another word, the gateway session management entity such as PGW-C+SMF does not blindly send the “connect path interruption event” to the policy control entity such as PCF which sends it to the call control entity such as P-CSCF.
  • IMS domain can be based on the “connect path interruption event” and “radio access type change event” to take proper and accurate actions to optimize the SIP signaling handling.
  • DL signaling buffering is triggered at the right time point, and it solves the issue related to signaling lost and signaling transfer delay.
  • the call setup time in case of EPS fallback with handover can be optimized.
  • the proposed solution can enhance the statistics in IMS when PGW-C+SMF reports the “connect path interruption event” and “radio access type change event” to PCF/P-CSCF.
  • the proposed solution can low down the network deployment complexity and maintenance complexity due to forwarding tunnels for EPS fallback with handover.
  • the embodiments herein are not limited to the features and advantages mentioned above. A person skilled in the art will recognize additional features and advantages upon reading the following detailed description.
  • FIG. 1a schematically shows a high level architecture in a 4G network
  • FIG. 1b schematically shows a high level architecture in a 5G network
  • FIG. 2 shows a flowchart of a method according to an embodiment of the present disclosure
  • FIG. 3 shows a flowchart of a method according to another embodiment of the present disclosure
  • FIG. 4 shows a flowchart of a method according to another embodiment of the present disclosure
  • FIG. 5 shows a flowchart of a method according to another embodiment of the present disclosure
  • FIG. 6 shows a flowchart of a method according to another embodiment of the present disclosure.
  • FIG. 7 shows a flowchart of a method according to another embodiment of the present disclosure.
  • FIG. 8 shows a flowchart of a method according to another embodiment of the present disclosure.
  • FIG. 9 shows a flowchart of a method of UPF buffering according to another embodiment of the present disclosure.
  • FIG. 10 shows a flowchart of a method of P-CSCF buffering according to another embodiment of the present disclosure
  • FIG. 11 shows a flowchart of a method of UPF buffering according to another embodiment of the present disclosure
  • FIG. 12 is a block diagram showing an apparatus suitable for practicing some embodiments of the disclosure.
  • FIG. 13 is a block diagram showing a gateway session management entity according to an embodiment of the disclosure.
  • FIG. 14 is a block diagram showing a policy control entity according to an embodiment of the disclosure.
  • FIG. 15 is a block diagram showing a call control entity according to an embodiment of the disclosure.
  • FIG. 16 is a block diagram showing an access and mobility management entity according to an embodiment of the disclosure.
  • FIG. 17 is a block diagram showing a gateway user plane entity according to an embodiment of the disclosure.
  • the term “network” refers to a network following any suitable wireless communication standards such as new radio (NR) , long term evolution (LTE) , LTE-Advanced, wideband code division multiple access (WCDMA) , high-speed packet access (HSPA) , Code Division Multiple Access (CDMA) , Time Division Multiple Address (TDMA) , Frequency Division Multiple Access (FDMA) , Orthogonal Frequency-Division Multiple Access (OFDMA) , Single carrier frequency division multiple access (SC-FDMA) and other wireless networks.
  • NR new radio
  • LTE long term evolution
  • WCDMA wideband code division multiple access
  • HSPA high-speed packet access
  • CDMA Code Division Multiple Access
  • TDMA Time Division Multiple Address
  • FDMA Frequency Division Multiple Access
  • OFDMA Orthogonal Frequency-Division Multiple Access
  • SC-FDMA Single carrier frequency division multiple access
  • a TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM) .
  • GSM Global System for Mobile Communications
  • An OFDMA network may implement a radio technology such as Evolved UTRA (E-UTRA) , Ultra Mobile Broadband (UMB) , IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDMA, Ad-hoc network, wireless sensor network, etc.
  • E-UTRA Evolved UTRA
  • UMB Ultra Mobile Broadband
  • IEEE 802.11 Wi-Fi
  • IEEE 802.16 WiMAX
  • IEEE 802.20 Flash-OFDMA
  • Ad-hoc network wireless sensor network
  • the terms “network” and “system” can be used interchangeably.
  • the communications between two devices in the network may be performed according to any suitable communication protocols, including, but not limited to, the communication protocols as defined by a standard organization such as 3GPP.
  • the communication protocols as may comprise the first generation (1G) , 2
  • entity refers to a network device or network node or network function in a communication network.
  • a core network device may offer numerous services to customers who are interconnected by an access network device. Each access network device is connectable to the core network device over a wired or wireless connection.
  • NF network function
  • the 5G system may comprise a plurality of NFs such as AMF (Access and mobility Function) , SMF (Session Management Function) , AUSF (Authentication Service Function) , UDM (Unified Data Management) , PCF (Policy Control Function) , AF (Application Function) , NEF (Network Exposure Function) , UPF (User plane Function) and NRF (Network Repository Function) , RAN (radio access network) , SCP (service communication proxy) , etc.
  • the network function may comprise different types of NFs for example depending on a specific type of network.
  • terminal device refers to any end device that can access a communication network and receive services therefrom.
  • the terminal device refers to a mobile terminal, user equipment (UE) , or other suitable devices.
  • the UE may be, for example, a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) .
  • SS Subscriber Station
  • MS Mobile Station
  • AT Access Terminal
  • the terminal device may include, but not limited to, a portable computer, an image capture terminal device such as a digital camera, a gaming terminal device, a music storage and a playback appliance, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet, a wearable device, a personal digital assistant (PDA) , a portable computer, a desktop computer, a wearable terminal device, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a laptop-embedded equipment (LEE) , a laptop-mounted equipment (LME) , a USB dongle, a smart device, a wireless customer-premises equipment (CPE) and the like.
  • a portable computer an image capture terminal device such as a digital camera, a gaming terminal device, a music storage and a playback appliance
  • a mobile phone a cellular phone, a smart phone, a voice over IP (VoIP) phone
  • a terminal device may represent a UE configured for communication in accordance with one or more communication standards promulgated by the 3GPP, such as 3GPP’ LTE standard or NR standard.
  • 3GPP 3GPP’ LTE standard or NR standard.
  • a “user equipment” or “UE” may not necessarily have a “user” in the sense of a human user who owns and/or operates the relevant device.
  • a terminal device may be configured to transmit and/or receive information without direct human interaction.
  • a terminal device may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the communication network.
  • a UE may represent a device that is intended for sale to, or operation by, a human user but that may not initially be associated with a specific human user.
  • a terminal device may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another terminal device and/or network equipment.
  • the terminal device may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as a machine-type communication (MTC) device.
  • M2M machine-to-machine
  • MTC machine-type communication
  • the terminal device may be a UE implementing the 3GPP narrow band internet of things (NB-IoT) standard.
  • NB-IoT narrow band internet of things
  • NB-IoT narrow band internet of things
  • a terminal device may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation.
  • a downlink, DL, transmission refers to a transmission from a network device to a terminal device
  • an uplink, UL, transmission refers to a transmission in an opposite direction.
  • references in the specification 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 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.
  • 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.
  • the term “and/or” includes any and all combinations of one or more of the associated listed terms.
  • FIGs. 1a-1b show some system architectures in which the embodiments of the present disclosure can be implemented.
  • the system architectures of FIGs. 1a-1b only depict some exemplary elements.
  • a communication system may further include any additional elements suitable to support communication between terminal devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or terminal device.
  • the communication system may provide communication and various types of services to one or more terminal devices to facilitate the terminal devices’ access to and/or use of the services provided by, or via, the communication system.
  • FIG. 1a schematically shows a high level architecture in a 4G network, which is same as Figure 4.2-1a of 3GPP TS 23.682 V16.6.0, the disclosure of which is incorporated by reference herein in its entirety.
  • the system architecture of FIG. 1a may comprise some exemplary elements such as SCS, AS, SCEF, HSS (home subscriber server) , UE, RAN (Radio Access Network) , SGSN (Serving GPRS (General Packet Radio Service) Support Node) , MME (Mobile Management Entity) , MSC (Mobile Switching Centre) , S-GW (Serving Gateway) , GGSN/P-GW (Gateway GPRS Support Node/PDN (Packet Data Network) Gateway) , MTC-IWF (Machine Type Communications-InterWorking Function) CDF/CGF (Charging Data Function/Charging Gateway Function) , MTC-AAA (Machine Type Communications-authentication, authorization and accounting) , SMS-SC/GMSC/IWM
  • FIG. 1b schematically shows a high level architecture in a 5G network, which is same as Figure 4.2.3-1 of 3GPP TS 23.501 V16.5.1, the disclosure of which is incorporated by reference herein in its entirety.
  • the system architecture of FIG. 1b may comprise some exemplary elements such as AMF, SMF, AUSF, UDM, PCF, AF, NEF, UPF and NRF, (R) AN, SCP, NSSF, NSSAAF, etc.
  • the network elements, reference points and interfaces as shown in FIG. 1b may be same as the corresponding network elements, reference points and interfaces as described in 3GPP TS 23.501 V16.5.1.
  • AMF informs the PGW-C+SMF of the forwarding tunnel status if it is not available:
  • the PGW-C+SMF could trigger UPF to buffer DL data and/or signaling of the UE.
  • PGW-C+SMF may report the event to P-CSCF and P-CSCF buffers the DL data and/or signaling of the UE.
  • FIG. 2 shows a flowchart of a method according to an embodiment of the present disclosure, which may be performed by an apparatus implemented in/as or communicatively coupled to a gateway session management entity.
  • the apparatus may provide means or modules for accomplishing various parts of the method 600 as well as means or modules for accomplishing other processes in conjunction with other components.
  • the gateway session management entity may be any suitable entity or node which can implement the packet data network gateway function and session management function.
  • the gateway session management entity may be PGW+SMF or PGW-C+SMF.
  • the gateway session management entity receives, from an access and mobility management entity, information indicating that a data forwarding tunnel is not available for a handover procedure of a terminal device.
  • the access and mobility management entity may be any suitable network entity which can support access and mobility management function.
  • the access and mobility management entity may be AMF or AMF-MME.
  • the information may be included in any suitable message which can be transferred between the gateway session management entity and the access and mobility management entity.
  • the information may be included in Nsmf_PDUSession_UpdateSMContext request as described in 3GPP TS 23.502 V16.4.0.
  • the handover may be happened duo to various reasons.
  • the terminal device such as UE camps on NG-RAN in the 5GS and an MO or MT IMS voice session establishment has been initiated.
  • Network initiated PDU session modification to setup QoS flow for voice reaches the NG-RAN.
  • NG-RAN may be configured to support EPS fallback for IMS voice and decides to trigger fallback to EPS, taking into account UE capabilities, indication from AMF that "Redirection for EPS fallback for voice is possible" , network configuration (e.g. N26 availability configuration) , radio conditions, etc.
  • the handover may be any suitable handover such as EPS fallback with handover.
  • the handover is fifth generation system (5GS) to evolved packet system (EPS) handover using N26 interface as described in clause 4.13.6.1 of 3GPP TS 23.502 V16.4.0.
  • 5GS fifth generation system
  • EPS evolved packet system
  • the data forwarding tunnel comprises at least one of an indirect forwarding tunnel and a direct forwarding tunnel.
  • the direct forwarding tunnel may be a tunnel between a source RAN and a target RAN and the downlink data and/or signaling may be forwarded from the source RAN towards the target RAN.
  • the downlink data and/or signaling may be forwarded from the source RAN towards the target RAN via at least one core network node such as UPF or PGW-U+UPF.
  • the information is received from the access and mobility management entity via an Intermediate Session Management Function (I-SMF) or a visited Session Management Function (V-SMF) .
  • I-SMF Intermediate Session Management Function
  • V-SMF visited Session Management Function
  • the AMF sends the Nsmf_PDUSession_UpdateSMContext Request including information indicating that a data forwarding tunnel is not available for a handover procedure of the UE to the PGW-C+SMF via V-SMF or I-SMF.
  • the gateway session management entity based on the received information, performs at least one of sending a message for triggering downlink data buffering for the terminal device in a gateway user plane entity to the gateway user plane entity; or sending a connect path interruption event of the terminal device to a policy control entity.
  • the gateway session management entity based on the received information, sends a message for triggering downlink data buffering for the terminal device in a gateway user plane entity to the gateway user plane entity.
  • the gateway user plane entity may be any suitable network entity which can provide user plane function.
  • the gateway user plane entity may be a PGW user plane (PGW-U) combined with a user plane function (UPF) (PGW-U+UPF) .
  • PGW-U PGW user plane
  • UPF user plane function
  • the gateway session management entity may immediately sends the message for triggering downlink data buffering for the terminal device in the gateway user plane entity to the gateway user plane entity.
  • the message may be any suitable message such as a modified existing message or a new message.
  • the message may be an N4 session modification request message that contains the update for the structured control information which defines how the PGW-U+UPF needs to behave.
  • the N4 session modification request message may trigger downlink data buffering for the terminal device in the gateway user plane entity.
  • the gateway session management entity based on the received information, sends a connect path interruption event of the terminal device to a policy control entity.
  • the policy control entity may be any suitable network entity which can provide policy control function.
  • the policy control entity may be a PCF.
  • the gateway session management entity may immediately sends the connect path interruption event of the terminal device to the policy control entity.
  • the connect path interruption event of the terminal device may be included in any suitable message such as a modified existing message or a new message.
  • the connect path interruption event of the terminal device may be reported to the policy control entity, in response to a subscription of the connect path interruption event of the terminal device by the policy control entity.
  • the PCF may send an Npcf_SMPolicyControl_UpdateNotify request (voice QoS flow reserve, data connectivity information (temporary interruption&recovery) ) to SMF.
  • FIG. 3 shows a flowchart of a method according to another embodiment of the present disclosure, which may be performed by an apparatus implemented in/as or communicatively coupled to a gateway session management entity.
  • the apparatus may provide means or modules for accomplishing various parts of the method 700 as well as means or modules for accomplishing other processes in conjunction with other components.
  • the gateway session management entity may be any suitable entity or node which can implement the packet data network gateway function and session management function.
  • the gateway session management entity may be PGW+SMF or PGW-C+SMF.
  • PGW+SMF Packet Control Function
  • the gateway session management entity receives, from an access and mobility management entity, information indicating that a data forwarding tunnel is not available for a handover procedure of a terminal device.
  • Block 702 is same as block 602 of FIG. 2.
  • the gateway session management entity based on the received information, sends a message for triggering downlink data buffering for the terminal device in a gateway user plane entity to the gateway user plane entity.
  • the gateway session management entity receives a modify bearer request relate to the terminal device from a serving gateway.
  • the modify bearer request comprises at least one serving gateway address for user plane and at least one tunnel endpoint identifier.
  • the at least one tunnel endpoint identifier may be SGW-U (serving gateway user plane) S5/S8 F-TEID (Fully Qualified Tunnel Endpoint Identifier) .
  • S5 is a reference point that provides user plane tunneling and tunnel management between SGW and PGW.
  • S8 is an Inter-PLMN reference point providing user and control plane between the SGW in the VPLMN (visited PLMN) and the PGW in the HPLMN (home PLMN) .
  • the serving gateway such as SGW may send a modify bearer request to the gateway session management entity such as the PGW-C+SMF as described in clause 4.11.1.2.1 of 3GPP TS 23.502 V16.4.0.
  • the gateway session management entity may determine a radio access type change event of the terminal device from the modify bearer request.
  • the gateway session management entity may determine the radio access type change event of the terminal device based on information element (such as at least one serving gateway address for user plane and at least one tunnel endpoint identifier, etc. ) included in the modify bearer request.
  • the modify bearer request may include information informing the gateway session management entity about the change of for example the RAT type.
  • the serving gateway may be a serving gateway control plane (SGW-C) and the buffered downlink data of the terminal device may be requested to be forwarded to a serving gateway user plane (SGW-U) .
  • SGW-C serving gateway control plane
  • SGW-U serving gateway user plane
  • the gateway session management entity sends, to the gateway user plane entity, a request for stopping the downlink data buffering for the terminal device in the gateway user plane entity and forwarding buffered downlink data of the terminal device to the serving gateway.
  • the PGW-C+SMF initiates a N4 Session Modification procedure towards the UPF+PGW-U to update the User Plane path, i.e.
  • the downlink User Plane for the indicated PDU session is switched to E-UTRAN and the PGW-C+SMF should stop the downlink data buffering for the terminal device (e.g., for the indicated PDU session) in the gateway user plane entity and forward the buffered downlink data for the terminal device (e.g., for the indicated PDU session) to the serving gateway.
  • the PGW-C+SMF should stop the downlink data buffering for the terminal device (e.g., for the indicated PDU session) in the gateway user plane entity and forward the buffered downlink data for the terminal device (e.g., for the indicated PDU session) to the serving gateway.
  • the method 700 is also applicable for RAT change scenario.
  • FIG. 4 shows a flowchart of a method according to another embodiment of the present disclosure, which may be performed by an apparatus implemented in/as or communicatively coupled to a gateway session management entity.
  • the apparatus may provide means or modules for accomplishing various parts of the method 800 as well as means or modules for accomplishing other processes in conjunction with other components.
  • the gateway session management entity may be any suitable entity or node which can implement the packet data network gateway function and session management function.
  • the gateway session management entity may be PGW+SMF or PGW-C+SMF.
  • PGW+SMF Packet Control Function
  • the gateway session management entity receives, from an access and mobility management entity, information indicating that a data forwarding tunnel is not available for a handover procedure of a terminal device.
  • Block 802 is same as block 602 of FIG. 2.
  • the gateway session management entity based on the received information, sends a connect path interruption event of the terminal device to a policy control entity.
  • the gateway session management entity receives a modify bearer request relate to the terminal device from a serving gateway, wherein the modify bearer request comprises at least one serving gateway address for user plane and at least one tunnel endpoint identifier.
  • Block 806 is same as block 706 of FIG. 3.
  • the gateway session management entity based on the modify bearer request, sends, a radio access type change event of the terminal device to the policy control entity.
  • the radio access type change event (such as data connectivity recovery) may be included in any suitable message.
  • the radio access type change event may be sent to the policy control entity, in response to a subscription of the radio access type change event by the policy control entity.
  • the PCF may send an Npcf_SMPolicyControl_UpdateNotify request (voice QoS flow reserve, data connectivity information (temporary interruption&recovery) ) to SMF.
  • FIG. 5 shows a flowchart of a method according to another embodiment of the present disclosure, which may be performed by an apparatus implemented in/as or communicatively coupled to a policy control entity.
  • the apparatus may provide means or modules for accomplishing various parts of the method 900 as well as means or modules for accomplishing other processes in conjunction with other components.
  • the policy control entity may be any suitable entity or node which can implement the policy control function.
  • the policy control entity may be PCF.
  • the policy control entity receives a connect path interruption event of a terminal device from a gateway session management entity.
  • the gateway session management entity may report connect path interruption event of the terminal device to the policy control entity in block 604 of FIG. 2, and then the policy control entity may receive the connect path interruption event of the terminal device from the gateway session management entity.
  • the policy control entity reports the connect path interruption event of the terminal device to a call control entity.
  • the call control entity may be any suitable network entity which can support call control function.
  • the call control entity may be P-CSCF.
  • the connect path interruption event of the terminal device may be included in any suitable message which can be transferred between the policy control entity and the call control entity.
  • the policy control entity receives a radio access type change event of the terminal device from the gateway session management entity.
  • the gateway session management entity may send the radio access type change event of the terminal device to the policy control entity in block 808 of FIG. 4, and then the policy control entity may receive the radio access type change event of the terminal device from the gateway session management entity.
  • the policy control entity reports the radio access type change event of the terminal device to the call control entity.
  • the radio access type change event of the terminal device may be included in any suitable message which can be transferred between the policy control entity and the call control entity.
  • the radio access type change event of the terminal device may be reported to the call control entity, in response to a subscription of the radio access type change event by the call control entity.
  • the subscription of the radio access type change event by the call control entity may be informed to the policy control entity in an authentication and authorization request from the call control entity.
  • the radio access type change event may be reported to the call control entity in a re-authentication request from the policy control entity.
  • the radio access type change event may be reported to the call control entity, in response to a subscription of the radio access type change event by the call control entity.
  • the subscription of the radio access type change event by the call control entity may be informed to the policy control entity in an authentication and authorization request from the call control entity.
  • the radio access type change event may be reported to the call control entity in a re-authentication request from the policy control entity.
  • FIG. 6 shows a flowchart of a method according to another embodiment of the present disclosure, which may be performed by an apparatus implemented in/as or communicatively coupled to a call control entity.
  • the apparatus may provide means or modules for accomplishing various parts of the method 1000 as well as means or modules for accomplishing other processes in conjunction with other components.
  • the call control entity may be any suitable entity or node which can implement the call control function.
  • the call control entity may be P-CSCF.
  • the description thereof is omitted here for brevity.
  • the call control entity receives a connect path interruption event of a terminal device from a policy control entity.
  • the policy control entity may report the connect path interruption event of a terminal device to the call control entity in block 904 of FIG. 5, and then the call control entity may receive the connect path interruption event of a terminal device.
  • the connect path interruption event of the terminal device may be received from the policy control entity, in response to a subscription of the connect path interruption event of the terminal device by the call control entity.
  • the subscription of the connect path interruption event of the terminal device by the call control entity may be informed to the policy control entity in an authentication and authorization request from the call control entity.
  • the data connectivity temporary interruption event may be received in a re-authentication request from the policy control entity.
  • the call control entity buffers at least one signaling related to the terminal device in the call control entity based at least in part on the connect path interruption event of the terminal device.
  • the signaling may be any suitable signaling such as SIP signaling.
  • the buffering operation may be designed to optimize the QoS and/or QoE (quality of experience) of a service of the terminal device.
  • the call control entity receives a radio access type change event of the terminal device from a policy control entity.
  • the policy control entity may report the radio access type change event of the terminal device to the call control entity in block 908 of FIG. 5, and then the call control entity may receive the radio access type change event of the terminal device.
  • the radio access type change event of the terminal device may be received from the policy control entity, in response to a subscription of the radio access type change event of the terminal device by the call control entity.
  • the subscription of the radio access type change event of the terminal device by the call control entity may be informed to the policy control entity in an authentication and authorization request from the call control entity.
  • the radio access type change event of the terminal device may be received in a re-authentication request from the policy control entity.
  • the call control entity resumes the at least one signaling related to the terminal device based at least in part on the radio access type change event of the terminal device. For example, the call control entity may resend the at least one signaling (such as SIP signaling for call setup) immediately.
  • FIG. 7 shows a flowchart of a method according to another embodiment of the present disclosure, which may be performed by an apparatus implemented in/as or communicatively coupled to an access and mobility management entity.
  • the apparatus may provide means or modules for accomplishing various parts of the method 1100 as well as means or modules for accomplishing other processes in conjunction with other components.
  • the access and mobility management entity may be any suitable entity or node which can implement access and mobility management function.
  • the access and mobility management entity may be AMF.
  • the access and mobility management entity determines that a data forwarding tunnel is not available for a handover procedure of a terminal device.
  • the access and mobility management entity may determine that the data forwarding tunnel is not available for the handover procedure of the terminal device in various ways. For example, the availability of a direct forwarding path may be determined in the source radio network node and indicated to the source access and mobility management entity. For example, if a connectivity is available between the source radio network node and the target radio network node, a direct forwarding path is available.
  • the source access and mobility management entity may send the availability of the direct forwarding path to the target access and mobility management entity. Then the target access and mobility management entity may determine whether a direct data forwarding tunnel is available for the handover procedure of the terminal device based on the availability of the direct forwarding path.
  • indirect forwarding may be used.
  • the source access and mobility management entity may use the availability of the direct forwarding path from the source RAN to determine whether to apply indirect forwarding.
  • the source access and mobility management entity indicates to the target access and mobility management entity whether indirect forwarding should apply. Based on this indication, the target access and mobility management entity determines whether it applies indirect forwarding.
  • the access and mobility management entity determines that a data forwarding tunnel is not available for a handover procedure of a terminal device as described in clause 4.11.1 of 3GPP TS 23.502 V16.4.0, such as clause 4.11.1.2.1 of 3GPP TS 23.502 V16.4.0.
  • the access and mobility management entity sends information indicating that the data forwarding tunnel is not available for the handover procedure of the terminal device to a gateway session management entity.
  • the information is sent to the access and mobility management entity via an Intermediate Session Management Function (I-SMF) or a visited Session Management Function (V-SMF) .
  • I-SMF Intermediate Session Management Function
  • V-SMF visited Session Management Function
  • FIG. 8 shows a flowchart of a method according to another embodiment of the present disclosure, which may be performed by an apparatus implemented in/as or communicatively coupled to a gateway user plane entity.
  • the apparatus may provide means or modules for accomplishing various parts of the method 1200 as well as means or modules for accomplishing other processes in conjunction with other components.
  • the gateway user plane entity may be any suitable entity or node which can implement user plane function.
  • the gateway user plane entity may be PGW-U+UPF.
  • the description thereof is omitted here for brevity.
  • the gateway user plane entity receives a message for triggering downlink data buffering of a terminal device in the gateway user plane entity from a gateway session management entity.
  • the gateway session management entity may send this message at block 604 of FIG. 2 and then the gateway user plane entity may receive this message.
  • the gateway user plane entity triggers downlink data buffering for the terminal device in the gateway user plane entity.
  • the gateway user plane entity receives, from the gateway session management entity, a request for stopping the downlink data buffering for the terminal device in the gateway user plane entity and forwarding buffered downlink data of the terminal device to a serving gateway.
  • the gateway session management entity may send this request at block 708 of FIG. 3 and then the gateway user plane entity may receive this request.
  • the gateway user plane entity stops the downlink data buffering for the terminal device in the gateway user plane entity
  • the gateway user plane entity forwards buffered downlink data of the terminal device to the serving gateway.
  • the serving gateway is a serving gateway control plane (SGW-C) and the buffered downlink data of the terminal device is forwarded to a serving gateway user plane (SGW-U) .
  • SGW-C serving gateway control plane
  • SGW-U serving gateway user plane
  • FIG. 9 shows a flowchart of a method of UPF buffering according to another embodiment of the present disclosure. Though only Rx is illustrated in FIG. 9, the solution of FIG. 9 is also applicable for N5. Only EPS fallback is described in FIG. 9, but the solution of FIG. 9 is also applicable for handover from 5GS to EPS.
  • AMF informs the PGW-C+SMF that data forwarding tunnel is not provided before sending handover command.
  • PGW-C+SMF triggers UPF to buffer DL signaling and/or data.
  • UE initiates IMS voice call.
  • P-CSCF/PCF requests PGW_C+SMF to setup a dedicated QoS flow for IMS voice.
  • NW Network (NW) initiated PDU session modification to setup QoS flow for IMS voice.
  • NG-RAN rejects QoS Flow Setup and trigger EPS fallback.
  • Steps 1-7 and 9 of FIG. 9 are same as the corresponding steps1-7 and 9 as described in clause 4.11.1.2.1 of 3GPP TS 23.502 V16.4.0.
  • AMF may send Nsmf_PDUSession_UpdateSMContext_Reuqest (forwarding tunnel is not available) to PGW_C_SMF (also called PGW_C+SMF) .
  • PGW_C_SMF based on the information received from AMF, PGW_C_SMF triggers the DL signaling and/or data buffering in PGW_U_UPF (also called PGW_U+UPF) .
  • Steps 10c-14a of FIG. 9 are same as the corresponding steps 10c-14a as described in clause 4.11.1.2.1 of 3GPP TS 23.502 V16.4.0.
  • PGW_C+SMF initiates a N4 Session Modification procedure towards the UPF+PGW-U to update the User Plane path and indicate the UPF+PGW-U to stop buffering DL signaling and/or data for the indicated PDU session, i.e. the downlink User Plane for the indicated PDU session is switched to E-UTRAN and the UPF+PGW-U should stop buffering DL signaling and/or data for the indicated PDU session.
  • Step 16 is same as the corresponding step 16 as described in clause 4.11.1.2.1 of 3GPP TS 23.502 V16.4.0.
  • FIG. 10 shows a flowchart of a method of P-CSCF buffering according to another embodiment of the present disclosure. Though only Rx is illustrated in FIG. 10, the solution of FIG. 10 is also applicable for N5. Only EPS fallback is described in FIG. 10, but the solution of FIG. 10 is also applicable for handover from 5GS to EPS.
  • AMF informs the PGW-C+SMF that forwarding tunnel is not provided before sending handover command.
  • PGW-C+SMF reports that forwarding tunnel is not provided to PCF, PCF further reports it to P-CSCF and P-CSCF buffers DL signaling.
  • Steps a, b, c, 1-7, 9 and 10a of FIG. 10 are same as the corresponding steps a, b, c, 1-7, 9 and 10a of FIG. 9.
  • PGW_C_SMF reports the event “connect path interruption” to PCF which sends the event to P-CSCF.
  • P-CSCF starts buffering the DL signaling for the UE.
  • Step 10c and 11a-12a of FIG. 10 are same as the corresponding steps 10c and 11a-12a as described in clause 4.11.1.2.1 of 3GPP TS 23.502 V16.4.0.
  • P-CSCF stops DL signaling buffering for the UE and resumes the call setup for the UE.
  • FIG. 11 shows a flowchart of a method of UPF buffering according to another embodiment of the present disclosure. Though only Rx is illustrated in FIG. 11, the solution of FIG. 11 is also applicable for N5. Only EPS fallback is described in FIG. 11, but the solution of FIG. 11 is also applicable for handover from 5GS to EPS.
  • AMF informs the I-SMF that forwarding tunnel is not provided before sending a handover command.
  • the I-SMF informs the PGW-C+SMF that forwarding tunnel is not provided and the PGW-C+SMF triggers UPF to buffer DL signaling and/or data.
  • Steps a, b, c, 1-7 and 9 of FIG. 11 are same as the corresponding steps a, b, c, 1-7 and 9 of FIG. 9.
  • AMF may send Nsmf_PDUSession_UpdateSMContext_Reuqest (forwarding tunnel is not available) to I-SMF.
  • I-SMF sends Nsmf_PDUSession Update Request (forwarding tunnel is not available) to PGW_C_SMF.
  • PGW_C_SMF sends N4 Session Modification to PGW_U_UPF.
  • PGW_U_UPF buffers DL signaling and/or data for the UE.
  • PGW_C_SMF sends Nsmf_PDUSession Update Response to I_SMF.
  • Steps 10c-14 of FIG. 11 are same as the corresponding steps 10c-14 as described in clause 4.11.1.2.1 of 3GPP TS 23.502 V16.4.0.
  • PGW_C+SMF requests to stop the DL signaling and/or data buffering for the UE in PGW_U_UPF.
  • Steps 16-17 of FIG. 11 are same as the corresponding steps 16-17 as described in clause 4.11.1.2.1 of 3GPP TS 23.502 V16.4.0.
  • the AMF when neither direct data forwarding nor indirect data forwarding is available, the AMF sends Nsmf_PDUSession_UpdateSMContext Request message to the PGW-C+SMF informing that data forwarding is not available.
  • a new information element (IE) may be provided to indicate the data forwarding is not available.
  • the PGW-C+SMF could trigger UPF to buffer DL packets (e.g SIP signaling) at the latest time point which need sending the SIP signaling to the UE, to avoid the SIP signaling lost.
  • DL packets e.g SIP signaling
  • the gateway session management entity may either inform a user plane to perform data buffering for the terminal device or forwarding this information to a policy control entity such as PCF which may cause a P-CSCF to perform DL signaling buffering for the terminal device.
  • a policy control entity such as PCF which may cause a P-CSCF to perform DL signaling buffering for the terminal device.
  • Embodiments herein afford many advantages, of which a non-exhaustive list of examples follows.
  • the proposed solution according to some exemplary embodiments can solve signaling and/or data loss in fallback, for example, the SIP signaling loss issue in EPS fallback.
  • the gateway session management entity such as PGW-C+SMF may report “connect path interruption event” to the policy control entity such as PCF, in another word, the gateway session management entity such as PGW-C+SMF does not blindly send the “connect path interruption event” to the policy control entity such as PCF which sends it to the call control entity such as P-CSCF.
  • IMS domain can be based on the “connect path interruption event” and “radio access type change event” to take proper and accurate actions to optimize the SIP signaling handling.
  • DL signaling buffering is triggered at the right time point, and it solves the issue related to signaling lost and signaling transfer delay.
  • the call setup time in case of EPS fallback can be optimized.
  • the proposed solution can enhance the statistics in IMS when PGW-C+SMF reports the “connect path interruption event” and “radio access type change event” to PCF/P-CSCF.
  • the proposed solution can low down the network deployment complexity and maintenance complexity due to forwarding tunnels for EPS fallback.
  • the embodiments herein are not limited to the features and advantages mentioned above. A person skilled in the art will recognize additional features and advantages upon reading the following detailed description.
  • FIGs. 2-11 may be viewed as method steps, and/or as operations that result from operation of computer program code, and/or as a plurality of coupled logic circuit elements constructed to carry out the associated function (s) .
  • the schematic flow chart diagrams described above are generally set forth as logical flow chart diagrams. As such, the depicted order and labeled steps are indicative of specific embodiments of the presented methods. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more steps, or portions thereof, of the illustrated methods. Additionally, the order in which a particular method occurs may or may not strictly adhere to the order of the corresponding steps shown.
  • Some messages as shown in FIGs. 2-11 may be similar to the corresponding messages as described in the 3GPP TS 23.502 V16.4.0, 3GPP TS 23.501 V16.4.0 and SIP protocol.
  • the underlined content may be added into clause 4.11.1.2.1 of 3GPP TS 23.502 V16.4.0.
  • the AMF sends the Nsmf_PDUSession_UpdateSMContext Request (data forwarding information) to the PGW-C+SMF. If multiple PGW-C+SMFs serves the UE, the AMF maps the EPS bearers for Data forwarding to the PGW-C+SMF address (es) based on the association between the EPS bearer ID(s) and PDU session ID (s) . In home-routed roaming case, the AMF requests the V-SMF to create indirect forwarding tunnel if indirect forwarding applies.
  • the AMF may send Nsmf_PDUSession_UpdateSMContext Request to indicate that direct/indirect data forwarding tunnel is not available.
  • the PGW-C+SMF may select an intermediate PGW-U+UPF for data forwarding.
  • the PGW-C+SMF maps the EPS bearers for Data forwarding to the 5G QoS flows based on the association between the EPS bearer ID (s) and QFI (s) for the QoS flow (s) in the PGW-C+SMF, and then sends the QFIs, Serving GW Address (es) and TEID (s) for data forwarding to the PGW-U+UPF.
  • the CN Tunnel Info is provided by the PGW-U+UPF to PGW-C+SMF in this response.
  • the V-SMF selects the V-UPF for data forwarding.
  • the PGW_C+SMF may trigger the DL data buffering in PGW_U_UPF.
  • the PGW-C+SMF initiates a N4 Session Modification procedure towards the UPF+PGW-U to update the User Plane path, i.e. the downlink User Plane for the indicated PDU session is switched to E-UTRAN.
  • the PGW-C+SMF releases the resource of the CN tunnel for PDU session in UPF+PGW-U.
  • the PGW-C+SMF can inform the UPF+PGW-U to stop buffering and forward the buffering DL packets to the SGW-U.
  • the underlined content may be added into clause 5.2.2.3.9 of 3GPP TS 29.502 V16.4.0.
  • the AMF may update the SMF with the information that the data forwarding tunnel is not available by sending a POST request with the dataForwarding IE set to "false" or without the dataForwarding IE.
  • the underlined content may be added into Table 6.1.6.2.4-1 of 3GPP TS 29.502 V16.4.0.
  • Table 6.1.6.2.4-1 of 3GPP TS 29.502 V16.4.0 may be amended as following:
  • FIG. 12 is a block diagram showing an apparatus suitable for practicing some embodiments of the disclosure.
  • any one of the gateway session management entity, the policy control entity, the call control entity, the access and mobility management entity, the gateway user plane entity described above may be implemented as or through the apparatus 1600.
  • the apparatus 1600 comprises at least one processor 1621, such as a digital processor (DP) , and at least one memory (MEM) 1622 coupled to the processor 1621.
  • the apparatus 1620 may further comprise a transmitter TX and receiver RX 1623 coupled to the processor 1621.
  • the MEM 1622 stores a program (PROG) 1624.
  • the PROG 1624 may include instructions that, when executed on the associated processor 1621, enable the apparatus 1620 to operate in accordance with the embodiments of the present disclosure.
  • a combination of the at least one processor 1621 and the at least one MEM 1622 may form processing means 1625 adapted to implement various embodiments of the present disclosure.
  • Various embodiments of the present disclosure may be implemented by computer program executable by one or more of the processor 1621, software, firmware, hardware or in a combination thereof.
  • the MEM 1622 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memories and removable memories, as non-limiting examples.
  • the processor 1621 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples.
  • general purpose computers special purpose computers
  • microprocessors microprocessors
  • DSPs digital signal processors
  • processors based on multicore processor architecture, as non-limiting examples.
  • the memory 1622 contains instructions executable by the processor 1621, whereby the gateway session management entity operates according to any step of any of the methods related to the gateway session management entity as described above.
  • the memory 1622 contains instructions executable by the processor 1621, whereby the policy control entity operates according to any step of the methods related to the policy control entity as described above.
  • the memory 1622 contains instructions executable by the processor 1621, whereby the call control entity operates according to any step of the methods related to the call control entity as described above.
  • the memory 1622 contains instructions executable by the processor 1621, whereby the access and mobility management entity operates according to any step of the methods related to the access and mobility management entity as described above.
  • the memory 1622 contains instructions executable by the processor 1621, whereby the gateway user plane entity operates according to any step of the methods related to the gateway user plane entity as described above.
  • FIG. 13 is a block diagram showing a gateway session management entity according to an embodiment of the disclosure.
  • the gateway session management entity 1700 comprises a receiving module 1702 and a performing module 1704.
  • the receiving module 1702 may be configured to receive, from an access and mobility management entity, information indicating that a data forwarding tunnel is not available for a handover procedure of a terminal device.
  • the performing module 1704 may be configured to, based on the received information, perform at least one of sending a message for triggering downlink data buffering for the terminal device in a gateway user plane entity to the gateway user plane entity; or sending a connect path interruption event of the terminal device to a policy control entity.
  • FIG. 14 is a block diagram showing a policy control entity according to an embodiment of the disclosure.
  • the policy control entity 1800 comprises a receiving module 1802 and a reporting module 1804.
  • the receiving module 1802 may be configured to receive a connect path interruption event of a terminal device from a gateway session management entity.
  • the reporting module 1804 may be configured to report the connect path interruption event of the terminal device to a call control entity.
  • FIG. 15 is a block diagram showing a call control entity according to an embodiment of the disclosure.
  • the call control entity 1900 comprises a receiving module 1902 and a buffering module 1904.
  • the receiving module 1902 may be configured to receive a connect path interruption event of a terminal device from a policy control entity.
  • the buffering module 1904 may be configured to buffer at least one signaling related to the terminal device in the call control entity based at least in part on the connect path interruption event of the terminal device.
  • FIG. 16 is a block diagram showing an access and mobility management entity according to an embodiment of the disclosure.
  • the access and mobility management entity 2000 comprises a determining module 2002 and a sending module 2004.
  • the determining module 2002 may be configured to determine that a data forwarding tunnel is not available for a handover procedure of a terminal device.
  • the sending module 2004 may be configured to send information indicating that the data forwarding tunnel is not available for the handover procedure of the terminal device to a gateway session management entity.
  • FIG. 17 is a block diagram showing a gateway user plane entity according to an embodiment of the disclosure.
  • the gateway user plane entity 2100 comprises a receiving module 2102 and a triggering module 2104.
  • the receiving module 2102 may be configured to receive a message for triggering downlink data buffering of a terminal device in the gateway user plane entity from a gateway session management entity.
  • the triggering module 2104 may be configured to trigger downlink data buffering for the terminal device in the gateway user plane entity.
  • unit or module may have conventional meaning in the field of electronics, electrical devices and/or electronic devices and may include, for example, electrical and/or electronic circuitry, devices, modules, processors, memories, logic solid state and/or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and/or displaying functions, and so on, as such as those that are described herein.
  • any of the gateway session management entity, the policy control entity, the call control entity, the access and mobility management entity and the gateway user plane entity may not need a fixed processor or memory, any computing resource and storage resource may be arranged from any of the gateway session management entity, the policy control entity, the call control entity, the access and mobility management entity, the gateway user plane entity in the communication system.
  • the introduction of virtualization technology and network computing technology may improve the usage efficiency of the network resources and the flexibility of the network.
  • a computer program product being tangibly stored on a computer readable storage medium and including instructions which, when executed on at least one processor, cause the at least one processor to carry out any of the methods as described above.
  • a computer-readable storage medium storing instructions which when executed by at least one processor, cause the at least one processor to carry out any of the methods as described above.
  • the present disclosure may also provide a carrier containing the computer program as mentioned above, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.
  • the computer readable storage medium can be, for example, an optical compact disk or an electronic memory device like a RAM (random access memory) , a ROM (read only memory) , Flash memory, magnetic tape, CD-ROM, DVD, Blue-ray disc and the like.
  • an apparatus implementing one or more functions of a corresponding apparatus described with an embodiment comprises not only prior art means, but also means for implementing the one or more functions of the corresponding apparatus described with the embodiment and it may comprise separate means for each separate function or means that may be configured to perform one or more functions.
  • these techniques may be implemented in hardware (one or more apparatuses) , firmware (one or more apparatuses) , software (one or more modules) , or combinations thereof.
  • firmware or software implementation may be made through modules (e.g., procedures, functions, and so on) that perform the functions described herein.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Divers modes de réalisation de la présente divulgation concernent des procédés et des appareils de gestion de services. Un procédé qui est mis en œuvre par une entité de gestion de session de passerelle consiste à recevoir, en provenance d'une entité de gestion d'accès et de mobilité, des informations indiquant qu'un tunnel de transfert de données n'est pas disponible pour une procédure de transfert intercellulaire d'un dispositif terminal. Le procédé consiste en outre, sur la base des informations reçues, à réaliser au moins une action parmi l'envoi d'un message pour déclencher une mise en mémoire tampon de données de liaison descendante pour le dispositif terminal dans une entité de plan utilisateur de passerelle vers l'entité de plan utilisateur de passerelle; ou l'envoi d'un événement d'interruption de trajet de connexion du dispositif terminal à une entité de commande de politique.
PCT/CN2021/114540 2020-08-25 2021-08-25 Procédé et appareil de gestion de services WO2022042606A1 (fr)

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Citations (5)

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CN102457420A (zh) * 2010-10-26 2012-05-16 智邦科技股份有限公司 建立路径数据的网络装置及其方法
US20170238215A1 (en) * 2014-11-04 2017-08-17 Huawei Technologies Co., Ltd. Mobility management method, apparatus, and system
US20180368042A1 (en) * 2016-02-29 2018-12-20 Huawei Technologies Co., Ltd. Mobility management method, apparatus, and system
CN109673061A (zh) * 2017-10-16 2019-04-23 华为技术有限公司 一种pdu会话处理的方法和装置
WO2019229219A1 (fr) * 2018-06-01 2019-12-05 Universitat Politècnica De Catalunya Procédé et système de transfert pour réseaux 5g

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102457420A (zh) * 2010-10-26 2012-05-16 智邦科技股份有限公司 建立路径数据的网络装置及其方法
US20170238215A1 (en) * 2014-11-04 2017-08-17 Huawei Technologies Co., Ltd. Mobility management method, apparatus, and system
US20180368042A1 (en) * 2016-02-29 2018-12-20 Huawei Technologies Co., Ltd. Mobility management method, apparatus, and system
CN109673061A (zh) * 2017-10-16 2019-04-23 华为技术有限公司 一种pdu会话处理的方法和装置
WO2019229219A1 (fr) * 2018-06-01 2019-12-05 Universitat Politècnica De Catalunya Procédé et système de transfert pour réseaux 5g

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