Communication method and terminal equipment

Abstract

The embodiment of the invention provides a communication method and terminal equipment, and relates to the technical field of communication. The call drop problem in the call process is solved. According to the specific scheme, a first DRB is used for sending first data to first network equipment, and the SN field length of an RLC head of the first data is a first value; under the condition that the response returned by the first network equipment for the first data is not received, sending a reestablishment request to the first network equipment; a first reconfiguration message from the first network device is received, the first reconfiguration message carries first indication information, and the first indication information is used for indicating that the length of the SN field configured by the first DRB in the first network device in the RLC layer is a second value; when the first value is not equal to the second value, sending a reconfiguration completion message to the first network device; and sending second data to the first network device by using the first DRB, wherein the SN field length of the RLC header information of the second data is the second value.

Description

[0001] This application is a divisional application. The application number of the original application is 202310750224.3, and the original application date is June 21, 2023. The entire contents of the original application are incorporated into this application by reference.

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on April 4, 2023, with application number 202310399285.X and application name “Call Processing Method and Device”, the entire contents of which are incorporated by reference in this application. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a communication method and terminal equipment. Background Art

[0004] With the development of the fifth generation (5G), more and more services based on 5G technology are being developed. For example, voice services are transmitted through the new radio (NR) air interface of 5G technology, where the language services transmitted through the NR air interface of 5G technology can be called voice over new radio (VoNR). It can be understood that the above-mentioned VoNR refers to the end-to-end voice service based on the 5G system and the IP Multimedia Subsystem (IMS). The VoNR call establishment time is short, and data services can still be transmitted at high speed, which can give users a better experience.

[0005] However, when a terminal device actually communicates with other terminals, call drops may occur easily. Summary of the invention

[0006] The embodiments of the present application provide a communication method and a terminal device for improving the problem of dropped calls (abnormal calls, resulting in call interruption) during a call.

[0007] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0008] In the first aspect, a communication method provided by an embodiment of the present application is applied to a call process of a terminal device, the method comprising: the terminal device uses a first DRB to send first data to a first network device, and the sequence number SN field length of the radio link RLC header information of the first data is a first value; when the terminal device does not receive a response returned by the first network device for the first data, the terminal device sends a re-establishment request (RRC re-establishment request, also referred to as an RRC connection re-establishment request) to the first network device. The terminal device receives a first reconfiguration message (first RRC reconfiguration message, also referred to as a first RRC connection reconfiguration message) from the first network device, wherein the first reconfiguration message carries a first indication information, and the first indication information is used to indicate that the SN field length configured by the first DRB in the RLC layer in the first network device is a second value. When the first value is not equal to the second value, the terminal device sends a reconfiguration completion message (RRC reconfiguration completion message) to the first network device. After sending the reconfiguration completion message, the terminal device uses the first DRB to send second data to the first network device, and the SN field length of the RLC header information of the second data is a second value.

[0009] In the above embodiment, during a call, after receiving the RRC reconfiguration message, the terminal device ignores whether it complies with the current protocol, reconfigures the SN field length of the first DRB at the RLC layer according to the second value in the RRC reconfiguration message, and feeds back an RRC reconfiguration completion message, which will not trigger RRC reestablishment again, thus avoiding being misjudged as a call abnormality and being instructed to end the call. In this way, the call drop rate can be effectively reduced.

[0010] In some embodiments, the second data and the first data may carry the same data content to ensure that the data content that may not have been successfully received by the first network device is retransmitted to the first network device. In other embodiments, the second data and the first data carry different data content, that is, the second data and the first data are different data that need to be transmitted through the first DRB.

[0011] In some embodiments, before the terminal device sends the first data to the first network device, the method also includes: the terminal device establishes a call through the second network device; during the call, the terminal device receives a second reconfiguration message from the second network device, the second reconfiguration message carries a switching indication, and the switching indication is used to instruct the terminal device to switch to the cell corresponding to the first network device, and the second reconfiguration message does not carry the first indication information.

[0012] In the above embodiment, the terminal device can perform cell switching during a call, thereby ensuring the call quality and reducing the probability of dropped calls.

[0013] In some embodiments, before the terminal device establishes the call through the second network device, the method further includes: after a connection is established between the terminal device and the second network device, receiving a third reconfiguration message from the second network device, the third reconfiguration message being used to indicate that the SN field length of the first DRB in the second network device configured at the RLC layer is the first value.

[0014] In the above embodiment, a call can be established through the second network device, and data interaction can be performed normally with the second network device.

[0015] In some embodiments, the first DRB is a DRB that enables a certain transmission mode.

[0016] In the above embodiment, the first DRB can ensure the reliability of data transmission.

[0017] In some embodiments, the first data and the second data are both call data, and the call process includes a call process established based on a 4G communication system, a 5G communication system, or a 6G communication system.

[0018] In the above embodiment, the terminal device and the first network device reduce the call drop rate while ensuring the normal conduct of the call.

[0019] In some embodiments, the terminal device does not receive a response returned by the first network device for the first data, including: the terminal device has retransmitted the first data to the first network device using the first DRB for a preconfigured first number of times, and has not received a response corresponding to the first data within a first time period after the last retransmission.

[0020] In the above embodiment, triggering unnecessary re-establishment requests can be avoided.

[0021] In a second aspect, a communication method provided by an embodiment of the present application is applied to a terminal device, and the method includes: after the terminal device establishes a call through a second network device, the terminal device uses a first DRB to send third data to the second network device, and the SN field length of the RLC header information of the third data is a first value; during the call, the terminal device receives a second reconfiguration message from the second network device, and the second reconfiguration message includes a switching indication, and the switching indication is used to instruct the terminal device to switch to the cell corresponding to the first network device; determine that the historical record data contains a second value, wherein the second value is the SN field length configured at the RLC layer for the first DRB in the first network device, and the first value is not equal to the second value; when the historical record data contains the second value and the second reconfiguration message does not contain the SN field length configured at the RLC layer for the first DRB in the first network device, the terminal device uses the first DRB to send second data to the first network device, and the SN field length of the RLC header information of the second data is the second value.

[0022] In some embodiments, before the terminal device establishes a call through the second network device, the method also includes: after establishing a connection between the terminal device and the second network device, receiving a third reconfiguration message from the second network device, the third reconfiguration message including a first value, and the first value is the SN field length configured in the RLC layer for the first DRB in the second network device.

[0023] In some embodiments, determining that the second value is included in the historical record data includes: after the terminal device receives the second reconfiguration message from the second network device, when the second reconfiguration message does not contain the SN field length configured for the first DRB in the first network device at the RLC layer, determining, based on the historical record data, that the SN field length configured for the first DRB in the RLC layer in the first network device is the second value; the method also includes: when the first value is not equal to the second value, the terminal device sends a reconfiguration completion message to the first network device.

[0024] In some embodiments, after the terminal device receives the second reconfiguration message, the method further includes: in response to the second reconfiguration message, the terminal device sends a reconfiguration completion message to the first network device; the terminal device sends first data to the first network device using the first DRB, and the SN field length of the RLC header information of the first data is the first value;

[0025] Determining that the second value is included in the historical record data includes: under a first condition, based on the historical record data, determining that the SN field length of the first DRB in the first network device in the RLC header information is the second value; wherein the first condition includes that the number of transmissions of the first data has reached a preconfigured second number, and no response corresponding to the first data has been received within a first time period after the last retransmission.

[0026] In a third aspect, an embodiment of the present application provides a terminal device, the terminal device includes one or more processors and a memory; the processor includes a modem processor, the memory is coupled to the processor, the memory is used to store computer program code, the computer program code includes computer instructions, when one or more processors execute the computer instructions, the one or more processors are used to execute the methods in the first aspect, the second aspect and possible embodiments thereof.

[0027] In a fourth aspect, an embodiment of the present application provides a computer storage medium, comprising computer instructions. When the computer instructions are executed on a terminal device, the terminal device executes the methods in the above-mentioned first aspect, second aspect and possible embodiments thereof.

[0028] In a fifth aspect, the present application provides a computer program product, which, when executed on the above-mentioned terminal device, enables the terminal device to execute the methods in the above-mentioned first aspect, second aspect and possible embodiments thereof.

[0029] In a sixth aspect, the present application provides a chip system, which is applied to a terminal device and stores a computer program. When the computer program is executed, the terminal device executes the methods in the above-mentioned first aspect, second aspect and possible embodiments thereof.

[0030] It can be understood that the terminal equipment, computer storage media and computer program products provided in the above aspects are all applied to the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods provided above and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 An example diagram of a communication system provided in an embodiment of the present application;

[0032] Figure 2 An example diagram of a communication system that can implement VoNR calls provided in an embodiment of the present application;

[0033] Figure 3 A signaling interaction diagram for initiating a VoNR call between a terminal device and a network device provided in an embodiment of the present application;

[0034] Figure 4 A schematic diagram of a scenario in which a terminal device provided in an embodiment of the present application selects a network device to be accessed;

[0035] Figure 5 An example diagram of a protocol stack supported by both the terminal device and the second network device provided in an embodiment of the present application;

[0036] Figure 6 An example diagram of the structure of an RLC data packet provided in an embodiment of the present application;

[0037] Figure 7 An example diagram of a scenario that can trigger a terminal device to switch the network device it is connected to, provided in an embodiment of the present application;

[0038] Figure 8 A signaling interaction diagram of a communication method provided in the related art;

[0039] Fig. 9 This is an example diagram of a communication abnormality scenario that occurs after the terminal device is reconfigured to access the first network device;

[0040] Fig.10 One of the signaling interaction diagrams of the communication method provided in the embodiment of the present application;

[0041] Fig.11 The second signaling interaction diagram of the communication method provided in the embodiment of the present application;

[0042] Fig.12 The third signaling interaction diagram of the communication method provided in the embodiment of the present application;

[0043] Fig.13 The fourth signaling interaction diagram of the communication method provided in the embodiment of the present application;

[0044] Fig.14 An example diagram of the hardware structure of a terminal device provided in an embodiment of the present application;

[0045] Fig.15 An example diagram of the hardware structure of the network device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The technical scheme in the embodiment of the present application will be described below in conjunction with the drawings in the embodiment of the present application. Wherein, in the description of the present application, unless otherwise specified, "at least one" refers to one or more, and "a plurality of" refers to two or more than two. In addition, in order to facilitate the clear description of the technical scheme of the embodiment of the present application, in the embodiment of the present application, the words "first", "second" and the like are used to distinguish the same items or similar items with substantially the same functions and effects. Those skilled in the art will understand that the words "first", "second" and the like do not limit the quantity and execution order, and the words "first", "second" and the like do not limit necessarily different.

[0047] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as wireless fidelity (WiFi) systems, vehicle to everything (V2X) communication systems, device-to-device (D2D) communication systems, Internet of Vehicles communication systems, fourth generation (4G) mobile communication systems, such as long term evolution (LTE) systems, worldwide interoperability for microwave access (WiMAX) communication systems, 5G, such as new radio (NR) systems, and future communication systems.

[0048] The present application will present various aspects, embodiments or features around a system that may include multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and / or may not include all of the devices, components, modules, etc. discussed in conjunction with the figures. In addition, combinations of these schemes may also be used.

[0049] In addition, in the embodiments of the present application, words such as "exemplary" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present concepts in a concrete way.

[0050] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. A person of ordinary skill in the art can appreciate that with the evolution of the network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0051] To facilitate understanding of the embodiments of the present application, first Figure 1 The communication system shown in the example is used to describe in detail the communication system applicable to the embodiment of the present application. Figure 1 A schematic diagram of the architecture of a communication system applicable to the communication method provided in the embodiment of the present application Figure 1 .

[0052] like Figure 1 As shown, the communication system mainly includes: terminal equipment (can be called terminal) and network device (can also be called network equipment).

[0053] The terminal device may be a terminal device with transceiver functions, or a chip or chip system that can be set in the terminal device. The terminal device may also be called user equipment (UE), access terminal, subscriber unit, user station, mobile station (MS), mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device in the embodiments of the present application can be a mobile phone, a cellular phone, a smart phone, a tablet computer, a wireless data card, a personal digital assistant (PDA), a wireless modem, a handheld device (handset), a laptop computer, a machine type communication (MTC) terminal, a computer with wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a vehicle-mounted terminal, a road side unit (RSU) with terminal function, etc. The terminal of the present application may also be a vehicle-mounted module, a vehicle-mounted module, a vehicle-mounted component, a vehicle-mounted chip or a vehicle-mounted unit built into the vehicle as one or more components or units.

[0054] The network device may be a network device, such as an access network (AN) device, or may be referred to as a radio access network (RAN) device. The RAN device may provide access functions for the terminal, and is responsible for functions such as radio resource management, quality of service (QoS) management, data compression and encryption on the air interface side. The RAN device may include 5G, such as a gNB in ​​an NR system, or one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G, or a network node constituting a gNB, a transmission point (TRP or transmission point, TP) or a transmission measurement function (TMF), such as a baseband unit (BBU), or a centralized unit (CU) or a distributed unit (DU), an RSU with a base station function, or a wired access gateway, or a core network element of a 5G. Alternatively, the RAN device may also include an access point (AP) in a wireless fidelity (WiFi) system, a wireless relay node, a wireless backhaul node, various forms of macro base stations, micro base stations (also called small stations), relay stations, access points, wearable devices, vehicle-mounted devices, etc. Alternatively, the RAN device may also include a next-generation mobile communication system, such as a 6G access network device, such as a 6G base station, or in the next-generation mobile communication system, the network device may also have other naming methods, which are all covered within the protection scope of the embodiments of the present application, and the present application does not make any limitation on this.

[0055] Understandably, Figure 1 This is a simplified schematic diagram for ease of understanding only. The communication system may also include other network devices and / or other terminal devices. Figure 1 Not drawn in.

[0056] In some embodiments, the terminal device in the above communication system can access the communication network (such as 5G network) corresponding to the network device through the network device, so that the terminal device can enable various communication services based on the accessed communication network. Exemplarily, the above communication services may include call services. Among them, the above call services can be calls based on the 5G communication system, such as VoNR calls, calls based on the 4G communication system, and calls based on future communication systems (such as 6G communication systems).

[0057] Take the above call service as an example, the VoNR call service is Figure 2 As shown, the above-mentioned communication system may include a terminal device 100, a NG RAN 101, a 5GC 102 and an IMS 103.

[0058] The terminal device 100 corresponds to Figure 1 The terminal equipment in NG RAN101 corresponds to Figure 1 Network devices in.

[0059] Exemplarily, the NG RAN 101 may include at least one node device, such as a base station (BS). It is understandable that the base station may be a device capable of communicating with a terminal device or other communication sites (such as a relay site). In addition, the base station may provide communication coverage for a specific physical area. For example, the base station may be a base transceiver station (BTS) or a base station controller (BSC) in GSM or CDMA; it may also be a node B (NB) in UMTS or a radio network controller (RNC) in UMTS; it may also be an evolutionary Node B (eNB or eNodeB) in LTE; it may also be a next generation Node B (gNB) in 5G NR; or it may be other access network devices that provide access services in a wireless communication network, which is not limited by the present invention.

[0060] In the case where the above-mentioned NG RAN101 includes gNB, after the terminal device 100 establishes a connection with the gNB in ​​the NG RAN101, the terminal device 100 can communicate with the gNB using the new radio (NR) access technology. In this way, the above-mentioned terminal device 100 and the gNB can communicate through the NR link. This process can also be called the terminal device 100 accessing the NG RAN101.

[0061] As another example, the 5GC 102 is used to exchange, forward, connect and route data. The network elements in the 5GC are functional virtual units, which may include but are not limited to: a unit for access and mobility management function (AMF), a unit for session management function (SMF), a network element for unified data management (UDM), and the like.

[0062] In some embodiments, a standalone (SA) networking mode may be adopted between the NG RAN 101 and 5GC 102. It can be understood that in the SA networking mode, both NG RAN and 5GC are built based on 5G technology, and the low latency experience is better. In subsequent embodiments, the communication network composed of NG RAN and 5GC may also be referred to as a 5G system. In other embodiments, the networking mode between the NG RAN 101 and 5GC 102 may also be a non-standalone (NSA) networking, which is not specifically limited in the embodiments of the present application.

[0063] As another example, the above-mentioned IMS 103 is used to manage IP data packets packaged with multimedia data such as voice and video, distinguish the signaling part and the multimedia data part of these IP data packets, and transmit the multimedia data part in the IP data packets between the terminal device 100 and the called end of its call. In this way, the IMS 103 can provide audio and video services for the terminal device 100. The IMS 103 can mainly include a call session control function (CSCF) and a home subscriber server (HSS). The CSCF is used to control signaling, authentication, and control sessions in cooperation with other network entities during multimedia call sessions. The HSS is used to manage user data.

[0064] like Figure 2 As shown, the 5G system can communicate with the IMS 103. In this way, after the terminal device 100 accesses the NG RAN 101, a communication connection can be established with the IMS 103 through the NG RAN 101 and the 5GC 102.

[0065] In some embodiments, after the terminal device 100 accesses the 5G system composed of NG RAN 101 and 5GC 102 through NG RAN 101, the terminal device 100 can initiate a call to other terminals through IMS 103 using various voice solutions, and perform audio and video communication after the other terminal answers the call. The above-mentioned VoNR is one of the optional voice solutions.

[0066] It can be understood that after the 5G system is connected to the IMS 103, the 5G system can package the multimedia data during the call and communication between the terminal device 100 and other terminals into IP data packets, and transmit them to the other terminals through the IMS 103. In other words, the 5G system can provide IMS-based audio and video services on circuit switching (PS) sessions, for example, the control plane signaling (IMS signalling) and user plane data (IMS traffic) generated by the terminal device 100 and other terminal devices during the call process are packaged into IP data packets, and these IP data packets are transmitted between the terminal device 100 and the other called terminals through the IMS 103.

[0067] In some embodiments, during a call, the other terminal devices being called (e.g., Figure 2 The terminal device 106 in the communication network also needs to establish a connection with the IMS 103 through the accessed communication network.

[0068] like Figure 2 As shown, the above communication system may also include a terminal device 106, a NG RAN 105 and a 5GC 104. Figure 2 In the scenario shown, the terminal device 106 can establish a connection with the IMS 103 through the 5G system composed of the NG RAN 105 and the 5GC 104.

[0069] The terminal device 106 is different from the terminal device 100. Of course, the terminal device 106 is similar to the terminal device 100, including smart terminals (for example, mobile phones, etc.), desktops, laptops, tablet computers, handheld computers, notebook computers, ultra-mobile personal computers (UMPC), netbooks, as well as cellular phones, personal digital assistants (PDA), televisions, VR devices, AR devices and other devices with communication capabilities, which can be connected to various communication systems.

[0070] Similarly, the SA networking mode or the NSA networking mode can be adopted between the above-mentioned NG RAN105 and 5GC104.

[0071] It is understandable that when different voice solutions are adopted, the communication network accessed by the terminal device 106 may also be different, and the embodiments of the present application do not specifically limit this.

[0072] Taking the terminal device 100 as the calling device (that is, the terminal that initiates the call) and the terminal device 106 as the called device (that is, the device that answers the call) as an example, the process of the terminal device 100 actively initiating a VoNR call to the terminal device 106 is described:

[0073] (1) The terminal device 100 requests to establish a Radio Resource Control (RRC) connection with the NG RAN 101 .

[0074] (2) The terminal device 100 sends a call request message to the 5GC 102 via the NG RAN 101. The call request message carries the identifier (eg, telephone number) of the terminal device 106. The identifier of the terminal device 106 can be used to instruct the IMS 103 to page the terminal device 106.

[0075] (3) After 5GC 102 receives the call request information from terminal device 100, it can also send a response message to terminal device 100 through NG RAN 101, indicating that 5GC 102 is processing the call initiated by terminal device 100. In addition, 5GC 102 can also send the call request information to terminal device 106 through IMS 103 to implement paging terminal device 106.

[0076] (4) After 5GC 102 receives the call request information from the terminal device 100, 5GC 102 can also establish a quality of service (Quality of Service, QoS) flow for the terminal device 100 to carry the session initiation protocol (SIP) signaling. The 5G QoS identifier (5QI) of the established QoS flow can be 5.

[0077] In addition, the NG RAN 101 may also establish a data radio bearer (DRB) for the terminal device 100 for transmitting SIP signaling.

[0078] (5) After receiving the call request information, the terminal device 106 may also establish an RRC connection with the NG RAN 105 .

[0079] (6) After the terminal device 106 requests to establish an RRC connection with the NG RAN 105, the 5GC 104 may also establish a quality of service (QoS) flow for carrying SIP signaling for the terminal device 106, and the 5QI of the established QoS flow may be 5.

[0080] In addition, the NG RAN 105 may also establish a DRB for the terminal device 106 for transmitting SIP signaling.

[0081] (7) The terminal device 100 and the terminal device 106 perform SIP session negotiation through the IMS 103, for example, negotiating information such as encoding mode, IP address, port number, etc.

[0082] (8) After the negotiation is completed, 5GC102 may also establish a QoS flow for carrying the real-time transport protocol (RTP) and a QoS flow for carrying the real-time transport control protocol (RTCP) for the terminal device 100. In this step, the 5QI of the established QoS flow may be 1.

[0083] In addition, the NG RAN 101 may also establish a DRB for the terminal device 100 for transmitting RTP and RTCP.

[0084] (9) After the negotiation is completed, 5GC 104 may also establish a Qos flow for carrying RTP and RTCP for the terminal device 106. The 5QI of the established Qos flow may be 1.

[0085] In addition, the NG RAN 105 may also establish a DRB for the terminal device 106 for transmitting RTP and RTCP.

[0086] (10) After that, the terminal device 106 can remind the user of the incoming call from the terminal device 100 by ringing, displaying, etc. After the terminal device 106 detects that the user answers the call, the terminal device 100 and the terminal device 106 can transmit voice data through the corresponding 5G system and IMS103 to start the call.

[0087] In summary, through the above steps, the terminal device 100 and the terminal device 106 can respectively establish corresponding bearers before the call starts, and then, based on the above bearers, establish an IMS session. In an embodiment of the present application, in the process of initiating a VoNR call, the established bearers include a default bearer and a dedicated bearer. Exemplarily, the default bearer includes a bearer corresponding to the Qosflow of 5IQ5, which is used to carry the call and control signaling during the call. Also exemplarily, the dedicated bearer includes a bearer corresponding to the Qosflow of 5IQ1, which is used to meet the Qos requirements of multimedia data transmitted between the terminal device 100 and the terminal device 106, for example, for carrying voice packets and / or video streams on the media plane. The IMS session is used to transmit audio and video data during the call between the terminal device 100 and the terminal device 106. In this way, after the terminal device 106 responds to the user's operation to connect the incoming call, a VoNR call can start between the terminal device 100 and the terminal device 106.

[0088] In addition, in the above embodiment, the process of the terminal device 100 initiating a call is only exemplarily introduced. In the specific implementation, the process includes more or fewer steps, which are not described here. In addition, in other embodiments, the terminal device 106 can also be a calling device, and the terminal device 100 can also be a called device. The process of the terminal device 106 talking to the terminal device 100 through VoNR can refer to the above embodiment, which is not described here. In the subsequent embodiments, the description is mainly based on the example that the calling device is the terminal device 100 and the called device is the terminal device 106.

[0089] In the above embodiment, the terminal device needs to be within the service range of the NG RAN before it can request access to the NG RAN. The service range of the NG RAN may be determined by the signal coverage of the node device (such as a 5G base station) in the NG RAN. In addition, the service range of the NG RAN may be divided into at least one cell, such as an NG RAN cell. In the case where the NG RAN includes multiple 5g base stations, the signal coverage of different 5g base stations may be different or overlapping. In addition, each cell of the NG RAN corresponds to the signal coverage of a 5G base station. The 5G base stations corresponding to different cells may be different or the same, and there is no specific limitation on this. In subsequent embodiments, the node devices in the NG RAN may be collectively referred to as network devices.

[0090] In addition, the terminal device 100 accessing the NG RAN 101 mentioned in the above process of establishing the VoNR call may refer to the terminal device 100 accessing an NG RAN cell in the NG RAN 101. In this way, establishing an RRC connection between the terminal device and the NG RAN may be establishing an RRC connection between the terminal device and the network device corresponding to the NG RAN cell.

[0091] refer to Figure 3 When a terminal device initiates a VoNR call, the interaction between the terminal device and the network device is as follows:

[0092] A1, establish an RRC connection between the terminal device and the second network device.

[0093] In some embodiments, before actually initiating a VoNR call, the terminal device may determine the NG RAN cell to be accessed and connect to the network device corresponding to the cell.

[0094] Exemplarily, when the terminal device is located in a cell corresponding to a network device, it can choose to access the network device.

[0095] by Figure 4 For example, the cells corresponding to the second network device and the first network device are neighboring cells, and there is an overlapping area between the two. It can be understood that the second network device and the first network device can be node devices in the same NG RAN or node devices in different NG RANs, and the embodiment of the present application does not specifically limit this.

[0096] like Figure 4 As shown, the user carrying the terminal device is located in the cell corresponding to the second network device, but has not entered the cell corresponding to the first network device. In this scenario, the terminal device chooses to access the second network device.

[0097] As another example, when the terminal device is located in an overlapping area of ​​cells corresponding to multiple network devices, the signal quality of the multiple network devices at the current location can be evaluated, and then the best network device can be selected based on the signal quality and accessed. For example, the terminal device determines that the signal quality of the radio signal from the second network device is better than the signal quality of the radio signal from the first network device, and determines to access the second network device.

[0098] Thus, in some embodiments, when a terminal device needs to select a network device to access, it can monitor the radio signal from the network device. Then, based on the detected radio signal, the signal quality corresponding to the network device that sent the radio signal is evaluated. Then, the network device with the best signal quality is selected and accessed.

[0099] For example, the above-mentioned radio signal may be a synchronization signal and channel state information from a network device. After monitoring the radio signal, the reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal receiving quality (RSRQ) and signal to interference plus noise ratio (SINR) corresponding to the network device may be evaluated. For specific implementation details, please refer to the relevant technology, which will not be described here. Then, based on the values ​​of one or more of the detected RSRP, RSSI, RSRQ and SINR, the signal quality corresponding to the network device is evaluated.

[0100] In the subsequent embodiments, the determination of accessing the second network device is taken as an example for description.

[0101] In some embodiments, the terminal device may initiate an RRC connection request to the second network device, and the second network device may establish an RRC connection with the terminal device. The specific process of establishing the RRC connection may refer to the provisions in the relevant protocol and will not be repeated here.

[0102] A2, the second network device sends a configuration message 1 to the terminal device, and the configuration message 1 includes the configuration of the first DRB in the second network device at the RLC layer.

[0103] Wherein, the second network device and the terminal device both support the NR wireless protocol stack. Figure 5 As shown, the NR wireless protocol stack indicates that the second network device and the terminal device both include an RRC layer, a packet data convergence protocol (PDCP) layer, a radio link (radio link control, RLC) layer, a MAC layer, etc.

[0104] Exemplarily, the above RRC layer is a high-level layer of the control plane, which is mainly responsible for controlling L1 / L2 to complete air interface resource transmission and providing information transmission services for other layers (such as non-access layer). Exemplarily, the RRC layer can be used to manage functions such as system message broadcasting, RRC connection control, mobility management, and measurement configuration reporting. Among them, RRC connection control management includes paging, establishing / modifying / suspending / resuming / releasing RRC connection, initial security activation, establishing / modifying / activating SRB / DRB, DC, CA mode cell management, and radio link failure recovery.

[0105] As another example, the PDCP layer is used to process RRC messages on the control plane and Internet Protocol (IP) data packets on the user plane. As an example, on the user plane, after the PDCP layer obtains the IP data packet from the upper layer, it can perform header compression and encryption on the IP data packet and then deliver it to the RLC layer. The PDCP layer also provides in-order submission and duplicate packet detection functions to the upper layer. In the control plane, the PDCP layer provides signaling transmission services for the upper layer RRC, implements encryption and consistency protection of RRC signaling, and implements decryption and consistency checking of RRC signaling in the reverse direction.

[0106] For example, the RLC layer mainly provides radio link control functions, providing services such as segmentation, retransmission control, and on-demand transmission for the upper layer. The RLC layer includes three transmission modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM), and mainly provides functions such as error correction, segmentation, and reassembly.

[0107] In the TM mode, after the RLC layer receives a message from the PDCP (eg, called PDCP data), it does not need to process and can directly pass it to the MAC layer.

[0108] In the AM mode, the PDCP data from the PDCP layer is added with the RLC layer header information (also called RLC header information) through the RLC layer, and after being sent, it needs to get a response from the peer device, otherwise it is considered that a data transmission abnormality has occurred. Similarly, after receiving the RLC data sent by the peer device using the AM mode, if it is determined that there is no abnormality in the data, it is also necessary to feedback the corresponding response to the peer device. In this way, the reliability of data transmission is improved. In addition, the terminal device and the network device that transmit data to each other can be referred to as peer devices to each other. In this way, the peer device of the network device can be a terminal device, and the peer device of the terminal device is a network device.

[0109] In UM mode, PDCP data from the PDCP layer is added with RLC header information by the RLC layer, and after being sent, there is no need to get a response from the peer device. Similarly, after receiving RLC data sent by the peer device in UM mode, there is no need to feed back a corresponding response to the peer device. In this way, the timeliness of data transmission is improved.

[0110] As another example, the MAC layer is used to provide mapping between logical channels and transport channels, multiplex RLC data from one or more logical channels into a transport block and pass it to the PHY layer; demultiplex the transport block transmitted from the PHY layer into multiple RLC data and pass it to one or more logical channels; report scheduling information; perform error correction through HARQ; manage priorities between users through dynamic scheduling; logical channel priority management, etc.

[0111] The PHY layer provides mechanical, electrical, functional, and regulatory characteristics for creating, maintaining, and dismantling the physical link required for data transmission. The physical layer can be used to ensure that the original data can be transmitted on various physical media.

[0112] In some embodiments, the NR wireless protocol stack may also include Figure 5 The protocol layers not shown in the figure, such as the non-access stratum (NAS) layer and the physical (PHY) layer, are not specifically limited in the embodiments of the present application.

[0113] It can be understood that the NR wireless protocol stack of the terminal device can be configured in the communication chip. For example, it can be configured in the modem processor of the terminal device. In this way, the modem processor can process the data to be received and sent according to the provisions of the NR wireless protocol stack.

[0114] Exemplarily, in the scenario where the above-mentioned terminal device sends data to other devices, after the PDCP layer configured in the modem processor receives the data to be sent, it adds PDCP layer header information to the data according to the corresponding protocol, obtains a PDCP protocol data unit (PDU), and passes it to the RLC layer. Then, the RLC layer adds RLC layer header information to the above-mentioned PDCP PDU (also referred to as PDCP data) according to the corresponding protocol to obtain RLC PDU. Afterwards, the MAC layer can add MAC layer header information to each RLC PDU (also referred to as RLC data) to obtain a MAC PDU. Then, according to the size of the transport block, one or more MAC PDUs are combined to obtain a MAC transport block protocol data unit (transport block PDU), also referred to as a data packet, and instruct the PHY layer to send the MAC transport block PDU using the corresponding physical link.

[0115] Exemplarily, in the scenario where the above-mentioned terminal device receives a data packet (MAC transport block PDU) from other devices, the PHY layer in the modem processor can pass the data packet to the MAC layer. The MAC layer can split multiple MAC PDUs from the data packet, and then parse the MAC layer header information of each MAC PDU, and obtain the data content carried in the MAC PDU, that is, the RLC PDU. Then, the MAC layer passes the parsed RLC PDU to the RLC layer, and then the RLC layer parses the RLC layer header information of the RLC PDU from the MAC layer, and obtains the data content carried in the RLC PDU, that is, the PDCP PDU. Then, the RLC layer passes the parsed PDCP PDU to the PDCP layer, and the PDCP layer parses it according to the corresponding protocol.

[0116] In some embodiments, after the RRC connection between the second network device and the terminal device is established, the second network device may send a configuration message 1 to the terminal device, which may also be referred to as a third reconfiguration message, or an RRCreconfiguration message. The configuration message 1 may include configuration parameters corresponding to multiple DRBs. The above-mentioned DRB is a bearer negotiated between the second network device and the corresponding core network for transmitting data between the second network device and the terminal device. For example, the first DRB and the second DRB are used to transmit communication service data between the second network device and the terminal device. Each DRB corresponds to a set of configurations, and the configurations corresponding to different DRBs may be different.

[0117] It can be understood that the configuration related to DRB can instruct each layer of the NR wireless protocol stack (such as PDCP layer, RLC layer, MAC layer, PHY layer, etc.) on how to handle the data to be transmitted through the DRB.

[0118] Exemplarily, the RLC layer supports data transmission modes such as TM mode, UM mode and AM mode. The second network device may configure the DRB in the RLC layer as TM mode, UM mode or AM mode.

[0119] For example, if the first DRB in the second network device is configured as AM mode in the RLC layer, after the communication service data a is sent to the terminal device using the first DRB, the RLC layer needs to wait for the terminal device to feedback a response, otherwise the data a will be resent.

[0120] Correspondingly, the configuration related to the first DRB in the configuration message 1 includes an identifier indicating the AM mode, a response waiting time, a number of retransmissions in the AM mode, etc. In this way, after the terminal device is configured according to the configuration message 1, it receives the communication service data from the second network device through the first DRB, and if the RLC layer header information of the communication service data is successfully parsed, a corresponding response can be sent to the second network device.

[0121] In addition, after the terminal device uses the first DRB to send communication service data to the second network device, if the corresponding response is not received within the response waiting time, the retransmission of the communication service data is triggered. If the number of retransmissions of the communication service data reaches the number of retransmissions in the configuration message 1, it is determined that there is a communication anomaly between the terminal device and the second network device.

[0122] For another example, if the second DRB in the second network device is configured as UM mode at the RLC layer, after the second network device uses the second DRB to send the communication service data b to the terminal device, the RLC layer of the second network device does not need to wait for the terminal device to feedback a response. Correspondingly, the configuration related to the second DRB in the configuration message 1 includes an identifier indicating the UM mode. In this way, after the terminal device is configured according to the configuration message 1, after the terminal device receives the communication service data from the second network device through the second DRB, it does not feedback a response to the second network device.

[0123] It can be understood that the RLC layer can add RLC layer header information (also referred to as RLC header information) to the data that needs to be sent using the first DRB or the second DRB. The RLC header information includes a sequence number (SN) field. The SN number carried in the SN field can ensure that the RLC PDU is sent in sequence, and when retransmission is required, the RLC PDU that needs to be retransmitted can be determined. The SN field of the above RLC header information can also be referred to as the RLC SN field.

[0124] In addition, the RLC layer can also split data (such as PDCP PDU) into multiple split data for easy transmission. Exemplarily, after a PDCP PDU is processed by the RLC layer, multiple split data can be obtained, and each split data can obtain multiple RLC PDUs after adding RLC header information. In the case where the data carried by multiple RLC PDUs come from the same PDCP PDU, the SN numbers in the RLC header information of the above multiple RLC PDUs have the same value.

[0125] According to protocol 38.311, "sn-FieldLength Indicates the RLC SN field size, see TS 38.322[4], in bits. Value size6 means 6 bits, value size12 means 12 bits, value size18 means 18 bits", the corresponding translation is: "sn-FieldLength" in the network device can indicate the length of the RLC SN field, see TS 38.322 for details, in bits. When the value of "sn-FieldLength" corresponding to the DRB is "size6", it indicates that the SN field length configured by the DRB at the RLC layer is 6 bits; when the value of "sn-FieldLength" corresponding to the DRB is "size12", it indicates that the SN field length configured by the DRB at the RLC layer is 12 bits; when the value of "sn-FieldLength" corresponding to the DRB is "size18", it indicates that the SN field length configured by the DRB at the RLC layer is 18 bits.

[0126] It can be seen that the network device can configure the SN field length corresponding to each DRB in the RLC layer in advance by configuring the "sn-FieldLength" corresponding to each DRB. For example, the "sn-FieldLength" corresponding to the first DRB (DRB using AM mode) or the second DRB (DRB using UM mode) is configured to be 12 bits. For the data to be sent by the first DRB or the second DRB, after being processed by the RLC layer, it has RLC layer header information with an SN field length of 12 bits. Of course, the above process of configuring "sn-FieldLength" can be called configuring the SN field length at the RLC layer.

[0127] The SN field length configured at the RLC layer for each DRB in the terminal device must be consistent with the SN field length configured at the RLC layer for the DRB in the connected network device.

[0128] In this way, the configuration related to the DRB using the AM mode or the UM mode in the configuration message 1 may also include the length of the SN field configured at the RLC layer of the DRB in the network device. It can be understood that the lengths of the SN fields configured at the RLC layer of different DRBs may be different or the same.

[0129] In the subsequent embodiments, the implementation details of the embodiments of the present application are introduced by taking the first DRB using the AM mode as an example.

[0130] Thus, in some embodiments, the configuration message 1 may include the configuration of the first DRB at the RLC layer. In subsequent embodiments, the configuration of the first DRB may include an SN field length of 12 bits, an identifier indicating an AM mode, a response waiting time of t, and a number of retransmissions in the AM mode of N. For example, N is a positive integer, which may also be referred to as the first number, and t is a positive value, which may also be referred to as the first duration.

[0131] In this example, after the terminal device is configured according to configuration message 1, Figure 6 As shown, for communication service data (such as PDCP data) that needs to be transmitted through the first DRB, the RLC layer of the terminal device can add RLC header information to the PDCP data to obtain RLC data. The RLC header information of the RLC data includes an SN field and other fields. Among them, the length of the SN field in the RLC header information is 12 bits.

[0132] In short, the configuration message 1 can synchronize the configuration of the DRB between the terminal device and the second network device. For example, for data to be transmitted by the same DRB, the terminal device and the second network device can synchronize the processing methods of each layer (such as PDCP layer, RLC layer, MAC layer, PHY layer, etc.), such as encoding method, decoding method, transmission method, etc.

[0133] In this way, after the terminal device receives a data packet from the second network device and identifies the DRB used to transmit the data packet, it can use a matching method to accurately parse the data packet. Similarly, after the second network device receives a data packet from the terminal device and identifies the DRB used to transmit the data packet, it can also use a matching method to accurately parse the data packet. This enables normal communication between the terminal device and the second network device.

[0134] In addition, the above configuration message 1 may also include the time-frequency resources and wireless resource configuration required for accessing the second network device, which will not be described in detail here.

[0135] A3: The terminal device initiates a call through the second network device.

[0136] For example, a VoNR call is initiated to other terminals through the second network device in the 5G communication system. The implementation details of establishing the VoNR call can refer to the above embodiment and will not be repeated here. After the call is established, the process enters A4.

[0137] A4, the terminal device can send call data to the second network device through the first DRB.

[0138] The above-mentioned call data may also be referred to as communication service data. In a possible embodiment, it may be call data sent based on different communication systems, such as call data sent based on a 5G communication system, call data sent based on a 6G communication system, or call data sent based on a 4G communication system.

[0139] It is understandable that, during the propagation process, as the propagation distance of the radio signal increases, the signal attenuation will occur. Thus, in the cell corresponding to the network device, the signal quality at different locations is different. In addition, the cell corresponding to the network device may also change, for example, due to the influence of environmental factors, or due to the influence of operating power, etc.

[0140] In this scenario (e.g., the location of the user carrying the terminal device changes, or the cell range of the second network device changes), the terminal device can trigger the method of switching to the NG RAN cell to ensure the communication quality. Of course, during the process of the terminal device using VoNR for a call, if it switches to the NG RAN cell and changes the connected network device, there is a possibility of call drop (call interruption), which directly affects the call quality.

[0141] For example, when a terminal device is making a VoNR call, when the terminal device switches from a network device connected to the NG RAN to another network device connected to the NG RAN, or when the terminal device switches from a network device connected to one NG RAN to a network device connected to another NG RAN, there is a possibility of dropped calls.

[0142] like Figure 7 In the scenario shown, after the user carries the terminal device into the overlapping area of ​​the cells corresponding to the second network device and the first network device, if the second network device determines that the terminal device needs to switch to the cell corresponding to the first network device, it can access the first network device by reconfiguration.

[0143] Exemplarily, the above reconfiguration method may be: the terminal device modifies the RRC connection so that the terminal device and the first network device can communicate with each other.

[0144] refer to Figure 8 , the SN field length configured at the RLC layer for the first DRB in the second network device is 12 bits, and the SN field length configured at the RLC layer for the first DRB in the first network device is 18 bits. When the terminal device initiates a VoNR call through the second network device, the SN field length configured at the RLC layer for the first DRB in the terminal device is 12 bits.

[0145] Afterwards, the process of the terminal device switching from the second network device to accessing the first network device is as follows:

[0146] B1: The terminal device performs neighboring cell detection.

[0147] B2, the terminal device reports a neighboring cell detection report to the second network device.

[0148] In some embodiments, the terminal device may perform neighboring cell detection in response to a measurement event sent by the second network device, and report a neighboring cell detection report to the base station if the corresponding conditions are met. In this way, the second network device may instruct the terminal device to perform a cell switch according to the neighboring cell detection report, or the terminal device may perform a cell switch autonomously.

[0149] For example, the measurement events may include: event A3, event A2, event B1, event B2, etc.

[0150] Among them, Event A3 is used to trigger the same-frequency measurement of the neighboring cell of the same network standard. When the Reference Signal Receiving Power (RSRP) value of the neighboring cell is higher than the RSRP of the resident cell and the RSRP value of the neighboring cell exceeds the corresponding threshold, the neighboring cell detection report is uploaded.

[0151] Event A2 is used to trigger measurement of the resident cell. When the RSRP value of the resident cell is lower than the corresponding threshold, a neighbor cell detection report is uploaded.

[0152] Event B1 can be used to trigger the measurement of a high-priority heterogeneous system cell. When the RSRP of the neighboring cell is higher than the corresponding threshold, the terminal uploads a neighboring cell detection report.

[0153] Event B2 can be used to trigger the measurement of heterogeneous system cells of the same or lower priority. When the RSRP of the resident cell is lower than the corresponding threshold and the RSRP of the heterogeneous system neighboring cell is higher than the corresponding threshold, the terminal uploads a neighboring cell detection report.

[0154] In the above embodiment, after the terminal device generates a neighboring cell detection report corresponding to the measurement event, it can report it to the second network device.

[0155] In addition, the above-mentioned neighboring area detection report can also be called a neighboring area measurement report. Exemplarily, the neighboring area detection report records the signal qualities corresponding to multiple accessible network devices. The above-mentioned multiple accessible network devices include a second network device and a neighboring area network device. In addition, the above-mentioned neighboring area network device can be a device that uses the same network standard as the second network device. In other embodiments, the terminal device can perform at least one neighboring area detection under preset conditions. Exemplarily, the above-mentioned preset conditions include at least one of the following:

[0156] (1) A detection cycle is configured in the terminal device, and the detection time point of each detection cycle is reached when the system time.

[0157] (2) The terminal device receives an operation from the user to refresh the network status.

[0158] (3) The terminal device detects that the signal quality of the second network device is lower than a preset first threshold value.

[0159] (4) The terminal device detects that the signal quality of other network devices is higher than a preset second threshold value, wherein the first threshold value may be smaller than the second threshold value.

[0160] Similarly, each time the terminal device generates a neighboring area detection report, it can be reported to the second network device. Similarly, the neighboring area detection report records the signal quality corresponding to multiple accessible network devices. The multiple accessible network devices include the second network device and the neighboring area network device.

[0161] B3, the second network device determines, based on the neighboring cell detection report, that it is necessary to instruct the terminal device to access the first network device with better communication quality.

[0162] Exemplarily, in a scenario where the second network device sends a measurement event to the terminal device, if the second network device receives a neighboring cell detection report corresponding to the measurement event, it determines that the terminal device needs to be instructed to access a network device with better signal quality. Also exemplarily, in a scenario where the second network device sends a measurement event to the terminal device, if the second network device receives a neighboring cell detection report corresponding to the measurement event, the same measurement event may be sent to the terminal device again to instruct the terminal device to perform neighboring cell detection again. After the second network device receives the neighboring cell detection report from the terminal device again, it can be determined that the terminal device currently needs to be instructed to access a network device with better signal quality. That is, the second network device may send the same measurement event to the terminal device multiple times, and after receiving neighboring cell detection reports corresponding to high measurement events multiple times, it determines that the terminal device needs to switch to other network devices. In this way, the timing of switching the NG RAN cell can be accurately identified, worthless cell switching can be avoided, and the communication quality of the terminal device can be guaranteed.

[0163] As another example, in a scenario where the terminal device actively performs neighbor detection in response to a preset condition, the second network device may first determine whether the terminal device needs to switch to a new network device, for example, from a neighbor detection report, determine whether the signal quality of the second network device is lower than a first threshold value. If the signal quality of the second network device is lower than the first threshold value, identify the scenario conditions that currently meet the triggering condition for the terminal device to switch to another network device.

[0164] In some embodiments, after determining that the terminal device needs to switch to other network devices, the second network device can also evaluate the target network device based on the signal quality of multiple network devices in the neighboring area detection report, the supported network standards, and whether it is compatible with the terminal device. For the specific evaluation process, please refer to the relevant technology and will not be repeated here. In addition, the target network device can be regarded as the network device with the best communication quality that the current terminal device can access. In the subsequent embodiments, the target network device is taken as the first network device as an example for description.

[0165] B4. The second network device sends a handover request to the first network device.

[0166] The switching request may indicate that the terminal device needs to access, and the switching request may also carry capability information of the terminal device.

[0167] B5. The first network device feeds back a switching request confirmation message to the second network device. The switching request confirmation message includes the configuration information corresponding to the first network device, and does not include the length of the SN field configured in the RLC layer for the first DRB in the first network device.

[0168] In some embodiments, the first network device responds to the handover request and, if the terminal device is accessible, can send a handover request confirmation message to the second network device. In the current protocol, there is no provision that the handover request confirmation message must carry the length of the SN field configured for the first DRB at the RLC layer. Thus, in actual scenarios, some handover request confirmation messages sent by the first network device to the second network device do not include the length of the SN field configured for the first DRB at the RLC layer.

[0169] B6, the second network device sends an RRC reconfiguration message 1 to the terminal device (including a switching indication, excluding the SN length configured in the RLC layer for the first DRB in the first network device).

[0170] The RRC reconfiguration message 1 may also be referred to as an RRC reconfiguration message. The RRC reconfiguration message 1 may be generated according to the configuration information from the first network device. It is understandable that the configuration information from the first network device does not contain the length of the SN field configured by the first DRB at the RLC layer, and the RRC reconfiguration message 1 does not contain the length of the SN field configured by the first DRB in the first network device at the RLC layer.

[0171] The above-mentioned switching indication may carry characteristic information of the first network device, such as the cell center frequency, cell identifier, etc., and is used to instruct the terminal device to switch to the cell corresponding to the first network device, or to instruct the terminal device to access the first network device.

[0172] B7, the terminal device switches according to RRC reconfiguration message 1.

[0173] It can be understood that the RRC reconfiguration message 1 includes a switching indication and is a message with a synchronization function. At the same time, the RRC reconfiguration message 1 does not contain the length of the SN field configured for the first DRB at the RLC layer. In this way, even after the terminal device accesses the first network device according to the RRC reconfiguration message 1, the length of the SN field configured for the first DRB at the RLC layer will not be modified, that is, the terminal device continues to inherit the configuration result of the second network device for the length of the SN field of the first DRB at the RLC layer.

[0174] B8, the terminal device sends an RRC reconfiguration completion message (indicating that the switching is completed) to the first network device.

[0175] The RRC reconfiguration complete message may also be referred to as RRC reconfiguration complete. In this way, the terminal device may start to send service data to the first network device.

[0176] B9, the terminal device uses the first DRB in AM mode to send data packet 1 to the first network device. The length of the SN field in the RLC header information of data packet 1 is 12 bits.

[0177] In some embodiments, before the terminal device sends data to the first network device, the corresponding DRB can be determined according to the QOSflow to which the data belongs. Then, according to the configuration of each layer of the DRB in the NR wireless protocol stack, the data is encapsulated layer by layer to obtain the corresponding data packet and sent to the first network device.

[0178] In this embodiment, the determined DRB is the first DRB. Fig. 9As shown, in the terminal device, the data to be transmitted through the first DRB is processed by the PDCP layer to obtain data 1 (e.g., PDCP status report). Then, the PDCP layer can pass data 1 to the RLC layer, and the RLC layer adds RLC header information to data 1 according to the SN field length inherited from the second network device (e.g., 12 bits). In this way, in the obtained RLC data, the SN field length of the RLC header information is 12 bits. After that, after encapsulation by the MAC layer, data packet 1 carrying data 1 is obtained.

[0179] Afterwards, the MAC layer may instruct the PHY layer to send the data packet 1 to the first network device through the matching physical link. The SN field length of the RLC header information corresponding to the data 1 in the data packet 1 is 12 bits.

[0180] Of course, if the SN field length of the above-mentioned first DRB in the first network device configured in the RLC layer is also 12 bits, after the first network device parses the RLC data containing data 1 from data packet 1, the RLC layer of the first network device can successfully parse the RLC header information of the RLC data and send a corresponding response to the terminal device.

[0181] If the length of the SN field configured at the RLC layer of the first DRB in the first network device is not equal to 12 bits, Fig. 9 As shown, when the SN field length of the first DRB in the first network device configured at the RLC layer is 18 bits, the process enters B10.

[0182] B10, the first network device parses the RLC header information according to the length of the SN field being 18 bits, and the parsing of data packet 1 is abnormal.

[0183] In some embodiments, after the MAC layer of the first network device parses the RLC data including the data 1 from the data packet 1, it transmits the RLC data to the RLC layer, such as Fig. 9 As shown, the length of the SN field configured in the RLC layer of the first DRB in the first network device is 18 bits. In this way, the RLC layer will parse the data packet 1 transmitted through the above DRB according to the SN field length of 18 bits, that is, the data with an actual length of 12 bits of the RLC SN field. Obviously, not only the accurate SN number cannot be parsed, but also the accurate RLC header information cannot be parsed, resulting in abnormal parsing of data packet 1.

[0184] In the case where the parsing of data packet 1 is abnormal, the first network device does not send a response to data packet 1 to the terminal device.

[0185] If the terminal device does not receive a response to data packet 1 within the response waiting time corresponding to the first DRB, it can resend data packet 1. When the number of retransmissions of data packet 1 reaches the number of retransmissions corresponding to the DRB, the process enters B11.

[0186] B11, when data packet 1 is sent multiple times and no response is received, the terminal device sends an RRC re-establishment request to the first network device.

[0187] Among them, when the number of retransmissions configured for the first DRB in the RLC layer is N and the response waiting time is t, the above-mentioned "sending data packet 1 multiple times and not receiving a response" may mean that data packet 1 is sent N times through the first DRB, and no response corresponding to data packet 1 is received within time t after data packet 1 is sent for the Nth time.

[0188] In addition, the RRC reestablishment request may also be referred to as an RRC Reestablishment Request, which is used to instruct to reestablish the RRC connection between the terminal device and the first network device. After the RRC connection between the terminal device and the first network device is reestablished, the process enters B12.

[0189] B12, the first network device sends an RRC reconfiguration message 2 to the terminal device, which includes the length (18 bits) of the SN field configured by the first network device at the RLC layer for the first DRB.

[0190] The RRC reconfiguration message 2 may also be an RRC reconfiguration message. The difference between the RRC reconfiguration message 2 and the RRC reconfiguration message 1 is that the RRC reconfiguration message 2 does not contain a switching indication, and according to the provisions of the current protocol, the RRC reconfiguration message 2 does not have a synchronization function.

[0191] It can be understood that when a network device to which a terminal device is connected changes, for example, when switching from a cell corresponding to one network device to a cell corresponding to another network device, the RRC reconfiguration message received by the terminal device contains a switching indication.

[0192] When the network device connected to the terminal device does not change, the received RRC reconfiguration message does not contain a switching indication. For example, after the terminal device has connected to the first network device, after sending an RRC re-establishment to the first network device, the RRC reconfiguration message 2 received by the terminal device does not contain a switching indication.

[0193] B13. When the SN field length (18 bits) configured at the RLC layer for the first DRB carried by the RRC reconfiguration message 2 is not equal to the SN field length (12 bits) configured at the RLC layer for the first DRB in the terminal device, the terminal device sends an RRC re-establishment request to the first network device.

[0194] Among them, the protocol 38.311 stipulates that "The value of sn-FieldLength for a DRB shall be changed only using reconfiguration with sync. The network configures only value size12 in SN-FieldLengthAM for SRB", which translates to: The value of "sn-FieldLength" corresponding to a DRB can only be changed through synchronous reconfiguration. The network only configures value size12 for SRB in SN-FieldLengthAM.

[0195] That is, the protocol stipulates that during the call service, the SN field length of the DRB at the RLC layer can only be changed through a reconfiguration message with a synchronization function (such as an RRC reconfiguration message carrying a switching indication). In this way, according to the provisions of the current protocol, the above RRC reconfiguration message 2 does not have the function of changing the SN field length of the first DRB configured at the RLC layer, but carries the SN field length configured for the first DRB at the RLC layer in the first network device. The terminal device can regard the RRC reconfiguration message 2 as abnormal and trigger RRC reestablishment. For example, an RRC reestablishment request, that is, an RRC Reestablishment Request, is sent to the first network device.

[0196] B14, the first network device sends a bye message to the terminal device, instructing the terminal device to end the call.

[0197] B15, the terminal device determines that the call is abnormal and ends the call.

[0198] It can be understood that before B12, the first network device can negotiate with the core network to determine multiple DRBs for transmitting communication service data between the first network device and the terminal device. The above multiple DRBs include the first DRB. After negotiation, the first network device sends an RRC reconfiguration message 2 to the terminal device, and the RRC reconfiguration message 2 includes the configuration of multiple DRBs in the first network device, for example, the length of the SN field configured in the RLC layer of the first DRB. However, since the length of the SN field configured in the RLC layer of the first DRB carried in the RRC reconfiguration message 2 is different from the length of the SN field configured in the RLC layer of the first DRB of the terminal device itself, and the RRC reconfiguration message 2 does not have a synchronization function (e.g., does not contain a switching indication), the terminal device can determine that the RRC reconfiguration message 2 does not comply with the protocol requirements and will not send an RRC reconfiguration completion message to the first network device.

[0199] In the case where the RRC reconfiguration completion message is not fed back to the first network device, the terminal device sends an RRC re-establishment request to the first network device again. In response to the RRC re-establishment request, the first network device requests negotiation with the core network again. Since the core network has not received the last negotiation feedback for the DRB of the terminal device, when the negotiation request is received again, it may trigger the core network to determine that the DRB between the first network device and the terminal device is abnormal (e.g., DRB is lost), and instruct the first network device to send a bye message to the terminal device, instructing the terminal device to end the call.

[0200] In order to improve the above-mentioned dropped call problem, in an embodiment of the present application, during a VoNR call, if the terminal device switches from one network device (e.g., the second network device) to access another network device (the first network device), the possibility of dropped call problems can be reduced.

[0201] like Fig.10 As shown, the SN field length configured in the RLC layer of the first DRB in the second network device is the first value. In this way, the SN field length in the RLC header information generated by the RLC layer of the second network device for the data corresponding to the first DRB is the first value. In addition, when the RLC layer of the second network device parses the RLC header information of the data from other devices and transmitted through the first DRB, it parses according to the RLC header information as the first value.

[0202] Similarly, the SN field length configured in the RLC layer of the first DRB in the first network device is the second value. In this way, the SN field length in the RLC header information generated by the RLC layer of the first network device for the data corresponding to the first DRB is the second value. In addition, when the RLC layer of the first network device parses the RLC header information of the data from other devices and transmitted using the first DRB, it parses it according to the second value of the RLC header information. In addition, the cells corresponding to the second network device and the first network device are neighboring cells.

[0203] like Fig.10 As shown, the communication method of the embodiment of the present application may include the following steps:

[0204] S101, the terminal device establishes a VONR call through the second network device.

[0205] In some embodiments, before the above S101, a connection can be established between the terminal device and the second network device. After the connection between the terminal device and the second network device is established, the second network device sends a configuration message 1 to the terminal device. The specific implementation process can refer to A1 and A2 in the above embodiments. Among them, the configuration message 1 includes that the SN field length of the first DRB in the second network device is configured at the RLC layer as the first value. In this way, after the terminal device is configured based on the configuration message 1, the data to be transmitted through the first DRB, after being processed by the RLC layer, the SN field length of the RLC header information is the first value.

[0206] In addition, the implementation process of the above S101 can refer to A3 in the aforementioned embodiment, which will not be repeated here. In this embodiment, the terminal device may initiate a VONR call while accessing the second network device. During the call, the terminal device uses the first DRB to send third data to the second network device, and the SN field length of the RLC header information of the third data is the first value. Then, the process enters S102.

[0207] S102, the terminal device performs neighboring cell detection.

[0208] In some embodiments, when the terminal device accesses the second network device, the terminal device can actively trigger the neighbor detection, or the second network device can trigger the neighbor detection. In addition, the method of triggering the neighbor detection can refer to step B1 in the aforementioned embodiment, and the neighbor detection method used can also refer to the relevant technology, which will not be repeated here.

[0209] In addition, under preset conditions, when the terminal device triggers multiple neighboring cell detections, multiple neighboring cell detections may be performed continuously or at intervals of a specified duration. After each neighboring cell detection is completed, a corresponding neighboring cell detection report may be generated, which may be referred to as a neighboring cell measurement report. Exemplarily, the signal quality of multiple access network devices is recorded in the neighboring cell detection report. The multiple access network devices may include a second network device and an access network device corresponding to a neighboring cell. For example, the multiple access network devices may include a second network device and a first network device.

[0210] In this way, whether the user is moving with the terminal device, or the signal quality of the second network device is affected by itself or the environment, the terminal device can promptly and accurately identify the decline in the quality of communication services provided by the second network device, and promptly trigger the subsequent network device switching process.

[0211] S103, the terminal device sends a neighboring cell detection report to the second network device.

[0212] In some embodiments, the implementation details of the above S103 can refer to step B2 in the aforementioned embodiment, which will not be repeated here.

[0213] S104: The second network device determines that it needs to switch to the first network device according to the neighboring cell detection report.

[0214] In some embodiments, the second network device may evaluate the target network device from at least one network device recorded in the neighbor detection report according to the neighbor detection report. For example, the target network device is determined to be the first network device, and the first network device can be used as the network device that the terminal device needs to switch to.

[0215] Exemplarily, the second network device evaluates the target network device based on multiple dimensions such as the signal quality of multiple network devices in the neighboring area detection report, the supported network standards, and whether it is compatible with the terminal device. For the specific evaluation process, reference may be made to the relevant technology, which will not be described in detail here. In the subsequent embodiments, the target network device determined is mainly described as the first network device.

[0216] S105: The second network device sends a switching request to the first network device.

[0217] The above-mentioned switching request may be referred to as a handover request. The implementation details of the above-mentioned S105 may refer to B4 in the above-mentioned embodiment, which will not be described in detail here.

[0218] S106, the first network device feeds back a switching request confirmation message to the second network device, where the switching request confirmation message includes configuration information corresponding to the first network device, and does not include the length of the SN field configured for the first DRB in the first network device at the RLC layer.

[0219] In some embodiments, the implementation details of the above S106 can be referred to B5 and will not be repeated here.

[0220] It can be understood that the current protocol does not stipulate that the switching request confirmation message sent by the first network device to the second network device must carry the SN field length configured for the first DRB in the RLC layer. In this way, the switching request confirmation message may not contain the SN field length configured for the first DRB in the first network device in the RLC layer.

[0221] In some embodiments, after receiving the handover request confirmation message from the first network device, the second network device may generate a corresponding RRC reconfiguration message, such as RRC reconfiguration message 3, and the process enters S107.

[0222] In some embodiments, the implementation details of the above S105 and S106 can be referred to the solution of terminal device switching cells in the related technology, which will not be repeated here.

[0223] S107, the second network device sends an RRC reconfiguration message 3 to the terminal device, including a switching indication, but not including the SN length configured in the RLC layer for the first DRB in the first network device.

[0224] In some embodiments, the switching indication in the RRC reconfiguration message 3 (such as the second reconfiguration message) is used to instruct the terminal device to switch from the cell of the second network device to the cell corresponding to the first network device by modifying the RRC connection, which can also be called accessing the first network device. For example, the switching indication carries information such as the central frequency of the cell corresponding to the first network device. In this embodiment, the above RRC reconfiguration message 3 does not contain "the SN field length configured at the RLC layer of the first DRB in the first network device is the second value".

[0225] S108, the terminal device switches according to RRC reconfiguration message 3.

[0226] In some embodiments, the terminal device reconfigures wireless resources (e.g., the communication link corresponding to VoNR) according to the RRC reconfiguration message 3, so that the terminal device can access the first network device and perform data interaction.

[0227] Of course, in this embodiment, the RRC reconfiguration message 3 has a synchronization function, but does not include "the SN field length of the first DRB in the first network device at the RLC layer". After the terminal device uses the RRC reconfiguration message 3 to modify the RRC connection, it will not modify the SN field length configured for the first DRB in the terminal device at the RLC layer. In this way, the SN field length actually configured for the first DRB in the terminal device at the RLC layer is still the first value. That is, the terminal device and the first network device do not synchronize the SN field length configured for the first DRB at the RLC layer.

[0228] S109, the terminal device sends an RRC reconfiguration completion message (indicating that the switching is completed) to the first network device.

[0229] Among them, the above-mentioned RRC reconfiguration completion message can also be called RRC reconfiguration complete.

[0230] In some embodiments, after the terminal device accesses the first network device according to the RRC reconfiguration message 3, it can send an RRC reconfiguration completion message to the first network device, after which data can be transferred between the terminal device and the first network device.

[0231] It is understandable that during the process of accessing the first network device by reconfiguration, the terminal device does not interrupt the ongoing VoNR call service. After the reconfiguration is completed, the terminal device can send the service data corresponding to the VoNR call through the first network device. For example, a PDCP status report is sent to test whether normal communication can be achieved after accessing the first network device.

[0232] S110, the terminal device sends a data packet 2 to the first network device through the first DRB in the AM mode, and the length of the SN field of the RLC header in the data packet 2 is a first value.

[0233] The implementation details of S110 can be referred to B9 in the above embodiment, which will not be described in detail here. Data packet 2 and data packet 1 both refer to communication service data to be transmitted through the first DRB, which will not be described in detail here. The data packet 2 can be the first data.

[0234] S111, the first network device parses the RLC header information in the data packet 2 according to the SN field length being the second value, wherein the parsing is abnormal when the first value is different from the second value.

[0235] It can be understood that the SN field length configured at the RLC layer of the first DRB in the first network device is the second value, that is, the SN field length configured at the RLC layer of the first DRB is the second value. In this way, after the first network device receives the data packet 2 transmitted through the first DRB, the RLC layer of the first network device parses the RLC header information in the data packet 2 according to the RLC SN field length being the second value.

[0236] In some embodiments, when the first value is different from the second value, the RLC data parsed by the first network device is inaccurate. In this way, the first network device may not send a response corresponding to the RLC data to the terminal device.

[0237] In actual applications, the first network device does not provide feedback response for RLC data (such as PDCP status reports, real-time video streams, etc.) sent by DRBs in AM mode (such as DRBs carrying IMS signaling) that contain abnormalities (such as data that the first network device cannot accurately parse).

[0238] It is understandable that the first DRB is also configured with the number of retransmissions (N) and the response waiting time (t) at the RLC layer. The response waiting time (t) refers to the length of time to wait for the feedback response from the opposite device after each data is sent through the first DRB.

[0239] For example, if the terminal device sends data packet 2 through the first DRB and does not receive a response from the first network device within time t, retransmission of data packet 2 is triggered.

[0240] The above-mentioned number of retransmissions (N) refers to the maximum number of times the same data is retransmitted through the first DRB.

[0241] For example, after the data packet 2 is retransmitted through the first DRB for the i-th time, the value of i is a positive integer less than N, and no response is received from the first network device within the time t, triggering the i+1-th retransmission of the data packet 2. After the data packet 2 is retransmitted through the first DRB for the Nth time, no response is received from the first network device within the time t, and it is determined that an abnormality occurs, and the process can enter S112.

[0242] In other embodiments, when the first value and the second value are the same, the first network device can accurately parse the data packet from the terminal device and obtain the data content carried by it. In this way, the terminal device and the first network device can communicate normally, and the terminal device can continue to make a VoNR call through the first network device. In addition, there is no need to perform subsequent process steps.

[0243] S112, when data packet 2 is sent multiple times and no response is received, the terminal device sends an RRC re-establishment request to the first network device.

[0244] In some embodiments, if a data packet 2 sent through the first DRB does not receive a response corresponding to the data packet 2 within the response waiting time corresponding to the first DRB, retransmission may be triggered. When the number of retransmissions of data packet 2 reaches the number of retransmissions N corresponding to the first DRB, and no response to data packet 2 is received, the terminal device may determine that there is an abnormality in the communication with the first network device. In this scenario, the terminal device may send an RRC reestablishment request (RRCReestablishment Reques) to the first network device, instructing the re-establishment of the RRC connection between the terminal device and the first network device. That is, the above "sending data packet 2 multiple times and not receiving a response" may mean sending data packet 2 N times, and not receiving a corresponding response within a time t after each sending.

[0245] After the RRC connection between the terminal device and the first network device is re-established, the process enters S113.

[0246] S113, the first network device sends an RRC reconfiguration message 4 to the terminal device, which includes the length (second value) of the SN field configured by the first network device at the RLC layer for the first DRB.

[0247] The RRC reconfiguration message 4 may also be an RRC reconfiguration message. In addition, the RRC reconfiguration message 4 does not have a synchronization function, but the RRC reconfiguration message 4 carries the second value of the SN field length configured at the RLC layer of the first DRB in the first network device, and may also be referred to as carrying the first indication information. The RRC reconfiguration message 4 may be referred to as a first reconfiguration message.

[0248] S114, during a call, when the second value is not equal to the first value, the terminal device configures the SN field length corresponding to the first DRB in the RLC layer to the second value.

[0249] In the embodiment of the present application, after the terminal device receives the RRC reconfiguration message 4 from the first network device, even if the RRC reconfiguration message 4 does not have a synchronization function (for example, it is not an RRC reconfiguration message carrying a switching indication), the SN field length configured at the RLC layer of the first DRB is modified to the second value according to the RRC reconfiguration message 4. The above process is not in compliance with the current protocol, but the terminal device can ignore the problem of non-compliance in modifying the SN field length this time.

[0250] After the SN field length of the first DRB in the terminal device is configured to be the second value at the RLC layer, the communication service data that needs to be sent through the first DRB, after being processed by the RLC layer, the SN field length of the obtained RLC header information is configured to be the second value.

[0251] In addition, it can be understood that in this embodiment, the first DRB is mainly used as an example, and the above method is also applicable to other DRBs between the terminal device and the first network device.

[0252] S115, the terminal device sends an RRC reconfiguration completion message to the first network device.

[0253] Among them, the above-mentioned RRC reconfiguration completion message can also be called RRC reconfiguration complete.

[0254] Afterwards, the SN field length of the RLC header information of the data to be transmitted through the first DRB in the terminal device is the second value, and the terminal device and the first network device can also communicate normally. When the terminal device modifies the SN field length configured in the RLC layer of the first DRB, it does not trigger the RRC re-establishment request to be sent to the first network device again, but sends an RRC reconfiguration completion message after the modification is completed, so as to avoid the core network corresponding to the first network device from misjudging the data bearer loss, thereby reducing the frequency of dropped calls and improving the quality of communication services.

[0255] After the SN field length configured in the RLC layer of the first DBR is modified to the second value, the terminal device can send second data to the first network device, and the SN field length of the RLC header information of the second data is the second value.

[0256] In some embodiments, the steps performed by the terminal device may be processed by a modem process.

[0257] Exemplarily, the above S101 may be executed by a call request module in a terminal device. The above S102 to S103 may be executed by a PHY layer in a terminal device. The above S108 to S109 may be executed by an RRC layer in a terminal device. S110 may be executed collaboratively by a PDCP layer, an RLC layer, a MAC layer, and a PHY layer in a terminal device. S112 may be executed by an RRC layer in a terminal device. S114 may be executed by an RLC layer in a terminal device. S115 may be executed by an RLC layer in a terminal device.

[0258] In some embodiments, the process of the terminal device executing the above method may be as follows: using the first DRB to send the first data to the first network device, the SN field length of the RLC header information of the first data is the first value; when the terminal device does not receive the response returned by the first network device for the first data, send a re-establishment request to the first network device; receive a first reconfiguration message from the first network device, wherein the first reconfiguration message carries the first indication information, and the first indication information is used to indicate that the SN field length configured at the RLC layer of the first DRB in the first network device is the second value; when the first value is not equal to the second value, send a reconfiguration completion message to the first network device. After sending the reconfiguration completion message, use the first DRB to send the second data to the first network device, the SN field length of the RLC header information of the second data is the second value, and the second data carries the same data content as the first data.

[0259] In other possible embodiments, Fig.11 As shown, the above communication method may also include:

[0260] S201, the terminal device establishes a VONR call through the second network device.

[0261] S202, the terminal device performs neighboring cell detection.

[0262] S203, the terminal device sends a neighboring cell detection report to the second network device.

[0263] S204: The second network device determines that it needs to switch to the first network device according to the neighboring cell detection report.

[0264] S205: The second network device sends a switching request to the first network device.

[0265] S206, the first network device feeds back a switching request confirmation message to the second network device, where the switching request confirmation message includes configuration information corresponding to the first network device, and does not include the length of the SN field configured for the first DRB in the RLC layer in the first network device.

[0266] S207, the second network device sends an RRC reconfiguration message 3 to the terminal device, including a switching indication, but not including the SN length configured in the RLC layer for the first DRB in the first network device.

[0267] The implementation details of the above S201 to S207 may refer to S101 to S107 in the aforementioned embodiment, which will not be described in detail here.

[0268] S208: The terminal device determines, based on historical record data, that the SN field length configured at the RLC layer for the first DRB in the first network device is a second value.

[0269] In some embodiments, after the terminal device accesses any network device, it can record the configuration of each DRB in the accessed network device to obtain historical record data.

[0270] In this way, when the terminal device has accessed the first network device and recorded the configuration of each DRB in the first network device, it can be queried in the historical record data that the SN field length configured by the first network device for the first DRB in the RLC layer is the second value.

[0271] In some embodiments, after receiving the RRC reconfiguration message 3, the terminal device determines to instruct the terminal device to switch to the cell corresponding to the first network device according to the content carried in the switching indication. Then, the terminal device can determine that the historical record data contains the second value corresponding to the first network device.

[0272] Exemplarily, the terminal device may determine that the historical record data contains the second value, which may include: after receiving the RRC reconfiguration message 3, determining that the RRC reconfiguration message 3 does not contain the SN field length configured by the first network device at the RLC layer for the first DRB. Then, the terminal device may query the historical record data according to the identifier of the first network device, determine that the SN field length configured by the first network device at the RLC layer for the first DRB is the second value, and the process enters S209.

[0273] S209, when the first value is different from the second value, the terminal device switches according to the RRC reconfiguration message 3, and modifies the SN field length configured for the first DRB at the RLC layer from the first value to the second value.

[0274] In this way, the terminal device performs cell switching according to the RRC reconfiguration message 3 and switches to the cell corresponding to the first network device, which can be called accessing the first network device. Afterwards, according to the second value queried from the historical record data, the SN field length configured by the terminal device at the RLC layer for the first DRB is modified from the first value to the second value, thereby achieving synchronization with the first network device.

[0275] S210, the terminal device sends an RRC reconfiguration completion message to the first network device.

[0276] S211, the terminal device sends a data packet 3 to the first network device through the first DRB in the AM mode, and the length of the SN field of the RLC header in the data packet 3 is the second value.

[0277] In some embodiments, the implementation details of the above S210 and S211 may refer to S109 and S110 in the above embodiments, which will not be described in detail here. The above data packet 3 may also be referred to as second data.

[0278] In addition, in some embodiments, the above-mentioned S209 of "changing the SN field length configured for the first DRB at the RLC layer from the first value to the second value" can be executed after S210 and before S211, and the embodiments of the present application do not make specific limitations on this.

[0279] S212: The first network device parses the RLC header information in the data packet 3 according to the SN field length being the second value.

[0280] In some embodiments, the first network device determines that the data packet 3 comes from a DRB using the AM mode, and after successfully parsing the data packet 3, the process enters S213.

[0281] S213, the first network device sends a response corresponding to the data packet 3 to the terminal device.

[0282] In the above embodiment, the terminal device uses historical record data to synchronize the SN field length of the RLC layer with the first network device. In this way, abnormalities during the call, such as silence in the call, can be avoided, triggering RRC re-establishment can be avoided, and the probability of call abnormalities can be reduced.

[0283] In other embodiments, Fig.12 As shown, the above method may also include:

[0284] S301, the terminal device establishes a VONR call through the second network device.

[0285] S302, the terminal device performs neighboring cell detection.

[0286] S303, the terminal device sends a neighboring cell detection report to the second network device.

[0287] S304: The second network device determines that it needs to switch to the first network device according to the neighboring cell detection report.

[0288] S305: The second network device sends a switching request to the first network device.

[0289] S306, the first network device feeds back a switching request confirmation message to the second network device, where the switching request confirmation message includes the configuration information corresponding to the first network device, and does not include the length of the SN field configured for the first DRB in the RLC layer in the first network device.

[0290] S307, the second network device sends an RRC reconfiguration message 3 to the terminal device, including a switching indication, but not including the SN length configured in the RLC layer for the first DRB in the first network device.

[0291] S308, the terminal device switches according to RRC reconfiguration message 3.

[0292] S309, the terminal device sends an RRC reconfiguration completion message to the first network device.

[0293] S310, the terminal device sends data packet 2 to the first network device through the first DRB in the AM mode, and the SN field length of the RLC header in the data packet 2 is the first value.

[0294] The data packet 2 mentioned above may be referred to as first data.

[0295] S311, the first network device parses the RLC header information in the data packet 2 according to the SN field length being the second value, wherein the parsing is abnormal when the first value is different from the second value.

[0296] It can be understood that the SN field length configured at the RLC layer of the first DRB in the first network device is the second value, that is, the SN field length configured at the RLC layer of the first DRB is the second value. In this way, after the first network device receives the data packet 2 transmitted through the first DRB, the RLC layer of the first network device parses the RLC header information in the data packet 2 according to the RLC SN field length being the second value.

[0297] In some embodiments, when the first value is different from the second value, the RLC data parsed by the first network device is inaccurate. In this way, the first network device may not send a response corresponding to data packet 2 to the terminal device. In the case of not receiving a response from the first network device, the terminal device may determine that the historical record data contains the second value corresponding to the first network device. Exemplarily, the method for determining that the historical record data contains the second value corresponding to the first network device can refer to S312.

[0298] S312, under the first condition, the terminal device determines from the historical record data that the length of the SN field configured at the RLC layer of the first DRB in the first network device is a second value.

[0299] The first condition may be that the number of times the data packet 2 is retransmitted reaches L times, and no response is received within a time period t after the Lth retransmission.

[0300] In some embodiments, the above L may be a preconfigured value, such as a second number. For example, the number of retransmissions configured for the first DRB at the RLC layer is N and the response waiting time is t. When N is a positive integer greater than 1, the above L may be a positive integer value less than N, for example, L may be equal to N-1.

[0301] In this way, after the terminal device sends data packet 2, if no response is received within time t, the first DRB can be used to retransmit data packet 2. After the Lth retransmission of data packet 2 through the first DRB, if no corresponding response is received within time t, it is determined that the first condition is currently met.

[0302] In a possible embodiment, L may also be equal to N. After data packet 2 is retransmitted for the Lth time through the first DRB, if no corresponding response is received within time t, the terminal device may be configured not to initiate an RRC re-establishment request and determine that the first condition is currently met.

[0303] In some embodiments, the terminal device determines from historical record data that the SN field length configured at the RLC layer of the first DRB in the first network device is the second value. Please refer to S208 in the aforementioned embodiment and will not repeat it here.

[0304] S313: When the first value is not equal to the second value, the terminal device modifies the SN field length configured in the RLC layer of the first DRB to the second value.

[0305] S314, the terminal device sends a data packet 4 to the first network device through the first DRB in the AM mode, and the length of the SN field of the RLC header in the data packet 4 is the second value.

[0306] The data content carried in data packet 4 and data packet 2 is the same, but the configured RLC header information is different, and the difference is that the RLC SN field length is different. Data packet 4 can also be the second data. Data packet 2 and data packet 4 carry the same data content, but the configured SN field length of the RLC layer header information is different.

[0307] S315, the first network device parses the RLC header information in the data packet 4 according to the SN field length being the second value.

[0308] S316, the first network device sends a response corresponding to the data packet 4 to the terminal device.

[0309] In this way, by not triggering the RRC re-establishment method, call abnormalities caused by the RRC re-establishment can be avoided, thereby reducing the call drop rate.

[0310] In other embodiments, Fig.13 As shown, the above communication method may also include:

[0311] S401, the terminal device establishes a VONR call through the second network device.

[0312] S402, the terminal device performs neighboring cell detection.

[0313] S403, the terminal device sends a neighboring cell detection report to the second network device.

[0314] S404: The second network device determines that it needs to switch to the first network device according to the neighboring cell detection report.

[0315] S405: The second network device sends a switching request to the first network device.

[0316] S406: The first network device feeds back a switching request confirmation message to the second network device, where the switching request confirmation message includes the length of the SN field configured at the RLC layer for the first DRB in the first network device.

[0317] S407, the second network device sends an RRC reconfiguration message 5 to the terminal device, including a switching indication and an SN length configured at the RLC layer for the first DRB in the first network device.

[0318] S408, the terminal device switches according to RRC reconfiguration message 5.

[0319] S409, the terminal device sends an RRC reconfiguration completion message to the first network device.

[0320] S410, the terminal device sends a data packet 5 to the first network device through the first DRB in the AM mode, and the length of the SN field in the RLC header of the data packet 5 is the second value.

[0321] In this way, the first network device can accurately parse the data packet 5 and send a response corresponding to the data packet 5 to the terminal device. The data packet 5 can be referred to as second data.

[0322] S411, the first network device parses the RLC header information in the data packet 5 according to the SN field length being the second value.

[0323] S412, the first network device sends a response corresponding to data packet 5 to the terminal device.

[0324] Fig.14 This is a schematic diagram of the structure of a terminal device provided in an embodiment of the present application. The terminal device may be the terminal device 100, the terminal device 106, etc. mentioned in the above embodiment.

[0325] like Fig.14As shown, the terminal device may include: a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charging management module 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, an earphone interface 170D, a sensor module 180, a button 190, a motor 191, an indicator 192, a camera 193, a display screen 194, and a subscriber identification module (SIM) card interface 195, etc.

[0326] Among them, the above-mentioned sensor module 180 may include sensors such as pressure sensor, gyroscope sensor, air pressure sensor, magnetic sensor, acceleration sensor, distance sensor, proximity light sensor, fingerprint sensor, temperature sensor, touch sensor, ambient light sensor and bone conduction sensor.

[0327] It is to be understood that the structure illustrated in this embodiment does not constitute a specific limitation on the terminal device. In other embodiments, the terminal device may include more or fewer components than shown in the figure, or combine some components, or split some components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0328] The processor 110 may include one or more processing units, for example, the processor 110 may include an application processor (AP), a modem, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a memory, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU), etc. Different processing units may be independent devices or integrated into one or more processors.

[0329] The controller can be the nerve center and command center of the terminal device. The controller can generate operation control signals according to the instruction operation code and timing signal to complete the control of instruction fetching and execution.

[0330] The processor 110 may also be provided with a memory for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. The memory may store instructions or data that the processor 110 has just used or cyclically used. If the processor 110 needs to use the instruction or data again, it may be directly called from the memory. This avoids repeated access, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0331] In some embodiments, the processor 110 may include one or more interfaces. The interface may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc.

[0332] It is understandable that the interface connection relationship between the modules illustrated in this embodiment is only a schematic illustration and does not constitute a structural limitation on the terminal device. In other embodiments, the terminal device may also adopt different interface connection methods in the above embodiments, or a combination of multiple interface connection methods.

[0333] The terminal device implements the display function through a GPU, a display screen 194, and an application processor. The GPU is a microprocessor for image processing, which connects the display screen 194 and the application processor. The GPU is used to perform mathematical and geometric calculations for graphics rendering. The processor 110 may include one or more GPUs that execute program instructions to generate or change display information.

[0334] The display screen 194 is used to display images, videos, etc. The display screen 194 includes a display panel. The display panel can be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode or an active-matrix organic light-emitting diode (AMOLED), a flexible light-emitting diode (FLED), Miniled, MicroLed, Micro-oLed, a quantum dot light-emitting diode (QLED), etc.

[0335] The terminal device can realize the shooting function through ISP, camera 193, video codec, GPU, display screen 194 and application processor.

[0336] ISP is used to process the data fed back by camera 193. For example, when taking a photo, the shutter is opened, and the light is transmitted to the camera photosensitive element (image sensor) through the lens. The light signal is converted into an electrical signal, and the camera photosensitive element transmits the electrical signal to ISP for processing and converts it into an image visible to the naked eye. ISP can also perform algorithm optimization on the noise, brightness, and skin color of the image. ISP can also optimize the exposure, color temperature and other parameters of the shooting scene. In some embodiments, ISP can be set in camera 193.

[0337] The camera 193 is used to capture still images or videos. The object generates an optical image through the lens and projects it onto the photosensitive element. The photosensitive element can be a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) phototransistor. The photosensitive element converts the optical signal into an electrical signal, and then passes the electrical signal to the ISP for conversion into a digital image signal. The ISP outputs the digital image signal to the DSP for processing. The DSP converts the digital image signal into an image signal in a standard RGB, YUV or other format. In some embodiments, the terminal device may include N cameras 193, where N is a positive integer greater than 1.

[0338] The digital signal processor is used to process digital signals. In addition to processing digital image signals, it can also process other digital signals. For example, when the terminal device is selecting a frequency point, the digital signal processor is used to perform Fourier transform on the frequency point energy.

[0339] Video codecs are used to compress or decompress digital videos. Terminal devices can support one or more video codecs. In this way, terminal devices can play or record videos in multiple coding formats, such as Moving Picture Experts Group (MPEG) 1, MPEG2, MPEG3, MPEG4, etc.

[0340] NPU is a neural network (NN) computing processor. It can quickly process input information and continuously self-learn by drawing on the structure of biological neural networks, such as the transmission mode between neurons in the human brain. NPU can realize applications such as intelligent cognition of terminal devices, such as image recognition, face recognition, voice recognition, text understanding, etc.

[0341] refer to Fig.15 , Fig.15 A schematic diagram of the structure of a network device provided in an embodiment of the present application. The network device may be any node device in the NG RAN in the above embodiment.

[0342] like Fig.15 As shown, the network device may include: one or more processors 1401, memory 1402, communication interface 1403, transmitter 1405, receiver 1406, coupler 1407 and antenna 1408. These components may be connected via bus 1404 or other means. Fig.15 Take bus connection as an example.

[0343] The communication interface 1403 can be used for the network device to communicate with other communication devices, such as the terminal device 100, 5GC 102 or other network devices. Specifically, the communication interface 1403 can be a communication interface of 5G or a future new air interface. Not limited to wireless communication interfaces, the network device can also be configured with a wired communication interface 1403 to support wired communication. For example, the backhaul link between a network device and other network devices can be a wired communication connection.

[0344] In some embodiments of the present application, the transmitter 1405 and the receiver 1406 can be regarded as a wireless modem. The transmitter 1405 can be used to transmit and process the signal output by the processor 1401. The receiver 1406 can be used to receive signals. In the network device, the number of the transmitter 1405 and the receiver 1406 can be one or more. The antenna 1408 can be used to convert the electromagnetic energy in the transmission line into electromagnetic waves in the free space, or to convert the electromagnetic waves in the free space into electromagnetic energy in the transmission line. The coupler 1407 can be used to divide the mobile communication signal into multiple paths and distribute it to multiple receivers 1406. It can be understood that the antenna 1408 of the network device can be implemented as a large-scale antenna array.

[0345] The memory 1402 is coupled to the processor 1401 and is used to store various software programs and / or multiple sets of instructions. Specifically, the memory 1402 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more disk storage devices, flash memory devices or other non-volatile solid-state storage devices.

[0346] The memory 1402 may store an operating system (hereinafter referred to as system), such as an embedded operating system such as uCOS, VxWorks, RTLinux, etc. The memory 1402 may also store a network communication program, which may be used to communicate with one or more additional devices, one or more terminal devices, or one or more network devices.

[0347] The processor 1401 may be used to read and execute computer-readable instructions. Specifically, the processor 1401 may be used to call a program stored in the memory 1402 .

[0348] Need to explain, Fig.15 The network device shown is only one implementation of the embodiment of the present application. In actual applications, the network device may also include more or fewer components, which is not limited here.

[0349] The embodiment of the present application also provides a chip system, which can be applied to the terminal device in the aforementioned embodiment. The chip system includes at least one processor and at least one interface circuit. The processor can be the processor in the above-mentioned terminal device. The processor and the interface circuit can be interconnected through a line. The processor can receive and execute computer instructions from the memory of the above-mentioned terminal device through the interface circuit. When the computer instructions are executed by the processor, the terminal device can execute the various steps in the above-mentioned embodiment. Of course, the chip system can also include other discrete devices, which are not specifically limited in the embodiment of the present application.

[0350] In some embodiments, through the description of the above implementation methods, technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device and unit described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0351] Each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of software functional units.

[0352] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as flash memory, mobile hard disk, read-only memory, random access memory, disk or optical disk.

[0353] The above is only a specific implementation of the embodiment of the present application, but the protection scope of the embodiment of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed in the embodiment of the present application should be included in the protection scope of the embodiment of the present application. Therefore, the protection scope of the embodiment of the present application should be based on the protection scope of the claims.

Claims

1. A communication method, characterized in that: Applied to a call process of a terminal device, the method includes: The terminal device establishes a call via the second network device; During the call, the terminal device receives a second reconfiguration message from the second network device, the second reconfiguration message carries a switching indication, the switching indication carries a cell identifier, the switching indication is used to instruct the terminal device to switch to a first cell corresponding to the cell identifier, the first cell corresponds to the first network device, and the second reconfiguration message does not carry the SN field length configured in the first network device for the first DRB at the RLC layer; The terminal device sends first data to the first network device using the first DRB, and the length of the sequence number SN field of the radio link RLC header information of the first data is a first value; In a case where the terminal device does not receive a response returned by the first network device in response to the first data, the terminal device sends a re-establishment request to the first network device; The terminal device receives a first reconfiguration message from the first network device, wherein the first reconfiguration message carries first indication information, and the first indication information is used to indicate that the SN field length of the first DRB configured at the RLC layer in the first network device is a second value; When the first value is not equal to the second value, the terminal device configures the SN field length corresponding to the first DRB at the RLC layer to the second value, and the terminal device sends a reconfiguration completion message to the first network device; After sending the reconfiguration completion message, the terminal device uses the first DRB to send second data to the first network device, and the SN field length of the RLC header information of the second data is the second value.

2. The method according to claim 1, characterized in that Before the terminal device establishes the call through the second network device, the method further includes: After a connection is established between the terminal device and the second network device, a third reconfiguration message is received from the second network device, where the third reconfiguration message is used to indicate that the SN field length of the first DRB in the second network device configured at the RLC layer is the first value.

3. The method according to any one of claims 1 to 2, characterized in that: The first DRB is a DRB with the transmission mode enabled as the confirmation mode AM.

4. The method according to any one of claims 1 to 3, characterized in that: The first data and the second data are both call data, and the call process includes a call process established based on a 4G communication system, a 5G communication system or a 6G communication system.

5. The method according to any one of claims 1 to 4, characterized in that: The terminal device does not receive a response returned by the first network device for the first data, including: the terminal device has retransmitted the first data to the first network device using the first DRB for a preconfigured first number of times, and has not received a response corresponding to the first data within a first time period after the last retransmission.

6. A communication method, characterized in that: Applied to a terminal device, the method comprises: After the terminal device establishes a call through the second network device, the terminal device sends third data to the second network device using the first DRB, and the SN field length of the RLC header information of the third data is the first value; During the call, the terminal device receives a second reconfiguration message from the second network device, the second reconfiguration message includes a switching indication, the switching indication carries a cell identifier, and the switching indication is used to instruct the terminal device to switch to a first cell corresponding to the cell identifier, and the first cell corresponds to the first network device; Determine that the historical record data includes a second value, wherein the second value is the length of the SN field configured at the RLC layer for the first DRB in the first network device; When the second value is included in the historical record data, the first value is not equal to the second value, and the second reconfiguration message does not contain the SN field length configured in the RLC layer for the first DRB in the first network device, the terminal device uses the first DRB to send second data to the first network device, and the SN field length of the RLC header information of the second data is the second value.

7. The method according to claim 6, characterized in that Before the terminal device establishes a call through the second network device, the method further includes: After a connection is established between the terminal device and the second network device, a third reconfiguration message is received from the second network device, the third reconfiguration message including the first value, where the first value is the SN field length configured at the RLC layer for the first DRB in the second network device.

8. The method according to claim 6 or 7, characterized in that: The determining that the historical record data includes the second value comprises: After the terminal device receives the second reconfiguration message from the second network device, if the second reconfiguration message does not contain the SN field length configured for the first DRB in the first network device at the RLC layer, determine, according to the historical record data, that the SN field length configured for the first DRB in the first network device at the RLC layer is the second value; The method further includes: when the first value is not equal to the second value, the terminal device sends a reconfiguration completion message to the first network device.

9. The method according to claim 6 or 7, characterized in that: After the terminal device receives the second reconfiguration message, the method further includes: In response to the second reconfiguration message, the terminal device sends a reconfiguration completion message to the first network device; The terminal device sends first data to the first network device using the first DRB, and the SN field length of the RLC header information of the first data is the first value; The determining that the historical record data includes the second value comprises: Under the first condition, based on the historical record data, it is determined that the SN field length of the first DRB in the first network device in the RLC header information is the second value; wherein the first condition includes that the number of transmissions of the first data has reached a preconfigured second number, and no response corresponding to the first data is received within a first time period after the last retransmission.

10. A terminal device, characterized in that: The terminal device comprises: a processor and a memory, wherein the processor comprises a modem processor, and the memory is used to store computer instructions. When the processor executes the computer instructions, the terminal device executes the method as claimed in any one of claims 1 to 9.

11. A chip system, applied to a terminal device, characterized in that: A computer program is stored, and when the computer program is executed, the terminal device executes the method according to any one of claims 1 to 9.

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