Method, device and storage medium for implementing voice service

Abstract

Embodiments of the present application relate to the technical field of communication, and disclose a voice service implementation method, device and storage medium. The voice service implementation method comprises: 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; determining whether an EPS Fallback process needs to be initiated for terminal voice service according to the service request message; and optimizing the EPS Fallback process. The voice service implementation method can reduce call delay and improve user perception under the premise of reducing network element association in a high-interference and high-resource-utilization scenario.

Description

Technical Field

[0001] This application relates to the field of communication technology, specifically to a method, device, and storage medium for implementing voice services. Background Technology

[0002] Based on the combination of base stations and the core network, 5G (Fifth Generation Mobile Communication Technology) is divided into two network types: NSA (Non-Standalone) and SA (Standalone) networks. NSA networking typically refers to a network architecture where 4G (Fourth Generation Mobile Communication Technology) base stations and 5G base stations coexist on the radio side, and the core network uses either a 4G or 5G core network. SA, on the other hand, refers to a network architecture where the radio side uses 5G base stations, and the core network uses a 5G core network. In the early stages of 5G development, NSA networking solutions are more commonly used. However, with the comprehensive coverage and deep optimization of 5G networks, SA networking solutions will become the preferred choice for various operators.

[0003] In the initial stage of 5G SA network deployment, the EPS (Evolved Packet System) fallback process is used to implement voice services for User Equipment (UE). Once 5G SA network coverage is mature, Voice Over New Radio (VONR) will be used to implement voice services for UE. VONR refers to the 5G access network and core network providing voice services based on IMS (IP Multimedia Subsystem).

[0004] However, even if the 5G SA network has been fully covered and optimized, using VONR to carry voice services for user equipment will still have problems such as call setup failure or, after successful setup, large latency, jitter, and dropped calls. Summary of the Invention

[0005] In view of the above problems, embodiments of this application provide a method for implementing voice services, an access network device, an access and mobility management function device, and a computer-readable storage medium to solve the problems of large delays, large jitters, and dropped calls in the prior art after voice service call establishment failure or successful establishment.

[0006] According to a first aspect of the embodiments of this application, a method for implementing a voice service is provided, the method comprising:

[0007] After establishing a Radio Resource Control (RRC) connection with a terminal for voice services, the access network device sends a service request message to the access and mobility management function (AM) device. The service request message carries a first indication, a second indication, and a third indication. The first indication indicates that the service request message is triggered by the terminal's voice service. The second indication indicates the signal transmission interference strength of the cell where the terminal is currently camped within a preset time period. The third indication indicates the physical resource utilization rate of the cell within the preset time period. The service message indicates whether the AM device needs to initiate an EPS fallback procedure for the terminal to implement the voice service.

[0008] When the access network device receives a fallback instruction from the access and mobility management function device, the access network device falls back the voice service bearer network of the terminal from the first network to the second network according to the fallback instruction;

[0009] The access network device receives a QoS flow establishment instruction from the access and mobility management function device, and 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.

[0010] In an alternative embodiment, before sending the service request message to the access and mobility management function device, the implementation method further includes:

[0011] During the process of establishing a Radio Resource Control (RRC) connection with a terminal for voice services, the access network device receives an RRC establishment completion message from the terminal, and the RRC establishment completion message carries the first indication.

[0012] The access network device determines, based on the first indication carried in the received RRC establishment completion message, that the RRC establishment completion message was triggered by the voice service of the terminal;

[0013] After determining that the RRC establishment completion message was triggered by the voice service of the terminal, the access network device carries the second indication and the third indication in the RRC establishment completion message to obtain the service request message.

[0014] In one alternative approach, after the access network device determines that the RRC establishment completion message is triggered by the voice service of the terminal, the second indication and the third indication are carried in the RRC establishment completion message, including:

[0015] After the access network device determines that the RRC establishment completion message is triggered by the voice service of the terminal, the access network device adds a second indicator bit and the third indicator pair bit to the RRC establishment completion message;

[0016] The access network device obtains the signal transmission interference strength of the cell where the terminal is camped within a preset time period, and determines whether the signal transmission interference strength is higher than a first preset threshold value. If so, the value of the second indicator bit is assigned to the first value; otherwise, the value of the second indicator bit is assigned to the second value. The indication on the second indicator bit is the second indication.

[0017] The access network device obtains the physical resource utilization rate of the cell within the preset time period and determines whether the physical resource utilization rate is higher than the second preset threshold. If so, the value of the third indicator bit is assigned to the first value; otherwise, the value of the second indicator bit is assigned to the second value. The indicator on the third indicator bit is the third indicator.

[0018] In an alternative embodiment, before the access network device falls back the terminal's voice service bearer network from the first network to the second network according to the fallback instruction, the implementation method further includes:

[0019] The access network device receives a context release instruction message sent by the access and mobility management function device when the context establishment process for the voice service of the terminal is interrupted, wherein the context release instruction message carries the fallback indication.

[0020] According to a second aspect of the embodiments of this application, a method for implementing a voice service is provided, comprising:

[0021] The access and mobility management function device receives a service request message from the access network device. 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 terminal's voice service. The second indication is used to indicate the signal transmission interference strength of the cell where the terminal is currently camped within a preset time. The third indication is used to indicate the physical resource utilization rate of the cell within the preset time.

[0022] The access and mobility management function device determines whether it is necessary to initiate an EPS fallback process for the terminal to implement the voice service based on the service request message;

[0023] When the EPS fallback process needs to be initiated, the access and mobility management function device sends a fallback instruction to the access device. The fallback instruction is used to instruct the terminal's voice service bearer network to fall back from the first network to the second network.

[0024] When the EPS fallback process is not required, the access and mobility management function device sends a QoS flow establishment instruction to the access device. The QoS flow establishment instruction is used to instruct the terminal to complete the voice service in the first network.

[0025] In one alternative approach, the access and mobility management function device determines, based on the service request message, whether an EPS fallback procedure needs to be initiated for the terminal to implement the voice service, including:

[0026] The access and mobility management function device determines, based on the first indication in the service request message, that the service request message is triggered by the voice service of the terminal;

[0027] The access and mobility management function device determines, based on the second and third indications in the service request message, whether the signal transmission interference intensity and physical resource utilization rate of the cell where the terminal is stationed are both higher than the corresponding preset threshold within a preset time.

[0028] If so, the access and mobility management function device determines that an EPS fallback process needs to be initiated for the terminal to implement the voice service;

[0029] If not, the access and mobility management function device determines that it is not necessary to initiate an EPS fallback process for the terminal to implement the voice service.

[0030] In one alternative approach, when the EPS fallback process needs to be initiated, the access and mobility management function device sends a fallback instruction to the access device, including:

[0031] When the EPS fallback process needs to be initiated, the access and mobility management function device interrupts the context establishment process for the voice service of the terminal, carries the fallback indication in the context release instruction message, and sends the context release instruction message to the access network device.

[0032] According to a third aspect of the embodiments of this application, an access network device is provided, including a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus;

[0033] The memory is used to store at least one executable instruction that causes the processor to execute the voice service implementation method as described in any of the preceding claims.

[0034] According to a fourth aspect of the embodiments of this application, an access and mobility management function device is provided, including a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus;

[0035] The memory is used to store at least one executable instruction that causes the processor to execute the voice service implementation method as described in any of the preceding claims.

[0036] According to a fifth aspect of the embodiments of this application, a computer-readable storage medium is provided, on which a computer program is stored, and when executed by a processor, the computer program implements the voice service implementation method as described in any of the preceding claims.

[0037] The first aspect of this application provides a method for implementing voice services, in which an access network device sends a service request message carrying a first indication, a second indication, and a third indication to an access and mobility management function device (AMD). The AMD instructs the AMD to determine, based on the first indication, that the service request message is triggered by a terminal's voice service. Then, based on the second and third indications, the AMD determines the signal transmission interference strength and physical resource utilization rate of the cell where the terminal is currently residing within a preset time period. Upon receiving a fallback indication from the AMD, the AMD falls back the terminal's voice service bearer network from a first network to a second network according to the fallback indication. Finally, upon receiving a flow establishment indication from the AMD, the access network device establishes a QoS flow according to the QoS flow establishment indication, thereby instructing the terminal to complete the voice service in the first network. The voice service implementation method provided in the first embodiment does not require dedicated bearer establishment during the EPS Fallback process, enabling rapid redirection to the ESP network. Furthermore, the access network device proactively reports the interference and resource utilization status of the terminal's current cell to the access and mobility management function (AMF) device. The AMF then determines, based on the interference and resource utilization of the current cell, whether to send a fallback instruction or a QoS flow establishment instruction to the access device, i.e., whether the voice service bearer mode for the terminal is VONR or VOLTE. Therefore, the voice service implementation method provided in the first embodiment reduces call latency and improves user experience by minimizing network element association in scenarios with high interference and high resource utilization.

[0038] The second aspect of this application provides a method for implementing voice services. This method involves receiving a service request message carrying a first indication, a second indication, and a third indication through an access and mobility management function (AVM). After determining that the service request message is triggered by a terminal's voice service based on the first indication, the method further determines the signal transmission interference intensity and physical resource utilization rate of the cell where the terminal is currently residing within a preset time period based on the second and third indications. Based on the determination results, it is then determined whether an EPS fallback process needs to be initiated for the terminal's voice service. If so, a fallback indication is sent to the access network device to instruct the terminal's voice service bearer network to fall back from the first network to the second network. If an EPS fallback process does not need 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, instructing the terminal to complete the voice service in the first network. The voice service implementation method provided in the fifth embodiment does not require dedicated bearer establishment during the fallback process, enabling rapid redirection to the ESP network. Furthermore, it determines whether to send a fallback instruction or a QoS flow establishment instruction to the access device based on the interference and resource utilization of the terminal's current cell, thus determining whether the voice service bearer mode for the terminal is VONR or VOLTE. Therefore, the voice service implementation method provided in the fifth embodiment reduces call latency and improves user experience by minimizing network element associations in scenarios with high interference and high resource utilization.

[0039] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0040] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0041] Figure 1 This is a schematic diagram of the signal flow in the existing EPS fallback process;

[0042] Figure 2 It is a mobile communication system that includes both 5G and 4G networks;

[0043] Figure 3 This is a schematic flowchart of a method for implementing voice services according to the first embodiment of this application;

[0044] Figure 4This is a schematic flowchart of a method for implementing voice services according to the second embodiment of this application;

[0045] Figure 5 This is a schematic diagram of the signal flow during the RRC establishment process between the access network device and the terminal in the voice service implementation method provided according to the embodiments of this application;

[0046] Figure 6 This is a schematic diagram of the signal flow of the voice service switching method provided according to the second embodiment of this application;

[0047] Figure 7 This is a flowchart of a method for implementing voice services according to the third embodiment of this application;

[0048] Figure 8 This is a schematic diagram of the implementation method of voice service according to the fifth embodiment of this application;

[0049] Figure 9 This is a schematic flowchart of a method for implementing voice services according to the sixth embodiment of this application;

[0050] Figure 10 This is a schematic diagram of the signal flow of a voice service implementation method provided according to the seventh embodiment of this application;

[0051] Figure 11 This is a schematic diagram of the signal flow of a voice service implementation method provided according to the eighth embodiment of this application;

[0052] Figure 12 This is a flowchart illustrating the method for implementing voice services according to the ninth embodiment of this application;

[0053] Figure 13 This application provides a voice service implementation apparatus according to its tenth embodiment.

[0054] Figure 14 This application provides an apparatus for implementing voice services according to its eleventh embodiment.

[0055] Figure 15 This is a schematic diagram of an access network device structure provided according to the twelfth embodiment of this application;

[0056] Figure 16 This is a schematic diagram of an access and mobility management function device provided according to the thirteenth embodiment of this application. Detailed Implementation

[0057] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0058] Before describing the various specific embodiments of this application, the technical terms involved in the various embodiments of this application will be introduced as follows, wherein the English and Chinese following “:” are respectively the English and Chinese explanations of the technical terms preceding “:”.

[0059] 5G: Fifth Generation Mobile Communication Technology.

[0060] 5GS: Fifth Generation System, 5G system.

[0061] 4G: Fourth Generation Mobile Communication Technology.

[0062] 3GPP: Third Generation Partnership Project.

[0063] AMF: Access and mobility management function.

[0064] AN: Access Network.

[0065] CMNET: China Mobile Network.

[0066] EPS: Evolved Packet System.

[0067] E-UTRAN: Evolved Universal Terrestrial Radio Access Network.

[0068] ENB: Evolved Node B.

[0069] GBR: Guaranteed Bit Rate.

[0070] GNB: Next Generation Node-B.

[0071] HSS: Home Subscriber Server.

[0072] IMS: IP Multimedia Subsystem.

[0073] IP: (Internet Protocol)

[0074] LTE: Long Term Evolution.

[0075] MO: Mobile Origination.

[0076] MT: Mobile Termination, the called party.

[0077] MME: Mobility Management Entity.

[0078] MCS: Modulation and Coding Scheme.

[0079] NG-(R)AN: Next Generation-(Radio)Access Network.

[0080] NAS: Non-Access Stratum. NR: New Radio.

[0081] NSA: Non-Standalone. NW: Network.

[0082] N26: The interface between the MME and AMF, used to transmit mobility management state and session management state between the source and target networks during 4G and 5G network interoperation.

[0083] PDU: Protocol Data Unit.

[0084] PGW: Packet Data Network Gateway.

[0085] PCF: Policy control function.

[0086] PRB: Physical Resource Block.

[0087] RRC: Radio Resource Control.

[0088] PRACH: Physical Random Access Channel.

[0089] PCRF: Policy and Charging Rules Function.

[0090] PGW-C: Packet Data Network Gateway-Control.

[0091] PGW-U: Packet Data Network Gateway User plane.

[0092] SR: Service Request.

[0093] SA: Standalone, independent.

[0094] S-CSCF: Serving-Call SessionControl Function.

[0095] SMF: Session Management Function.

[0096] SBC: Session Border Control.

[0097] SGW: Serving Gateway.

[0098] SINR: Signal to Interference plus Noise Ratio.

[0099] RAR: Random Access Response.

[0100] RAA: Random Access Area.

[0101] TAU: Tracking Area Update.

[0102] UE: User Equipment.

[0103] UPF: User Plane Function.

[0104] UDM: Unified Data Management.

[0105] VONR: Voice Over New Radio.

[0106] QoS: Quality of Service.

[0107] 5QI: 5G QoS Indicator.

[0108] QC: QoS Class Identification.

[0109] During their research, the inventors of this application discovered that consistently using VONR for voice services in SA networks can lead to call setup failures, and even after successful setup, issues such as high latency, jitter, and dropped calls may occur. The inventors attribute this to high interference and high utilization rates on the SA network's wireless side. If a user device is located in a high-interference SINR environment, low coding (e.g., low MCS) will be used to ensure bandwidth, consuming significant PRB resources. Furthermore, during the establishment of a dedicated flow, as it is a GBR service, the flow establishment process can preempt 5QI9 (5QI=9) services (CMNET data services). If several low-quality user devices in the same cell are making calls, it will inevitably consume a large amount of network resources. If the cell is also in an environment with high physical resource utilization, existing data service users will be unable to be scheduled, or may even experience dropped calls, because the May-trigger-pre-emption (which can trigger preemption) dedicated resources for video calls will heavily preempt resources from existing internet users.

[0110] Therefore, the voice service implementation method provided in this application adds a judgment on the signal transmission interference intensity and physical resource utilization rate in the SA network coverage area where the terminal resides during the voice service initiation stage. Based on the judgment result, it selects whether to initiate a handover or redirect to the ESP network to realize the voice service connection or continue to realize the terminal's voice service in the SA network using the VONR method.

[0111] Furthermore, this application optimizes the existing EPS Fallback process by employing the ESP Fallback procedure to switch or redirect to the ESP network for voice services. The existing ESP Fallback procedure involves the NG-RAN device selecting between measuring the LTE radio environment and the EPS Fallback procedure after receiving a 5QI1 (5G QoS Indicator) flow from the AMF device. Therefore, the existing ESP Fallback procedure requires establishing a QoS flow, which is useless for redirecting to the ESP network for voice services but adds latency and unnecessary signaling interactions. In contrast, the ESP Fallback procedure in this application involves the NG-RAN device initiating a 5GS to EPS redirection during the voice service establishment process, based on the AMF device's instructions. That is, in this application's ESP Fallback procedure, the AMF device directly decides to redirect to the ESP network for voice services during the transition from idle to active state, without waiting for the 5QI1 flow establishment request from the SMF network element, and the NG-RAN device rejecting the request before initiating the 5GS to EPS redirection. Furthermore, in this application, the redirection from 5GS to EPS can be either measurement-based redirection or blind redirection. Therefore, the voice service implementation method provided in this application can reduce associated network elements, decrease the possibility of signaling transmission failure in high-interference environments, reduce the complexity of existing processes, shorten the latency of the voice process carried by the EPS Fallback, and improve user experience.

[0112] To better distinguish this application from existing voice service implementation methods, before specifically introducing the voice service implementation method provided in this application, the existing voice service implementation methods will be introduced as follows:

[0113] The existing 5G voice process mainly involves the terminal registering with the AMF device and the S-CSCF of the IMS network element in the 5GS. In the MO or MT process, the network triggers PDU session modification to establish a QoS flow for IMS voice, and subsequently completes the voice connection through the VONR process. However, if the NG-RAN device chooses to carry IMS voice in fallback mode, it triggers ESP Fallback and notifies the network. The terminal enters the EPS network through handover or redirection. After the EPS session is restored, the network triggers PDN connection modification to establish a dedicated bearer for IMS voice, and completes the voice service connection in the form of EPS Fallback.

[0114] The existing EPS Fallback flowchart is as follows: Figure 1 As shown, Figure 1The EPS Fallback process is illustrated using a UE-initiated calling voice service as an example. The process is described as follows:

[0115] 1. When there is an IMS voice service with either the calling or receiving party, a QoS flow of 5QI=5 (5QI5) is established, and the UE changes from idle state to connected state;

[0116] 2. The core network initiates PDU session correction to the radio side to establish a QoS flow for IMS voice. That is, the QoS flow establishment of 5QI=1 (5Q11) is carried out. The process is that the UE reports the voice request to the SBC, the SBC finds a dedicated flow establishment strategy from the PCF, and sends it to the NG-RAN side through the SMF / AMF.

[0117] 3. The NG-RAN side triggers the EPS Fallback procedure. On one hand, the NG-RAN side sends the LTE radio environment measurement configuration to the UE, and on the other hand, the NG-RAN side notifies the AMF / SMF to refuse to establish a QoS flow with 5QI=1.

[0118] 4. Reject the PDU session modification request and inform the core network that IMS voice fallback is to be performed.

[0119] 5. NG-RAM can be redirected or switched to EPS based on the fallback indication. For example, it can switch to EPS based on N26.

[0120] 6a. Perform TAU.

[0121] 6b. (Based on N26) Perform an attach, request to establish a PDN connection, and the reason for the request is handover or redirection.

[0122] 7. After the UE successfully camps on the 4G network, the core network initiates PDN connection correction to establish a dedicated bearer for voice. That is, after returning to LTE, a dedicated bearer with QCI=1 is established.

[0123] 8. Continue the process of establishing an IMS voice session on the 4G network.

[0124] The existing EPS Fallback procedure occurs when the NG-RAN side receives a new 5QI=1 QoS flow request from the AMF side. The NG-RAN side uses the EPS Fallback procedure to continue the call. On the one hand, it reports to the AMF / SMF that it is unable to establish a dedicated 5QI1 flow and rejects the PDU session modification request, and informs the core network to perform IMS voice fallback. On the other hand, it instructs the UE to start LTE side measurement and report, and completes the 5GS to EPS handover according to the measurement report. After the handover is completed, the SGW is addressed according to the SGW side IP address indicated by 5GS during the handover process, and the SGW side triggers the establishment of QCI1 dedicated bearer again. As can be seen, in existing technologies, the EPS Fallback process is triggered by the upper layer and involves a stage where the PDU session initiated by the SMF is modified to establish a Qosflow for IMS voice communication. This stage specifically includes: the UE reporting a voice request to the SBC; the SBC searching for a dedicated flow establishment strategy from the PCF; the PCF instructing the SMF on the dedicated flow establishment strategy (RAR / RAA messages); the SMF / AMF sending NAMF_COMMUNICATION_N1N2MESSAGETRANSFER REQUEST messages and PDU SESSION MODIFICATIONCOMMAND messages to the NG-RAN side; the NG-RAN side reporting back to the AMF / SMF that it refuses to establish a 5QI1 dedicated flow; the NG-RAN side sending measurement configurations for LTE and completing the 5GS to EPS handover process in conjunction with the EPS and 5GS network elements based on the measurement report; and the SGW triggering the terminal to complete the establishment of a dedicated bearer with QCI 1 in the EPS network. Therefore, the existing EPS Fallback process must go through these multiple steps and requires the introduction of multiple network elements. The more network elements introduced, the greater the possibility of failure and the greater the latency. The EPS Fallback procedure provided in this application does not require dedicated bearer establishment during the fallback process, enabling rapid redirection to the ESP network. This application changes the existing passively triggered EPS Fallback procedure from the NG-RAN side to an active decision-making process by the AMF side guiding the NG-RAN to trigger the fallback procedure. This reduces call latency and improves user experience while minimizing network element correlation in high-interference scenarios.

[0125] The voice service implementation method provided in this application is applied to a wireless communication system, which includes a first network and a second network. The first network has a higher priority than the second network. In some embodiments, the first network is a 5G network and the second network is a 4G network (which can be referred to as an EPS network). Figure 1As shown, the 5G network includes: (Radio) Access Network (R)AN equipment, AMF equipment (or network elements), UDM network elements, PCF network elements, SMF network elements, and UPF network elements. The (R)AN equipment can be next-generation NG-RAN equipment or E-UTRAN equipment. The 4G network includes: E-UTRAN equipment, MME network elements, SGW, PGW, PCRF network elements, and HSS network elements. The E-UTRAN equipment can be an evolved Node B. The packet data gateway can include PGW-C network elements and PGW-U network elements. Some network elements of the 5G network and some network elements of the EPS network can be deployed on the same physical entity, enabling the 5G network and the 4G network to interact, for example... Figure 2 As shown, the HSS network element and UDM network element are deployed in the same physical entity, the PCF network element and PCRF network element are deployed in the same physical entity, the SMF network element and PGW-C network element are deployed in the same physical entity, and the UPF network element and PGW-U network element are deployed in the same physical entity. These network elements can also be separate network elements, and this embodiment does not limit this. There are interoperability interfaces between the 5G network and the 4G network. For example, the AMF network element can communicate with the MME network element through the N26 interface, and the MME network element can communicate with the MSC network element through the Sv interface. The aforementioned 4G network and 5G network may also include other devices or network elements, and this embodiment does not specifically limit these.

[0126] exist Figure 2 In the wireless communication system shown, the terminal equipment can also be referred to as User Equipment (UE), Access Terminal, User Unit, User Station, Mobile Station, Mobile Station, Remote Station, Remote Terminal, Mobile Device, User Terminal, Terminal, Wireless Communication Equipment, User Agent, or User Equipment. The terminal equipment can also be a station in a wireless local area network (WLAN), and can be a cellular phone, cordless phone, session initiation protocol phone, wireless local loop station, personal digital processing device, handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, vehicle-mounted device, or wearable device (also known as wearable smart device). The terminal equipment can also be a terminal equipment in next-generation communication systems, such as terminal equipment in 5G or in future evolved public terrestrial mobile networks, or terminal equipment in NR communication systems.

[0127] AMF (Automatic Facilitation) network elements are responsible for terminal device registration, mobility management, and tracking area update procedures. AMF network elements can also be called AMF devices or AMF entities. SMF (Sustainable Facilitation) network elements are responsible for terminal device session management. For example, session management includes user plane device selection, user plane device reselection, IP address allocation, Quality of Service (QoS) control, and session establishment, modification, or release. SMF network elements can also be called SMF entities or SMF devices.

[0128] PCF network elements include policy control and flow-based charging control functions. For example, PCF network elements can implement policy control functions, charging policy control functions, QoS control, etc. PCF network elements can also be called PCF entities or PCF devices. MME network elements are responsible for terminal device authentication, mobility management, and session management. MME network elements can also be called MME devices or MME entities. UDM devices have unified data management functions, mainly responsible for managing subscription data, user access authorization, etc. SMF devices have session management functions, mainly performing session management, execution of PCF-issued control policies, UPF selection, and UE Internet Protocol (IP) address allocation, etc. UPF devices are user plane function entities, acting as the interface with the data network, and completing user plane data forwarding, session / flow-based charging statistics, bandwidth limiting, etc.

[0129] Figure 2 Each network element can be a network component implemented on dedicated hardware, a software instance running on dedicated hardware, or an instance of virtualized functionality on a suitable platform, such as a cloud platform. The voice service implementation method provided in this application can be applied to... Figure 2 The specific network element or device in the communication system shown.

[0130] 5G (fifth-generation mobile communication technology) networks define two voice access methods: Voice over New Radio (VONR) and Evolved Packet System (EPS) fallback. VONR refers to voice services based on the IP Multimedia Subsystem provided by the 5G access network and core network, while EPS fallback refers to a UE falling back to the EPS network (4G network) when initiating an IMS call on the 5G network, thus enabling voice services through the 4G network.

[0131] Please see Figure 3 The diagram shown is a flowchart illustrating the implementation method of a voice service according to the first embodiment of this application. The implementation method of the voice service includes, but is not limited to, S12, S14, and S16, as described in detail below:

[0132] S12: After establishing a Radio Resource Control (RRC) connection with the terminal for voice services, the access network device sends a Service Request (SR) message to the Access and Mobility Management Function (AMF) device. The SR message carries a first indication, a second indication, and a third indication. The first indication indicates that the SR message is triggered by the terminal's voice service. The second indication indicates the signal transmission interference strength of the cell where the terminal is currently residing within a preset time period. The third indication indicates the physical resource utilization rate of the cell within the preset time period. The SR message indicates whether the AMF device needs to initiate an EPS fallback procedure for the terminal to implement the voice service.

[0133] The service request message can be a single message or multiple messages sent simultaneously or with a time difference less than a preset time difference. The first indication, second indication, and third indication can be indication data from three indication bits in the same message or indication data from corresponding indication bits in different messages. The terminal's voice service can refer to a calling voice service initiated by the terminal or a called voice service initiated by the terminal. Based on the first indication, it can be determined whether the service request message is triggered by the calling voice service or the called voice service. The terminal's voice service includes voice call service and video call service. The terminal's current registered cell refers to the network the terminal is currently registered with. In this embodiment, the service request message is used to request the terminal to implement voice service in the first network, and the terminal's current registered cell is the area covered by the first network where the terminal is registered. The preset time period can refer to the most recent preset time period within the terminal's registered cell, such as the most recent time period. The most recent preset time period refers to the previous preset time period. For the calling voice service, the interference intensity of the signal transmission refers to the uplink interference intensity, while for the called voice service, the interference intensity of the signal transmission refers to the downlink interference intensity. The physical resource utilization rate refers to the uplink physical resource utilization rate and / or the downlink physical resource utilization rate. The service message is used to instruct the access and mobility management function device whether it needs to initiate an EPS fallback procedure for the terminal to implement the voice service. Specifically, the first indication in the service request message instructs the mobility management function device to determine whether the service request message was triggered by the terminal's voice service. If so, a second and third indication are provided in the service request message to instruct the mobility management function device to determine whether it needs to initiate an EPS fallback procedure for the terminal to implement the voice service. Initiating an EPS fallback procedure for the terminal to implement the voice service includes making the bearer network for the terminal's voice service an LTE network, i.e., implementing the terminal's voice service using VoLTE sampling. The access network device can be an NG-RAN device.

[0134] S14: When the access network device receives a fallback instruction from the access and mobility management function device, the access network device falls back the terminal's voice service bearer network from the first network to the second network according to the fallback instruction. In the first embodiment, the first network is a 5G network, such as a 5G SA network deployed in SA networking mode. The second network is a 4G network, also known as an EPS network, such as an LTE network.

[0135] The access and mobility management function device determines whether the EPS fallback process needs to be initiated based on the first indication, the second indication, and the third indication in the service request message, in order to determine whether it is necessary to send the corresponding fallback indication or the QoS flow establishment indication to the access network device, and to determine whether the voice service bearer mode of the terminal is VONR or VOLTE.

[0136] S16: When the access network device receives a QoS flow establishment instruction from the access and mobility management function device, 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.

[0137] The terminal completing the voice service in the first network means that the terminal implements the voice service in the VONR manner.

[0138] As can be seen from the above, the voice service implementation method provided in the first embodiment involves the access network device sending a service request message carrying a first indication, a second indication, and a third indication to the access and mobility management function device. This instructs the access and mobility management function device to determine, based on the first indication, that the service request message is triggered by the terminal's voice service. Then, based on the second and third indications, the access network device determines the signal transmission interference strength and physical resource utilization rate of the cell where the terminal is currently residing within a preset time period. Upon receiving a fallback indication from the access and mobility management function device, the access network device falls back the terminal's voice service bearer network from the first network to the second network according to the fallback indication. Finally, upon receiving a flow establishment indication from the access and mobility management function device, the access network device establishes a QoS flow according to the QoS flow establishment indication, thereby instructing the terminal to complete the voice service in the first network. The voice service implementation method provided in the first embodiment does not require dedicated bearer establishment during the EPS Fallback process, enabling rapid redirection to the ESP network. Furthermore, the access network device proactively reports the interference and resource utilization status of the terminal's current cell to the access and mobility management function (AMF) device. The AMF then determines, based on the interference and resource utilization of the current cell, whether to send a fallback instruction or a QoS flow establishment instruction to the access device, i.e., whether the voice service bearer mode for the terminal is VONR or VOLTE. Therefore, the voice service implementation method provided in the first embodiment reduces call latency and improves user experience by minimizing network element association in scenarios with high interference and high resource utilization.

[0139] like Figure 4As shown, this is a method for implementing voice services according to the second embodiment of this application. In the second embodiment, the method for implementing voice services further includes the following steps before sending the service request message to the access and mobility management function device, i.e., before S12:

[0140] S09: During the process of establishing a Radio Resource Control (RRC) connection with a terminal for voice services, the access network device receives an RRC establishment completion message from the terminal, the RRC establishment completion message carrying the first indication.

[0141] S10: The access network device determines, based on the first indication carried in the received RRC establishment completion message, that the RRC establishment completion message was triggered by the voice service of the terminal.

[0142] S11: After determining that the RRC establishment completion message was triggered by the voice service of the terminal, the access network device carries the second indication and the third indication in the RRC establishment completion message to obtain the service request message.

[0143] The access network device (IG-RAN) can be a gNB, and the terminal is a UE. The access network device establishes an RRC connection for voice services with the terminal and interprets the RRC establishment completion message, as follows: Figure 5The diagram illustrates the signal flow of the RRC establishment process between the access network device and the terminal. After powering on, the UE attaches to the 5G network, establishes an IMS PDU session, registers with IMS, and enters the idle state. Before initiating an IMS voice service to another UE, the idle UE first triggers the establishment of an RRC connection with the NG-RAN device. The UE sends a random access preamble (Msg1) to the NG-RAN device (which can be a gNB) and listens on the physical downlink control channel within the RAR time window to receive the random access response (RAR) (Msg2) corresponding to the radio network temporary identifier. After receiving the RAR, the UE accesses the gNB. If the UE needs to initiate a voice service after accessing the gNB, it sends an RRC Setup Request message (RRC Setup Request) to the gNB (through the SRB0 channel). The gNB performs UE context establishment based on the RRC Setup Request message, confirms the resource allocation of the SRB1 channel, and then sends an RRC Setup instruction (RRC Setup) to the UE through the SRB0 channel. Finally, the UE sends an RRC Setup Complete message to the gNB via the SRB1 channel. After the RRC setup is completed, the terminal's state changes from idle to connected. The RRC Setup Complete message may carry the first indication. Based on the first indication in the RRC Setup Complete message, the gNB determines that the RRC Setup Complete message was triggered by the terminal's voice service. The first indication indicates that the reason for the RRC setup is the terminal's voice service. The first indication can represent the terminal's calling voice service, such as MO-VoiceCall, or the terminal's called voice service, such as MT-VoiceCall.

[0144] After receiving the RRC Setup Complete, the access network device determines that the reason for the RRC establishment is that the terminal attempts to initiate a voice service based on the first indication therein. After determining that the RRC Setup Complete is triggered by the terminal's voice service, the access network device obtains the signal transmission interference strength and material resource utilization rate of the cell where the terminal is currently camped within a preset time period, and adds the two pieces of information to the RRC Setup Complete as the second and third indications in the RRC Setup Complete.

[0145] After the NG-RAN adds the second and third instructions in RRC Setup Complete, it obtains the service request message. The service request message is a NAS message, INITIAL UE MESSAGE. The access network device sends this INITIAL UE MESSAGE to the AMF device. Specifically, as follows... Figure 6 The diagram illustrates the signal flow of the voice service handover method according to the second embodiment of this application. The UE sends an RRC Setup Complete message to the gNodeB (gNB). Upon receiving the RRC Setup Complete message, if the establishment reason value in the RRC Setup Complete message is the terminal's voice service, the NodeB adds interference (first indication) and resource (second indication) reporting fields to the RRC Setup Complete message, obtains the initial UE message, and reports this service request message to the 5G core network, such as to the AMF device in the 5G core network.

[0146] Taking an idle terminal as the calling party initiating a voice service request in an SA network as an example, the process first involves establishing an RRC connection with the access network equipment. After establishment, the terminal's state changes from idle to active. Subsequently, the terminal initiates a contention-based PRACH procedure, carrying the RRC establishment reason (RRC-Establishment-Cause) in the Initial UE Message element within Msg5 (RRCSetupComplet). The reason for the terminal's transition from idle to active state is indicated by the value of preparing to establish a voice or video call service, i.e., the first indication, such as MO-VoiceCall, MO-VideoCall, MT-VoiceCall, or MT-VideoCall.

[0147] like Figure 7 The diagram shows a flowchart of a voice service implementation method provided in the third embodiment of this application. In the third embodiment, S11: After determining that the RRC establishment completion message is triggered by the voice service of the terminal, the access network device carries the second indication and the third indication in the RRC establishment completion message, specifically including S111, S112, and S113.

[0148] S111: After determining that the RRC establishment completion message is triggered by the voice service of the terminal, a second indicator bit and the third indicator pair bit are added to the RRC establishment completion message.

[0149] S112: Obtain the signal transmission interference strength of the cell where the terminal is camped within a preset time period, and determine whether the signal transmission interference strength is higher than a first preset threshold value. If so, assign the value of the second indicator bit to the first value; otherwise, assign the value of the second indicator bit to the second value. The indication on the second indicator bit is the second indication.

[0150] S113: Obtain the physical resource utilization rate of the cell within the preset time period, and determine whether the physical resource utilization rate is higher than the second preset threshold value. If so, assign the value of the third indicator bit to the first value; otherwise, assign the value of the second indicator bit to the second value. The indicator on the third indicator bit is the third indicator.

[0151] Specifically, in the voice service implementation method provided according to the fourth embodiment of this 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 implementation method further includes: the access network device receiving a context release instruction message sent by the access and mobility management function device when interrupting the context establishment process for the voice service of the terminal, wherein the context release instruction message carries the fallback instruction.

[0152] The order of S111, S112, and S113 is not limited. The values ​​of the second and third indications can be obtained first, then the corresponding indication bits can be added, and the corresponding indication values ​​can be filled into the corresponding indication bits. Specifically, after receiving the RRC establishment completion message, the NG-RAN device determines, based on the first indication in the RRC establishment completion message, that the purpose of the terminal switching from idle state to service state is to initiate a voice call. Subsequently, the NG-RAN device queries the radio signal transmission interference strength and physical resource utilization rate of the cell where the terminal is currently camped in the previous time period. If the first indication in the RRC establishment completion message indicates that the RRC establishment completion message was not triggered by the terminal's voice service, then the NG-RAN device does not query the radio signal transmission interference strength and physical resource utilization rate, nor does it report the radio signal transmission interference strength and physical resource utilization rate to the AMF device. It continues to implement the terminal's voice service using the previous method, that is, it continues to use the VONR method to implement the terminal's voice service.

[0153] Specifically, the NG-RAN equipment calculates the uplink interference intensity of the cell where the terminal is currently camped for the most recent time period (initially set to a statistical period of 5 minutes before the terminal's call initiation time). When the uplink interference intensity of the cell is greater than or equal to the interference intensity threshold (initially set to -110 dBM) + OFFset, the cell is defined as an interfering cell in the previous time period, and the interference interference indicator bit (second indicator bit) for this terminal's current call is set to 1; otherwise, the interference interference indicator bit is set to 0. In addition, the NG-RAN equipment also queries and compares the uplink PRB utilization and downlink PRB utilization of the cell for the most recent time period (initially set to a statistical period of 5 minutes before the terminal's call initiation time). If either the uplink PRB utilization or the downlink PRB utilization is higher than the utilization threshold (initially defined as 80%), the cell is defined as a high-utilization cell in the previous time period, and the busy / idle filled indicator bit (third indicator bit) for this terminal's current call is set to 1; otherwise, the busy / idle filled indicator bit is set to 0. The NG-RAN device sends a service request message (INITIAL UE MESSAGE) carrying the first indication, the second indication, and the third indication to the AMF device. In this embodiment, the NG-RAN device only determines and analyzes the reason for the establishment of the service request message and whether the radio transmission interference strength and physical resource utilization of the cell where the terminal is camped have reached the corresponding set thresholds. The analysis results are then placed in the corresponding indication bits and reported to the AMF device. The specific use of the second and third indications is determined by the AMF device according to its policy. At this time, the INITIAL UE MESSAGE message includes RRCEstablishment Cause (first indication), information on the Interference bit (second indication), and information on the filled bit (third indication).

[0154] like Figure 8 As shown, it is a schematic flowchart of the voice service implementation method provided in the fifth embodiment of this application. The voice service implementation method includes, but is not limited to, S22, S24, S26 and S28.

[0155] S22: The access and mobility management function device receives a service request message from the access network device. 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 the signal transmission interference strength of the cell where the terminal is currently camped within a preset time. The third indication is used to indicate the physical resource utilization rate of the cell within the preset time.

[0156] S24: The access and mobility management function device determines whether it is necessary to initiate an EPS fallback process for the terminal to implement the voice service based on the service request message.

[0157] S26: When the EPS fallback process needs to be initiated, the access and mobility management function device sends a fallback instruction to the access device. The fallback instruction is used to instruct the terminal's voice service bearer network to fall back from the first network to the second network.

[0158] S28: When it is not necessary to initiate the EPS fallback process, the access and mobility management function device sends a QoS flow establishment instruction to the access device. The QoS flow establishment instruction is used to instruct the terminal to complete the voice service in the first network.

[0159] The Access and Mobility Management Function (AMF) device, upon receiving the service request message, first determines whether the service request message was triggered by the terminal's voice service based on a first indication in the message. If so, it further determines whether an EPS fallback procedure needs to be initiated for the terminal's voice service based on a second and third indication. If necessary, it sends a fallback indication to the NG-RAN (Next Generation Network) device, instructing the NG-RAN to trigger the terminal's voice bearer network to fall back from the current first network to the second network. Specifically, the fallback indication is used to switch or redirect the terminal's voice service bearer network from the 5G SA (Standalone) network mode to the ESP (Electronic Service Provider) network, thus switching the terminal's voice service bearer mode from VONR to VOLTE. If an EPS fallback procedure is not required, it sends a QoS (Quality of Service) flow establishment indication to the NG-RAN device, instructing the NG-RAN device to perform the QoS flow, thereby ensuring that the terminal's voice service bearer mode remains VONR.

[0160] As can be seen from the above, the voice service implementation method provided in the fifth embodiment involves the access and mobility management function device receiving a service request message carrying a first indication, a second indication, and a third indication. After determining that the service request message is triggered by the terminal's voice service according to the first indication, the device determines the signal transmission interference intensity and physical resource utilization rate of the cell where the terminal is currently residing within a preset time period according to the second indication and the third indication. Based on the determination result, the device determines whether it is necessary to initiate an EPS fallback process for the terminal's voice service. If it is necessary, a fallback indication is sent to the access network device to instruct the terminal's voice service bearer network to fall back from the first network to the second network. If it is not necessary to initiate an EPS fallback process, 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 instruct the terminal to complete the voice service in the first network. The voice service implementation method provided in the fifth embodiment does not require dedicated bearer establishment during the fallback process, enabling rapid redirection to the ESP network. Furthermore, it determines whether to send a fallback instruction or a QoS flow establishment instruction to the access device based on the interference and resource utilization of the terminal's current cell, thus determining whether the voice service bearer mode for the terminal is VONR or VOLTE. Therefore, the voice service implementation method provided in the fifth embodiment reduces call latency and improves user experience by minimizing network element associations in scenarios with high interference and high resource utilization.

[0161] like Figure 9 The diagram shown is a flowchart illustrating a method for implementing voice services according to the sixth embodiment of this application. In the sixth embodiment, S24 further includes S241, S242, S243, and S244.

[0162] S241: Based on the first indication in the service request message, determine that the service request message was triggered by the voice service of the terminal.

[0163] S242: Based on the second and third instructions in the service request message, determine whether the signal transmission interference intensity and physical resource utilization rate of the cell where the terminal is camped are both higher than the corresponding preset thresholds within a preset time period. If yes, proceed to S243; otherwise, proceed to S244.

[0164] S243: Determine that an EPS fallback process needs to be initiated for the terminal to implement the voice service.

[0165] S244: Determine that it is not necessary to initiate an EPS fallback process for the terminal to implement the voice service.

[0166] In the voice service implementation method provided according to the seventh embodiment of this application, S26 further includes: when it is necessary to initiate the EPS fallback process, interrupting the context establishment process for the voice service of the terminal, carrying the fallback indication in the context release instruction message, and sending the context release instruction message to the access network device.

[0167] Specifically, such as Figure 10 The diagram illustrates the signal flow of a voice service implementation method according to the seventh embodiment of this application. After receiving the service request message, the AMF device determines whether an EPS fallback procedure needs to be initiated based on the first, second, and third indications in the service request message. Specifically, after receiving the service request message, the AMF device confirms that the terminal is initiating a voice service context establishment request by using the RRC establishment cause value (first indication) as MO-VoiceCall or MO-VideoCall. It then further analyzes the interference indication information (second indication) and the cell resource indication bit filled information (third indication). If both the second and third indications are 1, it indicates that the terminal is initiating voice or video services in a cell with high utilization and high interference. In this case, the AMF device guides the terminal to continue the voice service to the LTE network, requiring the initiation of an EPS fallback procedure to directly redirect during the terminal's idle-to-service transition. Otherwise, the original VONR service procedure continues.

[0168] When the EPS fallback procedure needs to be initiated, the AMF device refuses to continue the terminal context establishment procedure (i.e., interrupts the context establishment procedure), and instead sends a UE CONTEXT RELEASE COMMAND (UE context release instruction) to the (R)AN device carrying a newly added reason value ESP-fallback-requird (fallback indication). Specifically, the UE CONTEXT RELEASE COMMAND message is sent through the N2 interface. 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, to trigger the terminal device's voice bearer mode to switch from VONR or redirect to VOLTE. After receiving the UE CONTEXT RELEASE COMMAND message, the access device sends an RRC release instruction to the UE. The RRC release instruction carries the redirected LTE frequency point (here, the frequency point can be directly selected from the co-located LTE site frequency point, or the current geographical environment's strong coverage LTE frequency point), and the UE completes the NR to LTE redirection according to the RRC release instruction. Specifically, the terminal initiates an Attach procedure of type TAU or Handover on the LTE network, completes LTE network camping, and initiates VoLTE call continuation on the LTE network.

[0169] like Figure 11 The diagram shown illustrates the signal flow of a voice service implementation method according to the eighth embodiment of this application. The voice service implementation method provided in the eighth embodiment is mainly applied to... Figure 2 The communication system shown below has the following main detailed process and technical details (it should be noted that...). Figure 11 The diagram only illustrates the EPS fallback based on the service request message; the VONR process is not shown.

[0170] 1. When an idle terminal initiates a voice request in an SA network as the calling party, it must first go through the RRC establishment process. The terminal first initiates a contention-based PRACH procedure and carries the establishment reason RRC-Establishment-Cause: MO-VoiceCall or MO-VideoCall in the Initial UEMessage cell in Msg5 (RRCSetupComplete). This indicates that the reason for the terminal's transition from idle state to connected state is to prepare for the establishment of a voice or video call service.

[0171] 2. When the NG-RAN device receives an RRCSetupComplete (Msg5) establishment request with the cause RRC-Establishment-Cause: MO-VoiceCall or MO-VideoCall, the NG-RAN device knows that the terminal's transition from idle state to service state is for voice call initiation. The NG-RAN device queries the radio interference and physical resource usage of the current cell in the previous time period. However, for service establishment requests other than voice and video requests, the NG-RAN device does not query interference and capacity status, nor does it report the status, continuing the previous approach.

[0172] 2.1: The NG-RAN equipment performs statistics on the uplink interference intensity of the cell in the most recent time period (initially set to a statistical period of 5 minutes before the terminal's call initiation time). When the uplink interference intensity of the cell is greater than the interference intensity threshold (initially set to -110 dBM) + OFFset, the cell in the previous time period is defined as an interfering cell. The interference interference indicator bit for the current call of this terminal is set to 1; otherwise, the interference interference indicator bit is set to 0.

[0173] 2.2: On the NG-RAN equipment side, if either the uplink or downlink PRB utilization rate of a cell exceeds a threshold (initially defined as 80%) in the most recent time period (preliminarily set to a statistical period of 5 minutes before the terminal's call initiation time), the cell is defined as a high-utilization cell in the previous time period. The busy / idle filled indicator bit (i.e., the physical resource utilization indicator bit) of the cell for this terminal's current call is set to 1; otherwise, the busy / idle filled indicator bit is set to 0.

[0174] 3: The NG-RAN equipment sends a request to the AMF via the INITIAL UE MESSAGE (Service Request) with the cause RRC-Establishment-Cause being MO-VoiceCall or MO-VideoCall. It also adds an Interference indicator bit and a filled resource usage indicator bit to the INITIAL UE MESSAGE message. The NG-RAN equipment's role here is simply to analyze the situation, set the analysis results, and report them to the AMF. How these two indicator bits are used is determined by the AMF according to its policy. At this point, the INITIAL UE MESSAGE message includes the RRC-Establishment-Cause, the Interference indicator, and the filled cell resource indicator bit.

[0175] 4. After receiving the INITIAL UE MESSAGE (Service Request) signaling, the AMF device confirms that the terminal initiated a voice service context establishment request via RRC-Establishment-Cause (MO-VoiceCall, MO-VideoCall). It then further analyzes the Interference indicator and the filled cell resource indicator. If both are 1, it indicates that the terminal initiated voice and video services in a cell with high utilization and high interference. In this case, the AMF device guides the terminal to connect the voice service to the LTE network and proceeds to step five (this proposal optimizes and simplifies the original EPSfallback process, directly redirecting during the terminal's idle-to-service transition). Otherwise, the original VONR service process continues. This proposal continues to step five; the original VONR process will not be described further.

[0176] 5: The AMF device refuses to continue the terminal context establishment process (interrupts the context establishment process), and instead guides the NG-RAN device to initiate a fast NR to LTE redirection process through the UE CONTEXT RELEASE COMMAND message (guided by adding the cause value EPS-fallback-required to Cause).

[0177] 6: The newly added cause value (EPS-fallback-required) in the UE CONTEXT RELEASE COMMAND received by the NG-RAN device indicates that the AMF device instructs the NG-RAN device not to continue the context establishment process, but instead decides to enable the Fallback procedure to complete the voice call setup process. The method for enabling the Fallback procedure to complete the voice call setup process can be to trigger RRC Relase redirection to LTE (where the redirection indicator frequency is a 5G site co-located or a strong coverage LTE frequency). That is, the NG-RAN device sends an RRC Relase indication to the terminal UE based on the newly added cause value EPS-fallback-required in the UE CONTEXT RELEASE COMMAND, and uses a blind redirection method to redirect the terminal to the LTE network to further shorten call latency.

[0178] 7: The UE completes the NR to LTE redirection based on the redirected LTE frequency point carried in the RRRCRelease (the frequency point can be directly selected from the co-located LTE site frequency point or the LTE frequency point with strong coverage in the current geographical environment).

[0179] 8: The terminal initiates an Attach procedure of type TAU or Handover on the LTE network. It completes LTE network camping and initiates a VoLTE call setup on the LTE network.

[0180] The voice service implementation method provided in the eighth embodiment of this application is actually a method for fast redirection and rescue of 5G voice services based on external environment. This method involves simultaneously adding uplink / downlink interference indication bits and physical resource utilization indication bits to the NAS message INITIAL UEMESSAGE (service request information) on the NG-RAN device side. The AMF device side determines whether to enable fast redirection to the EPS network to carry voice based on these two indication bits. When the cell has high interference and high utilization, the AMF device side refuses to continue the context establishment process and releases the context through the UE CONTEXT RELEASE COMMAND message. Simultaneously, by adding a cause value (fallback indication) EPS-fallback-required to the UE CONTEXT RELEASE COMMAND, the NG-RAN device side initiates the NR to LTE EPS Fallback process. After receiving this fallback indication, the NG-RAN device side interrupts the original UE-triggered service request. This actively triggers the AN carrying the inter-system frequency point. The release redirection process (carrying 5G co-located LTE frequency points or strong coverage LTE frequency points) is completed. The UE side completes the 5GS to EPS redirection process and completes the corresponding LTE network TAU or Handover type Attach process. Then, a VoLTE call setup is initiated on the LTE network.

[0181] As can be seen from the above, compared with the existing ESP Fallback process, the ESP Fallback process in the voice service implementation method provided in the eighth embodiment reduces most of the signaling from the idle state to the service state in the NR domain. After the RRC is established, the AMF directly initiates context release and guides the NG-RAN equipment to initiate the terminal's redirection, without requiring the terminal to establish a context and enter a fully connected state. In the IMS domain, the terminal no longer needs to initiate a call invitation in the SA network and no longer triggers the IMS process. This reduces the number of UE invitations to the SBC side, and the SBC no longer triggers the PCF to request the QoS policy. Furthermore, there is no subsequent execution of the 5QI1 dedicated flow establishment process in the NR domain. This saves the process complexity, latency, and network element connection in high interference and high load scenarios, improving the user experience.

[0182] like Figure 12The diagram shown is a flowchart illustrating a method for implementing voice services according to the ninth embodiment of this application. The voice service implementation method provided in the ninth embodiment is mainly applied to... Figure 2 The communication system shown has a main implementation process consisting of steps Sa to Sg, which are described in detail below.

[0183] Sa: When a UE initiates a call in the SA network idle state, it sends an RRCSetupComplete message with a cause value (first indication) to the access network device gNB: MO-VoiceCall or MO-VideoCall.

[0184] After receiving the RRCSetupComplete message carrying the first indication (MO-VoiceCall or MO-VideoCall), the Sb:gNB device queries the cell's interference and capacity status for the previous cycle and assigns the values ​​to the newly added indication bit in the INITIAL UE MESSAGE, and then reports it to the AMF device.

[0185] The Sc:AMF device determines whether the cell is a high-interference, high-utilization cell based on the information of the newly added indication bits in the INITIAL UE MESSAGE. Based on this, it determines whether the ESP Fallback procedure needs to be initiated for the UE's voice service. If the cell is determined to be a high-interference, high-utilization cell, Sd is executed; otherwise, Sg is executed.

[0186] Sd: The AMF device determines that the fast redirection procedure is enabled to continue the call and interrupt the context establishment procedure. It guides the gNB device to start the ESP Fallback procedure by adding the cause value (fallback indication) EPS-fallback-required to the UE CONTEXT RELEASE COMMAND.

[0187] The Se:gNB device triggers the UE to redirect to the LTE network, carries the corresponding redirected frequency, and completes the subsequent TAU ​​or Attach process.

[0188] Sf: The UE initiates a VoLTE call via Invite in the LTE network to achieve VoLTE.

[0189] Sg: The AMF device side successfully completed UE context establishment and followed the VONR procedure to complete voice connection.

[0190] As can be seen from the above, in the voice service implementation method provided in the ninth embodiment, the uplink / downlink interference indication bit and physical resource utilization indication bit for the most recent time period of the cell are simultaneously added to the NAS message INITIAL UE MESSAGE request on the NG-RAN side. The AMF side determines whether to enable fast redirection to the EPS network to carry voice based on the above two indications. When the cell is in a high interference and high utilization situation, the AMF side refuses to continue to complete the context establishment process and releases the context through the UECONTEXT RELEASE COMMAND message, while guiding the NG-RAN side to initiate the NR to LTE EPSFallback procedure. After receiving this indication, the NG-RAN side interrupts the original service request triggered by the UE. It actively triggers the AN Release redirection procedure carrying the cross-system frequency point (including the 5G co-located LTE frequency point or strong coverage LTE frequency point). The UE side completes the 5GS to EPS redirection procedure and completes the corresponding LTE network TAU or Handover type Attach procedure. And initiates VoLTE call continuation on the LTE network.

[0191] In the voice service implementation methods provided in the various embodiments of this application, considering the high interference and high utilization scenarios on the SA network radio side, if VONR is still used to carry voice services, call setup failures are inevitable, and even if setup is successful, voice calls may experience high latency, jitter, and dropped calls. Therefore, a method is chosen to determine whether high interference and high utilization are occurring on the SA network radio side during the setup phase. If so, a fast redirection to LTE is directly initiated to salvage the voice connection. Furthermore, the EPS Fallback process in the various embodiments of this application has undergone process optimization compared to the original EPS Fallback process. Instead of the original method where the NG-RAN side selects to measure the LTE radio environment and EPS Fallback process after receiving the 5QI1 FLOW from the AMF side, the NG-RAN side initiates a 5GS to EPS redirection during the UE's call initiation process based on the AMF instruction. This reduces associated network elements, lowers the possibility of signaling transmission failure under high interference conditions, reduces the complexity of the existing process, shortens the latency of the EPS fallback voice service, and improves user experience.

[0192] The voice service implementation methods provided in the various embodiments of this application can avoid the situation where VONR is still used to carry voice services in high interference and high utilization scenarios on the SA network radio side, thereby avoiding situations such as large latency, large jitter, and dropped calls even after call establishment failure or successful call establishment. Furthermore, the implementation methods can reduce associated network elements, decrease the possibility of signaling transmission failure in high interference environments, reduce the complexity of existing processes, shorten the latency of EPS fallback to carry voice processes, and improve user experience.

[0193] Please refer to Figure 13 This is a voice service implementation apparatus 130 provided according to the tenth embodiment of this application. The implementation apparatus 130 includes a service request module 131, a fallback module 132, and a QoS flow establishment module 133. The service request module 131, after establishing a Radio Resource Control (RRC) connection with the terminal for voice services, sends a service request message to the Access and Mobility Management (AMI) device. The service request message carries a first indication, a second indication, and a third indication. The first indication indicates that the service request message is triggered by the terminal's voice service. The second indication indicates the signal transmission interference strength of the cell currently occupied by the terminal within a preset time period. The third indication indicates the physical resource utilization rate of the cell within the preset time period. The service message indicates whether the AMI device needs to initiate an EPS fallback procedure for the terminal to implement the voice service. The fallback module 132, upon receiving a fallback indication from the AMI device, falls back the terminal's voice service bearer network from a first network to a second network according to the fallback indication. The QoS flow establishment 133 is used to establish a QoS flow according to the QoS flow establishment instruction when receiving a QoS flow establishment instruction from the access and mobility management function device, so as to instruct the terminal to complete the voice service in the first network.

[0194] In one alternative implementation, the implementation device 130 further includes an RRC establishment module ( Figure 13 (Not shown in the diagram), the RRC establishment module is used to receive an RRC establishment completion message from the terminal during the process of establishing a Radio Resource Control (RRC) connection with the terminal for voice services. The RRC establishment completion message carries the first indication. The service request acquisition module 121 determines, based on the first indication carried in the received RRC establishment completion message, that the RRC establishment completion message was triggered by the terminal's voice service. After determining that the RRC establishment completion message was triggered by the terminal's voice service, it carries the second indication and the third indication in the RRC establishment completion message to obtain the service request message.

[0195] In some optional implementations, the service request module 131 carries the second indication and the third indication in the RRC establishment completion message, specifically including: after the access network device determines that the RRC establishment completion message is triggered by the voice service of the terminal, the access network device adds a second indication bit and a third indication bit to the RRC establishment completion message; obtains the signal transmission interference strength of the cell where the terminal is camped within a preset time, and determines whether the signal transmission interference strength is higher than a first preset threshold value. If so, the value of the second indication bit is assigned a first value; otherwise, the value of the second indication bit is assigned a second value, and the indication on the second indication bit is the second indication; and obtains the physical resource utilization rate of the cell within the preset time, and determines whether the physical resource utilization rate is higher than a second preset threshold value. If so, the value of the third indication bit is assigned a first value; otherwise, the value of the second indication bit is assigned a second value, and the indication on the third indication bit is the third indication.

[0196] In some optional implementations, the fallback module 132 obtains the fallback indication specifically as follows:

[0197] The device receives a context release instruction message sent by the access and mobility management function device when it interrupts the context establishment process for the voice service of the terminal, wherein the context release instruction message carries the fallback indication.

[0198] As can be seen from the above, the voice service implementation apparatus 130 provided in this application embodiment sends a service request message carrying a first indication, a second indication, and a third indication to the access and mobility management function device (AMD) to instruct the AMD to determine that the service request message is triggered by the terminal's voice service according to the first indication. Then, according to the second indication and the third indication, the AMD determines the signal transmission interference strength and physical resource utilization rate of the cell where the terminal is currently camped within a preset time. When receiving a fallback indication sent by the AMD, the AMD falls back the terminal's voice service bearer network from the first network to the second network according to the fallback indication. And when receiving a flow establishment indication from the AMD, the AMD establishes a QoS flow according to the QoS flow establishment indication to instruct the terminal to complete the voice service in the first network. The EPS Fallback process of the implementation device 130 does not require dedicated bearer establishment during the fallback process, enabling rapid redirection to the ESP network. Furthermore, the implementation device 130 proactively reports the interference and resource utilization status of the terminal's current cell to the Access and Mobility Management Function (AMF) device. This allows the AMF to determine, based on the interference and resource utilization of the current cell, whether to send a fallback instruction or a QoS flow establishment instruction to the access device, i.e., to determine whether the voice service bearer mode for the terminal is VONR or VOLTE. Therefore, the implementation device 130 reduces call latency and improves user experience by minimizing network element association in scenarios with high interference and high resource utilization.

[0199] Please refer to Figure 14This is a voice service implementation apparatus 140 provided according to the eleventh embodiment of this application. The implementation apparatus 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 acquisition module 141 is used to receive a service request message from an access network device. The service request message carries a first indication, a second indication, and a third indication. The first indication indicates that the service request message is triggered by a terminal's voice service. The second indication indicates the signal transmission interference strength of the cell currently occupied by the terminal within a preset time period. The third indication indicates the physical resource utilization rate of the cell within the preset time period. The determination module 142 is used to determine, based on the service request message, whether an EPS fallback process needs to be initiated for the terminal to implement the voice service. The fallback indication module 143 is used to send a fallback indication to the access device when the EPS fallback process needs to be initiated. The fallback indication indicates that the terminal's voice service bearer network falls back from a first network to a second network. The QoS flow indication 144 is used to send a QoS flow establishment indication to the access device when the EPS fallback process does not need to be initiated. The QoS flow establishment indication is used to instruct the terminal to complete the voice service in the first network.

[0200] In an optional implementation, the determining module 142 is configured to determine, based on the first indication in the service request message, that the service request message is triggered by the voice service of the terminal, and based on the second and third indications in the service request message, determine whether the signal transmission interference intensity and physical resource utilization rate of the cell where the terminal is stationed are both higher than the corresponding preset thresholds within a preset time period; if yes, determine that an EPS fallback process needs to be initiated for the terminal to implement the voice service; if no, determine that an EPS fallback process does not need to be initiated for the terminal to implement the voice service.

[0201] In one optional implementation, the fallback indication module 143 is used to interrupt the context establishment process for the voice service of the terminal when the EPS fallback process needs to be initiated, and to carry the fallback indication in the context release instruction message, and to send the context release instruction message to the access network device.

[0202] The voice service implementation apparatus 140 provided in this application embodiment receives a service request message carrying a first indication, a second indication, and a third indication. After determining that the service request message is triggered by a terminal's voice service based on the first indication, it determines the signal transmission interference intensity and physical resource utilization rate of the cell where the terminal is currently residing within a preset time period based on the second indication and the third indication. Based on the determination result, it determines whether an EPS fallback process needs to be initiated for the terminal's voice service. If it is necessary, a fallback indication is sent to the access network device to instruct the terminal's voice service bearer network to fall back from the first network to the second network. If it is not necessary to initiate an EPS fallback process, 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 instruct the terminal to complete the voice service in the first network. The EPS Fallback process of the voice service implementation device 140 does not require dedicated bearer establishment during the fallback process, enabling rapid redirection to the ESP network. Furthermore, it determines whether to send a fallback instruction or a QoS flow establishment instruction to the access device based on the interference and resource utilization of the terminal's current cell, thus determining whether the bearer mode for the terminal's voice service is VONR or VOLTE. The voice service implementation device 140 reduces call latency and improves user experience by minimizing network element dependencies in scenarios with high interference and high resource utilization.

[0203] In the twelfth embodiment of this application, an access network device is also provided. Figure 15 The diagram shows a structural schematic of an access network device provided in an embodiment of this application. The specific implementation of the access network device is not limited by the specific embodiments of the present invention.

[0204] like Figure 15 As shown, the access network device may include: a processor 1502, a communications interface 1504, a memory 1506, and a communications bus 1508.

[0205] The processor 1502, communication interface 1504, and memory 1506 communicate with each other via communication bus 1508. Communication interface 1504 is used to communicate with other network elements such as clients or other servers. The processor 1502 executes program 1510, specifically performing the relevant steps described in the first to ninth embodiments.

[0206] Specifically, program 1510 may include program code, which includes computer-executable instructions.

[0207] The processor 1502 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application. The access network device may include one or more processors of the same type, such as one or more CPUs; or it may include processors of different types, such as one or more CPUs and one or more ASICs.

[0208] Memory 1506 is used to store program 1510. Memory 1506 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0209] Specifically, program 1510 can be called by processor 1502 to cause the access network device to perform the operations S12, S14 and S16 in the first embodiment described above.

[0210] In an alternative embodiment, the program 1510 is invoked by the processor 1502 to cause the access network device to execute S09, S10 and S11 in the second embodiment described above.

[0211] In an alternative embodiment, the program 1510 is invoked by the processor 1502 to cause the access network device to execute S111, S112 and S113 in the third embodiment described above.

[0212] In an alternative manner, the program 1510 is invoked by the processor 1502 to cause the access network device to perform the operation described in the fourth embodiment above: receiving a context release instruction message sent by the access and mobility management function device when interrupting the context establishment process for the voice service of the terminal, wherein the context release instruction message carries the fallback indication.

[0213] The access network device provided in this application embodiment sends a service request message carrying a first indication, a second indication, and a third indication to an access and mobility management function (AM) device. This instructs the AM device to determine, based on the first indication, that the service request message is triggered by a terminal's voice service. The device then determines, based on the second and third indications, the signal transmission interference strength and physical resource utilization rate of the cell where the terminal is currently residing within a preset time period. Upon receiving a fallback indication from the AM device, the device falls back the terminal's voice service bearer network from the first network to the second network according to the fallback indication. Furthermore, upon receiving a flow establishment indication from the AM device, the device establishes a QoS flow according to the QoS flow establishment indication, thereby instructing the terminal to complete the voice service in the first network. When implementing the EPS Fallback process, the access network device does not require dedicated bearer establishment during the fallback process, enabling rapid redirection to the ESP network. Furthermore, the access network device proactively reports the interference and resource utilization status of the terminal's current cell to the Access and Mobility Management Function (AMF) device. This allows the AMF to determine whether to send a fallback instruction or a QoS flow establishment instruction to the access device based on the interference and resource utilization of the current cell, thus determining whether the terminal's voice service bearer mode is VoNR or VoLTE. Therefore, this access network device helps reduce call latency and improve user experience by minimizing network element association in scenarios with high interference and high resource utilization.

[0214] In the thirteen embodiments according to this application, an access and mobility management function device (AMF device) is also provided. Figure 16 The diagram shows a structural schematic of an access and mobility management function device provided in an embodiment of this application. The specific embodiments of this invention do not limit the specific implementation of the access and mobility management function device.

[0215] like Figure 16 As shown, the access and mobility management function device may include: a processor 1602, a communications interface 1604, a memory 1606, and a communications bus 1608.

[0216] The processor 1602, communication interface 1604, and memory 1606 communicate with each other via communication bus 1608. Communication interface 1604 is used to communicate with other network elements such as clients or other servers. The processor 1602 executes program 1610, specifically performing the relevant steps described in the first to ninth embodiments.

[0217] Specifically, program 1610 may include program code, which includes computer-executable instructions.

[0218] The processor 1602 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application. The access network device includes one or more processors, which may be processors of the same type, such as one or more CPUs; or they may be processors of different types, such as one or more CPUs and one or more ASICs.

[0219] Memory 1606 is used to store program 1610. Memory 1606 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0220] Specifically, program 1610 can be called by processor 1602 to cause the access and mobility management function device to perform the operations S22, S24, S26 and S28 in the fifth embodiment described above.

[0221] In an alternative embodiment, the program 1610 is invoked by the processor 1602 to cause the access network device to execute S241, S242, S243 and S244 in the sixth embodiment described above.

[0222] In an alternative manner, the program 1610 is invoked by the processor 1602 to cause the access network device to perform the steps in the seventh embodiment above: when it is necessary to initiate the EPS fallback process, interrupt the context establishment process for the voice service of the terminal, carry the fallback indication in the context release instruction message, and send the context release instruction message to the access network device.

[0223] The Access and Mobility Management Function (APM) device provided in this application receives a service request message carrying a first indication, a second indication, and a third indication. After determining that the service request message is triggered by a terminal's voice service based on the first indication, it determines the signal transmission interference intensity and physical resource utilization of the cell where the terminal is currently residing within a preset time period based on the second and third indications. Based on the determination results, it determines whether an EPS fallback procedure needs to be initiated for the terminal's voice service. If so, it sends a fallback indication to the access network device to instruct the terminal's voice service bearer network to fall back from the first network to the second network. If an EPS fallback procedure is not needed, it sends a flow establishment indication to the access network device, causing the access network device to establish a QoS flow according to the QoS flow establishment indication, so that the terminal can complete the voice service in the first network. Furthermore, it can achieve rapid redirection to the ESP network without the need for dedicated bearer establishment during the EPS fallback process. It also determines whether to send a fallback indication or a QoS flow establishment indication to the access device based on the interference and resource utilization of the cell where the terminal is currently residing, i.e., determining whether the bearer mode of the terminal's voice service is VONR or VOLTE. Therefore, the access and mobility management function device can reduce call latency and improve user experience by reducing network element association in scenarios with high interference and high resource utilization.

[0224] Furthermore, embodiments of this application also provide a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the steps of the voice service implementation method as described in any of the listed embodiments. Since the various steps of the voice service implementation method have been described in detail above and the obtained technical effects are similar, they will not be repeated here.

[0225] Furthermore, this application also provides a communication system, which includes an access network device and an access and mobility management function device according to any one of the claims of this application. A schematic diagram of the communication system can be found here. Figure 1 As shown.

[0226] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification. Similarly, it should be understood that, in order to streamline the invention and aid in understanding one or more of the various aspects of the invention, features of the embodiments of this application are sometimes grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of the invention above. However, this disclosed approach should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Those skilled in the art will understand that modules in the apparatus of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules or units or components in the embodiments can be combined into a single module or unit or component, and can be divided into multiple sub-modules or sub-units or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination may be employed to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or apparatus so disclosed. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0227] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. A method for implementing a voice service, characterized in that, include: After establishing a Radio Resource Control (RRC) connection with the terminal for voice services, the access network device sends a service request message to the access and mobility management function device. During the process of establishing a Radio Resource Control (RRC) connection with a terminal for voice services, the access network device receives an RRC establishment completion message from the terminal, the RRC establishment completion message carrying a first indication; the access network device determines, based on the first indication carried in the received RRC establishment completion message, that the RRC establishment completion message was triggered by the terminal's voice service; after determining that the RRC establishment completion message was triggered by the terminal's voice service, the access network device obtains the signal transmission interference strength and physical resource utilization rate of the cell currently camped by the terminal within a preset time period, and then... The service request message is obtained by carrying the signal transmission interference strength as a second indication and the physical resource utilization rate as a third indication in the established message; wherein, the service request message carries the first indication, the second indication and the third indication, the first indication is used to indicate that the service request message is triggered by the terminal's voice service, the second indication is used to indicate the signal transmission interference strength of the cell where the terminal is currently camped within a preset time, the third indication is used to indicate the physical resource utilization rate of the cell within the preset time, and the service message is used to indicate whether the access and mobility management function device needs to initiate an EPS fallback process for the terminal to implement the voice service; When the access network device receives a fallback instruction from the access and mobility management function device, the access network device falls back the voice service bearer network of the terminal from the first network to the second network according to the fallback instruction; When the access network device receives a QoS flow establishment instruction from the access and mobility management function device, 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.

2. The implementation method according to claim 1, characterized in that, After determining that the RRC establishment completion message was triggered by the voice service of the terminal, the access network device obtains the signal transmission interference strength and physical resource utilization rate of the cell where the terminal is currently camped within a preset time period, and carries the signal transmission interference strength as a second indication and the physical resource utilization rate as a third indication in the RRC establishment completion message, including: After the access network device determines that the RRC establishment completion message is triggered by the voice service of the terminal, the access network device adds a second indicator bit and the third indicator pair bit to the RRC establishment completion message; The access network device obtains the signal transmission interference strength of the cell where the terminal is camped within a preset time period, and determines whether the signal transmission interference strength is higher than a first preset threshold value. If so, the value of the second indicator bit is assigned to the first value; otherwise, the value of the second indicator bit is assigned to the second value. The indication on the second indicator bit is the second indication. The access network device obtains the physical resource utilization rate of the cell within the preset time period and determines whether the physical resource utilization rate is higher than the second preset threshold. If so, the value of the third indicator bit is assigned to the first value; otherwise, the value of the second indicator bit is assigned to the second value. The indicator on the third indicator bit is the third indicator.

3. The implementation method according to claim 1, characterized in that, Before the access network device falls back the terminal's voice service bearer network from the first network to the second network according to the fallback instruction, the implementation method further includes: The access network device receives a context release instruction message sent by the access and mobility management function device when the context establishment process for the voice service of the terminal is interrupted, wherein the context release instruction message carries the fallback indication.

4. A method for implementing a voice service, characterized in that, include: An access and mobility management function (AMS) device receives a service request message from an access network device. During the process of establishing a Radio Resource Control (RRC) connection with a terminal for voice services, the access network device receives an RRC establishment completion message from the terminal. The RRC establishment completion message carries a first indication. Based on the first indication carried in the received RRC establishment completion message, the access network device determines that the RRC establishment completion message was triggered by the terminal's voice service. After determining that the RRC establishment completion message was triggered by the terminal's voice service, the access network device obtains the signal transmission interference strength and physical resource utilization rate of the cell currently in which the terminal is camped within a preset time period. The signal transmission interference strength is carried as a second indication, and the physical resource utilization rate is carried as a third indication in the RRC establishment completion message to obtain the service request message. The service request message carries the first, second, and third indications: the first indication indicates that the service request message was triggered by the terminal's voice service; the second indication indicates the signal transmission interference strength of the cell currently in which the terminal is camped within the preset time period; and the third indication indicates the physical resource utilization rate of the cell within the preset time period. The access and mobility management function device determines whether it is necessary to initiate an EPS fallback process for the terminal to implement the voice service based on the service request message; When the EPS fallback process needs to be initiated, the access and mobility management function device sends a fallback instruction to the access network device. The fallback instruction is used to instruct the voice service bearer network of the terminal to fall back from the first network to the second network. When the EPS fallback process is not required, the access and mobility management function device sends a QoS flow establishment instruction to the access network device. The QoS flow establishment instruction is used to instruct the terminal to complete the voice service in the first network.

5. The implementation method according to claim 4, characterized in that, The access and mobility management function device determines whether an EPS fallback process needs to be initiated for the terminal to implement the voice service based on the service request message, including: The access and mobility management function device determines, based on the first indication in the service request message, that the service request message is triggered by the voice service of the terminal; The access and mobility management function device determines, based on the second and third indications in the service request message, whether the signal transmission interference intensity and physical resource utilization rate of the cell where the terminal is stationed are both higher than the corresponding preset threshold within a preset time. If so, the access and mobility management function device determines that an EPS fallback process needs to be initiated for the terminal to implement the voice service; If not, the access and mobility management function device determines that it is not necessary to initiate an EPS fallback process for the terminal to implement the voice service.

6. The implementation method according to claim 4, characterized in that, When the EPS fallback process needs to be initiated, the access and mobility management function device sends a fallback instruction to the access network device, including: When the EPS fallback process needs to be initiated, the access and mobility management function device interrupts the context establishment process for the voice service of the terminal, carries the fallback indication in the context release instruction message, and sends the context release instruction message to the access network device.

7. An access network device, characterized in that, It includes a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other through the communication bus; The memory is used to store at least one executable instruction, which causes the processor to execute the method for implementing a voice service as described in any one of claims 1 to 3.

8. An access and mobility management function device, characterized in that, It includes a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other through the communication bus; The memory is used to store at least one executable instruction, which causes the processor to execute the method for implementing a voice service as described in any one of claims 4 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method for implementing voice services as described in any one of claims 1 to 6.

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