CN117177198A - Method, equipment and storage medium for realizing voice service - Google Patents

Abstract

The embodiment of the application relates to the technical field of communication and discloses a method, equipment and a storage medium for realizing voice service, wherein the method for realizing the voice service comprises the steps of obtaining a service request message carrying a first indication representing a service request reason, a second indication representing signal transmission interference intensity and a third indication representing physical resource utilization rate, determining whether an EPS Fallback process is required to be initiated for a terminal voice service according to the service request message, optimizing the EPS Fallback process, and reducing call delay on the premise of reducing network element association under the scene of high interference and high resource utilization rate.

Description

Method, equipment and storage medium for realizing voice service

Technical Field

The embodiment of the application relates to the technical field of communication, in particular to a method, equipment and a storage medium for realizing voice service.

Background

According to the collocation mode of the base station and the core network, 5G (Fifth Generation Mobile Communication Technology ) is divided into two networking types, namely NSA (Non-independent) networking and SA (independent) networking. NSA networking generally refers to coexistence of a wireless side 4G (Fourth Mobile Communication Technology, fourth generation mobile communication technology) base station and a 5G base station, and a core network adopts a networking architecture of a 4G core network or a 5G core network. And SA refers to a networking architecture that a 5G base station is adopted on a wireless side and a 5G core network is adopted on a core network. In the early development stage of 5G, NSA networking scheme is mostly adopted, and SA networking scheme becomes the preference of each operator along with the full coverage and deep optimization of 5G network.

In the initial stage of 5G SA network construction, a Fallback (EPS) flow is used to realize the voice service of User Equipment (UE). After the coverage of the 5G SA network is mature, the voice service of the user equipment is realized by using the new wireless bearing voice (Voice Over New Radio, VONR). The VONR means that voice service based on IMS (IP multiple subsystem, IP multimedia subsystem) is provided by the 5G access network and the core network.

However, even though the 5G SA network has been completely covered and optimized, the voice service carried by the ue by using the VONR method still has the problems of a call setup failure or a large delay, a large jitter, a dropped call, etc. of the voice after the call setup is successful.

Disclosure of Invention

In view of the above problems, embodiments of the present application provide a method for implementing a voice service, an access network device, an access and mobility management function device, and a computer readable storage medium, which are used to solve the problems in the prior art that a voice service call fails to be established or a voice has a large delay, a large jitter, a dropped call, and the like after the establishment is successful.

According to a first aspect of an embodiment of the present application, there is provided a method for implementing a voice service, the method including:

After establishing a Radio Resource Control (RRC) connection for performing voice service with a terminal, an access network device sends a service request message to an access and mobility management function device, wherein the service request message carries a first indication, a second indication and a third indication, the first indication is used for indicating that the service request message is triggered by the voice service of the terminal, the second indication is used for indicating the signal transmission interference strength of a cell where the terminal currently resides in within a preset time, the third indication is used for indicating the physical resource utilization rate of the cell within the preset time, and the service message is used for indicating whether the access and mobility management function device really needs to initiate an EPS fallback procedure for the terminal to realize the voice service;

when the access network equipment receives a fallback instruction from the access and mobility management function equipment, the access network equipment fallback the voice service bearing network of the terminal from a first network to a second network according to the fallback instruction;

and receiving QoS flow establishment instructions from the access and mobility management function equipment at the access network equipment, wherein the access network equipment establishes QoS flow according to the QoS flow establishment instructions so as to instruct the terminal to finish the voice service in the first network.

In an optional manner, before the service request message is sent to the access and mobility management function device, the implementation method further includes:

the access network equipment receives an RRC establishment completion message from a terminal in the process of establishing Radio Resource Control (RRC) connection for voice service with the terminal, wherein the RRC establishment completion message carries the first indication;

the access network equipment determines that the RRC establishment completion message is triggered by the voice service of the terminal according to the received first indication carried in the RRC establishment completion message;

and after determining that the RRC establishment completion message is triggered by the voice service of the terminal, the access network equipment carries the second indication and the third indication in the RRC establishment completion message to obtain the service request message.

In an optional manner, after the access network device determines that the RRC setup complete message is triggered by the voice service of the terminal, the carrying the second indication and the third indication in the RRC setup complete message includes:

after the access network device determines that the RRC establishment complete message is triggered by the voice service of the terminal, the access network device newly adds a second indication bit and the third indication pair bit in the RRC establishment complete message;

The access network equipment acquires the signal transmission interference intensity of a cell where the terminal resides in within a preset time, judges whether the signal transmission interference intensity is higher than a first preset threshold value, if yes, the value of the second indication bit is given to a first value, otherwise, the value of the second indication bit is given to a second value, and the indication on the second indication bit is a second indication;

the access network equipment acquires the physical resource utilization rate of the cell in the preset time, judges whether the physical resource utilization rate is higher than a second preset threshold value, if yes, the value of the third indication bit is given to a first value, otherwise, the value of the second indication bit is given to a second value, and the indication on the third indication bit is a third indication.

In an optional manner, before the access network device drops the voice service carrying network of the terminal from the first network to the second network according to the drop-back instruction, the implementation method further includes:

and the access network equipment receives a context release instruction message sent by the access and mobility management function equipment when the context establishment flow for the voice service of the terminal is interrupted, and whether the context instruction message carries the fallback instruction or not.

According to a second aspect of the embodiment of the present application, there is provided a method for implementing a voice service, including:

the method comprises the steps that an access and mobility management function device receives a service request message from an access network device, wherein the service request message carries a first indication, a second indication and a third indication, the first indication is used for indicating that the service request message is triggered by voice service of a terminal, the second indication is used for indicating signal transmission interference intensity of a cell where the terminal currently resides in within a preset time, and the third indication is used for indicating physical resource utilization rate of the cell within the preset time;

the access and mobility management function device determines whether to initiate an EPS fallback procedure for the terminal according to the service request message to realize the voice service;

when the EPS fallback flow needs to be initiated, the access and mobility management function equipment sends a fallback instruction to the access equipment, wherein the fallback instruction is used for indicating that a voice service bearing network of the terminal is fallback from a first network to a second network;

and when the EPS fallback flow does not need to be initiated, the access and mobility management function equipment sends a QoS flow establishment instruction to the access equipment, wherein the QoS flow establishment instruction is used for indicating the terminal to finish the voice service in the first network.

In an optional manner, the determining, by the access and mobility management function device according to the service request message, whether to initiate an EPS fallback procedure for the terminal to implement the voice service includes:

the access and mobility management function device determining that the service request message is triggered by the voice service of the terminal according to the first indication in the service request message;

the access and mobility management function equipment judges whether the signal transmission interference intensity and the physical resource utilization rate of the cell where the terminal resides in a preset time are higher than corresponding preset thresholds according to the second indication and the third indication in the service request message;

if yes, the access and mobility management function equipment determines that an EPS fallback process needs to be initiated for the terminal to realize the voice service;

if not, the access and mobility management function device determines that the EPS fallback process does not need to be initiated for the terminal to realize the voice service.

In an optional manner, when the EPS fallback procedure needs to be initiated, the access and mobility management function device sends a fallback indication to the access device, including:

And when the EPS fallback flow needs to be initiated, the access and mobility management function equipment interrupts a context establishment flow for the voice service of the terminal, carries a fallback instruction in a context release instruction message, and sends the context release instruction message to the access network equipment.

According to a third aspect of an embodiment of the present application, there is provided an access network device, including a processor, a memory, a communication interface, and a communication bus, where the processor, the memory, and the communication interface complete communication with each other through the communication bus;

the memory is configured to store at least one executable instruction that causes the processor to perform the method for implementing a voice service according to any one of the preceding claims.

According to a fourth aspect of embodiments of the present application, there is provided an access and mobility management function device, comprising a processor, a memory, a communication interface and a communication bus, the processor, the memory and the communication interface completing communication with each other through the communication bus;

the memory is configured to store at least one executable instruction that causes the processor to perform the method for implementing a voice service according to any one of the preceding claims.

According to a fifth aspect of embodiments of the present application, there is provided a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a method of implementing a voice service as described in any of the above.

According to the implementation method of the voice service provided by the first aspect of the embodiment of the application, after the access network equipment sends a service request message carrying a first instruction, a second instruction and a third instruction to the access and mobile management function equipment so as to instruct the access and mobile management function equipment to determine that the service request message is triggered by the voice service of the terminal according to the first instruction, the access network equipment respectively judges the signal transmission interference intensity and the physical resource utilization rate of the cell where the terminal currently resides in a preset time according to the second instruction and the third instruction, and when receiving a fallback instruction sent by the access and mobile management function equipment, the access network equipment fallback the voice service bearing network of the terminal from the first network to the second network according to the fallback instruction, and when receiving a flow establishment instruction from the access and mobile management function equipment, the access network equipment establishes QoS flow according to the QoS flow establishment instruction so as to instruct the terminal to complete the voice service in the first network. According to the implementation method of the voice service provided by the first embodiment, the EPS Fallback flow does not need to establish a special bearing in the Fallback process, so that quick redirection to an ESP network can be realized, and the access network equipment actively reports the interference condition and the resource utilization condition of the current resident cell of the terminal to the access and mobility management function equipment, so that AMF can determine whether to send a Fallback instruction or a QoS flow establishment instruction to the access equipment according to the interference condition and the resource utilization ratio of the current resident cell, namely, whether the bearing mode of the voice service of the terminal is VONR or VOLTE is determined. Therefore, the implementation method of voice service provided in the first embodiment reduces call delay and improves user perception on the premise of reducing network element association under the scene of high interference and high resource utilization.

According to the implementation method of the voice service provided by the second aspect of the embodiment of the application, the access and mobile manageability function equipment receives the service request message carrying the first indication, the second indication and the third indication, after determining that the service request message is triggered by the voice service of the terminal according to the first indication, respectively judging the signal transmission interference intensity and the physical resource utilization rate of the cell where the terminal currently resides in a preset time according to the second indication and the third indication, determining whether the current need to initiate an EPS fallback flow for the voice service of the terminal according to the judging result, if the current need to send a fallback indication to the access network equipment to indicate that the voice service bearing network of the terminal falls back from the first network to the second network, and if the EPS fallback flow does not need to be initiated, when sending a flow establishment indication to the access network equipment, enabling the access network equipment to establish QoS flow according to the QoS flow establishment indication to instruct the terminal to complete the voice service in the first network. According to the implementation method of the voice service provided by the fifth embodiment, the EPS Fallback flow does not need to establish a special bearer in the Fallback process, so that quick redirection to an ESP network can be realized, and whether a Fallback instruction or a QoS flow establishment instruction is sent to the access equipment is determined according to the interference condition and the resource utilization condition of the current resident cell of the terminal, namely, whether the bearing mode of the voice service of the terminal is VONR or VOLTE is determined. Therefore, the implementation method of voice service provided in the fifth embodiment reduces call delay and improves user perception on the premise of reducing network element association under the scene of high interference and high resource utilization.

The foregoing description is only an overview of the technical solutions of the embodiments of the present application, and may be implemented according to the content of the specification, so that the technical means of the embodiments of the present application can be more clearly understood, and the following specific embodiments of the present application are given for clarity and understanding.

Drawings

The drawings are only for purposes of illustrating embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

fig. 1 is a signal flow diagram in the conventional EPS fallback procedure;

fig. 2 is a mobile communication system including 5G and 4G networks;

fig. 3 is a flowchart illustrating a method for implementing a voice service according to a first embodiment of the present application;

fig. 4 is a flowchart illustrating a method for implementing a voice service according to a second embodiment of the present application;

fig. 5 is a signal flow diagram of an RRC establishment procedure of an access network device and a terminal in a method for implementing a voice service according to an embodiment of the present application;

fig. 6 is a signal flow diagram of a voice service switching method according to a second embodiment of the present application;

Fig. 7 is a flowchart of a method for implementing a voice service according to a third embodiment of the present application;

fig. 8 is a flowchart illustrating a method for implementing a voice service according to a fifth embodiment of the present application;

fig. 9 is a flowchart illustrating a method for implementing a voice service according to a sixth embodiment of the present application;

fig. 10 is a signal flow diagram of a method for implementing a voice service according to a seventh embodiment of the present application;

fig. 11 is a signal flow diagram of a method for implementing a voice service according to an eighth embodiment of the present application;

fig. 12 is a flowchart illustrating a method for implementing a voice service according to a ninth embodiment of the present application;

fig. 13 is a device for implementing a voice service according to a tenth embodiment of the present application;

fig. 14 is a device for implementing a voice service according to an eleventh embodiment of the present application;

fig. 15 is a schematic structural diagram of an access network device according to a twelfth embodiment of the present application;

fig. 16 is a schematic structural diagram of an access and mobility management function device according to a thirteenth embodiment of the present application.

Detailed Description

Exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein.

Before describing the various embodiments of the present application, the following description is made of the technical terms related to the various embodiments of the present application, in which: "English and Chinese after" are respectively ": "English interpretation and Chinese interpretation of the technical term before".

5G: fifth Generation Mobile Communication Technology, fifth generation mobile communication technology.

5GS: fifth Generation System,5G system.

4G: fourth Generation Mobile Communication Technology, fifth generation mobile communication technology.

3GPP: third Generation Partnership Project, third generation partnership project.

AMF: access and mobility management function, access and mobility management functions.

AN: access Network, access Network.

CMNET: china Mobile Network, china Mobile Internet.

EPS: evolved Packet System, evolved packet system.

E-UTRAN: evolved Universal Terrestrial Radio Access Network, evolved universal terrestrial radio access network.

ENB: an Evolved Node B, an Evolved Node B.

GBR: guaranteed Bit Rate, non-guaranteed bit rate.

GNB: next Generation Node-B, next generation node B.

HSS: home Subscriber Server, and a home subscriber server.

IMS: IP Multimedia Subsystem, IP multimedia subsystem.

IP: (Internet Protocol ).

LTE: long Term Evolution, long term evolution.

MO: mobile Origination, caller.

MT: mobile Termination, called.

MME: mobilityManagement Entity, mobility management entity.

MCS: modulation and Coding Scheme, modulation and coding scheme.

NG- (R) AN: next Generation- (Radio) Access Network, next Generation (Radio) Access Network.

NAS: non-Access Stratum, non-Access Stratum. NR: new Radio, new Radio.

NSA: non-standby, independent. NW: network, network.

N26: an interface between the MME and the AMF for transferring mobility management state and session management state between the source network and the target network during the 4G network and 5G network interworking.

PDU: protocol Data Unit, protocol data unit.

PGW: packet Data Network Gateway, packet data gateway.

PCF: policy control function, policy control function.

PRB: physical Resource Block, physical resource modules.

RRC: radio Resource Control, radio resource control layer.

PRACH: physical Random Access Channel physical random access channel.

PCRF: policy and Charging Rules Function policy and charging rules function.

PGW-C: packet Data Network Gateway-Control, packet data gateway-Control plane.

PGW-U: packet Data Network Gateway User plane, packet data gateway-user plane.

SR: service Request, service Request.

SA: and (3) stand alone.

S-CSCF: serving-Call SessionControl Function, serving call session control functions.

SMF: session Management Function, session management function.

SBC: session Border Controlle session border control.

SGW: and (5) Serving Gateway service.

SINR: signal to Interference plus Noise Ratio downlink signal to interference plus noise ratio.

RAR: random Access Response, access response.

RAA: random access area Random Access Area.

TAU: tracking Area Update, tracking domain updates.

UE: user Equipment, user Equipment.

UPF: user Plane Function, user plane functions.

UDM: unified Data Management, unified data management.

VONR: voice Over New Radio, the new radio carries voice.

QoS: quality of Service quality of service.

5QI:5G QoS Indicator,5G quality of service identification.

QC: qoS Class Identification quality of service class labels.

The inventor discovers in the research process that if the voice service is realized in the SA network by adopting the VONR mode, the call establishment failure exists, and the situations of large time delay, large jitter, call drop and the like of the voice can occur even if the call establishment is successful. The inventors analyzed that this is due to the high interference and high utilization at the wireless side of the SA network. If the user equipment is located at the environment point of the wireless high interference SINR, the guaranteed bandwidth can enable low coding (such as low MCS), and occupied PRB resources are more. Meanwhile, in the process of establishing the special flow, the flow establishment process is capable of preempting 5QI9 (5 QI=9) service (CMNET data service) due to GBR service. Once several poor quality user equipment in the same cell talk, a large amount of network resources are likely to be occupied, and if the cell is in an environment with higher physical resource utilization rate at this time, the original data service user cannot be scheduled or even dropped, because the dedicated resources of the video talk May-trigger-pre-transmission (which can trigger preemption) largely preempt the original internet user resources.

Therefore, in the implementation manner of the voice service provided by the application, the judgment of the signal transmission interference intensity and the physical resource utilization rate in the coverage area of the SA network where the terminal resides is added in the initiation stage of the voice service, and the voice service of the terminal is realized by selecting whether to start switching or redirecting to the ESP network to realize the connection of the voice service or continuously adopting the VONR mode in the SA network according to the judgment result.

In addition, in the process of realizing the voice service, when the voice service is realized by switching or redirecting the ESP Fallback flow to an ESP network, compared with the existing EPS Fallback flow, the application makes flow optimization change. The existing ESP Fallback flow is: and the NG-RAN equipment selectively measures the LTE wireless environment and the EPS Fallback flow after receiving the 5QI1 (5G QoS Indicator,5G quality of service identifier) flow (flow) issued by the AMF equipment. Thus, existing ESP Fallback procedures require QoS flow to be established, which is useless for redirecting voice traffic to the ESP network, but with increased latency and unnecessary signaling interactions. The ESP Fallback flow of the present application is: in the process of establishing the voice service, the NG-RAN equipment initiates 5GS to EPS redirection according to the indication of the AMF equipment. In the ESP Fallback flow, AMF equipment directly decides to redirect to an ESP network to realize voice service in the idle state service state process, and does not need to wait for a 5QI1 flow establishment request sent by an SMF network element, and the NG-RAN equipment refuses the request and then redirects 5GS to EPS. Furthermore, in the present application, the redirection of 5GS to EPS may select either a measurement-based redirection or a blind redirection. Therefore, the voice service implementation method provided by the application can reduce the gateway network element, reduce the possibility of signaling transmission failure in a high-interference environment, reduce the complexity of the existing process, shorten the time delay of the EPS Fallback bearing voice process, and improve the user perception.

In order to better distinguish the application from the existing voice service implementation method, before specifically introducing the voice service implementation method provided by the application, the existing voice service implementation method is introduced as follows:

the existing 5G voice flow mainly comprises an AMF device of a terminal in 5GS and an S-CSCF of an IMS network element for registering, and in MO or MT flow, a network triggers PDU session modification, qoS flow is established for IMS voice, and voice connection is completed by VONR flow. But if the NG-RAN device chooses to carry IMS voice in Fallback mode, then ESP Fallback is triggered and the network is notified. The terminal enters an EPS network through switching or redirection, after the EPS resumes the conversation, the network triggers PDN connection modification, establishes a special bearer for IMS voice, and completes the connection of voice service in an EPS Fallback mode.

The flow chart of the existing EPS Fallback is shown in fig. 1, and the flow chart of the EPS Fallback in fig. 1 is illustrated by taking a calling voice service initiated by UE as an example, and the flow chart is described as follows:

1. when there is IMS voice service of calling party or called party, QOS flow of 5QI=5 (5 QI 5) is established, UE is converted from idle state to connection state;

2. the core network initiates PDU session modification to the wireless side to establish a QOS flow for IMS voice. Namely QOS flow establishment of 5 qi=1 (5Q 11), the process is that the UE reports voice demand to the SBC, the SBC finds a dedicated flow establishment policy to the PCF, and issues to the NG-RAN side through SMF/AMF.

ng-RAN side triggers EPS Fallback procedure. On the one hand, the NG-RAN side sends down the measurement LTE wireless environment measurement configuration to the UE, and on the other hand, the NG-RAN side informs the AMF/SMF of refusing to establish the QOS flow with the value of 5 QI=1.

4. The PDU session modification request is denied and the core network is informed that a fallback of IMS voice is to be performed.

And 5, redirecting or switching the NG-RAM to the EPS according to the fallback instruction. For example, switching to EPS may be based on N26.

And 6a, TAU is performed.

Attachment (based on N26), request to establish PDN connection, and request reason for handover or redirection.

7. After the UE successfully resides in the 4G network, the core network initiates PDN connection modification to establish a dedicated bearer for voice. That is, after LTE is returned, dedicated establishment of qci=1 is performed.

8. And continuing to complete the establishment process of the IMS voice session in the 4G network.

The existing EPS Fallback flow appears after the NG-RAN side receives a QOS flow request of newly built 5 QI=1 at the AMF side, the NG-RAN side policy selects EPS Fallback flow to continue the call, on one hand, the special 5QI1 special flow cannot be established for AMF/SMF feedback, and PDU session modification request is refused, and the core network is informed to carry out IMS voice Fallback, on the other hand, UE is instructed to start LTE side measurement and report, 5 GS-EPS switching is completed according to a measurement report, SGW is addressed according to an SGW side IP address indicated by 5GS in the switching process after the switching is completed, and the SGW side triggers establishment of QCI1 special bearing again. In the prior art, the EPS Fallback procedure is triggered by an upper layer, and the middle phase of modifying the PDU session initiated by SMF into the IMS voice establishment Qos flow is undergone, and the phase specifically includes: the UE reports a voice request to the SBC, and the SBC searches a special flow establishment strategy from the PCF; PCF indicates SMF special flow establishment strategy (RAR/RAA message); transmitting NAMF_COMMUNICATION_N1N MESSAGETRANSFER REQUEST message and PDU SESSION MODIFICATION COMMAND message to NG-RAN side through SMF/AMF; NG-RAN side AMF/SMF feedback refuses to establish 5QI1 dedicated flow; the NG-RAN side issues measurement configuration for LTE and completes a switching process from 5GS to EPS by combining EPS and 5GS network elements according to a measurement report; and the SGW triggers the terminal to complete the establishment of the special bearer with the QCI of 1 in the EPS network. Therefore, the existing EPS Fallback flow has to go through the above steps, and multiple network elements need to be introduced, and the more the network elements are introduced, the greater the possibility of failure and the more the time delay is introduced. The EPS Fallback flow provided by the application does not need special bearing establishment in the fall-back process, and can realize rapid redirection to an ESP network. In the application, the traditional passive triggering EPS Fallback flow from the NG-RAN side is changed into the active judging guiding NG-RAN triggering Fallback flow from the AMF side. Therefore, on the premise of reducing network element association under a high interference scene, the call delay is reduced, and the user perception is improved.

The implementation method of the voice service provided by the embodiment of the application is applied to a wireless communication system, wherein the wireless communication system comprises a first network and a second network, the priority level of the first network is higher than that of the second network, in some embodiments, the first network is a 5G network, and the second network is a 4G network (which can be called as an EPS network). As shown in fig. 1, the 5G network includes: (radio) access network (R) AN device, AMF device (or network element), UDM network element, PCF network element, SMF network element, UPF network element. The (R) AN equipment can be the next generation NG-RAN equipment or E-UTRAN equipment. The 4G network includes: E-UTRAN equipment, MME network element, SGW, PGW, PCRF network element and HSS network element. The E-UTRAN device may be an evolved Node B. The packet data gateway may include a PGW-C network element, and a PGW-U network element. The part of network elements of the 5G network and the part of network elements of the EPS network may be disposed on the same physical entity, so that the 5G network and the 4G network may interact, for example, as shown in fig. 2, the HSS network element and the UDM network element are disposed on the same physical entity, the PCF network element and the PCRF network element are disposed on the same physical entity, the SMF network element and the PGW-C network element are disposed on the same physical entity, the UPF network element and the PGW-U network element are disposed on the same physical entity, and the above network elements may also be separate network elements. An interoperable interface exists between the 5G network and the 4G network, for example, the AMF network element may communicate with the MME network element through an N26 interface, and the MME network element may communicate with the MSC network element through an Sv interface. The above 4G network and 5G network may further include other devices or network elements, and embodiments of the present application are not limited in detail.

In the wireless communication system shown in fig. 2, the terminal device may also be referred to as a user equipment UE, 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 a user equipment. The terminal device may also be a site in a wireless local area network, and may be a cellular telephone, a cordless telephone, a session initiation protocol telephone, a wireless local loop station, a personal digital processing device, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device (which may also be referred to as a wearable smart device). The terminal device may also be a terminal device in a next generation communication system, for example, a terminal device in 5G or a terminal device in a future evolved public land mobile network, a terminal device in an NR communication system, or the like.

The AMF network element may be responsible for registration of terminal devices, mobility management, tracking area update procedures, etc. An AMF network element may also be referred to as an AMF device or an AMF entity. The SMF network element may be responsible for session management of the terminal device. Session management includes, for example, selection of user plane devices, reselection of user plane devices, IP address assignment, quality of service QoS control, and establishment, modification, or release of sessions, etc. The SMF network element may also be referred to as an SMF entity or an SMF device.

The PCF network element includes policy control and flow based charging control functions, e.g., the PCF network element may implement policy control functions, charging policy control functions, qoS control, etc. PCF network elements may also be referred to as PCF entities or PCF devices. The MME network element may be responsible for authentication, mobility management and session management of the terminal device. MME network elements may also be referred to as MME devices or MME entities. The UDM device has a function of unified data management, and is mainly responsible for managing subscription data, user access authorization, and the like. The SMF device has a session management function, and mainly performs the functions of session management, execution of PCF issuing control strategies, UPF selection, internet protocol (internet protocol, IP) address allocation of the UE, and the like. The UPF equipment is a user plane functional entity and is used as an interface with a data network to finish the functions of user plane data forwarding, charging statistics based on session/stream level, bandwidth limitation and the like.

Each network element in fig. 2 may be a network element implemented on dedicated hardware, or may be a software instance running on dedicated hardware, or may be an instance of a virtualized function on a suitable platform, for example, the virtualized platform may be a cloud platform. The implementation method of the voice service provided by the embodiment of the application can be applied to specific network elements or equipment in the communication system shown in fig. 2.

Two voice access modes are defined in a 5G (fifth generation mobile communication technology) network: the new wireless voice carries VONR and evolved packet system fallback EPS fallback. The VONR mode refers to providing voice service based on an IP multimedia subsystem by a 5G access network and a core network, and the EPS fallback scheme refers to that when a UE initiates an IMS call on the 5G network, the UE falls back to an EPS network (4G network) and realizes the voice service through the 4G network.

Fig. 3 is a flow chart illustrating a method for implementing a voice service according to a first embodiment of the present application. The implementation method of the voice service includes, but is not limited to, S12, S14, and S16, and is specifically described as follows:

s12: the access network device sends a service request message (SR) to the access and mobility management function device after establishing a radio resource control RRC connection with the terminal for performing the voice service. The service request message carries a first indication, a second indication and a third indication, wherein the first indication is used for indicating that the service request message is triggered by voice service of a terminal, the second indication is used for indicating signal transmission interference strength of a cell where the terminal currently resides in within a preset time, the third indication is used for indicating physical resource utilization rate of the cell within the preset time, and the service message is used for indicating whether the access and mobility management function device really needs to initiate an EPS fallback procedure for the terminal to realize the voice service.

The service request message may be one message or may be a plurality of messages sent simultaneously or with a time difference less than a preset time difference. The first indication, the second indication and the third indication may be indication data on three indication bits in the same message, or may be indication data on corresponding indication bits in different messages. The voice service of the terminal may refer to a calling voice service actively initiated by the terminal, or may be a called voice service of the terminal. According to the first indication, whether the service request message is triggered by the main teaching voice service or the called voice service can be determined. The voice service of the terminal comprises a voice call service and a video call service. The current residence cell of the terminal refers to the network currently registered by the terminal. In this embodiment, the service request message is used to request the terminal to implement a voice service in the first network, where the current residence cell of the terminal is an area covered by the first network where the terminal resides. The preset time period may refer to a latest preset time period, such as a latest time period, of the cell in which the terminal resides. The latest preset time period refers to the current previous preset time period. For the calling voice service, the interference strength of the signal transmission refers to uplink interference strength, and for the called voice service, the interference strength of the signal transmission refers to downlink interference strength. The physical resource utilization rate refers to an uplink physical resource utilization rate and/or a downlink physical resource utilization rate. The service message is used for indicating whether the access and mobility management function device is actually required to initiate an EPS fallback procedure for the terminal to implement the voice service, that is, the first indication in the service request message is used for indicating the mobility management function device to determine whether the service request message is triggered by the voice service of the terminal, if yes, a second indication and a third indication of the service request message are provided to indicate the mobility management function device to determine whether the EPS fallback procedure is required to be initiated for the terminal to implement the voice service. The step of initiating an EPS fallback procedure for the terminal to realize the voice service includes enabling a bearing network of the voice service of the terminal to be an LTE network, namely, realizing the voice service of the terminal in a VOLTE sampling mode. The access network device may be an NG-RAN device.

S14: and when the access network equipment receives the fallback indication from the access and mobility management function equipment, the access network equipment fallback the voice service bearing network of the terminal from the first network to the second network according to the fallback indication. In the first embodiment, the first network is a 5G network, such as a 5G SA network that is configured in SA networking mode. The second network is a 4G network, i.e. an EPS network, such as an LTE network.

And the access and mobility management function equipment determines whether the EPS fallback process needs to be initiated according to the first indication, the second indication and the third indication in the service request message so as to determine whether a corresponding fallback indication or a QoS flow establishment indication needs to be sent to the access network equipment at present so as to determine whether the voice service bearing mode of the terminal is a VONR mode or a VOLTE mode.

S16: and when receiving the QoS flow establishment instruction from the access and mobility management function equipment on the access network, the access network equipment establishes QoS flow according to the QoS flow establishment instruction so as to instruct the terminal to finish the voice service in the first network.

The terminal completing the voice service in the first network means that the terminal realizes the voice service in a VONR manner.

As can be seen from the foregoing, in the implementation method of a voice service provided in the first embodiment, a service request message carrying a first indication, a second indication and a third indication is sent to an access and mobile management function device through an access network device, so as to instruct the access and mobile management function device to determine, according to the first indication, that the service request message is triggered by a voice service of a terminal, and then, according to the second indication and the third indication, respectively determine, according to signal transmission interference strength and physical resource utilization rate of a cell in which the terminal currently resides within a preset time, and when a fallback indication sent by the access and mobile management function device is received, a voice service bearer network of the terminal is fallback from a first network to a second network according to the fallback indication, and when a flow establishment indication from the access and mobile management function device is received, the access network device establishes QoS according to the QoS flow establishment indication, so as to instruct the terminal to complete the voice service in the first network. According to the implementation method of the voice service provided by the first embodiment, the EPS Fallback flow does not need to establish a special bearing in the Fallback process, so that quick redirection to an ESP network can be realized, and the access network equipment actively reports the interference condition and the resource utilization condition of the current resident cell of the terminal to the access and mobility management function equipment, so that AMF can determine whether to send a Fallback instruction or a QoS flow establishment instruction to the access equipment according to the interference condition and the resource utilization ratio of the current resident cell, namely, whether the bearing mode of the voice service of the terminal is VONR or VOLTE is determined. Therefore, the implementation method of voice service provided in the first embodiment reduces call delay and improves user perception on the premise of reducing network element association under the scene of high interference and high resource utilization.

As shown in fig. 4, a method for implementing a voice service according to a second embodiment of the present application is provided. In the second embodiment, the method for implementing a voice service further includes, before sending the service request message to the access and mobility management function device, that is, before S12, the following steps:

s09: and the access network equipment receives an RRC establishment completion message from the terminal in the process of establishing Radio Resource Control (RRC) connection with the terminal for voice service, wherein the RRC establishment completion message carries the first indication.

S10: and the access network equipment determines that the RRC establishment completion message is triggered by the voice service of the terminal according to the received first indication carried in the RRC establishment completion message.

S11: and after determining that the RRC establishment completion message is triggered by the voice service of the terminal, the access network equipment carries the second indication and the third indication in the RRC establishment completion message to obtain the service request message.

The access network device IG-RAN may be a gNB, and the terminal is a UE. The access network device establishes an RRC connection of the voice service with the terminal and interprets the process of the RRC establishment complete message, as shown in fig. 5, which is a signal flow diagram of the RRC establishment process of the access network device with the terminal. After the terminal UE is started, the terminal UE is attached to a 5G network, then an IMS PDU session is established, the terminal UE is registered in an IMS, and the terminal UE enters an idle state. The UE in idle state first triggers the establishment of an RRC connection with the NG-RAN device before preparing to initiate IMS voice service to another UE. The UE sends a random access preamble (Msg 1) to the NG-RAN device (which may be a gNB) and listens to the physical downlink control channel for a RAR time window to receive a random access response RAR (Msg 2) corresponding to the radio network temporary identity. The UE accesses the gNB after receiving the RAR. After accessing the gNB, if the UE needs to initiate voice service, the UE sends an RRC setup request message RRC Setup Request to the gNB (through the SRB0 channel). And the gNB establishes the UE context according to the RRC establishment request message, confirms the resource allocation of the SRB1 channel, and then sends an RRC establishment instruction RRC Setup to the UE through the SRB0 channel. Finally, the UE is sending an RRC setup complete message RRC Setup Complete to the gNB over the SRB1 path. After the RRC establishment is completed, the state of the terminal is converted from an idle state to a connected state. The first indication may be carried in RRC setup complete, and the gNB determines that the RRC setup complete message is a message triggered by a voice service of the terminal according to the first indication in RRC Setup Complete. The first indication indicates that the reason for RRC establishment is voice service of the terminal, and the first indication may indicate calling voice service of the terminal, such as MO-voiceecall, or may indicate called voice service of the terminal, such as MT-voiceecall, MT-voiceecall.

After the access network device receives RRC Setup Complete, the reason for the RRC establishment is determined to be that the terminal intends to initiate voice service according to the first indication. After determining that RRC Setup Complete is triggered by the voice service of the terminal, the access network device obtains the signal transmission interference strength and the material resource utilization rate of the cell where the terminal currently resides in within a preset time, and adds the obtained two pieces of information in RRC Setup Complete as a second indication and a third indication in RRC Setup Complete.

The NG-RAN obtains the service request message after adding the second indication and the third indication in RRC Setup Complete. The service request message is a NAS message INITIAL UE MESSAGE. The access network device sends the INITIAL UE MESSAGE to the AMF device. Fig. 6 is a signal flow diagram of a voice service switching method according to a second embodiment of the present application. The UE sends RRC Setup Complete to the gndeb (gNB). After receiving RRC Setup Complete, if the establishment cause value in RRC Setup Complete is the voice service of the terminal, the NodeB adds an interference (first indication) and resource (second indication) reporting field in RRC Setup Complete to obtain an initial UE message (INITIAL UE MESSAGE), and reports the service request message to the 5G core network, and to the AMF device in the 5G core network.

Taking an idle terminal as a calling party to initiate a voice service request in an SA network as an example, firstly, the terminal needs to go through an RRC establishment process with access network equipment, and after the establishment is completed, the state of the terminal is changed from the idle state to the service state. Thereafter, the terminal first initiates a contention-based PRACH procedure and carries the RRC Establishment Cause RRC-es-Cause in Initial UE Message cells in Msg5 (rrcsetup complete). The reason value for representing the idle state to the connection state of the terminal is the first indication, which is that the voice or video call service is ready to be established, wherein the first indication is as follows: MO-Voiceall, MO-video call, MT-Voiceall or MT-video call.

Fig. 7 is a flowchart of a method for implementing a voice service according to a third embodiment of the present application. In the third embodiment, S11: the access network device carries the second indication and the third indication in the RRC establishment complete message after determining that the RRC establishment complete message is triggered by the voice service of the terminal, and specifically includes S111, S112 and S113.

S111: and after determining that the RRC establishment completion message is triggered by the voice service of the terminal, newly adding a second indication bit and the third indication pair bit in the RRC establishment completion message.

S112: acquiring signal transmission interference intensity of a cell where the terminal resides in within a preset time, judging whether the signal transmission interference intensity is higher than a first preset threshold value, if so, giving a first value to a value of the second indication bit, otherwise, giving a second value to the value of the second indication bit, wherein the indication on the second indication bit is a second indication.

S113: and acquiring the physical resource utilization rate of the cell in the preset time, judging whether the physical resource utilization rate is higher than a second preset threshold value, if so, giving a first value to the value of the third indication bit, otherwise, giving a second value to the value of the second indication bit, wherein the indication on the third indication bit is a third indication.

Specifically, in the method for implementing a voice service according to the fourth embodiment of the present application, before the access network device establishes a QoS flow according to the QoS flow establishment instruction to instruct the terminal to complete the voice service in the first network, the implementing method further includes: and the access network equipment receives a context release instruction message sent by the access and mobility management function equipment when the context establishment flow for the voice service of the terminal is interrupted, and whether the context instruction message carries the fallback instruction or not.

The sequence of S111, S112, and S113 is not limited, and the values of the second indication and the third indication may be obtained first, the corresponding indication bit is added, and the corresponding indication bit is filled with the corresponding indication value. Specifically, after receiving the RRC establishment complete message, the NG-RAN device determines, according to the first indication in the RRC establishment complete message, that the purpose of the terminal from the idle state to the service state is to call by voice. Thereafter, the NG-RAN device queries the radio signal transmission interference strength and the physical resource usage in the previous time period of the cell in which the terminal is currently camping. If the first indication in the RRC establishment completion message indicates that the voice service of the non-terminal of the RRC establishment completion message is triggered, the NG-RAN equipment does not inquire the wireless signal transmission interference intensity and the physical resource utilization rate, does not report the wireless signal transmission interference intensity and the physical resource utilization rate to the AMF equipment, and realizes the voice service of the terminal in a continuous early mode, namely, continuously adopts the VONR mode to realize the voice service of the terminal.

Specifically, the NG-RAN device counts the uplink Interference strength of the cell where the terminal currently resides in a latest time period (the statistical period 5 minutes before the initial call starting time point of the terminal can be initially set), and when the uplink Interference strength of the cell is greater than or equal to an Interference strength threshold (initially set to-110 dBM) +offset (OFFset threshold), defines the latest time period of the cell as an Interference cell, and sets a cell Interference indication bit (second indication bit) of the current call of the terminal to be 1, otherwise, the Interference indication bit is 0. In addition, the NG-RAN device also performs query and comparison calculation on the uplink PRB utilization rate and the downlink PRB utilization rate of the cell in the last time period (the statistical period 5 minutes before the initial call time point of the terminal may be initially set), where one of the uplink PRB utilization rate and the downlink PRB utilization rate is higher than the utilization rate threshold (which may be initially defined as 80%), defines the last time period of the cell as a high utilization rate cell, and places the busy/idle_indicated bit (the third indication bit) of the cell called by the terminal at this time in 1, otherwise, the busy/idle_indicated bit is 0. The NG-RAN device sends a service request message (INITIAL UE MESSAGE) carrying the first, second and third indications to the AMF device. In this embodiment, the NG-RAN device only determines and analyzes the cause of the establishment of the service request message, and whether the radio transmission interference strength and the physical resource usage rate of the cell in which the terminal resides reach the corresponding set thresholds, and places the analysis result in the corresponding indication bit, and reports the analysis result to the AMF device, and specifically how to use the second indication and the third indication, and the AMF device determines according to the policy. At this time, the INITIAL UE MESSAGE message includes RRC Establishment Cause (first indication), information on the cell Interference indication bit (second indication), and information on the cell resource indication bit (third indication).

As shown in fig. 8, a flowchart of a method for implementing a voice service according to a fifth embodiment of the present application is shown, where the method for implementing a voice service includes, but is not limited to, S22, S24, S26, and S28.

S22: the access and mobile management function device receives a service request message from an access network device, wherein the service request message carries a first indication, a second indication and a third indication, the first indication is used for indicating that the service request message is triggered by voice service of a terminal, the second indication is used for indicating signal transmission interference intensity of a cell where the terminal currently resides in within a preset time, and the third indication is used for indicating physical resource utilization rate of the cell within the preset time.

S24: and the access and mobile management function equipment determines whether an EPS fallback process needs to be initiated for the terminal according to the service request message to realize the voice service.

S26: when the EPS fallback flow needs to be initiated, the access and mobile manageability function device sends a fallback instruction to the access device, wherein the fallback instruction is used for indicating that the voice service bearing network of the terminal is fallback from the first network to the second network.

S28: and when the EPS fallback flow does not need to be initiated, the access and mobile manageability function equipment sends a QoS flow establishment instruction to the access equipment, wherein the QoS flow establishment instruction is used for indicating the terminal to finish the voice service in the first network.

After receiving the service request message, the access and mobile management function device, i.e. the AMF device, firstly determines whether the service request message is triggered by the voice service of the terminal according to a first indication in the service request message, and if yes, further determines whether to initiate an EPS fallback procedure for the voice service of the terminal according to the second indication and a third indication. If so, sending a fallback instruction to an access network device (NG-RAN) to instruct the NG-RAN to trigger the voice bearing network of the terminal to fall back from the current first network to the second network. The fallback indication is used for indicating that the voice service bearing network of the terminal is switched or redirected to the ESP network by a 5G SA network mode, so that the bearing mode of the voice service of the terminal is switched from VONR to VOLTE. If the EPS fallback flow does not need to be initiated, a QOS flow establishment instruction is sent to the access network equipment to instruct the access network equipment to QOS flow, so that the bearing mode of the voice service of the terminal is continuously maintained as VONR.

As can be seen from the foregoing, in the implementation method of a voice service provided in the fifth embodiment, the access and mobile manageability function device receives a service request message carrying a first indication, a second indication and a third indication, so as to determine, according to the first indication, that the service request message is triggered by the voice service of the terminal, respectively determine, according to the second indication and the third indication, the signal transmission interference strength and the physical resource usage rate of a cell in which the terminal currently resides within a preset time, determine, according to a determination result, whether an EPS fallback procedure is required to be initiated for the voice service of the terminal, if an EPS fallback indication is required to be sent back to the access network device, so as to instruct the voice service bearer network of the terminal to fall back from the first network to the second network, and if the EPS fallback procedure is not required to be initiated, when a flow establishment indication is sent to the access network device, so that the access network device establishes QoS flow according to the QoS flow establishment indication, so as to instruct the terminal to complete the voice service in the first network. According to the implementation method of the voice service provided by the fifth embodiment, the EPS Fallback flow does not need to establish a special bearer in the Fallback process, so that quick redirection to an ESP network can be realized, and whether a Fallback instruction or a QoS flow establishment instruction is sent to the access equipment is determined according to the interference condition and the resource utilization condition of the current resident cell of the terminal, namely, whether the bearing mode of the voice service of the terminal is VONR or VOLTE is determined. Therefore, the implementation method of voice service provided in the fifth embodiment reduces call delay and improves user perception on the premise of reducing network element association under the scene of high interference and high resource utilization.

Fig. 9 is a flowchart illustrating a method for implementing a voice service according to a sixth embodiment of the present application. In the sixth embodiment, S24 further includes S241, S242, S243, and S244.

S241: and determining that the service request message is triggered by the voice service of the terminal according to the first indication in the service request message.

S242: and judging whether the signal transmission interference intensity and the physical resource utilization rate of the cell where the terminal resides in a preset time are higher than corresponding preset thresholds or not according to the second indication and the third indication in the service request message. If yes, S243 is executed, and if no, S244 is executed.

S243: and determining that an EPS fallback procedure needs to be initiated for the terminal to realize the voice service.

S244: and determining that the EPS fallback process does not need to be initiated for the terminal to realize the voice service.

In the method for implementing a voice service according to the seventh embodiment of the present application, S26 further includes: when the EPS fallback flow needs to be initiated, interrupting a context establishment flow for the voice service of the terminal, carrying a fallback instruction in a context release instruction message, and sending the context release instruction message to the access network equipment.

Specifically, as shown in fig. 10, a signal flow diagram of a method for implementing a voice service according to a seventh embodiment of the present application is shown. After the AMF device acquires the service request message, determining whether an EPS fallback flow is required to be initiated currently according to the first indication, the second indication and the third indication in the service request message. Specifically, after the AMF device receives the service request message, it is confirmed that the terminal initiates the voice service context establishment request through the RRC establishment cause value (first indication) being MO-voiceecall or MO-VideoCall, so as to further analyze information of Interference indication (second indication), and information of the cell resource indication bit file (third indication). If the second indication and the third indication are both 1, the terminal initiates voice and video services in the cell with high utilization rate and high interference, the AMF device guides the terminal to connect the voice services to the LTE network, and an EPSfallback process needs to be initiated to directly redirect in the idle service transferring process of the terminal, otherwise, the original VONR service process is continued.

When the epsfallbback procedure needs to be initiated, the AMF device side refuses to continue to complete the terminal context establishment procedure (i.e. interrupts the context establishment procedure), but sends UE CONTEXT RELEASE COMMAND (UE context release instruction) carrying the newly added cause value ESP-fallback-request to the (R) AN device. Specifically, the UE CONTEXT RELEASE COMMAND message is sent through the N2 interface, and the fallback indication in the UE CONTEXT RELEASE COMMAND message is used to instruct the (R) AN device to initiate a fast redirection procedure from NR to LTE, that is, trigger the voice bearer mode of the terminal device to be switched from VONR or redirected to VOLTE. After acquiring UE CONTEXT RELEASE COMMAND the access device sends an RRC release indication to the UE. The RRC release indication carries a redirection LTE frequency point (where the frequency point may directly select a co-sited LTE site frequency point, or a current geographical environment strongly covers an LTE frequency point), and the UE completes the redirection from NR to LTE according to the RRC release indication. Specifically, the terminal initiates a TAU or Handover type Attach process in the LTE network, completes the residence of the LTE network, and initiates VOLTE call connection on the LTE network.

Fig. 11 is a signal flow diagram of a method for implementing a voice service according to an eighth embodiment of the present application. The implementation method of the voice service provided in the eighth embodiment is mainly applied to the communication system shown in fig. 2, and the main detailed flow and technical details thereof are as follows (it should be noted that fig. 11 only illustrates a EPSfallback, VONR flow according to a service request message, which is not illustrated):

1: the idle state terminal, as a caller, initiates a voice request at the SA network, first goes through an RRC setup procedure. The terminal firstly initiates a PRACH process based on competition, and carries an Establishment Cause RRC-Establishment-Cause in Initial UE Message cells carried in Msg5 (RRCSetup complete), wherein MO-Voicecall and MO-video call are prepared to establish voice or video call service by representing a Cause value for the terminal to change from an idle state to a connection state.

2: when the NG-RAN equipment receives an RRCSetup complete (Msg 5) Establishment request of the RRC-Establishment-Cause of MO-Voiceall and MO-video call, the NG-RAN equipment knows that the purpose of converting the idle state into the service state of the terminal is voice call initiation. And the NG-RAN equipment side inquires the wireless interference and the physical resource use condition in the previous time period of the current cell. And the NG-RAN equipment side establishes the service aiming at non-voice and video requests, does not inquire the interference and capacity state, does not report the state, and extends the early mode.

2.1: the NG-RAN equipment side counts the uplink interference intensity of the cell in the last time period (the statistical period 5 minutes before the initial call starting time point of the terminal can be initially set), and when the uplink interference intensity of the cell is greater than the interference intensity threshold (initially set to-110 dBM) +OFFset (OFFset threshold), the last time period of the cell is defined as an interference cell. And indicating the cell Interference indication position 1 of the current call of the terminal, otherwise, indicating the cell Interference indication position 0.

2.2: the NG-RAN equipment side defines the last time period of the cell as a high-utilization cell, wherein one of the utilization rates of uplink and downlink PRBs of the last time period (the statistical period 5 minutes before the initial call starting time point of the terminal can be initially set) of the cell is higher than a threshold (the initial time period can be initially defined as 80%). And the terminal calls the busy and idle indication bit (namely the physical resource utilization indication bit) of the cell at this time to be 1, otherwise, the busy and idle indication bit is 0.

3: the NG-RAN device side sends a Request to the AMF for the reason RRC-es tablishment-Cause to MO-VoiceCall through INITIAL UE MESSAGE (Service Request), and supplements an Interference indication bit (Interference) and a resource usage indication bit (file) in INITIAL UE MESSAGE messages. The NG-RAN device side performs only judgment and analysis, sets the analysis result, and reports the analysis result to the AMF side, and specifically how to use the two indication bits is judged by the AMF side according to the policy. At this time, the INITIAL UE MESSAGE message includes RRC Establishment Cause, and the cell Interference indication Interference, and the cell resource indication bit file.

4: after receiving INITIAL UE MESSAGE (Service Request) signaling, the AMF device receives the signaling and confirms that the terminal initiates a voice Service context Establishment Request through the RRC-Establishment-Cause as MO-Voiceall and MO-video call, and then further analyzes Interference indication Interference and cell resource indication bit file. If the voice service and the video service are both 1, the voice service and the video service are initiated by the representative terminal in the cell with high utilization rate and high interference, the AMF equipment guides the terminal to connect the voice service to the LTE network, and the step five is entered (the proposal optimizes and simplifies the original EPSfallback flow and directly redirects the terminal in the idle service conversion process), otherwise, the original VONR service flow is continued. The present proposal continues with step five, and the original VONR procedure is not described.

5: the AMF device side refuses to continue to complete the terminal context setup procedure (interrupt the context setup procedure), but directs the NG-RAN device side to initiate a fast redirection procedure from NR to LTE through UE CONTEXT RELEASE COMMAND message (EPS-fallback-required guidance through Cause newly added Cause value).

6: the new Cause value Cause new value (fall-back indication) in UE CONTEXT RELEASE COMMAND received by the NG-RAN device side indicates that the AMF device indicates that the NG-RAN device does not need to continue to establish the context establishment procedure, but decides to enable the Fallback procedure to complete the voice connection procedure. The implementation method for completing the voice connection procedure by using the Fallback procedure may be to adopt triggering RRC relay redirection to LTE (where redirection indicates that the redirect frequency point is a 5G site co-location or a strong coverage LTE frequency point). The NG-RAN equipment sends RRCRelease indication to the terminal UE according to the new Cause value (Cause) in UE CONTEXT RELEASE COMMAND and sends RRCRelease indication to the terminal UE by adopting a blind redirection mode so as to redirect the terminal to the LTE network, thereby further shortening the call delay.

7: and the UE completes the redirection from NR to LTE according to the redirection LTE frequency point carried in RRCRelease (the frequency point can directly select the frequency point of the co-sited LTE station or the current geographic environment strongly covers the LTE frequency point).

8: and the terminal initiates an Attach process of TAU or Handover type in the LTE network. And finishing the residence of the LTE network, and initiating VOLTE call connection on the LTE network.

The implementation method of the voice service provided by the eighth embodiment of the present application is actually a method for fast redirecting and rescuing a 5G voice service based on AN external environment, and the method includes that in a latest time period (AN uplink and downlink interference indication bit and a physical resource usage indication bit) of a cell where a carrying terminal currently resides is newly added in AN NG-RAN device side NAS message INITIAL UE MESSAGE (service request information), the AMF device side decides whether to enable fast redirecting to AN EPS network to carry voice through the two indication bits, when the cell is in a high interference and high utilization condition, the AMF device side refuses to continue to complete a context establishment process, and releases context through UE CONTEXT RELEASE COMMAND messages, and simultaneously, initiates AN EPS-Fallback procedure of NR to LTE through a new added cause value (Fallback indication) in UE CONTEXT RELEASE COMMAND, and after receiving the Fallback indication, interrupts a service request triggered by AN original UE.

As can be seen from the above, compared with the existing ESP Fallback flow, in the ESP Fallback flow in the implementation method of the voice service provided by the eighth embodiment, most of signaling that the terminal changes from the idle state to the service state is reduced in the NR domain, so that after the terminal is established in RRC, the AMF directly initiates the release of the context and directs the NG-RAN device side to initiate the redirection of the terminal, and the terminal establishment context does not need to enter a complete connection state. In the IMS domain, the terminal does not need to initiate call Invite in the SA network, does not trigger IMS flow any more, reduces Invite from UE to SBC side Invite, and the SBC does not trigger PCF to request QOS strategy, and does not execute 5QI1 special flow establishment flow in the NR domain, thereby saving flow complexity, time delay and network element connection of the three parts in high-interference and high-load scene and improving user perception.

Fig. 12 is a flowchart illustrating a method for implementing a voice service according to a ninth embodiment of the present application. The implementation method of the voice service provided in the ninth embodiment is mainly applied to the communication system shown in fig. 2, and the implementation flow steps mainly include Sa to Sg, which are specifically described below.

Sa, UE calls in the SA network idle state, and sends RRCSetup complete carrying reason value (first indication) to access network equipment gNB: MO-Voiceall or MO-video call.

Sb: after receiving RRCSetup complete carrying first indication (MO-Voiceall or MO-video call), gNB equipment inquires about the previous period interference and capacity condition of the cell, assigns the new indication bit in INITIAL UE MESSAGE, and reports the new indication bit to AMF equipment.

And Sc, the AMF equipment judges whether the cell is a high-interference and high-utilization cell according to the information of the newly added indication bit of INITIAL UE MESSAGE so as to judge whether an ESP Fallback flow needs to be initiated for the voice service of the UE currently, if so, sd is executed, and otherwise, sg is executed.

Sd: the AMF device determines that the quick redirection flow is started to continue calling and interrupt the establishment context flow, and guides the gNB device to start the ESP Fallback flow through UE CONTEXT RELEASE COMMAND of the EPS-Fallback-required newly added cause value (Fallback indication).

And triggering the UE to redirect to the LTE network by the gNB equipment, carrying corresponding redirecting frequency points, and finishing a later TAU or Attach procedure.

Sf: and the UE initiates a VOLTE call through Invite in the LTE network to realize VOLTE.

And Sg, the AMF equipment side normally completes the establishment of the UE context and completes the voice connection along with the VONR flow.

As can be seen from the above, in the implementation method of voice service provided in the ninth embodiment, the uplink and downlink interference indication bit and the physical resource usage indication bit in the latest time period of the cell are newly added in the NG-RAN side NAS message INITIAL UE MESSAGE request. The AMF side decides whether to enable quick redirection to EPS network to bear voice through the indication, when the cell is in a high interference and high utilization rate, the AMF side refuses to continue to complete the context establishment process, releases the context through UE CONTEXT RELEASE COMMAND information, and guides the NG-RAN side to initiate an EPS Fallback flow of NR to LTE at the same time, and after receiving the indication, the NG-RAN side interrupts the service request triggered by the original UE. AN AN Release redirection procedure carrying a different system frequency point is actively triggered (wherein the AN Release redirection procedure carries a 5G co-located station LTE frequency point or a strong coverage LTE frequency point). And the UE side completes a redirection flow from 5GS to EPS and completes the Attach process of the TAU or the Handover type of the corresponding LTE network. And initiates VOLTE call connection on the LTE network.

In the implementation method of the voice service provided by each embodiment of the application, under the condition that the SA network wireless side has high interference and high utilization rate, if the VONR bearing voice service is still used, the conditions of call establishment failure, large time delay, large jitter, call drop and the like can possibly exist even if the voice is established successfully. And selecting a method for judging whether high interference and high utilization rate occur at the wireless side of the SA network in the establishment stage, and if so, directly starting the method for rapidly redirecting to the LTE rescue voice connection. In addition, compared with the original EPS Fallback FLOW, the EPS Fallback FLOW in each embodiment of the application makes FLOW optimization change, changes the original NG-RAN side and selects and measures the LTE wireless environment and the EPS Fallback FLOW after receiving the 5QI1 FLOW issued by the AMF side, but initiates 5GS to EPS redirection according to AMF indication by the NG-RAN side in the starting call process of the UE, reduces the gateway network element, reduces the possibility of failure of signaling transmission in the high interference environment, reduces the complexity of the existing FLOW, shortens the delay of the EPS Fallback bearing voice FLOW, and improves the user perception.

The implementation method of the voice service provided by each embodiment of the application can avoid the situation that the VONR bearing voice service is still used under the conditions of high interference and high utilization rate on the wireless side of the SA network, thereby avoiding the situations that the call establishment fails or the voice is likely to have large time delay, large jitter, dropped call and the like after the call establishment is successful. The implementation method can reduce the network connection element, reduce the possibility of signaling transmission failure in a high-interference environment, reduce the complexity of the existing flow, shorten the delay of the EPS fallback bearing voice flow, and improve the perception of users.

Fig. 13 is a schematic diagram showing a voice service implementation apparatus 130 according to a tenth embodiment of the present application. The implementation device 130 includes a service request module 131, a fallback module 132, and a QOS flow establishment module 133. The service request module 131 is configured to send a service request message to an access and mobility management function device after establishing a radio resource control RRC connection for performing a voice service with a terminal, where the service request message carries a first indication, a second indication and a third indication, the first indication is used to indicate that the service request message is triggered by the voice service of the terminal, the second indication is used to indicate a signal transmission interference strength of a cell in which the terminal currently resides in a preset time, the third indication is used to indicate a physical resource usage rate of the cell in the preset time, and the service message is used to indicate whether the access and mobility management function device actually needs to initiate an EPS fallback procedure for the terminal to implement the voice service. The fallback module 132 is configured to, when receiving a fallback instruction from the access and mobility management function device, fallback the voice service bearer network of the terminal from the first network to the second network according to the fallback instruction. The QoS flow establishment 133 is configured to, when receiving a QoS flow establishment instruction from the access and mobility management function device, establish a QoS flow according to the QoS flow establishment instruction, so as to instruct the terminal to complete the voice service in the first network.

In an alternative implementation manner, the implementation apparatus 130 further includes an RRC establishment module (not illustrated in fig. 13), where the RRC establishment module is configured to receive an RRC establishment complete message from the terminal in a process of establishing a radio resource control RRC connection for performing a voice service with the terminal, and the RRC establishment complete message carries the first indication. The service request obtaining module 121 determines that the RRC establishment complete message is triggered by the voice service of the terminal according to the first indication carried in the received RRC establishment complete message, and carries the second indication and the third indication in the RRC establishment complete message after determining that the RRC establishment complete message is triggered by the voice service of the terminal, so as to obtain the service request message.

In some optional implementations, the service request module 131 carries the second indication and the third indication in the RRC setup complete message, and specifically includes: after the access network device determines that the RRC establishment complete message is triggered by the voice service of the terminal, the access network device newly adds a second indication bit and the third indication pair bit in the RRC establishment complete message; acquiring signal transmission interference intensity of a cell where the terminal resides in within preset time, judging whether the signal transmission interference intensity is higher than a first preset threshold value, if so, giving a first value to a value of the second indication bit, otherwise, giving a second value to the value of the second indication bit, wherein the indication on the second indication bit is a second indication; and acquiring the physical resource utilization rate of the cell within the preset time, judging whether the physical resource utilization rate is higher than a second preset threshold value, if so, giving a first value to the value of the third indication bit, otherwise, giving a second value to the value of the second indication bit, wherein the indication on the third indication bit is a third indication.

In some alternative implementations, the obtaining the fallback indication by the fallback module 132 is specifically:

and receiving a context release instruction message sent by the access and mobility management function equipment when the context establishment flow for the voice service of the terminal is interrupted, wherein whether the context instruction message carries the fallback instruction or not.

As can be seen from the foregoing, in the implementation apparatus 130 of a voice service provided in the embodiment of the present application, a service request message carrying a first indication, a second indication and a third indication is sent to an access and mobile management function device, so as to instruct the access and mobile management function device to determine that the service request message is triggered by a voice service of a terminal according to the first indication, and then, according to the second indication and the third indication, the signal transmission interference strength and the physical resource utilization rate of a cell in which the terminal currently resides are respectively determined in a preset time, and when a fallback indication sent by the access and mobile management function device is received, a voice service bearer network of the terminal is fallback from a first network to a second network according to the fallback indication, and when a flow establishment indication from the access and mobile management function device is received, qoS is established according to the QoS flow establishment indication, so as to instruct the terminal to complete the voice service in the first network. The EPS Fallback flow of the implementing apparatus 130 does not need dedicated bearer establishment in the Fallback process, and may implement fast redirection to the ESP network, and the implementing apparatus 130 actively reports the interference condition and resource utilization condition of the current residence cell of the terminal to the access and mobility management function device, so that the AMF determines whether to send a Fallback indication or a QoS flow establishment indication to the access device according to the interference condition and resource utilization ratio of the current residence cell, that is, determines whether the bearer mode of the voice service of the terminal is VONR or VOLTE. Therefore, the implementation device 130 reduces the call delay and improves the user perception on the premise of reducing the association of network elements in the scene of high interference and high resource utilization.

Fig. 14 is a schematic diagram showing a voice service implementation apparatus 140 according to an eleventh embodiment of the present application. The implementation device 140 includes a service request acquisition module 141, a determination module 142, a fallback indication module 143, and a QOS flow indication module 144. The service request obtaining module 141 is configured to receive a service request message from an access network device, where the service request message carries a first indication, a second indication and a third indication, the first indication is used to indicate that the service request message is triggered by a voice service of a terminal, the second indication is used to indicate signal transmission interference strength of a cell where the terminal currently resides in a preset time, and the third indication is used to indicate physical resource usage of the cell in the preset time. The determining module 142 is configured to determine whether an EPS fallback procedure needs to be initiated for the terminal to implement the voice service according to the service request message. The fallback indication module 143 is configured to send a fallback indication to the access device when the EPS fallback procedure needs to be initiated, where the fallback indication is used to indicate that the voice service bearer network of the terminal falls back from the first network to the second network. And the QoS flow indication 144 is configured to send a QoS flow establishment indication to the access device when the EPS fallback procedure does not need to be initiated, where the QoS flow establishment indication is used to instruct the terminal to complete the voice service in the first network.

In an alternative implementation manner, the determining module 142 is configured to determine, according to the first indication in the service request message, that the service request message is triggered by the voice service of the terminal, and determine, according to the second indication and the third indication in the service request message, whether both the signal transmission interference strength and the physical resource usage rate of the cell in which the terminal resides within a preset time are higher than corresponding preset thresholds; if yes, determining that the EPS fallback process is required to be initiated for the terminal to realize the voice service, and if not, determining that the EPS fallback process is not required to be initiated for the terminal to realize the voice service.

In an optional implementation manner, the fallback indication module 143 is configured to interrupt a context establishment procedure for the voice service of the terminal when the EPS fallback procedure needs to be initiated, carry a fallback indication in a context release instruction message, and send the context release instruction message to the access network device.

According to the implementation device 140 of the voice service provided by the embodiment of the application, after the service request message carrying the first indication, the second indication and the third indication is received to determine that the service request message is the voice service trigger of the terminal according to the first indication, the signal transmission interference intensity and the physical resource utilization rate of the cell where the terminal currently resides in within the preset time are respectively judged according to the second indication and the third indication, whether the current need to initiate an EPS fallback flow for the voice service of the terminal is determined according to the judging result, if a fallback indication is required to be sent to the access network equipment to indicate that the voice service bearing network of the terminal falls back from the first network to the second network, and if the EPS fallback flow is not required to be initiated, when a flow establishment indication is sent to the access network equipment, the access network equipment is enabled to establish QoS flow according to the QoS flow establishment indication to indicate that the terminal completes the voice service in the first network. The EPS Fallback flow of the implementing device 140 of voice service does not need to establish a dedicated bearer in the Fallback process, so that quick redirection to the ESP network can be implemented, and whether to send a Fallback instruction or a QoS flow establishment instruction to the access device is determined according to the interference condition and the resource utilization condition of the current resident cell of the terminal, that is, whether the bearer mode of the voice service of the terminal is VONR or VOLTE is determined. The device 140 for implementing voice service reduces call delay and improves user perception on the premise of reducing network element association under the scenes of high interference and high resource utilization.

In a twelfth embodiment according to the present application, the present application also provides an access network device. Fig. 15 shows a schematic structural diagram of an access network device according to an embodiment of the present application, and the specific embodiment of the present application does not limit the specific implementation of the access network device.

As shown in fig. 15, the access network device may include: a processor 1502, a communication interface (Communications Interface) 1504, a memory 1506, and a communication bus 1508.

Wherein: the processor 1502, communication interface 1504, and memory 1506 perform communication with one another via a communication bus 1508. A communication interface 1504 for communicating with network elements of other devices, such as clients or other servers. The processor 1502 is configured to execute the program 1510, and may specifically perform the relevant steps in the first embodiment to the ninth embodiment.

In particular, the program 1510 may include program code including computer-executable instructions.

The processor 1502 may be a Central Processing Unit (CPU) or a specific integrated circuit ASIC (Application Specific Integrated Circuit) or one or more integrated circuits configured to implement embodiments of the present application. The one or more processors comprised by the access network device may be the same type of processor, such as one or more CPUs; but may also be different types of processors such as one or more CPUs and one or more ASICs.

A memory 1506 for storing a program 1510. The memory 1506 may include high-speed RAM memory, and may also include non-volatile memory (non-volatile memory), such as at least one disk memory.

The program 1510 may be specifically invoked by the processor 1502 to cause the access network device to perform the following operations S12, S14, and S16 in the first embodiment described above.

In an alternative way, the program 1510 is invoked by the processor 1502 to cause the access network device to perform S09, S10, and S11 in the second embodiment described above.

In an alternative way, the program 1510 is invoked by the processor 1502 to cause the access network device to perform S111, S112, and S113 in the third embodiment described above.

In an alternative manner, the program 1510 is invoked by the processor 1502 to cause the access network device to perform the operations of the fourth embodiment described above: and receiving a context release instruction message sent by the access and mobility management function equipment when the context establishment flow for the voice service of the terminal is interrupted, wherein whether the context instruction message carries the fallback instruction or not.

The access network device provided by the embodiment of the application sends the service request message carrying the first indication, the second indication and the third indication to the access and mobile management function device so as to instruct the access and mobile management function device to determine that the service request message is triggered by the voice service of the terminal according to the first indication, respectively judges the signal transmission interference intensity and the physical resource utilization rate of the cell where the terminal currently resides in a preset time according to the second indication and the third indication, and when receiving the fallback indication sent by the access and mobile management function device, the voice service carrying network of the terminal is fallback from the first network to the second network according to the fallback indication, and when receiving the flow establishment indication from the access and mobile management function device, the QoS flow is established according to the QoS flow establishment indication so as to instruct the terminal to complete the voice service in the first network. When the access network device realizes the EPS Fallback flow, a special bearer establishment is not needed in the Fallback process, the quick redirection to the ESP network can be realized, and the access network device actively reports the interference condition and the resource utilization condition of the current resident cell of the terminal to the access and mobility management function device, so that the AMF can determine whether to send a Fallback instruction or a QoS flow establishment instruction to the access device according to the interference condition and the resource utilization ratio of the current resident cell, namely, whether the bearing mode of the voice service of the terminal is VONR or VOLTE is determined. Therefore, the access network equipment is beneficial to reducing the call delay and improving the user perception on the premise of reducing the association of network elements under the scenes of high interference and high resource utilization rate.

In a thirteenth embodiment according to the present application, there is further provided an access and mobility management function device (AMF device), and fig. 16 is a schematic structural diagram of the access and mobility management function device according to the embodiment of the present application, which is not limited by the specific embodiment of the present application.

As shown in fig. 16, the access and mobility management function device may include: a processor 1602, a communication interface (Communications Interface) 1604, a memory 1606, and a communication bus 1608.

Wherein: the processor 1602, communication interface 1604, and memory 1606 communicate with each other via a communication bus 1608. A communication interface 1604 for communicating with other devices, such as network elements of a client or other server, etc. The processor 1602 is configured to execute the program 1610, and may specifically perform the relevant steps in the first to ninth embodiments.

In particular, program 1610 may include program code comprising computer-executable instructions.

The processor 1602 may be a central processing unit CPU, or a specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement embodiments of the present application. The one or more processors comprised by the access network device may be the same type of processor, such as one or more CPUs; but may also be different types of processors such as one or more CPUs and one or more ASICs.

A memory 1606 for storing programs 1610. The memory 1606 may include high-speed RAM memory or may also include non-volatile memory (non-volatile memory), such as at least one disk memory.

The program 1610 may be specifically invoked by the processor 1602 to cause the access and mobility management function device to perform the following operations S22, S24, S26, and S28 in the fifth embodiment described above.

In an alternative manner, the program 1610 is invoked by the processor 1602 to cause the access network device to perform S241, S242, S243 and S244 in the sixth embodiment described above.

In an alternative way, the program 1610 is invoked by the processor 1602 to cause the access network device to perform the steps of the seventh embodiment described above: when the EPS fallback flow needs to be initiated, interrupting a context establishment flow for the voice service of the terminal, carrying a fallback instruction in a context release instruction message, and sending the context release instruction message to the access network equipment.

After receiving a service request message carrying a first indication, a second indication and a third indication to determine that the service request message is a voice service trigger of a terminal according to the first indication, the access and mobile administrative function device according to the second indication and the third indication respectively judges signal transmission interference intensity and physical resource utilization rate of a cell where the terminal currently resides in within a preset time, determines whether to initiate an EPS fallback procedure for the voice service of the terminal currently according to a judging result, if a fallback indication is required to be sent to an access network device to indicate that a voice service bearing network of the terminal falls back from a first network to a second network, and if the EPS fallback procedure is not required to be initiated, when a flow establishment indication is sent to the access network device, the access network device establishes a QoS flow according to the QoS flow establishment indication to indicate that the terminal completes the voice service in the first network. The method can realize that no special bearing is needed to be established in the falling process of the EPS Fallback flow, further can realize quick redirection to an ESP network, and determines whether to send a falling instruction or a QoS flow establishment instruction to the access equipment according to the interference condition and the resource utilization condition of the current resident cell of the terminal, namely, determines whether the bearing mode of the voice service of the terminal is VONR or VOLTE. Therefore, the access and mobility management function equipment can reduce the call delay and improve the user perception on the premise of reducing the association of network elements under the scene of high interference and high resource utilization rate.

In addition, the embodiment of the application further provides a computer readable storage medium, and the computer readable storage medium stores a computer program, and the computer program realizes the steps in the method for realizing the voice service in any embodiment in the market when being executed by a processor. Since the above steps in the implementation method of the voice service have been described in detail and the obtained technical effects are similar, they will not be described in detail.

In addition, the application also provides a communication system which comprises the access network equipment and the access and mobility management function equipment according to any one of the application. A schematic structure of the communication system may be shown with reference to fig. 1.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description. Similarly, it should be appreciated that in the above description of exemplary embodiments of the application, various features of the embodiments of the application are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be construed as reflecting the intention that: i.e., the claimed application requires more features than are expressly recited in each claim. Those skilled in the art will appreciate that the modules in the apparatus of the embodiments may be adaptively changed and disposed in one or more apparatuses different from the embodiments. The modules or units or components of the embodiments may be combined into one module or unit or component, and they may be divided into a plurality of sub-modules or sub-units or sub-components. Any combination of all features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or units of any method or apparatus so disclosed, may be used in combination, except insofar as at least some of such features and/or processes or units are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, third, etc. do not denote any order. These words may be interpreted as names. The steps in the above embodiments should not be construed as limiting the order of execution unless specifically stated.

Claims (10)

1. The method for realizing the voice service is characterized by comprising the following steps:

after establishing a Radio Resource Control (RRC) connection for performing voice service with a terminal, an access network device sends a service request message to an access and mobility management function device, wherein the service request message carries a first indication, a second indication and a third indication, the first indication is used for indicating that the service request message is triggered by the voice service of the terminal, the second indication is used for indicating the signal transmission interference strength of a cell where the terminal currently resides in within a preset time, the third indication is used for indicating the physical resource utilization rate of the cell within the preset time, and the service message is used for indicating whether the access and mobility management function device really needs to initiate an EPS fallback procedure for the terminal to realize the voice service;

When the access network equipment receives a fallback instruction from the access and mobility management function equipment, the access network equipment fallback the voice service bearing network of the terminal from a first network to a second network according to the fallback instruction;

and when the access network equipment receives the QoS flow establishment instruction from the access and mobility management function equipment, the access network equipment establishes QoS flow according to the QoS flow establishment instruction so as to instruct the terminal to finish the voice service in the first network.

2. The implementation method according to claim 1, wherein before the sending the service request message to the access and mobility management function device, the implementation method further comprises:

the access network equipment receives an RRC establishment completion message from a terminal in the process of establishing Radio Resource Control (RRC) connection for voice service with the terminal, wherein the RRC establishment completion message carries the first indication;

the access network equipment determines that the RRC establishment completion message is triggered by the voice service of the terminal according to the received first indication carried in the RRC establishment completion message;

And after determining that the RRC establishment completion message is triggered by the voice service of the terminal, the access network equipment carries the second indication and the third indication in the RRC establishment completion message to obtain the service request message.

3. The implementation method according to claim 2, wherein said carrying the second indication and the third indication in the RRC setup complete message after the access network device determines that the RRC setup complete message is triggered by the voice service of the terminal, comprises:

after the access network device determines that the RRC establishment complete message is triggered by the voice service of the terminal, the access network device newly adds a second indication bit and the third indication pair bit in the RRC establishment complete message;

the access network equipment acquires the signal transmission interference intensity of a cell where the terminal resides in within a preset time, judges whether the signal transmission interference intensity is higher than a first preset threshold value, if yes, the value of the second indication bit is given to a first value, otherwise, the value of the second indication bit is given to a second value, and the indication on the second indication bit is a second indication;

The access network equipment acquires the physical resource utilization rate of the cell in the preset time, judges whether the physical resource utilization rate is higher than a second preset threshold value, if yes, the value of the third indication bit is given to a first value, otherwise, the value of the second indication bit is given to a second value, and the indication on the third indication bit is a third indication.

4. The implementation method according to claim 1, wherein before the access network device drops the voice service bearer network of the terminal from the first network to the second network according to the drop-back indication, the implementation method further comprises:

and the access network equipment receives a context release instruction message sent by the access and mobility management function equipment when the context establishment flow for the voice service of the terminal is interrupted, and whether the context instruction message carries the fallback instruction or not.

5. The method for realizing the voice service is characterized by comprising the following steps:

the method comprises the steps that an access and mobility management function device receives a service request message from an access network device, wherein the service request message carries a first indication, a second indication and a third indication, the first indication is used for indicating that the service request message is triggered by voice service of a terminal, the second indication is used for indicating signal transmission interference intensity of a cell where the terminal currently resides in within a preset time, and the third indication is used for indicating physical resource utilization rate of the cell within the preset time;

The access and mobility management function device determines whether to initiate an EPS fallback procedure for the terminal according to the service request message to realize the voice service;

when the EPS fallback flow needs to be initiated, the access and mobility management function equipment sends a fallback instruction to the access equipment, wherein the fallback instruction is used for indicating that a voice service bearing network of the terminal is fallback from a first network to a second network;

and when the EPS fallback flow does not need to be initiated, the access and mobility management function equipment sends a QoS flow establishment instruction to the access equipment, wherein the QoS flow establishment instruction is used for indicating the terminal to finish the voice service in the first network.

6. The implementation method according to claim 5, wherein the determining, by the access and mobility management function device according to the service request message, whether an EPS fallback procedure needs to be initiated for the terminal to implement the voice service includes:

the access and mobility management function device determining that the service request message is triggered by the voice service of the terminal according to the first indication in the service request message;

The access and mobility management function equipment judges whether the signal transmission interference intensity and the physical resource utilization rate of the cell where the terminal resides in a preset time are higher than corresponding preset thresholds according to the second indication and the third indication in the service request message;

if yes, the access and mobility management function equipment determines that an EPS fallback process needs to be initiated for the terminal to realize the voice service;

if not, the access and mobility management function device determines that the EPS fallback process does not need to be initiated for the terminal to realize the voice service.

7. The implementation method according to claim 5, wherein the sending, by the access and mobility management function device, a fallback indication to the access device when the EPS fallback procedure needs to be initiated includes:

and when the EPS fallback flow needs to be initiated, the access and mobility management function equipment interrupts a context establishment flow for the voice service of the terminal, carries a fallback instruction in a context release instruction message, and sends the context release instruction message to the access network equipment.

8. An access network device, comprising a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface complete communication with each other through the communication bus;

the memory is configured to store at least one executable instruction that causes the processor to perform the method for implementing a voice service according to any one of claims 1 to 4.

9. An access and mobility management function device comprising a processor, a memory, a communication interface and a communication bus, said processor, said memory and said communication interface completing communication with each other via said communication bus;

the memory is configured to store at least one executable instruction that causes the processor to perform the method for implementing a voice service according to any one of claims 5 to 7.

10. A computer readable storage medium, characterized in that the computer readable storage medium has stored thereon a computer program which, when executed by a processor, implements a method of implementing a voice service according to any of claims 1 to 7.