CN113709903A

CN113709903A - Communication method, device and system

Info

Publication number: CN113709903A
Application number: CN202010437779.9A
Authority: CN
Inventors: 魏海涛; 丁辉; 叶进洲; 陆长奇
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-05-21
Filing date: 2020-05-21
Publication date: 2021-11-26
Also published as: WO2021233264A1

Abstract

The application provides a communication method, equipment and system. The method can comprise the following steps: the AMF equipment receives a first service request message from the access network equipment, wherein the first service request message is used for requesting a terminal service in the 5G network; the AMF equipment determines that the first service request message is triggered by the voice service of the terminal; and the AMF equipment sends a fallback indication to the access network equipment, wherein the fallback indication is used for indicating the access network equipment to fallback the voice service of the terminal from the 5G network to the 4G network. In the application, the AMF device instructs the access network device to execute the EPS fallback by determining that the current service of the terminal is a voice service, so that the terminal can perform the voice service without being affected by the problems of the capability of the base station, the deployment of a wireless network and the like.

Description

Communication method, device and system

Technical Field

The present application relates to the field of wireless communication technologies, and in particular, to a communication method, device and system.

Background

In a 5G (fifth generation mobile communication technology) network, a new voice over new radio (VoNR) is used to implement a voice service of a User Equipment (UE). The VoNR scheme refers to that a 5G access network and a core network provide voice services based on an IP Multimedia Subsystem (IMS).

At present, due to the problems of the capability of the base station, the deployment of the wireless network, and the like, the UE cannot perform the voice service in the VoNR manner on the 5G network, and at this time, how to implement the voice service of the UE becomes a problem to be solved urgently.

Disclosure of Invention

The application provides a communication method, equipment and a system to realize the voice service of UE.

In a first aspect, the present application provides a communication method, which may be applied to an AMF device in a communication system, where a 5G network may interoperate with a 4G network under a system architecture of the communication system. Then, when the UE performs a voice service, first, an access and mobility management function (AMF) device receives a first Service Request (SR) message from an access network device, where the first SR message is used to request a service of a terminal in a 5G network. Then, the AMF device determines that the first SR message is triggered by a voice service of the terminal, where the voice service may be a calling voice service or a called voice service. And finally, the AMF equipment sends a fallback indication to the access network equipment to indicate the access network equipment to fallback the voice service of the terminal from the 5G network to the 4G network, namely, executing EPS fallback on the voice service of the terminal.

In the application, the AMF device indicates the access network device to execute the EPS fallback by determining that the current service of the terminal is the voice service, so that the terminal can perform the voice service without being affected by the problems of the capability of the base station, the deployment of a wireless network and the like, and resources are saved. Further, when the terminal is in an idle state, in a scenario where an EPS fallback is performed on a voice service of the terminal, a procedure of establishing a QoS Flow with voice 5QI ═ 1 at 5GC may be reduced, so as to shorten a call establishment delay of the EPS fallback.

Based on the first aspect, in some possible embodiments, the AMF device carries the fallback indication in an initial context setup request (initial context setup request) message, and sends the initial context setup request message to the access network device, so that the access network device may initiate an EPS fallback according to the indication of the initial context setup request after receiving the initial context setup request, so that the terminal is switched or redirected to the EPC, thereby implementing that the voice service of the terminal is performed in a 4G network.

Based on the first aspect, in some possible embodiments, when the voice service of the terminal is the called voice service, the AMF device receives a downlink data notification from the terminal of the SMF device, and then the AMF device determines the downlink data notification and pages the terminal.

In this application, the AMF device may determine that the first service request message is triggered by a called voice service of the terminal according to a paging cause of the paging. Here, the paging reason is determined by the AMF device according to a Paging Policy Indicator (PPI) transmitted by the SMF device.

Based on the first aspect, in some possible embodiments, the AMF device sends a paging message to the access network device, where the paging message carries a paging reason, and the paging reason is a called voice service of the terminal.

In the application, in a called scenario, the AMF device sends a paging reason to the terminal to inform the terminal that the paging is due to its own called voice service.

Based on the first aspect, in some possible embodiments, the first service request message carries a first indication, where the first indication is used to indicate a paging cause; then, the AMF device determines that the first service request message is triggered by the called voice service of the terminal according to the first indication carried in the first service request message.

In the application, the first indication is carried in the first service request message to inform the AMF device that the SR message is triggered by the called voice service of the terminal, so that the AMF device can initiate an EPS fallback to the called voice service of the terminal, the called voice service of the terminal is not affected by the capability of the base station, the deployment of a wireless network, and other problems, and resources are saved.

Based on the first aspect, in some possible embodiments, the first service request message carries a second indication, where the second indication is used to indicate that the first service request message is triggered by a calling voice service of the terminal; correspondingly, the AMF device determines that the first service request message is triggered by the calling voice service of the terminal according to the second indication carried in the first service request message.

In the application, the second indication is carried in the first service request message to inform the AMF device that the SR message is triggered by the calling voice service of the terminal, so that the AMF device can initiate an EPS fallback to the calling voice service of the terminal, the calling voice service of the terminal is not affected by the capability of the base station, the deployment of the wireless network, and other problems, and resources are saved.

In a second aspect, the present application provides a communication method, including: after establishing RRC connection for carrying out voice service with a terminal, an access network device sends a first service request message to AMF equipment, wherein the first service request message is used for requesting the service of the terminal in a 5G network; the access network equipment receives a fallback indication sent by the AMF equipment; and the access network equipment drops the voice service of the terminal from the 5G network to the 4G network according to the drop-back instruction.

Based on the second aspect, in some possible embodiments, the receiving, by the access network device, the fallback indication sent by the AMF device includes: the access network equipment receives an initial context setting request message sent by the AMF equipment, wherein the initial context request message carries a fallback indication.

The method further comprises the following steps: the method comprises the steps that in the process of establishing RRC connection, an RRC setup complete (RRC setup complete) message from a terminal is received by access network equipment, wherein the RRC setup complete message carries a second service request message, and the second service request message carries a third indication, and the third indication is used for indicating that the second service request is triggered by voice service of the terminal; the access network equipment sends a first service request message to the AMF equipment, and the first service request message comprises: and the access network equipment sends the first service request message to the AMF equipment according to the second service request message.

Based on the second aspect, in some possible embodiments, the method further includes: the method comprises the steps that in the process of establishing RRC connection, an access network device receives an RRC setup request (RRC setup request) message from a terminal, wherein the RRC setup request message carries a fourth indication, and the fourth indication indicates that the RRC setup request message is triggered by a voice service of the terminal; the access network equipment sends a first service request message to the AMF equipment, and the first service request message comprises: the access network equipment receives an RRC establishment completion message sent by the terminal, wherein the RRC establishment completion message carries a second service request message sent by the terminal; the access network device sends a first service request message to the AMF device.

Based on the second aspect, in some possible embodiments, before the access network device establishes an RRC connection with the terminal for performing the voice service, the method further includes: the access network equipment receives a paging message sent by the AMF equipment, wherein the paging message carries a paging reason, and the paging reason is a called voice service of a terminal; and the access network equipment sends the paging message to the terminal.

Based on the second aspect, in some possible embodiments, the third indication or the fourth indication is obtained by the terminal based on a paging reason.

In a third aspect, the present application provides a communication method, including: the terminal receives a paging message from the access network equipment, wherein the paging message carries a paging reason, and the paging reason is called voice service of the terminal; and the terminal sends a second service request message to the access network equipment according to the paging reason.

Based on the third aspect, in some possible embodiments, the terminal sends the second service request message according to the paging reason, including: in the process of establishing the RRC connection, the terminal sends an RRC setup complete (RRC setup complete) message to the access network device, where the RRC setup complete message carries a second service request message, the second service request message carries a third indication, and the third indication is obtained based on a paging reason.

Based on the third aspect, in some possible embodiments, before the terminal sends the second service request message according to the paging reason, the method further includes: and the terminal sends an RRC establishment request message to the access network equipment in the process of establishing the RRC connection, wherein the RRC establishment request message carries a fourth indication, and the fourth indication is obtained based on the paging reason.

In a fourth aspect, the present application provides a communication device, which may be a chip or a system on a chip in an AMF device, and may also be a functional module in the AMF device for implementing the method according to the first aspect or any possible implementation manner of the first aspect. For example, the communication device includes: a first receiving module, configured to receive a first service request message from an access network device, where the first service request message is used to request a service of a terminal in a 5G network; a first processing module, configured to determine that the first service request message is triggered by a voice service of the terminal; the first sending module is used for sending a fallback instruction to the access network device, where the fallback instruction is used for instructing the access network device to fallback the voice service of the terminal from the 5G network to the 4G network.

Based on the fourth aspect, in some possible embodiments, the first sending module is configured to carry the fallback indication in the initial context setup request message, and send the initial context setup request message to the access network device.

Based on the fourth aspect, in some possible embodiments, the apparatus further includes: a second receiving module, configured to receive a downlink data notification of the terminal before the first receiving module receives the first service request message from the access network device; the first sending module is further configured to page the terminal according to the downlink data notification.

Based on the fourth aspect, in some possible embodiments, the first processing module is specifically configured to determine that the first service request message is triggered by a called voice service of the terminal according to a paging reason of the paging.

Based on the fourth aspect, in some possible embodiments, the first sending module is specifically configured to send a paging message to the access network device, where the paging message carries a paging reason, and the paging reason is a called voice service of the terminal.

Based on the fourth aspect, in some possible embodiments, the first service request message carries a first indication, where the first indication is used to indicate a paging cause; the first processing module is specifically configured to determine, according to a first indication carried in the first service request message, that the first service request message is triggered by a called voice service of the terminal.

Based on the fourth aspect, in some possible embodiments, the first service request message carries a second indication, where the second indication is used to indicate that the first service request message is triggered by a calling voice service of the terminal; the first processing module is specifically configured to determine, according to the second indication carried in the first service request message, that the first service request message is triggered by the calling voice service of the terminal.

In a fifth aspect, the present application provides a communication apparatus, which may be a chip or a system on a chip in an access network device, and may also be a functional module in the access network device for implementing the method according to the second aspect or any possible implementation manner of the second aspect. For example, the communication device includes: a second sending module, configured to send a first service request message to the AMF device after establishing an RRC connection for performing a voice service with the terminal, where the first service request message is used to request the message to perform a service of the terminal in the 5G network; the third receiving module is used for receiving a fallback indication sent by the AMF equipment; and the second processing module is used for dropping the voice service of the terminal from the 5G network to the 4G network according to the drop-back instruction.

Based on the fifth aspect, in some possible embodiments, the third receiving module is specifically configured to receive an initial context setup request message sent by the AMF device, where the initial context setup request message carries a fallback indication.

Based on the fifth aspect, in some possible embodiments, the above apparatus further includes: a fourth receiving module, configured to receive an RRC establishment complete message from the terminal in a process of establishing an RRC connection, where the RRC establishment complete message carries a second service request message, and the second service request message carries a third indication, where the third indication is used to indicate that the second service request is triggered by a voice service of the terminal; and a second sending module, configured to send the first service request message to the AMF device according to the second service request message.

Based on the fifth aspect, in some possible embodiments, the above apparatus further includes: a fourth receiving module, configured to receive an RRC establishment request message from the terminal in a process of establishing an RRC connection, where the RRC establishment request message carries a fourth indication, and the fourth indication indicates that the RRC establishment request message is triggered by a voice service of the terminal; receiving an RRC establishment completion message sent by the terminal, wherein the RRC establishment completion message carries a second service request message sent by the terminal; a second sending module, configured to send the first service request message to the AMF device.

Based on the fifth aspect, in some possible embodiments, the third receiving module is configured to receive a paging message sent by the AMF device before establishing an RRC connection for performing a voice service with the terminal, where the paging message carries a paging reason, and the paging reason is a called voice service of the terminal; the above-mentioned device still includes: and the third sending module is used for sending the paging message to the terminal.

Based on the fifth aspect, in some possible embodiments, the third indication or the fourth indication is obtained by the terminal based on a paging reason.

In a sixth aspect, the present application provides a communication device, which may be a chip or a system on a chip in a terminal, and may also be a functional module in the terminal for implementing the method according to the third aspect or any possible implementation manner of the third aspect. For example, the communication device includes: a fifth receiving module, configured to receive a paging message from the access network device, where the paging message carries a paging reason, and the paging reason is a called voice service of the terminal; and a fourth sending module, configured to send the second service request message according to the paging reason.

Based on the sixth aspect, in some possible embodiments, the fourth sending module is specifically configured to send an RRC setup complete (RRC setup complete) message to the access network device in a process of establishing an RRC connection, where the RRC setup complete message carries a second service request message, the second service request message carries a third indication, and the third indication is obtained based on a paging reason.

Based on the sixth aspect, in some possible embodiments, the fourth sending device is further configured to send, before the access network device sends the second service request message according to the paging reason, an RRC establishment request message to the access network device in a process of establishing an RRC connection, where the RRC establishment request message carries a fourth indication, and the fourth indication is obtained based on the paging reason.

In a seventh aspect, the present application provides a communications apparatus, comprising: a processor and a memory; a processor is coupled to the memory, the processor being configured to read and execute instructions in the memory to implement the communication method according to any of the possible embodiments of the first, second or third aspect.

In an eighth aspect, the present application provides a communication system, comprising: the system comprises a terminal, AMF equipment and access network equipment;

an AMF device for performing the communication method as described in the first aspect or any possible implementation manner of the first aspect; an access network device for performing the communication method according to the second aspect or any of the possible embodiments of the second aspect; and (4) a terminal. For performing a communication method as described in the third aspect or any possible implementation manner of the third aspect.

In a ninth aspect, the present application provides a computer-readable storage medium storing instructions for performing the communication method according to the first to tenth aspects or any possible implementation manner thereof when the instructions are executed on a computer.

In a tenth aspect, the present application provides a computer program or a computer program product, which when executed on a computer, causes the computer to implement the communication method as described in the first to tenth aspects or any possible implementation thereof.

It should be understood that the fourth to tenth aspects of the present application are consistent with the technical solutions of the first to third aspects of the present application, and the beneficial effects achieved by the aspects and the corresponding possible embodiments are similar, and are not described again.

In the technical solutions provided in all the above aspects, the access network device is a base station.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be described below.

Fig. 1 is a schematic structural diagram of a communication system in an embodiment of the present application;

fig. 2 is a flowchart illustrating a communication method according to an embodiment of the present application;

fig. 3 is a schematic flow chart of a method of a calling voice service in an embodiment of the present application;

fig. 4 is a flowchart illustrating a method of a called voice service in an embodiment of the present application;

fig. 5 is a schematic structural diagram of a communication device in an embodiment of the present application;

fig. 6 is a schematic structural diagram of a communication device in the embodiment of the present application;

fig. 7 is a schematic structural diagram of a communication device in an embodiment of the present application;

fig. 8 is a hardware diagram of an AMF device/access network device in an embodiment of the present application;

fig. 9 is a schematic structural diagram of an access network device in an embodiment of the present application.

Detailed Description

The embodiments of the present application will be described below with reference to the drawings. In the following description, if one or more specific method steps are described, the corresponding apparatus may comprise one or more units, such as functional units, to perform the described one or more method steps (e.g., a unit performs one or more steps, or a plurality of units, each of which performs one or more of the plurality of steps), even if such one or more units are not explicitly described or illustrated in the figures. On the other hand, for example, if a particular apparatus is described based on one or more units, such as functional units, the corresponding method may comprise one step to perform the functionality of the one or more units (e.g., one step performs the functionality of the one or more units, or multiple steps, each of which performs the functionality of one or more of the plurality of units), even if such one or more steps are not explicitly described or illustrated in the figures. Further, it is to be understood that features of the various exemplary embodiments and/or aspects described herein may be combined with each other, unless explicitly stated otherwise.

In a 4G (fourth generation mobile communication technology) network, when a User Equipment (UE) initiates a voice service, there are two ways: voice over long-term evolution (VoLTE) and circuit switched fallback (CS fallback). For the CS fallback mode, when initiating a voice service, the UE may carry an Extended Service Request (ESR) to the core network device, and directly initiate the CS fallback.

Two voice access methods are defined in a 5G (fifth generation mobile communication technology) network: new radio over new radio (VoNR) and evolved packet system fallback (EPS fallback). The VoNR scheme is that a 5G access network and a core network provide voice services based on an IP Multimedia Subsystem (IMS), and the EPS fallback scheme is that a UE falls back to an EPS (fourth generation mobile communication technology (4G)) when initiating an IMS call on the 5G network, and the voice services are implemented through the 4G network.

An embodiment of the present application provides a communication system, in which a 4G network and a 5G network may coexist, and a UE may perform interworking through the 4G communication network and the 5G communication network. Fig. 1 is a schematic structural diagram of a communication system in the embodiment of the present application, and referring to fig. 1, the 4G network may be a Long Term Evolution (LTE) network. The 4G communication network includes a 4G access network and a 4G Core Network (CN), the 4G core network may be an EPC network, and the 4G access network may include an evolved-universal terrestrial radio access network (E-UTRAN). In a 4G network, the UE, E-UTRAN, and EPC may constitute an Evolved Packet System (EPS). In the 4G core network, a Mobility Management Entity (MME), a Serving Gateway (SGW), a packet data network gateway (PGW), a Policy and Charging Rules Function (PCRF) device, and a Home Subscriber Server (HSS) may be included.

The 5G communication network may include a 5G Access Network (AN) and a 5G core network (5 GC). The 5G access network may include a next generation radio access network (NG RAN). The 5G core network may include: an AMF device, a User Plane Function (UPF) device, a Session Management Function (SMF) device, a Policy Control Function (PCF) device, a Unified Data Management (UDM) device, and the like.

Referring to fig. 1, the HSS and the UDM may be deployed in a unified manner, denoted by HSS + UDM. Specifically, a function of the UDM may be added in the HSS, or a function of the HSS may be added in the UDM, or the functions of the HSS and the UDM may be simultaneously implemented in another device. Of course, the HSS and the UDM may also be separately deployed and communicatively connected, and the embodiment of the present application is not limited.

The PCRF and the PCF can be deployed in a unified way and are represented by PCRF + PCF. Specifically, a PCF function may be added to the PCRF, or a PCRF function may be added to the PCF, or another device may implement the functions of the PCRF and the PCF at the same time. Certainly, the PCRF and the PCF may also be separately deployed and communicatively connected, which is not limited in this embodiment of the present application.

The SMF and PGW-C (PGW control plane function) may be deployed in combination, denoted as SMF + PGW-C. Specifically, the function of PGW-C may be added to SMF, or the function of SMF may be added to PGW-C, or the functions of SMF and PGW-C may be simultaneously implemented in another device. Of course, the SMF and the PGW-C may also be separately deployed and communicatively connected, and the embodiment of the present application is not limited.

UPF and PGW-U (PGW user plane function) can be deployed in a unified way and are represented by UPF + PGW-C. Specifically, the function of the PGW-U may be added to the UPF, or the UPF function may be added to the PGW-U, or the UPF and PGW-U functions may be simultaneously implemented in another device. Of course, the UPF and the PGW-U may also be separately deployed and communicatively connected, and the embodiment of the present application is not limited.

The 4G network and the 5G network may further include other devices, and the embodiment of the present application is not particularly limited.

In the above communication system, the UE may access the 5G core network through a 3rd generation partnership project (3 GPP) technology and/or a non-3GPP technology. Specifically, the UE may access the 5G core network through the 3GPP access network device, or may access the 5G core network through the non-3GPP access network device and the gateway device. In this embodiment, the non-3GPP access network device may be a Wireless Access Point (WAP) in a Wireless Local Area Network (WLAN), an access device in Worldwide Interoperability for Microwave Access (WiMAX), a switch or a router of a Code Division Multiple Access (CDMA) network, and the like. The gateway device may be a non-3GPP interworking function (N3 IWF) device, and the like.

In the above communication system, the UDM device has a function of unified data management. The system is mainly responsible for functions of managing subscription data, user access authorization and the like.

The PCF device has a policy control function, and is mainly responsible for policy decisions related to charging policies, QoS bandwidth guarantees, policies, and the like for sessions and service flows. In the framework, PCFs connected to the AMF device and the SMF device respectively correspond to an AM PCF (PCF for Access and Mobility Control) and an SM PCF (PCF for Session Management), and may not be the same PCF entity in an actual deployment scenario.

The SMF device has a session management function, and mainly performs functions such as session management, execution of control policies issued by the PCF, selection of the UPF, and allocation of an Internet Protocol (IP) address of the UE.

The AMF equipment has access and mobility management functions, and mainly has the functions of mobility management, access authentication/authorization and the like. In addition, the method is also responsible for transferring the user policy between the UE and the PCF.

The UPF device is a user plane functional entity and is used as an interface with a data network to complete functions of user plane data forwarding, session/stream level-based charging statistics, bandwidth limitation and the like.

The functions of each interface are described as follows:

n7: the interface between the PCF and the SMF is used to issue control policies for Packet Data Unit (PDU) session granularity and traffic data stream granularity.

N3: a communication interface between the UPF + PGW-U and the NG-RAN.

N15: and the interface between the PCF and the AMF is used for issuing the UE strategy and the access control related strategy.

N4: the interface between the SMF and the UPF is used for transmitting information between the control plane and the user plane, and comprises the control of issuing of forwarding rules, QoS control rules, flow statistic rules and the like facing the user plane and the information reporting of the user plane.

N11: and the interface between the SMF and the AMF is used for transmitting PDU session tunnel information between the RAN and the UPF, transmitting control information sent to the UE, transmitting radio resource control information sent to the RAN and the like.

N2: and the interface between the AMF and the RAN is used for transmitting radio bearer control information from the core network side to the RAN and the like.

N1: the interface between the AMF and the UE, access independence, is used to deliver QoS control rules to the UE, etc.

N8: and the interface between the AMF and the UDM is used for acquiring the subscription data and the authentication data related to access and mobility management from the UDM by the AMF, registering the current mobility management related information of the UE from the UDM by the AMF and the like.

N10: and the interface between the SMF and the UDM is used for acquiring the subscription data related to the session management from the SMF to the UDM, registering the related information of the current session of the UE from the SMF to the UDM, and the like.

N26: and an interface between the MME and the AMF, which is used for transmitting the mobility management state and the session management state between the source network and the target network in the interoperation process of the 4G network and the 5G network.

S6 a: communication interface between MME and HSS + UDM.

S11: a communication interface between the MME and the SGW.

S1-MME: a communication interface between the MME and the E-UTRAN.

S1-U: a communication interface between the E-UTRAN and the SGW.

S5-C: a control plane communication interface between the SGW and the SMF + PGW-C.

S5-U: and a communication interface of the user plane between the SGW and the UPF + PGW-U.

It should be noted that the UE in the embodiment of the present application is a terminal device with a wireless communication function, and may be deployed on land, including indoors or outdoors, handheld, wearable, or vehicle-mounted; can also be deployed on the water surface (such as a ship and the like); and may also be deployed in the air (e.g., airplanes, balloons, satellites, etc.). The terminal device may be a mobile phone (mobile phone), a tablet computer (Pad), a computer with a wireless transceiving function, a Virtual Reality (VR) terminal device, an Augmented Reality (AR) terminal device, a wireless terminal in industrial control (industrial control), a wireless terminal in self-driving (self-driving), a wireless terminal in remote medical (remote medical), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), and the like. The terminal device may also be a handheld device having wireless communication capabilities, a vehicle mounted device, a wearable device, a computing device or other processing device connected to a wireless modem, or the like. The terminal devices may be called different names in different networks, for example: a terminal device, an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent or user device, a cellular telephone, a cordless telephone, a Session Initiation Protocol (SIP) telephone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a terminal device in a 5G network or a future evolution network, etc.

In the communication system shown in fig. 1, functions and interfaces of the respective devices are merely exemplary, and not all functions of the respective devices are necessary when applied to the embodiments of the present application. All or part of the devices of the core network may be physical devices, or may be virtualized devices, which is not limited herein. Of course, the communication system in the embodiment of the present application may further include other devices not shown in fig. 1, which is not limited herein.

First, it should be noted that, in the embodiment of the present application, "and/or" is only one kind of association relation describing an association object, and indicates that three kinds of relations may exist. For example, a and/or B, may represent: a exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the present application, "a plurality" means two or more than two.

At present, in a 5G network, due to problems such as capability of a base station, deployment of a wireless network, and the like, a UE may not be able to perform a voice service in a VoNR manner in the 5G network, and then, in order to implement the voice service of the UE, the network may execute an EPS fallback for the UE. In the EPS fallback scheme, a User Equipment (UE) registers to 5G first, establishes an IMS PDU session (session), and successfully registers in the IMS, and then the UE enters an idle (idle) state. When there is voice service, the terminal tries to establish a quality of service flow (QoS flow) for the voice service in the 5G network, and executes EPS fallback after the NG RAN of the 5G network refuses to establish the QoS flow. However, the above procedure of attempting to establish the QoS flow may additionally add unnecessary delay and increase signaling overhead.

In order to solve the above problem, embodiments of the present application provide a communication method, which may be applied to a 5G network, and the 5G network and a 4G network may interoperate. Hereinafter, if not specifically stated, the access network device refers to an access network device of a 5G network, such as a base station (e.g., a gNB) of the 5G network.

Then, fig. 2 is a schematic flowchart of a communication method in an embodiment of the present application, and referring to fig. 2, the method may include:

s201: a terminal (UE) establishes RRC connection for voice service with access network equipment;

in the embodiment of the present application, the voice service of the terminal refers to a calling voice service initiated by the terminal, and may also refer to a called voice service of a calling terminal.

In some possible embodiments, the UE may be a UE registered on a 5G network.

S202: the UE sends a second Service Request (SR) message to the access network equipment;

the second SR message is triggered by the UE according to the calling voice service or the called voice service.

S203: the access network equipment sends a first SR message to the AMF equipment according to the second SR message;

the first SR message may be a second SR message transparently transmitted by the access network device, or the first SR message may also be an SR message generated by the access network device in response to the second SR message.

S204: the AMF equipment determines that the first SR message is triggered by the voice service of the UE;

since the first SR message is obtained by the access network device according to the second SR message, the second SR message is triggered by the UE according to the calling voice service or the called voice service, and it can be understood that the first SR message is also triggered by the UE according to the calling voice service or the called voice service.

S205: the AMF equipment sends a fallback indication to the access network equipment;

s206: and the access network equipment drops the voice service of the UE from 5G to 4G according to the drop-back indication.

The access network equipment can send a switching request to the AMF equipment, the AMF equipment responds to the switching request to start a switching process, and the UE is switched to the 4G network, so that the UE can perform voice service in the 4G network; or, the access network device may further send a redirection request to the AMF device, and the AMF device starts a redirection procedure in response to the redirection request, and redirects the UE to the 4G network, so that the UE may perform a voice service in the 4G network.

The communication method will be described below with reference to the communication system.

First, in a calling scenario, a voice service flow of the UE is described.

Fig. 3 is a schematic flow chart of a method of a calling voice service in an embodiment of the present application, and referring to fig. 3, the method may include:

s301: UE random access to a gNB (access network equipment);

after the UE is started, the UE is attached to the 5G network, then an IMS PDU session is established and registered in an IMS, and the UE enters an idle state. The UE in idle state first triggers the establishment of an RRC connection with the NG RAN before it is ready to initiate IMS voice services to another UE. The UE sends a random access preamble (random access preamble) to the gNB, and monitors a Physical Downlink Control Channel (PDCCH) in an RAR time window (RA response window) to receive a random access response RAR corresponding to a radio network temporary identity (RA-RNTI). And the UE accesses the gNB after receiving the RAR.

S302: the UE sends an RRC setup request (RRC setup request) message to the gNB;

s303: RRC setup (RRC setup) message sent by the gNB to the UE;

s304: the UE sends an RRC setup complete (RRC setup complete) message to the gNB;

wherein, the RRC setup complete may carry a second SR message.

In some possible embodiments, to inform the AMF device that it is ready to initiate the calling IMS voice service, the UE may configure an RRC establishment cause (RRC initialization cause) in the RRC setup request as a fourth indication (e.g., MO-VoiceCall) and carry in the RRC setup request of S302 to inform the gNB that the UE is ready to initiate the IMS calling voice service. Here, the fourth indication is for indicating that the RRC setup request is triggered by the calling voice service of the UE.

In other possible embodiments, in order to inform the AMF device that the current SR message flow is triggered by the UE 'S calling voice service, that is, the second SR message is triggered by the UE' S calling voice service, the UE may further send a third indication (e.g., MO-VoiceCall) to the gNB in the RRC setup complete of S304. Here, the third indication indicates that the second SR message is triggered by the calling voice service of the UE.

So far, the UE and the gNB complete establishing RRC connection, and the UE enters a connected state (connection).

S305: the gNB sends a first SR message to the AMF equipment;

the first SR message may carry a second indication, where the second indication may be used to indicate that the first SR message is triggered by a calling service of the terminal, and the second indication may be MO-VoiceCall.

And after determining that the second SR message is triggered by the calling voice service of the UE according to the second SR message sent by the UE, the gNB sends the first SR message to the AMF equipment.

In some possible embodiments, through the above S301 to S304, the UE sends a fourth indication (i.e., MO-VoiceCall) to the gNB in the process of establishing the RRC connection with the gNB, and after receiving the fourth indication, the gNB may directly pass the fourth indication (e.g., the second indication) to the AMF device; or the gNB may further create a second indication according to the fourth indication, which is not specifically limited in this embodiment of the application.

S306: the AMF equipment determines that the first SR message is triggered by calling voice service of the UE;

after receiving the first SR message, the AMF device may determine that the current SR message flow is triggered by the calling voice service of the UE according to a second indication, that is, MO-VoiceCall, carried in the first SR message, and then the AMF device determines to drop the calling voice service of the UE from the 5G network to the 4G network, that is, perform EPS fallback on the calling voice service of the UE.

In practical application, for a UE supporting a 5G network, the AMF device may execute an EPS fallback on a voice service of the UE, that is, after determining that the first SR message is triggered by a calling voice service of the UE, the AMF device may instruct the gNB to execute the EPS fallback on the calling voice service of the UE, and then the AMF device executes S307.

S307: the AMF equipment sends a fallback indication to the gNB;

in some possible embodiments, the AMF device may carry a fallback indication, such as an EPS fallback indicator, in an initial context setup request (initial context setup request) and send the initial context setup request to the gNB.

In other embodiments of the present application, the AMF device may determine whether to execute the EPS fallback on the calling voice service of the UE according to other policies, such as the capability of the gNB, the operating state, the operator policy, the deployment of the wireless network, and the like, in addition to executing the EPS fallback on the calling voice service of the UE, if yes, execute S307, and if no, the AMF device may further send a request message to the gNB to request to establish a QoS Flow for the calling voice service for the UE, so as to complete the calling voice service of the UE in the 5G network.

For example, if the AMF device learns that the UE only supports VoNR, the AMF device determines not to execute EPS fallback on the calling voice service of the UE; or, if the AMF device learns that the gNB only supports the EPS fallback according to the local policy, the AMF device determines to execute the EPS fallback on the calling voice service of the UE. And if the AMF equipment learns that the gNB is in an overload state, executing EPS fallback on calling voice service of the UE.

Of course, the AMF device may also determine whether to execute EPS fallback on the calling voice service of the UE according to other conditions, which is not specifically limited herein.

S308: the gNB initiates a switching process or a redirection process according to the fallback indication;

and the gNB sends RRC reconfiguration to the UE, and modifies RRC connection so that the UE is switched or redirected to the EPC.

S309: UE switches or redirects to EPS;

and the UE performs switching or redirection according to the RRC reconfiguration, and then sends an RRC reconfiguration complete to the gNB to complete the RRC reconfiguration.

S310: and the UE initiates the IMS voice service in the EPS.

The above is the calling voice service flow for the UE to initiate a voice call. When the UE is in an idle state, in a scenario where the calling voice service triggers the EPS fallback, by reducing the process of establishing the QoS Flow with voice 5QI ═ 1 at 5GC, the call establishment delay of the EPS fallback is shortened, and network resources are also saved.

Next, in a called scenario, a voice service flow of the UE will be described.

Fig. 4 is a schematic flow chart of a method of called voice service in the embodiment of the present application, and referring to fig. 4, the method may include:

s401: the UPF equipment receives a downlink message sending request (SIP INVITE) from the IMS;

when needing to call the UE, the calling UE may initiate a call on the 5G network or the 4G network, and the IMS domain sends a downlink packet sending request to the 5GC of the called UE, where the request includes SIP INVITE message.

S402: if the UPF equipment can not be connected to the UE, sending a Downlink Data Notification (DDN) message to the SMF equipment;

in some possible embodiments, if the UPF device supports a Paging Policy Differentiation (PPD) function, and if the SMF device activates it for this N4 session, the UPF device may also include a Differentiated Services Code Point (DSCP) in a type of service (TOS) (IPv4) or Text Contract (TC) (IPv6) value from an Internet Protocol (IP) header of a downlink message and send the DSCP to the SMF device carried in a DDN.

S403: the SMF equipment informs the AMF equipment of the downlink service of the UE according to the DDN message;

in some possible embodiments, if the DDN sent by the UPF device to the SMF device carries a DSCP, the SMF device may determine a Paging Policy Indicator (PPI) according to the DSCP, and send the PPI to the AMF device by carrying the PPI in an N11 message, so that the AMF device knows that there is a voice service of the UE according to the PPI.

Optionally, the SMF device may further carry, in the N11 message, an Allocation Retention Priority (ARP), a 5QI, and the like corresponding to the downlink service of the UE. Then, the AMF device may also be aware of the IMS voice service of the UE according to, for example, 5QI ═ 5.

S404: the AMF equipment determines that the downlink service is an IMS voice service;

the AMF device determines that the downlink service is the IMS Voice service according to PPI or 5QI ═ 5, and then the AMF device may determine that the paging cause of the paging is the called Voice service of the UE, and may set the value of the paging cause as MT-Voice. In practical application, the AMF device may also confirm that the downlink service of the UE is the IMS voice service in other manners, which is not specifically limited in the embodiment of the present application.

S405: AMF equipment pages (paging) UE and sends paging message to gNB;

the AMF device sends a paging message to the gNB, where the paging reason (MT-Voice) can be carried in the paging message to inform the UE that the paging is due to its own called Voice service.

S406: the gNB sends the paging message to the UE;

s407: the UE sends RRC setup request to the gNB;

s408: the gNB sends RRC setup to the UE;

s409: the UE sends RRC setup complete to the gNB;

wherein, the RRC setup complete may carry a second SR message.

In some possible embodiments, in order to inform the AMF device that the current SR message flow is triggered by the called IMS voice service of the UE, the UE may configure an RRC establishment cause (RRC initialization cause) in the RRC setup request as a fourth indication (e.g., MT-VoiceCall) and carry the fourth indication in the RRC setup request of S407. Here, the fourth indication is for indicating that the RRC setup request is triggered by the called voice service of the UE.

In other possible embodiments, in order to inform the AMF device that the current SR message flow is triggered by the called voice service of the UE, that is, the second SR message is triggered by the called voice service of the UE, the UE may further send a third indication (e.g., MT-VoiceCall) to the gNB in the RRC setup complete of S409. Here, the third indication indicates that the second SR message is triggered by the called voice service of the UE.

It should be noted that the third indication and the fourth indication may correspond to different specific values in different voice service scenarios. For example, in a calling voice service scenario, the values of the third indication and the fourth indication may be MO-VoiceCall, and in a called voice service scenario, the values of the third indication and the fourth indication may be MT-VoiceCall.

To this end, the UE and the gNB complete establishing RRC connection, and the UE is in a connected state (connection).

S410: the gNB sends a first SR message to the AMF equipment;

the first SR message may carry a first indication (MT-VoiceCall), where the first indication is used to indicate a paging reason of the current paging.

And after determining that the second SR message is triggered by the called voice service of the UE according to the first indication sent by the UE, the gNB sends the first SR message to the AMF equipment.

In some possible embodiments, through the above S407 to S409, the UE sends a third indication or a fourth indication (MT-VoiceCall) to the gNB in the process of establishing the RRC connection with the gNB, and after receiving the third indication or the fourth indication, the gNB may directly pass the third indication or the fourth indication through to the AMF device; or, the gNB may further create the first indication according to the third indication or the fourth indication, which is not specifically limited in this embodiment of the application.

S411: the AMF equipment determines that the first SR message is triggered by called voice service of the UE;

after receiving the first SR message, the AMF device, according to the first indication, namely MT-

The VoiceCall can determine that the current SR message flow is triggered by the called voice service of the UE, and then the AMF device determines that the called voice service of the UE falls back to the 4G network from the 5G network, that is, performs EPS fallback on the called voice service of the UE.

In practical application, for a UE supporting a 5G network, the AMF device may execute an EPS fallback on a voice service of the UE, that is, after determining that the first SR message is triggered by a called voice service of the UE, the AMF device may instruct the gNB to execute the EPS fallback on the called voice service of the UE, and then the AMF device executes S412.

S412: the AMF equipment sends a fallback indication to the gNB;

in some possible embodiments, the AMF device may carry a fallback indication, such as an EPS fallback indicator, in the initial context setup request and send the initial context setup request to the gNB.

In other embodiments of the present application, the AMF device may determine whether to execute the EPS fallback on the called voice service of the UE according to other policies, such as the capability of the gNB, the operating state, operator policies, deployment of a wireless network, and the like, in addition to executing the EPS fallback on the called voice service of the UE, if so, execute S412, and if not, the AMF device may also send a request message to the gNB to request to establish a QoS Flow for the called voice service for the UE, so as to complete the called voice service of the UE in the 5G network.

The process of determining whether to execute the EPS fallback on the called voice service of the UE by the AMF device according to the policy is similar to the process of determining whether to execute the EPS fallback on the calling voice service of the UE by the AMF device according to the policy in the above embodiment, and is not described herein again.

S413: the gNB initiates a switching process or a redirection process according to the fallback indication;

s414: UE switches or redirects to EPC;

s415: the PGW-U sends SIP INVITE to the UE through the EPC;

s416: the UE responds SIP INVITE to conduct the called voice service on the EPC.

The called voice service process for initiating the voice call for the UE is described above. When the UE is in an idle state, in a scenario where the called voice service needs an EPS fallback, by reducing the process of establishing QoS Flow with voice 5QI of 1 at 5GC, the call establishment delay of the EPS fallback is shortened, and meanwhile, network resources are saved.

In other embodiments of the present application, in S404, the AMF device determines that the paging reason of the current paging is the called voice service of the UE, and then, the AMF device may record the paging reason of the current paging, and after S404, the AMF device may not carry the paging reason in the paging message when executing S405. Then, in the following procedure of establishing the RRC connection S407 to S409, the UE may not send the third indication and/or the fourth indication to the gNB, but send a second SR message in a common format to the gNB, so that the gNB can determine that the second SR message is triggered by the service of the UE, but it is not clear which service is. And the gNB sends a first SR message to the AMF equipment according to the second SR message, and at the moment, the first SR message does not carry the first indication.

Accordingly, S411 may include: the AMF device determines that the first SR message is triggered by the called voice service of the UE according to the local record. It can be understood that, after receiving the first SR message, the AMF device may query the local record to obtain the paging reason corresponding to the UE, so as to know that the first SR message is triggered by the called voice service of the UE, and then execute S412 to S416 to drop the called voice service of the UE from the 5G network to the 4G network, which is not described herein again in detail.

In some possible embodiments, in S404, the AMF device records the paging reason of the current paging, and may carry the paging reason in the paging message when performing S405, and in the process of establishing the RRC connection in the following S407 to S409, the UE may not send the third indication and/or the fourth indication to the gNB, but send the second SR message in the general format to the gNB. In this way, the gNB can determine that the second SR message is triggered by the UE's traffic, but it is not clear which traffic is. And the gNB sends the first SR message to the AMF device according to the second SR message, and at this time, the first SR message does not carry the first indication either. Accordingly, S411 may include: the AMF device determines that the first SR message is triggered by the called voice service of the UE according to the local record, that is, the paging reason obtained by the previous record, and as can be understood, after receiving the first SR message, the AMF device may query the local record to obtain the paging reason corresponding to the UE, so as to know that the first SR message is triggered by the called voice service of the UE, and then execute S412 to S416 to drop the called voice service of the UE from the 5G network to the 4G network, which is not described herein again.

As can be seen from the above, the AMF device may record the paging reason of the current paging when performing S404, and thus, the AMF device may not notify the UE of the paging reason when paging the UE, so that the UE is transparent to the whole process of determining to execute the EPS fallback, and the influence on the UE is reduced.

Based on the same inventive concept, the present application further provides a communication device, which may be a chip or a system on a chip in an AMF device, and may also be a functional module in the AMF device for implementing the method described in the foregoing embodiments and any possible implementation manner thereof. For example, fig. 5 is a schematic structural diagram of a communication device in the embodiment of the present application, and referring to fig. 5, the communication device 500 may include: a first receiving module 501, configured to receive a first service request message from an access network device, where the first service request message is used to request a service of a terminal in a 5G network; a first processing module 502, configured to determine that the first service request message is triggered by a voice service of the terminal; a first sending module 503, configured to send a fallback indication to the access network device, where the fallback indication is used to indicate the access network device to fallback the voice service of the terminal from the 5G network to the 4G network.

In some possible embodiments, the first sending module is configured to carry the fallback indication in the initial context setup request message, and send the initial context setup request message to the access network device.

In some possible embodiments, the apparatus further comprises: a second receiving module, configured to receive a downlink data notification of the terminal before the first receiving module receives the first service request message from the access network device; the first sending module is further configured to page the terminal according to the downlink data notification.

In some possible embodiments, the first processing module is specifically configured to determine, according to a paging cause of the paging, that the first service request message is triggered by a called voice service of the terminal.

In some possible embodiments, the first sending module is specifically configured to send a paging message to the access network device, where the paging message carries a paging cause, and the paging cause is a called voice service of the terminal.

In some possible embodiments, the first service request message carries a first indication, where the first indication is used to indicate a paging cause; the first processing module is specifically configured to determine, according to a first indication carried in the first service request message, that the first service request message is triggered by a called voice service of the terminal.

In some possible embodiments, the first service request message carries a second indication, where the second indication is used to indicate that the first service request message is triggered by a calling voice service of the terminal; the first processing module is specifically configured to determine, according to the second indication carried in the first service request message, that the first service request message is triggered by the calling voice service of the terminal.

In the embodiment of the present application, the first transmitting module may be a transmitting circuit, a transmitting interface, or a transmitter; the first receiving module and the second receiving module can be a receiving circuit, a receiving interface or a receiver; the first processing module may be one or more processors.

Based on the same inventive concept, embodiments of the present application provide a communication apparatus, which may be a chip or a system on a chip in an access network device, and may also be a functional module in the access network device for implementing the method described in the foregoing embodiments and any possible implementation manner thereof. For example, fig. 6 is another schematic structural diagram of a communication device in the embodiment of the present application, and referring to fig. 6, the communication device 600 may include: a second sending module 601, configured to send a first service request message to the AMF device after establishing an RRC connection for performing a voice service with the terminal, where the first service request message is used to request the message to perform a service of the terminal in the 5G network; a third receiving module 602, configured to receive a fallback indication sent by the AMF device; the second processing module 603 is configured to drop the voice service of the terminal from the 5G network to the 4G network according to the drop indication.

In some possible embodiments, the third receiving module is specifically configured to receive an initial context setup request message sent by the AMF device, where the initial context setup request message carries a fallback indication.

In some possible embodiments, the apparatus further comprises: a fourth receiving module, configured to receive an RRC establishment complete message from the terminal in a process of establishing an RRC connection, where the RRC establishment complete message carries a second service request message, and the second service request message carries a third indication, where the third indication is used to indicate that the second service request is triggered by a voice service of the terminal; and a second sending module, configured to send the first service request message to the AMF device according to the second service request message.

In some possible embodiments, the apparatus further comprises: a fourth receiving module, configured to receive an RRC establishment request message from the terminal in a process of establishing an RRC connection, where the RRC establishment request message carries a fourth indication, and the fourth indication indicates that the RRC establishment request message is triggered by a voice service of the terminal; receiving an RRC establishment completion message sent by the terminal, wherein the RRC establishment completion message carries a second service request message sent by the terminal; a second sending module, configured to send the first service request message to the AMF device.

In some possible embodiments, the third receiving module is configured to receive a paging message sent by the AMF device before establishing RRC connection for performing a voice service with the terminal, where the paging message carries a paging cause, and the paging cause is a called voice service of the terminal; the above-mentioned device still includes: and the third sending module is used for sending the paging message to the terminal.

In some possible embodiments, the third indication or the fourth indication is obtained by the terminal based on a paging reason.

In this embodiment of the application, the second sending module and the third sending module may be a sending circuit, a sending interface, or a sender; the third receiving module and the fourth receiving module can be a receiving circuit, a receiving interface or a receiver; the second processing module may be one or more processors.

Based on the same inventive concept, the embodiments of the present application provide a communication device, which may be a chip or a system on a chip in a terminal, and may also be a functional module in the terminal for implementing the method described in the above embodiments and any possible implementation manner thereof. For example, fig. 7 is a schematic structural diagram of a communication device in the embodiment of the present application, and referring to fig. 7, the communication device 700 may include: a fifth receiving module 701, configured to receive a paging message from an access network device, where the paging message carries a paging reason, and the paging reason is a called voice service of a terminal; a fourth sending module 702, configured to send the second service request message according to the paging reason.

In some possible embodiments, the fourth sending module is specifically configured to send an RRC setup complete (RRC setup complete) message to the access network device in a process of establishing an RRC connection, where the RRC setup complete message carries a second service request message, the second service request message carries a third indication, and the third indication is obtained based on a paging reason.

In some possible embodiments, the fourth sending device is further configured to send, before the access network device sends the second service request message according to the paging reason, an RRC setup request (RRC setup request) message to the access network device in a process of establishing an RRC connection, where the RRC setup request message carries a fourth indication, and the fourth indication is obtained based on the paging reason.

In this embodiment of the present application, the fourth sending module may be a sending circuit, a sending interface, or a sender; the fifth receiving module and the second receiving module may be a receiving circuit, a receiving interface, or a receiver.

Based on the same inventive concept, the embodiments of the present application further provide an AMF device and an access network device, which are consistent with the AMF device/access network device described in one or more of the above embodiments. Fig. 8 is a hardware schematic diagram of an AMF device and an access network device in this embodiment, and referring to fig. 8, both the AMF device and the access network device provided in this embodiment of the present application use general-purpose computer hardware, and include a processor 801, a memory 802, a bus 803, an input device 804, and an output device 805.

In some possible implementations, the memory 802 may include computer storage media in the form of volatile and/or nonvolatile memory such as read only memory and/or random access memory. Memory 802 may store an operating system, application programs, other program modules, executable code, program data, user account data, user subscription data, and the like.

An input device 804 may be used to input commands and information to the AMF device/access network device, the input device 804 such as a keyboard or pointing device such as a mouse, trackball, touch pad, microphone, joystick, game pad, satellite dish, scanner, or the like. These input devices may be connected to the processor 801 by a bus 803.

Output device 805 may be used to output information from the AMF device/access network device, and in addition to a monitor, output device 805 may also be provided as other peripheral outputs such as speakers and/or a printing device, which may also be connected to processor 801 via bus 703.

The AMF device/access network device may be connected to a network, such as a Local Area Network (LAN), via network interface 806. In a networked environment, computer-executable instructions stored in the AMF device/access network device may be stored in a remote memory storage device and are not limited to being stored locally.

When the processor 801 in the AMF device executes the executable code or the application program stored in the memory 802, the AMF device performs the method steps on the AMF device side in the above embodiments, such as performing S204, S205, S306, S307, S404, S405, S411, S412, and the like. For a specific implementation process, reference is made to the above embodiments, which are not described herein again.

When the processor 801 in the access network device executes the executable code or application stored in the memory 802, the access network device may perform the method steps on the access network device side in the above embodiments, such as performing steps S203, S206, S303, S305, S308, S309, S406, S408, S410, S413, and the like. For a specific implementation process, reference is made to the above embodiments, which are not described herein again.

Further, the memory 802 stores therein computer-executable instructions for implementing the functions of the first receiving module 501, the first processing module 502, and the first transmitting module 503 in fig. 5. The functions/implementation processes of the first receiving module 501, the first processing module 502 and the first sending module 503 in fig. 5 can be implemented by the processor 801 in fig. 8 calling a computer executing instruction stored in the memory 802, and the specific implementation processes and functions refer to the above related embodiments.

For the embodiment of the access network device, the memory 802 stores computer-executable instructions for implementing the functions of the second sending module 601, the third receiving module 602, and the second processing module 603 in fig. 6. The functions/implementation processes of the second sending module 601, the third receiving module 602 and the second processing module 603 in fig. 6 may be implemented by the processor 801 in fig. 8 calling a computer executing instruction stored in the memory 802, and the specific implementation processes and functions refer to the above related embodiments.

Based on the same inventive concept, an access network device is further provided in the embodiments of the present application, fig. 9 is a schematic structural diagram of the access network device in the embodiments of the present application, and referring to fig. 9, the access network device may be a gNB described in the embodiments above.

The access network equipment may include a transceiver 901 and a controller/processor 902. The transceiver 901 may be used to support transceiving information between the access network device and the UE described in the above embodiments, and to support radio communication between the UE and other UEs. A controller/processor 902 may be used to perform various functions for communicating with the UE or other network devices. In the uplink, uplink signals from the UE are received via the antenna, conditioned by the transceiver 901, and further processed by the controller/processor 902 to recover traffic data and signaling information sent by the UE. On the downlink, traffic data and signaling messages are processed by a controller/processor 902 and conditioned by a transceiver 901 to generate a downlink signal, which is transmitted via an antenna to the UEs. The controller/processor 902 is further configured to perform the communication method as described in the above embodiments, and drop the voice traffic of the UE from the 5G network to the 4G network according to the drop indication sent by the AMF device. The controller/processor 902 may also be configured to perform the processes of fig. 2-4 related to the access network device and/or other processes for the techniques described in the embodiments of the present application, such as sending a first service request message for requesting a service of the terminal in the 5G network to the AMF device after establishing an RRC connection for performing a voice service with the terminal, receiving a fallback indication sent by the AMF device, and dropping the voice service of the terminal from the 5G network to the 4G network according to the fallback indication. The access network equipment may also include memory 903 which may be used to store program codes and data for the access network equipment. The access network device may further comprise a communication unit 904 for supporting the access network device to communicate with other network entities. For example, to support communication between the access network device and the AMF device and the UE.

It will be appreciated that fig. 9 only shows a simplified design of the access network equipment. In practical applications, the access network device may include any number of transmitters, receivers, processors, controllers, memories, communication units, etc., and all access network devices that may implement the embodiments of the present application are within the scope of the embodiments of the present application.

Based on the same inventive concept, embodiments of the present application provide a computer-readable storage medium storing instructions for performing a communication method as described in the above embodiments and any possible implementation manner thereof when the instructions are executed on a computer.

Based on the same inventive concept, the embodiments of the present application provide a computer program or a computer program product, which, when executed on a computer, causes the computer to implement the communication method as described in the above embodiments and any possible implementation manner thereof.

Those of skill in the art will appreciate that the functions described in connection with the various illustrative logical blocks, modules, and algorithm steps described in the disclosure herein may be implemented as hardware, software, firmware, or any combination thereof. If implemented in software, the functions described in the various illustrative logical blocks, modules, and steps may be stored on or transmitted over as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. The computer-readable medium may include a computer-readable storage medium, which corresponds to a tangible medium, such as a data storage medium, or any communication medium including a medium that facilitates transfer of a computer program from one place to another (e.g., according to a communication protocol). In this manner, a computer-readable medium may generally correspond to (1) a non-transitory tangible computer-readable storage medium, or (2) a communication medium, such as a signal or carrier wave. A data storage medium may be any available medium that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementing the techniques described herein. The computer program product may include a computer-readable medium.

By way of example, and not limitation, such computer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. It should be understood, however, that the computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transitory media, but are instead directed to non-transitory tangible storage media. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

The instructions may be executed by one or more processors, such as one or more Digital Signal Processors (DSPs), general purpose microprocessors, Application Specific Integrated Circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Thus, the term "processor," as used herein may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. Additionally, in some aspects, the functions described by the various illustrative logical blocks, modules, and steps described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated in a combined codec. Also, the techniques may be fully implemented in one or more circuits or logic elements.

The techniques of this application may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an Integrated Circuit (IC), or a set of ICs (e.g., a chipset). Various components, modules, or units are described in this application to emphasize functional aspects of means for performing the disclosed techniques, but do not necessarily require realization by different hardware units. Indeed, as described above, the various units may be combined in a codec hardware unit, in conjunction with suitable software and/or firmware, or provided by an interoperating hardware unit (including one or more processors as described above).

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

The above description is only an exemplary embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of communication, comprising:

receiving a first service request message from access network equipment by access and mobility management function (AMF) equipment, wherein the first service request message is used for requesting a service of a terminal in a 5G network;

the AMF device determines that the first service request message is triggered by a voice service of the terminal;

and the AMF equipment sends a fallback indication to the access network equipment, wherein the fallback indication is used for indicating the access network equipment to fallback the voice service of the terminal from the 5G network to the 4G network.

2. The method of claim 1, wherein the AMF device sending a fallback indication to the access network device comprises:

and the AMF equipment carries the fallback indication in an initial context setting request message and sends the initial context setting request message to the access network equipment.

3. The method according to claim 1 or 2, wherein before the AMF device receives the first service request message from the access network device, the method further comprises:

the AMF equipment receives a downlink data notification of the terminal;

and the AMF equipment pages the terminal according to the downlink data notification.

4. The method of claim 3, wherein the AMF device determining that the first service request message is triggered by a voice service of a terminal comprises:

and the AMF equipment determines that the first service request message is triggered by the called voice service of the terminal according to the paging reason of the paging.

5. The method of claim 3, wherein the AMF device pages the terminal, comprising:

and the AMF equipment sends a paging message to the access network equipment, wherein the paging message carries a paging reason, and the paging reason is called voice service of the terminal.

6. The method of claim 5, wherein the first service request message carries a first indication, and wherein the first indication is used for indicating the paging cause;

the determining, by the AMF device, that the first service request message is triggered by a voice service of the terminal includes:

and the AMF equipment determines that the first service request message is triggered by a called voice service of the terminal according to a first indication carried in the first service request message.

7. The method according to any one of claims 1 to 6, wherein the first service request message carries a second indication, and the second indication is used for indicating that the first service request message is triggered by a calling voice service of the terminal;

and the AMF equipment determines that the first service request message is triggered by the calling voice service of the terminal according to a second indication carried in the first service request message.

8. A method of communication, comprising:

after establishing Radio Resource Control (RRC) connection for voice service with a terminal, an access network device sends a first service request message to an access and mobility management function (AMF) device, wherein the first service request message is used for requesting the service of the terminal in a 5G network;

the access network equipment receives a fallback indication sent by the AMF equipment;

and the access network equipment drops the voice service of the terminal from the 5G network to the 4G network according to the drop indication.

9. The method of claim 8, wherein the receiving, by the access network device, the fallback indication sent by the AMF device comprises:

and the access network equipment receives an initial context setting request message sent by the AMF equipment, wherein the initial context request message carries the fallback indication.

10. The method according to claim 8 or 9, characterized in that the method further comprises:

the access network equipment receives an RRC establishment completion message from the terminal in the process of establishing the RRC connection, wherein the RRC establishment completion message carries a second service request message, the second service request message carries a third indication, and the third indication is used for indicating that the second service request is triggered by the voice service of the terminal;

the access network device sends a first service request message to the AMF device, including:

and the access network equipment sends the first service request message to the AMF equipment according to the second service request message.

11. The method according to claim 8 or 9, characterized in that the method further comprises:

the access network equipment receives an RRC establishment request message from the terminal in the process of establishing the RRC connection, wherein the RRC establishment request message carries a fourth indication, and the fourth indication indicates that the RRC establishment request message is triggered by a voice service of the terminal;

the access network equipment receives an RRC establishment completion message sent by the terminal, wherein the RRC establishment completion message carries a second service request message sent by the terminal;

12. The method according to claim 10 or 11, wherein before the access network device establishes the RRC connection with the terminal for conducting the voice service, the method further comprises:

the access network equipment receives a paging message sent by the AMF equipment, wherein the paging message carries a paging reason, and the paging reason is called voice service of the terminal;

and the access network equipment sends the paging message to the terminal.

13. An access and mobility management function, AMF, device, comprising: a processor and a memory; a processor is coupled to the memory, the processor being configured to read and execute instructions in the memory to implement the communication method of claims 1 to 7.

14. An access network device, comprising: a processor and a memory; a processor is coupled to the memory, the processor being configured to read and execute instructions in the memory to implement the communication method of claims 8 to 13.

15. A communication system, comprising: access and mobility management function, AMF, equipment and access network equipment;

the AMF device for performing the communication method of claims 1 to 7;

the access network device configured to perform the communication method according to claims 8 to 13.