Communication method and device and readable storage medium

Abstract

The invention relates to the technical field of communication, in particular to a communication method and device and a readable storage medium, and the method comprises the steps: releasing DRBs of all first sessions activated on a first system; sending a registration request message to a first network device of a second system; the registration request message comprises session information of one or more second sessions, and the one or more second sessions are in one-to-one mapping with all the first sessions activated by the terminal device on the first system; the registration request message is used for initiating a registration request and initiating a request for establishing a DRB for the one or more second sessions; the first system and the second system are different communication systems; receiving a first message; the first message comprises information of one or more DRBs established by the access network device of the second system for the one or more second sessions. According to the embodiment of the invention, the problem of hedging of the user plane establishment process and the signaling plane process of the same session can be solved, and the user experience is ensured.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a communication method, device and readable storage medium. Background Art

[0002] With the continuous development of communication technology, user equipment (UE) can obtain communication services through various communication systems, such as long term evolution (LTE) and new generation wireless access technology (NR) communication systems, so as to meet people's various needs in daily work, life and entertainment. Understandably, when there are multiple communication systems that can provide services for UE, UE may often encounter interoperability between different systems during actual communication, such as reselection, switching, and redirection. Among them, redirection is a change in the service system when the UE is in a connected state. Compared with switching, redirection is a switching preparation process without switching operations. It is a transitional means prepared for UE that does not support switching.

[0003] However, after the UE performs interoperation between different systems, the UE's application may experience obvious lag, which seriously reduces the user experience. Taking the redirection or switching of the UE between different systems as an example, after the UE completes the redirection between different systems, or after the switching between different systems fails, the network side will most likely send a signaling plane process of session modification (Session Modify) of a certain session to the UE. This signaling plane process often conflicts with the user plane establishment process initiated by the UE for the same session. This conflict may cause the network to release the link abnormally, and the user plane cannot be established in time, resulting in obvious lag in the UE's application, thus seriously reducing the user experience.

[0004] Currently, solutions to conflicts between user plane processes and signaling plane processes in the same session are still being explored. Summary of the invention

[0005] The embodiments of the present application provide a communication method, an apparatus, and a readable storage medium, which can solve the problem of hedging between the user plane establishment process and the signaling plane process of the same session, or the problem of deadlock after hedging, thereby ensuring user experience.

[0006] The present application is introduced below from different aspects. It should be understood that the implementation methods and beneficial effects of the following different aspects can be referenced to each other.

[0007] In a first aspect, the present application provides a communication method, applied to a terminal device, the method comprising: releasing data radio bearers (DRBs) of all first sessions activated on a first system; sending a registration request message to a first network device of a second system; the registration request message comprising session information of one or more second sessions, the one or more second sessions being mapped one-to-one with all first sessions activated by the terminal device on the first system; the registration request message being used to initiate a registration request and to initiate a request to establish a DRB for the one or more second sessions; the first system and the second system being different communication systems; receiving a first message; the first message comprising information of one or more DRBs established by an access network device of the second system for the one or more second sessions.

[0008] After the UE performs interoperation between different systems, the UE application may experience obvious freezes, which seriously reduces the user experience. In an embodiment of the present application, after the UE releases the DRBs of all sessions activated on the source system, when initiating a registration request to the target system, it can tell the target system network side which sessions' DRBs need to be established, that is, carry the information of these sessions in the registration request message, and these sessions that need to establish DRBs are mapped one by one with all the sessions activated by the UE on the source system. This allows the target system network side to establish the DRBs for these sessions when the registration is accepted, and send the information of the established DRBs to the UE together with the registration result. Different from the prior art, the UE only carries the session information of the sessions that need to establish DRBs in the registration request message when it perceives that there is data to be transmitted before sending the registration request message. In an embodiment of the present application, the UE can perceive which sessions are activated on the source system (that is, there are DRBs), so that when registering with the target system, it can request the target system network side to establish DRBs for the sessions corresponding to all the sessions activated on the source system, instead of only requesting when it perceives that there is data to be transmitted. After the registration process, the UE does not need to start another service process to request the establishment of DRBs for these sessions, thus avoiding the conflict between the subsequent session modification process sent by the target system network side and ensuring user experience.

[0009] In a possible implementation, before releasing the DRBs of all first sessions activated on the first system, the method further includes: receiving a redirection indication message from an access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system.

[0010] When the UE is redirected between different systems, conflicts between the user plane process and the signaling plane process of the same session may occur later. In the scenario where the UE is redirected between different systems, in an embodiment of the present application, the UE can tell the target system in the registration request message which sessions' DRBs need to be established. In this way, the target system network side can establish the DRBs for these sessions when the registration is accepted, so that after the registration process is completed, the UE does not need to start another business process to request the establishment of the DRBs for these sessions, thereby avoiding the situation where the subsequent session modifications issued by the target system network side will have process hedging, thereby ensuring user experience.

[0011] In a possible implementation, before releasing the DRBs of all first sessions activated on the first system, the method further includes: receiving a switching indication message from an access network device of the first system, wherein the switching indication message is used to instruct the terminal device to switch from the first system to the second system.

[0012] In the case where the UE fails to switch between different systems, conflicts between the user plane process and the signaling plane process of the same session are likely to occur later. For the scenario where the UE fails to switch between different systems, in an embodiment of the present application, the UE can tell the target system in the registration request message which sessions' DRBs need to be established. In this way, the target system network side can establish the DRBs for these sessions when the registration is accepted, so that after the registration process is completed, the UE does not need to start another business process to request the establishment of the DRBs for these sessions, thereby avoiding the subsequent process hedging of the session modifications issued by the target system network side, and ensuring the user experience.

[0013] In a possible implementation manner, the session information of the one or more second sessions is carried in an uplink data status field or a reserved field of the registration request message.

[0014] In the embodiment of the present application, the UE may carry the session information of the session for which the DRB needs to be established in the uplink data status field or the reserved field in the registration request message. When the information is carried in the uplink data status field, the limited fields in the registration request message may be saved for other purposes; when the information is carried in the reserved field, the meaning of the existing uplink data status field may not be modified.

[0015] In a possible implementation, after receiving the first message, the method further includes: receiving a session modification message from a second network device of the second system; the session modification message is used to instruct the terminal device to modify a target second session, where the target second session is a session among the one or more second sessions; modifying the target second session in response to the session modification message, and sending a modification completion message to the second network device of the second system.

[0016] In an embodiment of the present application, when the UE completes the registration process, the session for establishing the DRB is also established. Thereafter, if the UE receives a session modification message sent by the target system network side, the UE can respond normally to the session modification message and can send a modification completion message to the target system network side after completing the modification.

[0017] In one possible implementation, the first system is a third-generation mobile communication system 3G, and the second system is a fourth-generation mobile communication system 4G; or, the first system is 4G, and the second system is 3G or a fifth-generation mobile communication system 5G; or, the first system is 5G, and the second system is 4G.

[0018] In the embodiment of the present application, the UE may be interoperable between a 3G system and a 4G system, or may be interoperable between a 4G system and a 5G system.

[0019] In a second aspect, the present application provides a communication method, applied to a first network device, the method comprising: receiving a registration request message sent by a terminal device; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and to initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems; an indication message is sent to an access network device of the second system; the indication message is used to instruct the access network device to establish one or more DRBs for the one or more second sessions.

[0020] In an embodiment of the present application, the first network device of the target system can learn which sessions the UE needs to establish DRBs for when receiving the registration request message of the UE, and these sessions that need to establish DRBs are mapped one by one to all the sessions that the UE has activated on the source system. Then, the first network device sends an indication message to the access network device, instructing the access network device to establish DRBs for these sessions. After the registration process, the UE does not need to start another service process to request the establishment of DRBs for these sessions, thereby avoiding the subsequent hedging of the session modification process issued by the network side of the target system and ensuring the user experience.

[0021] In a possible implementation, the first system is 3G, and the second system is 4G; or, the first system is 4G, and the second system is 3G or 5G; or, the first system is 5G, and the second system is 4G.

[0022] In the embodiment of the present application, the UE may be interoperable between a 3G system and a 4G system, or may be interoperable between a 4G system and a 5G system.

[0023] In a third aspect, the present application provides a communication method, applied to a terminal device, the method comprising: sending a first service request to a first network device of a second system; the first service request is a request to establish one or more DRBs for a target session; in a case where no response message to the first service request is received, receiving a session modification message from a second network device of the second system; the session modification message is used to instruct the terminal device to modify the target session; in response to the session modification message, the target session is modified, and a modification completion message is sent to the second network device of the second system.

[0024] In an embodiment of the present application, when a conflict occurs between the user plane establishment process and the signaling plane process of the same session (i.e., the target session), in order to resolve the conflict, the UE can actively respond to the session modification message sent by the second system network side, and suspend the request to establish the DRB for the target session without waiting for the response message of the second system network side to the first service request, thereby resolving the conflict between the user plane establishment process and the signaling plane process of the same session (i.e., the target session) and ensuring user experience.

[0025] In a possible implementation, after sending the modification completion message to the second network device of the second system, the method further includes: sending a second service request to the first network device of the second system, wherein the second service request is a request to establish one or more DRBs for the modified target session.

[0026] In an embodiment of the present application, after resolving the conflict between the user plane establishment process and the signaling plane process of the same session (i.e., the target session), the UE can resend a request to establish a DRB (i.e., a second service request) to the target system network side, thereby avoiding the situation where the DRB is not established because the target system network side does not respond to the previous request (i.e., the first service request), thereby affecting the transmission of service data.

[0027] In a possible implementation, before sending the first service request to the first network device of the second system, the method also includes: receiving a redirection indication message or a switching indication message from an access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system, and the switching indication message is used to instruct the terminal device to switch from the first system to the second system; the first system and the second system are different communication systems; sending a registration request message to the first network device of the second system; and receiving a registration acceptance message from the first network device of the second system.

[0028] In the case where the UE fails to redirect or switch between different systems, conflicts between the user plane process and the signaling plane process of the same session may easily occur later. For the scenario where the UE fails to redirect or switch between different systems, in an embodiment of the present application, the UE can tell the target system in the registration request message which sessions' DRBs need to be established. In this way, the target system network side can establish the DRBs for these sessions when the registration is accepted, so that after the registration process is completed, the UE does not need to start another business process to request the establishment of the DRBs for these sessions, thereby avoiding the situation where the subsequent session modifications issued by the target system network side will have process hedging, thereby ensuring user experience.

[0029] In a possible implementation, the receiving a registration acceptance message from the first network device of the second system includes: receiving a registration acceptance message from the first network device of the second system at a first moment; the sending a first service request to the first network device of the second system includes: sending the first service request to the first network device of the second system at a second moment; the difference between the first moment and the second moment is greater than or equal to a preset value.

[0030] In an embodiment of the present application, after receiving the registration acceptance message from the second system network side, the UE can wait for a period of time, and then send a request to the second system network side to establish a target session DRB (i.e., a first service request), so as to minimize the conflict between the user plane establishment process and the signaling plane process of the same session (i.e., the target session) and ensure user experience.

[0031] In a possible implementation manner, the preset value is greater than or equal to 10 milliseconds.

[0032] In an embodiment of the present application, after receiving the registration acceptance message from the second system network side, the UE may wait for a period of time greater than or equal to 10 milliseconds, and then send a request to the second system network side to establish a target session DRB (i.e., a first service request). If the waiting time is less than 10 milliseconds, the effect of reducing the conflict between the user plane establishment process and the signaling plane process of the same session (i.e., the target session) may be slightly worse.

[0033] In a possible implementation, the first system is 3G, and the second system is 4G; or, the first system is 4G, and the second system is 3G or 5G; or, the first system is 5G, and the second system is 4G.

[0034] In the embodiment of the present application, the UE may be interoperable between a 3G system and a 4G system, or may be interoperable between a 4G system and a 5G system.

[0035] In a fourth aspect, the present application provides a communication method, applied to a terminal device, the method comprising: sending a registration request message to a first network device of a second system; receiving a registration acceptance message from the first network device of the second system at a first moment; sending a service request to the first network device of the second system at a second moment; the service request is a request to establish one or more DRBs for a target session, and the difference between the first moment and the second moment is greater than or equal to a preset value.

[0036] In an embodiment of the present application, after receiving the registration acceptance message from the second system network side, the UE can wait for a period of time, and then send a request to the second system network side to establish a target session DRB (i.e., a first service request), so as to minimize the conflict between the user plane establishment process and the signaling plane process of the same session (i.e., the target session) and ensure user experience.

[0037] In a possible implementation manner, the preset value is greater than or equal to 10 milliseconds.

[0038] In a possible implementation, before sending a registration request message to the first network device of the second system, the method further includes: receiving a redirection indication message or a switching indication message from an access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system, and the switching indication message is used to instruct the terminal device to switch from the first system to the second system; the first system and the second system are different communication systems.

[0039] In a possible implementation, the first system is 3G, and the second system is 4G; or, the first system is 4G, and the second system is 3G or 5G; or, the first system is 5G, and the second system is 4G.

[0040] In the embodiment of the present application, the UE may be interoperable between a 3G system and a 4G system, or may be interoperable between a 4G system and a 5G system.

[0041] In a fifth aspect, the present application provides a communication device, which may include: a processing unit, configured to release DRBs of all first sessions activated on a first system;

[0042] A sending unit, configured to send a registration request message to a first network device of a second system; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all the first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems;

[0043] A receiving unit is used to receive a first message; the first message includes information about one or more DRBs established by the access network device of the second system for the one or more second sessions.

[0044] In a possible implementation, before the processing unit releases the DRBs of all first sessions activated on the first system, the receiving unit is further used to receive a redirection indication message from an access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system.

[0045] In a possible implementation, before the processing unit releases the DRBs of all first sessions activated on the first system, the receiving unit is further used to receive a switching indication message from an access network device of the first system, wherein the switching indication message is used to instruct the terminal device to switch from the first system to the second system.

[0046] In a possible implementation manner, the session information of the one or more second sessions is carried in an uplink data status field or a reserved field of the registration request message.

[0047] In a possible implementation, after the receiving unit receives the first message, the receiving unit is further used to receive a session modification message from a second network device of the second system; the session modification message is used to instruct the terminal device to modify a target second session, where the target second session is a session in the one or more second sessions;

[0048] The processing unit is further configured to modify the target second session in response to the session modification message;

[0049] The sending unit is further configured to send a modification completion message to the second network device of the second system.

[0050] In a possible implementation, the first system is 3G, and the second system is 4G; or, the first system is 4G, and the second system is 3G or 5G; or, the first system is 5G, and the second system is 4G.

[0051] In a sixth aspect, the present application provides a communication device, which may include: a receiving unit, configured to receive a registration request message sent by a terminal device; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems;

[0052] A sending unit is used to send an indication message to the access network device of the second system; the indication message is used to instruct the access network device to establish one or more DRBs for the one or more second sessions.

[0053] In a possible implementation, the first system is 3G, and the second system is 4G; or, the first system is 4G, and the second system is 3G or 5G; or, the first system is 5G, and the second system is 4G.

[0054] In a seventh aspect, the present application provides a communication device, which may include: a first sending unit, configured to send a first service request to a first network device of a second system; the first service request is a request to establish one or more DRBs for a target session;

[0055] a receiving unit, configured to receive a session modification message from a second network device of the second system when no response message to the first service request is received; the session modification message is used to instruct the terminal device to modify the target session;

[0056] a processing unit, configured to modify the target session in response to the session modification message;

[0057] The second sending unit is used to send a modification completion message to the second network device of the second system.

[0058] In one possible implementation, after the second sending unit sends a modification completion message to the second network device of the second system, the first sending unit is also used to send a second service request to the first network device of the second system, and the second service request is a request to establish one or more DRBs for the modified target session.

[0059] In a possible implementation, before the first sending unit sends the first service request to the first network device of the second system, the receiving unit is further used to receive a redirection indication message or a switching indication message from the access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system, and the switching indication message is used to instruct the terminal device to switch from the first system to the second system; the first system and the second system are different communication systems;

[0060] The first sending unit is further used to send a registration request message to the first network device of the second system;

[0061] The receiving unit is further configured to receive a registration acceptance message from the first network device of the second system.

[0062] In a possible implementation manner, the receiving unit is specifically configured to:

[0063] receiving, at a first moment, a registration acceptance message from a first network device of the second system;

[0064] The first sending unit is specifically configured to:

[0065] The first service request is sent to the first network device of the second system at a second moment; and the difference between the first moment and the second moment is greater than or equal to a preset value.

[0066] In a possible implementation manner, the preset value is greater than or equal to 10 milliseconds.

[0067] In a possible implementation, the first system is 3G, and the second system is 4G; or, the first system is 4G, and the second system is 3G or 5G; or, the first system is 5G, and the second system is 4G.

[0068] In an eighth aspect, the present application provides a communication device, which may include: a first sending unit, configured to send a registration request message to a first network device of a second system;

[0069] A receiving unit, configured to receive a registration acceptance message from a first network device of the second system at a first moment;

[0070] The second sending unit is used to send a service request to the first network device of the second system at a second moment; the service request is a request to establish one or more DRBs for a target session, and the difference between the first moment and the second moment is greater than or equal to a preset value.

[0071] In a possible implementation manner, the preset value is greater than or equal to 10 milliseconds.

[0072] In a possible implementation, before the first sending unit sends a registration request message to the first network device of the second system, the receiving unit is also used to receive a redirection indication message or a switching indication message from the access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system, and the switching indication message is used to instruct the terminal device to switch from the first system to the second system; the first system and the second system are different communication systems.

[0073] In a possible implementation, the first system is 3G, and the second system is 4G; or, the first system is 4G, and the second system is 3G or 5G; or, the first system is 5G, and the second system is 4G.

[0074] In a ninth aspect, the present application provides a communication device, which may include a processor, a transceiver, and a memory. The memory is used to store a computer program, the transceiver is used to send and receive various messages, and the computer program includes program instructions. When the processor runs the program instructions, the communication device executes the method described in the first aspect, the second aspect, the third aspect, the fourth aspect, or any possible implementation method of any one of the aspects. The transceiver may be a radio frequency module in the communication device, or a combination of a radio frequency module and an antenna, or an input and output interface of a chip or circuit.

[0075] In the tenth aspect, the present application provides a computer-readable storage medium having program instructions stored thereon, which, when executed on a computer, enables the computer to execute the method described in the first aspect, or the second aspect, or the third aspect, or the fourth aspect, or any possible implementation of any one of the aspects therein.

[0076] In an eleventh aspect, the present application provides a program product comprising program instructions, which, when executed, enables the method described in the first aspect, or the second aspect, or the third aspect, or the fourth aspect, or any possible implementation of any one of the aspects therein to be executed.

[0077] In a twelfth aspect, the present application provides a communication device, which can be implemented in the form of a chip or in the form of a device, and the device includes a processor. The processor is used to read and execute a program stored in a memory to execute the communication method provided by one or more of the above-mentioned first aspect, the second aspect, the above-mentioned third aspect, the above-mentioned fourth aspect, or any possible implementation of any aspect thereof. Optionally, the communication device also includes a memory, and the memory is connected to the processor through a circuit. Further optionally, the communication device also includes a communication interface, and the processor is connected to the communication interface. The communication interface is used to receive a data packet and / or information to be processed, and the processor obtains the data packet and / or information from the communication interface, processes the data packet and / or information, and outputs the processing result through the communication interface. The communication interface can be an input and output interface.

[0078] Optionally, the processor and memory may be physically independent units, or the memory may be integrated with the processor.

[0079] In the thirteenth aspect, the present application provides a wireless communication system, which includes a terminal device and a network device; the terminal device is used to execute the method described in the first aspect, or the third aspect, or the fourth aspect, or any possible implementation of any one of the aspects above, and the network device is used to execute the method described in the second aspect or any possible implementation of the second aspect.

[0080] The technical effects achieved in the above-mentioned aspects can be referred to each other or to the beneficial effects in the method embodiments shown below, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0082] Figure 1a This is a schematic diagram of a scenario architecture to which a communication method provided in an embodiment of the present application can be applied;

[0083] Figure 1b It is a schematic diagram of the architecture of a communication system provided by an embodiment of the present application;

[0084] Figure 2 It is a simplified structural diagram of a UE and a base station provided in an embodiment of the present application;

[0085] Figure 3 It is a flow diagram of the conflict between the user plane flow and the signaling plane flow;

[0086] Figure 4aIt is a flow chart of a communication method provided in an embodiment of the present application;

[0087] Figure 4b It is a flowchart of another communication method provided in an embodiment of the present application;

[0088] Figure 4c It is a flowchart of another communication method provided in an embodiment of the present application;

[0089] Figure 5 It is a flowchart of another communication method provided in an embodiment of the present application;

[0090] Figure 6 It is a flowchart of another communication method provided in an embodiment of the present application;

[0091] Figure 7 is a structural diagram of a communication device provided in an embodiment of the present application;

[0092] Figure 8 is a schematic diagram of the structure of another communication device provided in an embodiment of the present application;

[0093] Fig. 9 is a schematic diagram of the structure of another communication device provided in an embodiment of the present application;

[0094] Fig.10 is a schematic diagram of the structure of another communication device provided in an embodiment of the present application;

[0095] Fig.11 is a schematic diagram of the structure of another communication device provided in an embodiment of the present application;

[0096] Fig.12 It is a structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0097] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0098] In the description of this application, words such as "first" and "second" are only used to distinguish different objects, and do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different. For example, the first business request and the second business request are only used to distinguish different information, and do not limit their order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0099] In the description of this application, unless otherwise specified, " / " means "or", for example, A / B can mean A or B. "And / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, "at least one (item)", "the following one (item) or more (items)" or similar expressions refer to any combination of these items, including any combination of single items (items) or plural items (items). For example, at least one item (item) of a, b, or c can mean: a, b, c; a and b; a and c; b and c; or a, b and c. Among them, a, b, c can be single or multiple.

[0100] In the description of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described in this application as "exemplary", "for example" or "for example" should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a concrete way.

[0101] It can be understood that in the description of this application, "when", "if" and "if" all mean that the device will take corresponding actions under certain objective circumstances, but do not limit the time, nor do they require that the device must have a judgment action when it is implemented, nor do they mean that there are other limitations.

[0102] The term “simultaneously” in the present application may be understood as at the same time point, within a period of time, or within the same cycle, and may be understood in conjunction with the context.

[0103] Elements used in the singular herein are intended to mean "one or more" rather than "one and only one" unless specifically stated otherwise.

[0104] Additionally, the terms "system" and "network" are often used interchangeably herein.

[0105] It can be understood that in each embodiment of the present application, "A and B correspond" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and / or other information.

[0106] It can be understood that in the embodiment of the present application, "used for indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. When describing "a certain indication information is used to indicate A" or "indication information of A", it may include that the indication information directly indicates A or indirectly indicates A, but it does not mean that the indication information must carry A. The information indicated by a certain information (such as the indication information of the coefficient described below) is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, wherein there is an association relationship between the other information and the information to be indicated. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, the indication of specific information can also be realized by means of the arrangement order of each information agreed in advance (such as specified by the protocol), thereby reducing the indication overhead to a certain extent. At the same time, the common parts of each information can also be identified and uniformly indicated to reduce the indication overhead caused by indicating the same information separately. In addition, the specific indication method can also be various existing indication methods, such as but not limited to the above indication methods and various combinations thereof. The specific details of various indication methods can refer to the prior art, and will not be repeated herein. As described above, for example, when it is necessary to indicate multiple information of the same type, different indication methods may occur. In the specific implementation process, the required indication method can be selected according to specific needs. The embodiment of the present application does not limit the selected indication method. In this way, the indication method involved in the embodiment of the present application should be understood as covering various methods that can enable the party to be indicated to know the information to be indicated. The information to be indicated can be sent as a whole, or it can be divided into multiple sub-information and sent separately, and the sending period and / or sending time of these sub-information can be the same or different. The specific sending method is not limited in this application. Among them, the sending period and / or sending time of these sub-information can be pre-defined, for example, pre-defined according to the protocol, or can be configured by the transmitting end device by sending configuration information to the receiving end device. Among them, the configuration information can, for example, but not limited to, include one or a combination of at least two of radio resource control signaling, MAC layer signaling and physical layer signaling.

[0107] The technical solutions of the embodiments of the present application can be applied to various communication systems, for example: universal mobile telecommunications system (UMTS) or third generation (3G) system, long term evolution (LTE) system or fourth generation (4G) system, world-wide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) system, such as new generation wireless access technology (new radio, NR), a network integrating multiple systems, an Internet of Things system, an Internet of Vehicles system, and future communication systems, such as a 6G system.

[0108] It should be understood that the network architecture described in the embodiments of the present application is for the purpose of more clearly illustrating the technical solutions of the embodiments of the present application, and does 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 know that with the evolution of the network architecture, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0109] In the embodiments of the present application, some scenarios are explained by taking the scenario in which the UE is redirected or switched from the LTE network in the wireless communication network to the NR network as an example. It should be understood that the scheme in the embodiments of the present application can also be applied to redirection or switching scenarios between other wireless communication networks, such as redirection or switching from 3G to LTE, redirection or switching from LTE to 3G, redirection or switching from 5G to LTE, etc. The names of various systems and the names of various messages in the system in various scenarios can also be replaced by the names of corresponding functions in other wireless communication networks.

[0110] In order to better understand the communication method, device and readable storage medium disclosed in the embodiments of the present application, the following first describes the scenario architecture to which the embodiments of the present application can be applied. Figure 1a , Figure 1a is a schematic diagram of a scenario architecture to which a communication method provided in an embodiment of the present application can be applied, such as Figure 1a As shown, the architecture may include user equipment (UE), 4G system (such as LTE system) network side equipment, 5G system (such as NR system) network side equipment and data network (DN).

[0111] DN can be the Internet, IP Multimedia Service (IMS) network, regional network, i.e. local network, such as multi access edge computing (MEC) network, etc. DN is the destination of UE's packet data network (PDN) session or protocol data unit (PDU) session access. DN can include or deploy application servers, which can perform data transmission with UE and provide business services for UE.

[0112] 4G system network side equipment may include wireless access equipment (such as Figure 1a eNB in ​​the mobile management entity (MME), service gateway (SGW) and public data network gateway (PDN gateway, PGW) and other network elements, and may also include other network elements for authentication and billing ( Figure 1a The charging system may include a home subscriber server (HSS), a policy and charging rules function (PCRF), an online charging system (OCS), and an offline charging system (OFCS).

[0113] MME is mainly responsible for mobility management, session management, user authentication and key management, encryption and integrity protection of non-access stratum (NAS) layer signaling, tracking area list (TA LIST) management, and PGW / SGW selection.

[0114] SGW is mainly responsible for packet routing and forwarding functions, Internet protocol (IP) header compression, idle (IDLE) state termination point, downlink data cache, anchor point for handover between eNodeBs, route optimization, and transmission of data services during handover.

[0115] PGW is mainly responsible for allocating IP addresses to UEs, while providing IP routing and forwarding functions; performing different billing and policies based on users and services; and providing gateway functions for accessing external PDNs.

[0116] 5G system network side equipment may include wireless access network equipment (such as Figure 1a(R)AN in the network), user plane function (UPF) network element, access and mobility management function (AMF) network element, session management function (SMF) network element, etc., and may also include other network elements for slicing, authentication, billing or policy management ( Figure 1a (not shown), for example, a policy control function (PCF) network element, an application function (AF) network element, a unified data management (UDM) network element, an authentication server function (AUSF) network element, and a network slice selection function (NSSF) network element.

[0117] The UPF network element is mainly responsible for processing user messages, such as forwarding and billing. It can receive user messages from the DN and transmit them to the UE through the RAN equipment; it can also receive user messages from the UE through the RAN equipment and forward them to the DN. The transmission resources and scheduling functions that the UPF network element provides to the UE are managed and controlled by the SMF network element.

[0118] The AMF network element can access the UE's non-access stratum (NAS) signaling (including session management (SM) signaling) through the N1 interface and the RAN signaling through the N2 interface to complete the UE registration process and the forwarding of SM signaling and mobility management. In an embodiment of the present application, after the terminal device (UE) is redirected from the 4G system to the 5G system, or when the switch from the 4G system to the 5G system fails, when initiating the registration process to the AMF, it tells the network side in the registration request which PDU Session DRBs need to be established, so that the network side establishes the DRBs of these PDU Sessions when the registration is accepted, and the PDN Sessions corresponding to these PDU Sessions are activated on LTE.

[0119] The SMF network element is mainly responsible for session management in the mobile network, such as session establishment, modification, release, and update processes. Specific functions include allocating IP addresses to users, selecting UPF network elements that provide message forwarding functions, etc. In the embodiment of the present application, the session modification message sent by the 5G system network side is completed by the SMF network element.

[0120] Each network element in the above 4G system network side and 5G system network side can also be called a functional entity, which can be a network element implemented on dedicated hardware, a software instance running on dedicated hardware, or an instance of a virtualized function on an appropriate platform. For example, the above virtualization platform can be a cloud platform. Different network elements or devices can communicate through interfaces. Figure 1a The interface name shown is only an example and is not specifically limited in the embodiments of the present application.

[0121] As for the architecture between the wireless access network device and the terminal device in the embodiment of the present application, please refer to Figure 1b , Figure 1b Schematic diagram of the architecture of a communication system provided by an embodiment of the present application. Figure 1b As shown, the communication system includes a wireless access network 100, and the wireless access network 100 may include at least one wireless access network device (such as Figure 1b 110a and 110b), and may also include at least one terminal device (such as Figure 1b 120a-120j in the figure). The terminal device can be connected to the wireless access network device in a wireless manner, and the terminal devices and the wireless access network devices can be connected to each other in a wired or wireless manner.

[0122] The radio access network equipment is the access equipment that the terminal uses to access the communication system wirelessly. The radio access network equipment can be a base station (BS), an evolved NodeB (eNodeB, eNB for short), a transmission reception point (TRP), a next generation NodeB (gNB) in the fifth generation (5G) mobile communication system, a next generation base station in the sixth generation (6G) mobile communication system, a base station in a future mobile communication system, or an access node in a wireless fidelity (WiFi) system, etc.; it can also be a module or unit that completes part of the functions of the base station, for example, it can be a centralized unit (CU) or a distributed unit (DU). A base station including a CU and a DU can also be called a base station with a CU and a DU separated, such as the base station including a gNB-CU and a gNB-DU. Among them, CU can also be separated into CU control plane (CU control plane, CU-CP) and CU user plane (CU user plane, CU-CP), such as the base station includes gNB-CU-CP, gNB-CU-UP and gNB-DU. The CU here can complete the functions of the radio resource control protocol and packet data convergence layer protocol (packet data convergence protocol, PDCP) of the base station, and can also complete the function of the service data adaptation protocol (service data adaptation protocol, SDAP); DU can complete the functions of the radio link control layer and medium access control (medium access control, MAC) layer of the base station, and can also complete part of the physical layer or all of the physical layer. For the specific description of the above-mentioned protocol layers, please refer to the relevant technical specifications of the 3rd Generation Partnership Project (3GPP). The wireless access network device can be a macro base station (such as Figure 1b 110a), or a micro base station or an indoor station (such as Figure 1b 110b), may also be a relay node or a donor node, etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the wireless access network device.

[0123] In the embodiment of the present application, the device for realizing the function of the wireless access network device may be a wireless access network device; or it may be a device capable of supporting the wireless access network device to realize the function, such as a chip system, or a communication module, or a modem, etc., and the device may be installed in the wireless access network device. In the technical solution provided in the embodiment of the present application, the device for realizing the function of the wireless access network device is a wireless access network device, and the wireless access network device is a base station as an example to describe the technical solution provided in the embodiment of the present application. The base station may support networks with the same or different access technologies. The embodiment of the present application does not limit the specific technology and specific device form adopted by the wireless access network device.

[0124] The terminal device is a device with wireless transceiver function, which can send signals to the base station or receive signals from the base station. The terminal device can also be called a terminal, user equipment (UE), mobile station, mobile terminal, etc. The terminal device can be widely used in various scenarios, for example, device-to-device (D2D), vehicle to everything (V2X) communication, machine-type communication (MTC), Internet of Things (IOT), virtual reality, augmented reality, industrial control, automatic driving, telemedicine, smart grid, smart furniture, smart office, smart wear, smart transportation, smart city, etc. The terminal can be a mobile phone, a tablet computer, a computer with wireless transceiver function, a wearable device, a vehicle, an airplane, a ship, a robot, a mechanical arm, a smart home device, etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal.

[0125] Base stations and terminals can be fixed or movable. Base stations and terminals can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on the water surface; they can also be deployed on airplanes, balloons, and artificial satellites. The embodiments of this application do not limit the application scenarios of base stations and terminals.

[0126] The roles of the base station and the terminal can be relative, for example, Figure 1b The helicopter or drone 120i in the figure can be configured as a mobile base station. For the terminal 120j that accesses the wireless access network 100 through 120i, the terminal 120i is a base station; but for the base station 110a, 120i is a terminal, that is, 110a and 120i communicate through the wireless air interface protocol. Of course, 110a and 120i can also communicate through the interface protocol between base stations. In this case, relative to 110a, 120i is also a base station. Therefore, base stations and terminals can be collectively referred to as communication devices. Figure 1b 110a and 110b in the figure may be referred to as communication devices having base station functions. Figure 1b 120a-120j in the figure can be called communication devices with terminal functions.

[0127] Base stations and terminals, base stations and base stations, and terminals and terminals can communicate through authorized spectrum, through unlicensed spectrum, or through both authorized spectrum and unlicensed spectrum. They can communicate through spectrum below 6 gigahertz (GHz), through spectrum above 6 GHz, or through both spectrum below 6 GHz and spectrum above 6 GHz at the same time.

[0128] In the embodiment of the present application, the device for realizing the function of the terminal may be a terminal; or it may be a device capable of supporting the terminal to realize the function, such as a chip system, or a communication module, or a modem, etc., which may be installed in the terminal. In the embodiment of the present application, the chip system may be composed of chips, or may include chips and other discrete devices. In the technical solution provided in the embodiment of the present application, the device for realizing the function of the terminal is a terminal, and the terminal is a UE as an example to describe the technical solution provided in the embodiment of the present application. The embodiment of the present application does not limit the specific technology and specific device form adopted by the terminal device.

[0129] In some scenarios, the UE can also be used to act as a base station. For example, the UE can act as a scheduling entity that provides sidelink signals between UEs in vehicle-to-everything (V2X), device-to-device (D2D), or peer-to-peer (P2P).

[0130] In some scenarios, the UE can also be used as a relay node. For example, the UE can act as a relay device (relay) or an integrated access and backhaul (IAB) node to provide wireless backhaul services for terminal devices.

[0131] Optionally, the above Figure 1a and Figure 1b In the present invention, the terminal device may be configured with one or more antennas for transmitting and receiving data / information. Similarly, the wireless access network device may also be configured with one or more antennas for transmitting and receiving data / information. It is understood that the wireless access network device and the terminal device may also include multiple components related to data / information transmission and reception (for example, a processor, a modulator, a multiplexer, a demodulator or a demultiplexer, etc.). It is also understood that the above Figure 1bThis is only a schematic diagram. The communication system may also include other devices, such as core network devices (such as Figure 1a MME, AMF and other network elements in the network), wireless relay equipment and / or wireless backhaul equipment, etc. Figure 1b It is also understood that the above Figure 1a and Figure 1b This is only an example, and the embodiments of the present application do not limit the number of wireless access network devices and terminal devices included in the communication system.

[0132] In the embodiments of the present application, the term "wireless communication" may also be referred to as "communication", and the term "communication" may also be described as "data transmission", "information transmission" or "transmission".

[0133] See also Figure 2 , Figure 2 is a simplified structural diagram of a UE and a base station provided in an embodiment of the present application. For simplicity, Figure 2 Only base station 110 (corresponding to Figure 1b 110a and 110b) and UE120 (corresponding to Figure 1b In the embodiment of the present invention, the structure of the base station and the UE may be more than 120a-120j). Figure 2 Parts shown, less than Figure 2 The components shown may also include only Figure 2 It should be understood that Figure 2 The base station shown can adopt either a CU-DU separation architecture or a non-CU-DU separation architecture. The simplified structure of the core network equipment can refer to the structure of the base station and UE, and will not be expanded separately. Figure 2 A brief introduction to each component in it.

[0134] The base station 110 includes an interface 111 and a processor 112. The processor 112 may optionally store a program 114. The base station 110 may optionally include a memory 113. The memory 113 may optionally store a program 115. The UE 120 includes an interface 121 and a processor 122. The processor 122 may optionally store a program 124. The UE 120 may optionally include a memory 123. The memory 123 may optionally store a program 125. These components work together to provide various functions described in this application. For example, the processor 112 and the interface 111 work together to provide a wireless connection between the base station 110 and the UE 120. The processor 122 and the interface 121 work together to implement downlink transmission and / or uplink transmission of the UE 120.

[0135] The processor (e.g., processor 112 and / or processor 122) may include one or more processors and be implemented as a combination of computing devices. The processor (e.g., processor 112 and / or processor 122) may include one or more of the following: a microprocessor, a microcontroller, a digital signal processor (DSP), a digital signal processing device (DSPD), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic device (PLD), a gating logic, a transistor logic, a discrete hardware circuit, a processing circuit or other suitable hardware, firmware and / or a combination of hardware and software to perform the various functions described in this application. The processor (e.g., processor 112 and / or processor 122) may be a general-purpose processor or a dedicated processor. For example, processor 112 and / or processor 122 may be a baseband processor or a central processing unit. The baseband processor may be used to process communication protocols and communication data. The central processing unit may be used to enable the base station 110 and / or UE 120 to execute software programs and process data in the software programs.

[0136] The interface (e.g., interface 111 and / or 121) may include a device for implementing communication with one or more computer devices (e.g., UE, BS, and / or network node). In some embodiments, the interface may include wires for coupling wired connections, or pins for coupling wireless transceivers, or chips and / or pins for wireless connections. In some embodiments, the interface may include a transmitter, a receiver, a transceiver, and / or an antenna. The interface may be configured to use any available protocol (e.g., 3GPP standard).

[0137] The program in this application can be used to represent software in a broad sense. Non-limiting examples of software are program codes, programs, subroutines, instructions, instruction sets, codes, code segments, software modules, applications, software applications, etc. The program can be run in a processor and / or a computer to enable the base station 110 and / or the UE 120 to perform various functions and / or processes described in this application.

[0138] Memory (e.g., memory 113 and / or memory 123) can store data manipulated by processors 112, 122 when executing software. Memories 113, 123 can be implemented using any storage technology. For example, the memory can be any available storage medium that can be accessed by the processor and / or computer. Non-limiting examples of storage media include: RAM, ROM, EEPROM, CD-ROM, removable media, optical disk storage, magnetic disk storage media, magnetic storage devices, flash memory, registers, state memory, remote mounted storage, local or remote memory components, or any other medium that can carry or store software, data or information and can be accessed by the processor / computer.

[0139] The memory (e.g., memory 113 and / or memory 123) and the processor (e.g., processor 112 and / or processor 122) may be separately arranged or integrated together. The memory may be used to connect to the processor so that the processor can read information from the memory and store and / or write information in the memory. The memory 113 may be integrated into the processor 112. The memory 123 may be integrated into the processor 122. The processor (e.g., processor 112 and / or processor 122) and the memory (e.g., memory 113 and / or memory 123) may be arranged in an integrated circuit (e.g., the integrated circuit may be arranged in a UE or a base station or other network node).

[0140] Optionally, the components in the above-mentioned base station 110 and UE 120 may also exist in the form of various interaction modules, for example, a radio resource control (RRC) signaling interaction module, that is, a module used by the base station 110 and UE 120 to send and receive RRC signaling; a MAC signaling interaction module, that is, a module used by the base station 110 and UE 120 to send and receive medium access control-control element (MAC-CE) signaling; a PHY signaling and data interaction module, that is, a module used by the base station 110 and UE 120 to send and receive uplink / downlink control signaling, and uplink / downlink data.

[0141] The above content explains the communication system architecture that can be applied to the embodiments of the present application. In order to better understand the technical solutions of the embodiments of the present application, several terms or nouns related to the present application are briefly introduced below to facilitate understanding by technical personnel in this field.

[0142] 1. Radio bearer (RB), data radio bearer (DRB), signaling radio bearer (SRB)

[0143] RB is a general term for different layer protocol entities and configurations allocated by the base station to the UE, which can include a series of resources allocated by the PDCP protocol entity, the radio link control (RLC) protocol entity, the MAC protocol entity, and the physical (PHY) protocol entity. RB is the channel connecting the base station and the UE through the Uu interface (including PHY, MAC, RLC, and PDCP). Any data transmitted on the Uu interface must pass through the RB.

[0144] Among them, RB includes SRB and DRB. SRB is the channel for the actual transmission of the system's signaling messages, that is, the signaling plane connection between the UE and the base station, or called the control plane connection; DRB is the channel for the actual transmission of user data, that is, the data plane connection between the UE and the base station, or called the user plane connection. The embodiment of the present application can solve the problem of conflict between the user plane process and the signaling plane process of the same session, and ensure user experience.

[0145] 2. Session

[0146] A session refers to the process of communication between a UE and a data network (DN). In mobile communications, Session can be understood as a logical connection from UE to DN, and the establishment of a session is to establish a data transmission channel between UE and DN. Among them, in 4G systems, sessions are generally called packet data network (PDN) sessions; in 5G systems, sessions are generally called protocol data unit (PDU) sessions. When the UE is redirected or switched between different systems, the session will be mapped. For example, when the UE is redirected from a 4G system to a 5G system, the PDN session and the PDU session will be mapped to ensure normal communication between the UE and the data network.

[0147] The redirection or switching operation of the UE between different systems may be initiated based on services, coverage or capacity, and mainly involves events such as A1 / A2 / B1 / B2 used for signal quality judgment. Therefore, after redirection or switching, the UE often receives a session modification message sent by the network side, which is used to instruct the UE to modify a certain session. At this time, if the UE also initiates a user plane establishment process for the session, the user plane process of the session will conflict with the signaling plane process. The embodiment of the present application can solve the problem of conflict between the user plane process and the signaling plane process of the same session after the UE is redirected between different systems or the switching fails, thereby ensuring user experience.

[0148] First, the technical problems to be solved by this application are analyzed and proposed. Take the example of UE redirection from 4G system to 5G system. Figure 3 , Figure 3 It is a flowchart of the conflict between the user plane process and the signaling plane process. Since the session parameters of the UE on the LTE and NR systems may be different, after the UE redirects from LTE to NR (LTE to NR redirection, L2NR), the 5G system network side will most likely send down a signaling plane process of PDU Session modification (Modify). Understandably, since it is L2NR, it means that the UE was in a connected state on LTE before, that is, the UE most likely transmitted data on LTE. However, because data services may be intermittent data packets, when the UE initiates a registration request to the 5G system (corresponding to Figure 3 In step 2), there is a high probability that the data cannot be sensed, but the data is sensed during the registration request or after the registration is completed, causing the UE to immediately send a service request process to the network side after the registration is completed, requesting to establish a data plane (i.e., DRB) for the PDU Session to transmit service data. At this time, the user plane establishment process and the signaling plane process of the same PDU Session are concurrent, and a conflict occurs (corresponding to Figure 3 In step 4 and step 5 of the protocol, both the UE and the network can only wait for one process to complete before proceeding to the other process, causing the UE to wait for the network's response message to the service request after L2NR, and the network to wait for the UE's modification completion message for the session modification. The link will not be released until the timer of the PDU Session Modify process on the network expires, causing the UE to be unable to establish the user plane, and the application to experience obvious lag, which seriously affects the user experience. At present, solutions to this hedging process are still being explored.

[0149] To this end, the present application proposes a communication method, device and readable storage medium, which can solve the problem of hedging between the DRB establishment request sent by the UE and the session modification (Session Modify) sent by the network side after the UE redirects between different systems, or after the UE fails to switch between different systems, or the problem of deadlock after hedging occurs. Specifically,

[0150] Method 1: Taking the UE's L2NR process as an example, since the UE is in a connected state on LTE before being redirected to the 5G system, the UE can sense which PDN Sessions are activated on LTE, that is, it can sense which PDN Sessions have DRBs. Based on this, the UE can tell the network side in the registration request after L2NR which PDU Session DRBs need to be established, so that the network side can establish the DRB when the registration is accepted, and send its information to the UE together with the registration result. In this way, by allowing the establishment of DRB to proceed with the registration process, the UE does not need to start another service process to request the establishment of DRB after the registration process, thereby avoiding the subsequent hedging of the PDU Session Modify sent by the network side.

[0151] Method 2: Taking the UE's L2NR process as an example, after the UE is redirected to the 5G system and completes the registration process, if it detects that the request to establish a DRB for a certain PDU Session is initiating and conflicts with the Modify process for this PDUSession sent by the network side, the UE can actively respond to the PDU Session Modify process on the network side, and then request the network side to establish the DRB for this PDU Session after the Modify process is completed. In other words, the UE actively resolves the hedging.

[0152] Method 3: Taking the UE's L2NR process as an example, after the UE is redirected to the 5G system and completes the registration process, the UE can wait for a period of time. During this period of time, it does not send a request to the network side to establish a DRB, but waits for the network side to send the PDUSession Modify process, so as to minimize the conflict between the user plane establishment process and the signaling plane process of the same PDU Session after the UE completes the registration.

[0153] For ease of understanding, the technical solution provided by this application will be described below in conjunction with more drawings.

[0154] In this application, unless otherwise specified, the same or similar parts between various embodiments or implementations can refer to each other. In each embodiment of this application, and each implementation method / implementation method / implementation method in each embodiment, if there is no special explanation and logical conflict, the terms and / or descriptions between different embodiments and each implementation method / implementation method / implementation method in each embodiment are consistent and can be referenced to each other. The technical features in different embodiments and each implementation method / implementation method / implementation method in each embodiment can be combined to form new embodiments, implementation methods, implementation methods, or implementation methods according to their inherent logical relationships. The implementation methods of this application described below do not constitute a limitation on the scope of protection of this application.

[0155] See also Figure 4a , Figure 4a is a flow chart of a communication method provided in an embodiment of the present application, which can be applied to the above Figure 1a or Figure 1b The UE described in the above Figure 1a or Figure 1b The UE described in the foregoing may be used to support and perform Figure 4a The method flow steps are shown in FIG. Figure 4a As shown, the communication method includes but is not limited to the following steps:

[0156] S401: The UE releases the DRBs of all first sessions activated on the first system.

[0157] S402: The UE sends a registration request message to the first network device of the second system.

[0158] S403: The UE receives the first message.

[0159] Among them, the second system network side includes a first network device. In step S402, the registration request message sent by the UE to the first network device of the second system (such as the MME in the 4G system or the AMF in the 5G system) may include session information of one or more second sessions, and these second sessions have a one-to-one mapping relationship with all the first sessions activated by the UE on the first system. The UE can initiate a registration request to the second system through the registration request message, and initiate a request to establish a DRB for these second sessions. In other words, the UE can tell the second system network side in the registration request message which Session DRBs need to be established, as long as the UE's original sessions on the first system corresponding to these Sessions (such as PDN sessions) are activated, that is, all the first sessions activated on the first system. In this way, the second system network side can establish the DRBs of these sessions when the registration is accepted, so that after the registration process is completed, the UE does not need to start a service process to request the establishment of the DRBs of these sessions, thereby avoiding the subsequent hedging of the Session Modify sent by the second system network side.

[0160] The first message received by the UE in step S403 may be an RRC reconfiguration message or a part of the RRC reconfiguration message (in this case, the RRC reconfiguration message may also include a registration acceptance). The first message includes information about the DRB established by the second system network side for one or more second sessions in the registration request message, so that the UE does not need to initiate a service request (i.e., a request to establish a DRB) for the one or more second sessions after the registration process.

[0161] Optionally, before step S401, the above communication method may further include step S400.

[0162] S400: The UE receives a redirection indication message / switching indication message from the first system network side.

[0163] Specifically, the above-mentioned redirection indication message is used to indicate that the UE is redirected from the first system to the second system; the above-mentioned switching indication message is used to indicate that the UE is switched from the first system to the second system. At this time, the first system can be referred to as the source system, and the second system can be referred to as the target system. In the case where the UE fails to redirect or switch between different systems, conflicts between the user plane process and the signaling plane process of the same session may occur later (such as the prior art). For the scenario where the UE fails to redirect or switch between different systems, in an embodiment of the present application, the UE can tell the target system in the registration request message which Session DRBs need to be established. In this way, the network side of the target system can establish the DRBs of these sessions at the time of registration accept, so that after the registration process is completed, the UE does not need to start another service process to request the establishment of the DRBs of these sessions, thereby avoiding the subsequent hedging of the Session Modify sent by the network side of the target system.

[0164] Exemplarily, after receiving the redirection indication message sent by the network side of the first system, the UE exits the connected state and releases the DRBs of all sessions activated on the first system, redirects to the second system and initiates the registration process. The redirection indication message may be an RRC connection release message. Alternatively, after receiving the switching indication message sent by the network side of the first system, the UE attempts to switch from the first system to the second system. If the switching fails during the attempt, the UE releases the DRBs of all sessions (i.e., the first session) activated on the first system (corresponding to step S401), and then attempts to access the second system and initiates the registration process (corresponding to step S402).

[0165] Optionally, the above communication method may further include steps S403a, S404 and S405 after step S403.

[0166] S403a: The UE sends a second message to the first network device of the second system (not shown in the figure).

[0167] S404: The UE receives a session modification message sent by the second network device of the second system.

[0168] S405: The UE sends a modification completion message to the second network device of the second system.

[0169] Exemplarily, after receiving the first message, the UE may send a second message to the second system network side (corresponding to step S403a) to notify the second system network side that the DRBs of the one or more second sessions have been established.

[0170] Optionally, the second system network side includes a second network device. After step S403, the UE may receive a session modification message (corresponding to step S404) from the second network device of the second system (such as the MME in the 4G system or the SMF in the 5G system). The session modification message is used to instruct the UE to modify the session in the one or more second sessions. Because, when the UE initiates a registration request to the second system network side, it also initiates a request to establish a DRB for the one or more second sessions. Therefore, after completing the registration process, the UE does not need to initiate another request to establish a DRB for the one or more second sessions, so that there will be no user plane process initiated by the UE to establish a DRB for the one or more second sessions and the session modification process issued by the second system network side for the one or more second sessions. The UE can respond normally to the session modification message issued by the second system network side (such as the MME in the 4G system or the SMF in the 5G system), and can send a modification completion message to the second system network side after completing the session modification (corresponding to step S405).

[0171] Optionally, the first system in the above embodiment may be a 4G system, and the second system may be a 5G system. Alternatively, the first system may be a 5G system, and the second system may be a 4G system; alternatively, the first system may be a 4G system, and the second system may be a 3G system; alternatively, the first system may be a 3G system, and the second system may be a 4G system, and no specific limitation is made here. It is understandable that when the first system and the second system are the above-mentioned different systems, the names of the various messages in the above steps S400-S405 may be different in different systems, and their specific names are not limited here.

[0172] For ease of understanding, the following is a brief description using the first system as a 4G system and the second system as a 5G system as an example. Figure 4b , Figure 4b It is a flowchart of another communication method provided by an embodiment of the present application, including but not limited to the following steps:

[0173] S410: The UE receives a redirection indication message / switching indication message from the 4G system network side.

[0174] S411: The UE releases the DRBs of all PDN sessions activated on the 4G system.

[0175] S412: The UE sends a registration request message to the first network device of the 5G system.

[0176] S413: The UE receives the first message.

[0177] S414: The UE receives a session modification message sent by the second network device of the 5G system.

[0178] S415: The UE sends a modification completion message to the second network device of the 5G system.

[0179] The description of S410-S415 can refer to the above Figure 4a See the relevant descriptions in S400-S405.

[0180] Exemplarily, after the UE receives a redirection indication message from the 4G system network side (e.g., access network device) instructing the UE to redirect to the 5G system (corresponding to step S410), the UE needs to exit the connected state and release the DRBs of all PDN sessions (i.e., the first session) that have been activated on the 4G system (corresponding to step S411). The redirection indication message may be an RRC connection release message. Alternatively, after the UE receives a switching indication message from the 4G system network side (e.g., access network device) instructing the UE to switch to the 5G system, the UE attempts to switch from the 4G system to the 5G system. If the switching fails, the UE releases the DRBs of all PDN sessions (i.e., the first session) that have been activated on the 4G system, and then attempts to access the 5G system and initiate a registration process.

[0181] Subsequently, when the UE initiates a registration request message (corresponding to step S412) to the 5G system network side (corresponding to the first network device, such as AMF), the session information of the PDU session for which the DRB needs to be established is carried in the registration request message. For example, the session that the UE has activated on the 4G system is PDN session 7 (taking session ID 7 as an example), and there is a one-to-one mapping relationship between the UE's PDU session 7 on the 5G system and the PDN session 7. Therefore, when the UE sends a registration request message to the 5G system, it can simultaneously request to establish the DRB for PDU session 7. This allows the UE to avoid the need to initiate another service process to request the establishment of the DRB for PDU session 7 after the registration process, thereby avoiding the subsequent hedging of the Session Modify process for PDU session 7 issued by the 5G system network side.

[0182] In a possible implementation, the session information of the one or more second sessions may be carried in the uplink data status IE field or the reserved field of the registration request message in step S412. Exemplarily, the session IDs of the one or more second sessions for which DRBs need to be established may be carried in the uplink data status field in the registration request message. Different from the prior art, before sending a registration request message, if the UE promptly perceives that there is data to be transmitted, it will carry the session information in the uplink data status field to request the establishment of the DRB for the session to transmit the data perceived by the UE before registration. In an embodiment of the present application, because the UE is in a connected state on the first system before sending a registration request to the second system, the UE can perceive which of its sessions on the first system are in an activated state, that is, the UE can perceive which of its sessions on the first system have DRBs. Based on this, when the UE initiates a registration request to the second system, it can directly request to establish a DRB for the sessions corresponding to the sessions activated on the first system. That is to say, the UE carries the session information of the sessions on the second system (i.e., one or more second sessions) that have a mapping relationship with the sessions activated on the first system (i.e., all first sessions) in the uplink data status field, instead of carrying it only when it senses that there is data to be transmitted.

[0183] Alternatively, in step S412, the UE may carry the session IDs of the one or more second sessions for which DRB needs to be established in the reserved field in the registration request message. Optionally, the usage of the uplink data status field in the registration request message at this time may still be the same as the prior art, that is, the UE carries the session information of the session for which DRB needs to be established in the uplink data status field only when it perceives that there is data to be transmitted before initiating registration with the second system; for the reserved field, the UE may first perceive all the sessions activated on the first system (i.e., all the first sessions) before initiating a registration request to the second system, and after mapping all the sessions activated on the first system with the sessions of the second system (i.e., the second sessions) one by one, carry the session information of the sessions of the second system (i.e., the second sessions) in the reserved field to request the network side of the second system to establish DRB for these sessions of the second system (i.e., the second sessions).

[0184] Exemplarily, if the uplink data status field does not carry any session information (that is, the UE does not perceive that data needs to be transmitted before initiating registration), and the reserved field carries session information (session ID, such as session 7 and session 8), the second system network side can establish DRB for session 7 and session 8 when the registration is accepted; if the uplink data status field carries session information (such as session 5 and session 6), the reserved field also carries session information (such as session 7 and session 8), and the session information carried by the two fields does not overlap, the second system network side may establish DRB for session 7 and session 8 when the registration is accepted. DRBs can be established for all these sessions (including session 5, session 6, session 7, and session 8); if the uplink data state carries session information (for example, session 6 and session 7), the reserved field also carries session information (for example, session 7 and session 8), and the session information carried by the two fields overlaps (that is, session 7), the second system network side can establish DRBs for all these sessions (including session 6, session 7, and session 8) when registration is accepted, among which the DRBs for the sessions with overlapping session information can be established first, that is, the DRB for session 7 can be established first.

[0185] After step S413, when the UE receives the session modification message (corresponding to step S414) from the 5G system network side (corresponding to the second network device, such as SMF), it can respond normally to the session modification message sent by the 5G system network side, and after completing the session modification, it can send a modification completion message to the 5G system network side (corresponding to step S415). Optionally, after receiving the first message sent by the 5G system network side, the UE can correspondingly send a second message (corresponding to step S413a) to the 5G system network side to notify the 5G system network side that the DRB establishment is completed.

[0186] For ease of understanding, a simple explanation is given by taking the first system as a 5G system, the second system as a 4G system, and the UE redirecting from the 5G system to the 4G system as an example. Figure 4c , Figure 4c : is a flow chart of another communication method provided in an embodiment of the present application, and the communication method includes but is not limited to the following steps:

[0187] S420: The UE receives a redirection indication message / switching indication message from the 5G system network side.

[0188] S421: The UE releases the DRBs of all PDU sessions activated on the 5G system.

[0189] S422: The UE sends a registration request message to the 4G system network side.

[0190] S423: The UE receives the first message.

[0191] S424: The UE receives a session modification message sent by the 4G system network side.

[0192] S425: The UE sends a modification completion message to the 4G system network side.

[0193] The description of S420-S425 can refer to the above Figure 4a S400-S405 and Figure 4b Related descriptions of S410-S415.

[0194] Exemplarily, the registration request message in step S422 may be a tracking area update request (TAU Request) message. Before registering, the UE may sense whether there is a DRB for the PDUsession on the 5G system (such as NR) or whether there is an activated PDU Session. If so, the UE may set the Active Flag in the EPS update type IE to 1 in the TAU Request message to inform the 4G network side that the UE needs to establish user plane resources after registration is completed (corresponding to step S422).

[0195] Correspondingly, after receiving the TAU Request message from the UE, the 4G system network side can establish user plane resources for the UE according to the active flag carried therein, and give the user plane resources to the UE through a first message (corresponding to step S423), the first message can be an RRC Recfg message, and the first message can also carry a TAU ACC to the UE.

[0196] After step S423, when the UE receives the session modification message (for example, ModifyEPS bearer context request, corresponding to step S424) from the 4G system network side, it can respond normally to the session modification message sent by the 4G system network side, and can send a modification completion message (for example, ModifyEPS bearer context accept, corresponding to step S425) to the 4G system network side after completing the session modification.

[0197] In summary, in the above embodiments, after redirection between different systems (such as L2NR, or NR2L) or after a failed handover between different systems, the UE can, when registering with the target system, use a registration request message to tell the target system network side which sessions' DRBs need to be established, as long as these sessions and the corresponding sessions of the UE on the source system are activated or DRBs exist. The target system network side can establish the DRB when the registration is accepted, and send its information to the UE together with the registration result. In this way, by allowing the establishment of the DRB to proceed together with the registration process, the UE does not need to initiate another service process to request the establishment of the DRB after the registration process, thereby avoiding the subsequent hedging of the Session Modify sent by the target system network side, thereby ensuring the user experience.

[0198] See also Figure 5 , Figure 5 is a flow chart of another communication method provided in an embodiment of the present application, which can be applied to the above Figure 1a or Figure 1b The UE described in the above Figure 1a or Figure 1b The UE described in the foregoing may be used to support and perform Figure 5 The method flow steps are shown in FIG. Figure 5 As shown, the communication method includes but is not limited to the following steps:

[0199] S500: The UE sends a first service request to a first network device of the second system.

[0200] S501: When the UE does not receive a response message to the first service request, the UE receives a session modification message from the second network device of the second system.

[0201] S502: The UE modifies the target session in response to the session modification message, and sends a modification completion message to the second network device of the second system.

[0202] Among them, the first service request is a request initiated by the UE to the second system network side (corresponding to the first network device, such as AMF, MME) to establish one or more DRBs for the target session. Exemplarily, if the second system is a 5G system, the target session is a PDU session, and if the second system is a 4G system, the target session is a PDD session. If the UE receives a session modification message from the second network device of the second system (such as MME in the 4G system or SMF in the 5G system) without receiving a response message to the service request, and the session modification message is used to instruct the UE to modify the above-mentioned target session, there will be a conflict between the user plane establishment process and the signaling plane process of the same session (ie, the target session). In order to resolve this conflict, the UE can actively respond to the session modification message sent by the second system network side, and suspend the request to establish DRB for the target session, without waiting for the response message of the second system network side to the first service request, thereby resolving the conflict between the user plane establishment process and the signaling plane process of the same session (ie, the target session).

[0203] Optionally, after step S502, the communication method may further include step S503.

[0204] S503: The UE sends a second service request to the first network device of the second system.

[0205] Specifically, the second service request is a request to establish one or more DRBs for the modified target session. That is to say, after the UE responds to the session modification message sent by the network side of the second system and completes the modification of the target session, it can resend the request to establish DRBs for the target session (i.e., the second service request) to the first network device of the second system (such as MME in the 4G system or AMF in the 5G system). At this time, the first network device of the second system can normally process the second service request of the UE and establish DRBs for the target session. Therefore, after processing the conflict between the user plane establishment process and the signaling plane process of the same session (i.e., the target session), the UE re-initiates the request to establish DRBs for the target session (i.e., the second service request), which can avoid the situation where DRBs are not established because the network side of the second system does not respond to the first service request, thereby affecting the service data transmission.

[0206] Optionally, before step S500, the communication method may further include steps S504-S506, wherein:

[0207] S504: The UE receives a redirection indication message or a switching indication message from the access network device of the first system.

[0208] S505: The UE sends a registration request message to the first network device of the second system.

[0209] S506: The UE receives a registration acceptance message from the first network device of the second system.

[0210] The redirection indication message in S504 is used to instruct the terminal device to redirect from the first system to the second system, and the switching indication message is used to instruct the terminal device to switch from the first system to the second system; the first system and the second system are different communication systems. After receiving the redirection indication message or the switching indication message, the UE can redirect from the first system or switch to the second system.

[0211] Optionally, the registration request message sent by the UE in the above step S505 may or may not carry the session information of the session for which the DRB needs to be established. Exemplarily, when the UE registers with the second system (corresponding to step S505) after redirection between different systems (such as L2NR, or NR2L) or after a handover between different systems fails, the UE may carry the session information of the session for which the DRB needs to be established (i.e., the target session) in the registration request message. However, due to some reasons, the network side of the second system fails to establish the DRB for the target session, and only accepts the registration and sends a registration acceptance message (corresponding to step S506), resulting in the UE sending a first service request (corresponding to step S500) after the registration process to request the establishment of a DRB for the target session. Alternatively, when the UE registers with the second system (corresponding to step S505), it does not request to establish a DRB for the target session, that is, it does not carry the session information of the target session in the registration request message. This may be because the UE did not perceive the existence of the data plane before sending the registration request message, and thus did not carry the session information of the target session in the registration request message (such as the method of the prior art). However, after sending the registration request message, the UE perceives the existence of the data plane, so after receiving the registration acceptance message sent by the network side of the second system (corresponding to step S506), the UE sends a first service request (corresponding to step S500) to request to establish the DRB of the target session.

[0212] Optionally, after receiving the registration acceptance message from the network side of the second system, the UE may wait for a period of time before sending the first service request, so as to minimize the conflict between the user plane establishment process and the signaling plane process of the same session (i.e., the target session). Exemplarily, after receiving a redirection indication message or a switching indication message, the UE performs redirection between different systems (e.g., L2NR, or NR2L), or after the switching between different systems fails, it initiates a registration request to the second system, receives a registration acceptance message from the first network device of the second system at a first moment, and then sends a first service request to the first network device of the second system at a second moment. The difference between the first moment and the second moment is greater than or equal to a preset value. That is to say, after receiving the registration acceptance message from the network side of the second system, the UE may wait for a period of time before sending the first service request. Exemplarily, the implementation method of the UE waiting for a period of time may be a timer, the length of the timer being the above-mentioned preset value, and when the UE receives the registration acceptance message, the timer is started until the timer times out, and the UE sends the first service request.

[0213] If during this waiting time, the UE receives a session modification message sent by the network side of the second system, the UE can respond normally, because the UE has not yet sent the first service request, and there is no conflict between the user plane establishment process and the signaling plane process of the same session (i.e., the target session). It should be noted that the UE waiting time (i.e., the above-mentioned preset value) can be set according to the service type or service priority carried by the session, which is not further explained here. Exemplarily, the above-mentioned preset value can be greater than or equal to 10 milliseconds. It can be understood that the preset value can also be a value within a range. If it is lower than 10 milliseconds, the effect of reducing conflicts may be slightly worse, but the UE waiting time is short. If it is higher than 10 milliseconds, the effect of reducing conflicts may be slightly better, but the UE waiting time is long. Therefore, the preset value can be set according to the actual situation, and is not specifically limited here.

[0214] Optionally, the first system in the above embodiment may be a 4G system, and the second system may be a 5G system. Alternatively, the first system may be a 5G system, and the second system may be a 4G system; alternatively, the first system may be a 4G system, and the second system may be a 3G system; alternatively, the first system may be a 3G system, and the second system may be a 4G system, and no specific limitation is made here. It is understandable that when the first system and the second system are the above-mentioned different systems, the names of the various messages in the above steps S500-S506 may be different in different systems, and their specific names are not limited here.

[0215] For ease of understanding, take the scenario where UE performs L2NR redirection as an example. After redirecting to the 5G system, the UE sends a registration request message to the 5G system network side. The registration request message can be consistent with the registration request message in the prior art, that is, the UE does not tell the 5G system network side in the registration request message which PDU Session DRBs need to be established. During the registration process, the UE senses that there is data to be transmitted, and can immediately reissue a service request after receiving the registration acceptance message from the 5G system network side to request the establishment of the DRB for the target session. Thereafter, if the UE detects that the DRB establishment process of a PDUSession (i.e., the target session) being initiated conflicts with the Modify process for this PDU Session issued by the 5G system network side, the UE can actively respond to the PDU Session Modify process on the 5G network side, and then request the 5G system network side to establish the DRB for this PDU Session after the Modify is completed.

[0216] In summary, in the above embodiments, when there is a conflict between the user plane process and the signaling plane process of the same session, the UE can suspend the user plane process and actively respond to the signaling plane process sent by the network side, without waiting for the network side to respond to the user plane process, thereby resolving the conflict between the user plane establishment process and the signaling plane process of the same session, thereby ensuring user experience.

[0217] See also Figure 6 , Figure 6 is a flow chart of another communication method provided in an embodiment of the present application, which can be applied to the above Figure 1a or Figure 1b The UE described in the above Figure 1a or Figure 1b The UE described in the foregoing may be used to support and perform Figure 6 The method flow steps are shown in FIG. Figure 6 As shown, the communication method includes but is not limited to the following steps:

[0218] S600: The UE sends a registration request message to a first network device of the second system.

[0219] S601: The UE receives a registration acceptance message from the first network device of the second system at a first moment.

[0220] S602: The UE sends a service request to the first network device of the second system at a second moment.

[0221] Among them, the service request is a request initiated by the UE to the second system network side (corresponding to the first network device, such as AMF, MME) to establish one or more DRBs for the target session. After receiving the registration acceptance message sent by the second system network side, the UE waits for a period of time (i.e., the preset value) and then sends a service request to the second system network side. If the second system network side sends a session modification message during this waiting time, because the UE does not initiate a request to establish a DRB, there will be no conflict between the user plane process and the signaling plane process of the same session during this period, and the UE can respond normally to the session modification message sent by the second system network side. Exemplarily, the above preset value can be greater than or equal to 10 milliseconds, or it can be other values, which are not specifically limited here.

[0222] Optionally, if the UE does not receive a session modification message within the waiting time, but receives a session modification message after sending a service request without receiving a response message from the second system network side, and a conflict occurs between the user plane process and the signaling plane process of the same session, the UE may also actively respond to the session modification message to resolve the conflict and thereby ensure user experience.

[0223] Optionally, the registration request message sent by the UE in the above step S600 may carry the session information of the session for which the DRB needs to be established, or may not carry it. Please refer to the relevant description of the above step S505, which will not be repeated here.

[0224] Optionally, before step S600, the communication method may further include step S603.

[0225] S603: The UE receives a redirection indication message or a switching indication message from the access network device of the first system.

[0226] Among them, the redirection indication message is used to indicate that the UE is redirected from the first system to the second system; the switching indication message is used to indicate that the UE is switched from the first system to the second system. Exemplarily, if the UE determines that the registration process of the above steps S600 and S601 is performed after the redirection process (such as L2NR, NR2L process) between different systems is completed or the switching between different systems fails, and the subsequent process is not a process in which the UE actively initiates the session modification, the UE can start a timer (timer) after receiving the registration acceptance message to wait for the second system network side to send the session modification process, and temporarily do not send the service request. Because, in the scenario where the UE redirects or fails to switch between different systems, the network side is likely to send a session modification message after the UE completes the registration process. Therefore, if the UE does not send a service request within a period of time after the registration process is completed, it is possible to avoid the conflict between the user plane process and the signaling plane process of the same session. Optionally, if there is a conflict between the user plane process and the signaling plane process of the same session after this waiting time, the UE can also actively respond to the session modification message sent by the network side to resolve the conflict.

[0227] Optionally, the first system in the above embodiment may be a 4G system, and the second system may be a 5G system. Alternatively, the first system may be a 5G system, and the second system may be a 4G system; alternatively, the first system may be a 4G system, and the second system may be a 3G system; alternatively, the first system may be a 3G system, and the second system may be a 4G system, which is not specifically limited here.

[0228] For ease of understanding, take the scenario of UE performing L2NR as an example. After being redirected to the 5G system, the UE sends a registration request message to the 5G system network side. The registration request message can be consistent with the registration request message in the prior art, that is, the UE does not tell the 5G system network side in the registration request message which PDU Session DRBs need to be established. After receiving the registration acceptance message from the 5G system network side, the UE can start a timer to wait for the 5G system network side to send the PDU Session Modify process. Until the timer times out, the UE requests the 5G system network side to establish the DRB for the target session.

[0229] In summary, in the above embodiment, after the registration process is completed, the UE can wait for a period of time and temporarily not send a request to the network side to establish a DRB for the target session (i.e., a service request), so as to avoid conflicts between the user plane process and the signaling plane process of the same session and ensure user experience.

[0230] It should be noted that the above embodiments are mainly described based on the situation where the UE is redirected or switched from a 4G system to a 5G system. The solution of the present application is also applicable to the scenario where the UE is redirected or switched from a 5G system to a 4G system, or the UE is redirected or switched between a 3G system and a 4G system. It can also be applied to the scenario where the UE interoperates (such as redirection or switching) between other different systems, for example, a 5G system and a 6G system.

[0231] The above content describes the method provided by the present application. In order to facilitate the implementation of the above scheme of the embodiment of the present application, the embodiment of the present application also provides corresponding devices or equipment.

[0232] The present application divides the functional modules of the device according to the above method embodiment. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. The device of the embodiment of the present application will be described below in conjunction with the accompanying drawings.

[0233] See also Figure 7 , Figure 7 is a schematic diagram of a communication device provided in an embodiment of the present application. The communication device 10 can be used to implement the above Figure 4a-4c The functions of the UE in the method embodiment involved can also achieve the beneficial effects of the above method embodiment. In the embodiment of the present application, the communication device 10 can be as follows Figure 1b One of the terminals 120a-120j shown may also be a module (such as a chip) applied to a terminal.

[0234] like Figure 7 As shown, the communication device 10 may include a processing unit 100, a sending unit 101 and a receiving unit 102. The communication device 10 may be used to implement the above Figure 4a-4cFunctions of UE in the method embodiment involved. Among them, the processing unit 100 can be used to release the DRBs of all first sessions activated on the first system; the sending unit 101 can be used to send a registration request message to the first network device of the second system; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all the first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems; the receiving unit 102 can be used to receive a first message; the first message includes information of one or more DRBs established by the access network device of the second system for the one or more second sessions.

[0235] In a possible implementation, before the processing unit releases the DRBs of all first sessions activated on the first system, the receiving unit is further used to receive a redirection indication message from an access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system.

[0236] In a possible implementation, before the processing unit releases the DRBs of all first sessions activated on the first system, the receiving unit is further used to receive a switching indication message from an access network device of the first system, wherein the switching indication message is used to instruct the terminal device to switch from the first system to the second system.

[0237] In a possible implementation manner, the session information of the one or more second sessions is carried in an uplink data status field or a reserved field of the registration request message.

[0238] In a possible implementation, after the receiving unit receives the first message, the receiving unit is further used to receive a session modification message from a second network device of the second system; the session modification message is used to instruct the terminal device to modify a target second session, where the target second session is a session in the one or more second sessions;

[0239] The processing unit is further configured to modify the target second session in response to the session modification message;

[0240] The sending unit is further configured to send a modification completion message to the second network device of the second system.

[0241] In a possible implementation, the first system is 3G, and the second system is 4G; or, the first system is 4G, and the second system is 3G or 5G; or, the first system is 5G, and the second system is 4G.

[0242] It should be noted that the functions of each functional unit / module in the communication device described in the embodiments of the present application can be found in the relevant description in the above method embodiments and will not be repeated here.

[0243] See also Figure 8 , Figure 8 is a schematic diagram of the structure of another communication device provided in an embodiment of the present application. The communication device 20 can be used to implement the above Figure 4a-4c The function of the first network device in the method embodiment involved can also achieve the beneficial effects of the above method embodiment. In the embodiment of the present application, the communication device 20 can be as follows Figure 1a AMF or MME shown.

[0244] like Figure 8 As shown, the communication device 20 may include a receiving unit 200 and a sending unit 201. The communication device 20 may be used to implement the above Figure 4a-4c Functions of the first network device in the method embodiment involved. The receiving unit 200 may be used to receive a registration request message sent by a terminal device; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems; the sending unit 201 may be used to send an indication message to an access network device of the second system; the indication message is used to instruct the access network device to establish one or more DRBs for the one or more second sessions.

[0245] In a possible implementation, the first system is 3G, and the second system is 4G; or, the first system is 4G, and the second system is 3G or 5G; or, the first system is 5G, and the second system is 4G.

[0246] It should be noted that the functions of each functional unit / module in the communication device described in the embodiments of the present application can be found in the relevant description in the above method embodiments and will not be repeated here.

[0247] See also Fig. 9 , Fig. 9 is a schematic diagram of the structure of another communication device provided in an embodiment of the present application. The communication device 30 can be used to implement the above Figure 5The functions of the UE in the method embodiment involved can also achieve the beneficial effects of the above method embodiment. In the embodiment of the present application, the communication device 30 can be as follows Figure 1b One of the terminals 120a-120j shown may also be a module (such as a chip) applied to a terminal.

[0248] like Fig. 9 As shown, the communication device 30 may include a first sending unit 300, a receiving unit 301, a processing unit 302, and a second sending unit 303. The communication device 30 may be used to implement the above Figure 5 Functions of the UE in the method embodiment involved. The first sending unit 300 is used to send a first service request to a first network device of the second system; the first service request is a request to establish one or more DRBs for a target session;

[0249] The receiving unit 301 is configured to receive a session modification message from a second network device of the second system when no response message to the first service request is received; the session modification message is used to instruct the terminal device to modify the target session;

[0250] The processing unit 302 is configured to modify the target session in response to the session modification message;

[0251] The second sending unit 303 is configured to send a modification completion message to the second network device of the second system.

[0252] In one possible implementation, after the second sending unit 303 sends a modification completion message to the second network device of the second system, the first sending unit 300 is also used to send a second service request to the first network device of the second system, and the second service request is a request to establish one or more DRBs for the modified target session.

[0253] In a possible implementation, before the first sending unit 300 sends the first service request to the first network device of the second system, the receiving unit 301 is further used to receive a redirection indication message or a switching indication message from the access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system, and the switching indication message is used to instruct the terminal device to switch from the first system to the second system; the first system and the second system are different communication systems;

[0254] The first sending unit 300 is further used to send a registration request message to the first network device of the second system;

[0255] The receiving unit 301 is further configured to receive a registration acceptance message from the first network device of the second system.

[0256] In a possible implementation, the receiving unit 301 is specifically configured to:

[0257] receiving, at a first moment, a registration acceptance message from a first network device of the second system;

[0258] The first sending unit 300 is specifically configured to:

[0259] The first service request is sent to the first network device of the second system at a second moment; and the difference between the first moment and the second moment is greater than or equal to a preset value.

[0260] In a possible implementation manner, the preset value is greater than or equal to 10 milliseconds.

[0261] In a possible implementation, the first system is 3G, and the second system is 4G; or, the first system is 4G, and the second system is 3G or 5G; or, the first system is 5G, and the second system is 4G.

[0262] It should be noted that the functions of each functional unit / module in the communication device described in the embodiments of the present application can be found in the relevant description in the above method embodiments and will not be repeated here.

[0263] See also Fig.10 , Fig.10 is a schematic diagram of the structure of another communication device provided in an embodiment of the present application. The communication device 40 can be used to implement the above Figure 6 The functions of the UE in the method embodiment involved can also achieve the beneficial effects of the above method embodiment. In the embodiment of the present application, the communication device 30 can be as follows Figure 1b One of the terminals 120a-120j shown may also be a module (such as a chip) applied to a terminal.

[0264] like Fig.10 As shown, the communication device 40 may include a first sending unit 400, a receiving unit 401, and a second sending unit 402. The communication device 40 may be used to implement the above Figure 6 Functions of the UE in the method embodiment involved. Wherein, the first sending unit 400 is configured to send a registration request message to the first network device of the second system;

[0265] The receiving unit 401 is configured to receive a registration acceptance message from a first network device of the second system at a first moment;

[0266] The second sending unit 402 is used to send a service request to the first network device of the second system at a second moment; the service request is a request to establish one or more DRBs for a target session, and the difference between the first moment and the second moment is greater than or equal to a preset value.

[0267] In a possible implementation manner, the preset value is greater than or equal to 10 milliseconds.

[0268] In a possible implementation, before the first sending unit 400 sends a registration request message to the first network device of the second system, the receiving unit 401 is also used to receive a redirection indication message or a switching indication message from the access network device of the first system; the redirection indication message is used to indicate that the terminal device is redirected from the first system to the second system, and the switching indication message is used to indicate that the terminal device switches from the first system to the second system; the first system and the second system are different communication systems.

[0269] In a possible implementation, the first system is 3G, and the second system is 4G; or, the first system is 4G, and the second system is 3G or 5G; or, the first system is 5G, and the second system is 4G.

[0270] It should be noted that the functions of each functional unit / module in the communication device described in the embodiments of the present application can be found in the relevant description in the above method embodiments and will not be repeated here.

[0271] It is understandable that the specific description of the receiving unit, the sending unit and the processing unit shown in the above device embodiment is only an example. For the specific functions or execution steps of the receiving unit, the sending unit and the processing unit, etc., reference can be made to the above Figure 4a , Figure 4b , Figure 4c , Figure 5 or Figure 6 The method embodiments involved will not be described in detail here.

[0272] The above describes the communication device of the embodiment of the present application, and the following describes possible product forms of the communication device. It should be understood that any device having the above Figure 7 , Figure 8 , Fig. 9 or Fig.10 Any form of product with the functions of the communication device described above falls within the protection scope of the embodiments of the present application. It should also be understood that the following description is only an example and does not limit the product form of the communication device of the embodiments of the present application to this.

[0273] In a possible implementation, the above Figure 7 , Figure 8 , Fig. 9 or Fig.10 In the communication device shown, the processing unit 100 or the processing unit 302 may be one or more processors; the sending unit 101, the receiving unit 102, the receiving unit 200, the sending unit 201, the first sending unit 300, the receiving unit 301, the second sending unit 303, the first sending unit 400, the receiving unit 401 and the second sending unit 402 may be transceivers; or, the sending unit 101, the sending unit 201, the first sending unit 300, the second sending unit 303, the first sending unit 400 and the second sending unit 402 may be transmitters, and the receiving unit 102, the receiving unit 200, the receiving unit 301 and the receiving unit 401 may be receivers. In the embodiment of the present application, the processor and the transceiver may be coupled, etc., and the embodiment of the present application does not limit the connection mode between the processor and the transceiver. In the process of executing the above method, the process of sending information in the above method can be understood as the process of outputting the above information by the processor. When outputting the above information, the processor outputs the above information to the transceiver so that it is transmitted by the transceiver. After the information is output by the processor, it may need to undergo other processing before it reaches the transceiver. Similarly, the process of receiving information in the above method can be understood as the process of the processor receiving the input information. When the processor receives the input information, the transceiver receives the information and inputs it into the processor. Furthermore, after the transceiver receives the information, the information may need to undergo other processing before it is input into the processor.

[0274] See also Fig.11 , Fig.11 1 is a schematic diagram of the structure of another communication device provided in an embodiment of the present application. The communication device 50 may be the communication device 10, or the communication device 20, or the communication device 30, or the communication device 40, or a chip therein. Fig.11 Only the main components of the communication device 50 are shown. In addition to the processor 1001 and the transceiver 1002, the communication device 50 may further include a memory 1003 and an input and output device (not shown).

[0275] The processor 1001 is mainly used to process the communication protocol and communication data, and to control the entire communication device, execute the software program, and process the data of the software program. The memory 1003 is mainly used to store the software program and data. The transceiver 1002 may include a control circuit and an antenna. The control circuit is mainly used to convert the baseband signal and the radio frequency signal and process the radio frequency signal. The antenna is mainly used to send and receive radio frequency signals in the form of electromagnetic waves. The input and output devices, such as a touch screen, a display screen, a keyboard, etc., are mainly used to receive data input by the user and output data to the user.

[0276] When the communication device is turned on, the processor 1001 can read the software program in the memory 1003, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be sent wirelessly, the processor 1001 performs baseband processing on the data to be sent, and outputs the baseband signal to the radio frequency circuit. The radio frequency circuit performs radio frequency processing on the baseband signal and then sends the radio frequency signal outward in the form of electromagnetic waves through the antenna. When data is sent to the communication device, the radio frequency circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor 1001. The processor 1001 converts the baseband signal into data and processes the data.

[0277] In another implementation, the RF circuit and antenna may be arranged independently of the processor performing baseband processing. For example, in a distributed scenario, the RF circuit and antenna may be arranged remotely from the communication device.

[0278] The transceiver 1002 may include a receiver and a transmitter, wherein the receiver is used to perform a receiving function (or operation) and the transmitter is used to perform a transmitting function (or operation), and the transceiver is used to communicate with other devices / apparatuses through a transmission medium.

[0279] The processor 1001 , the transceiver 1002 , and the memory 1003 may be connected via a communication bus.

[0280] Exemplarily, when the communication device 50 is used to execute the steps, methods or functions executed by the above-mentioned communication device 10, the processor 1001 is used to release the DRBs of all first sessions activated on the first system; the transceiver 1002 is used to send a registration request message to the first network device of the second system; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all the first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and to initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems; the transceiver 1002 is also used to receive a first message; the first message includes information of one or more DRBs established by the access network device of the second system for the one or more second sessions.

[0281] Exemplarily, when the communication device 50 is used to execute the steps, methods or functions executed by the above-mentioned communication device 20, the transceiver 1002 is used to receive a registration request message sent by a terminal device; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and to initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems; the transceiver 1002 is also used to send an indication message to an access network device of the second system; the indication message is used to instruct the access network device to establish one or more DRBs for the one or more second sessions.

[0282] Exemplarily, when the communication device 50 is used to execute the steps, methods or functions executed by the above-mentioned communication device 30, the transceiver 1002 is used to send a first service request to the first network device of the second system; the first service request is a request to establish one or more DRBs for a target session; the transceiver 1002 is also used to receive a session modification message from the second network device of the second system without receiving a response message to the first service request; the session modification message is used to instruct the terminal device to modify the target session; the processor 1001 is used to modify the target session in response to the session modification message; the transceiver 1002 is also used to send a modification completion message to the second network device of the second system.

[0283] Exemplarily, when the communication device 50 is used to execute the steps, methods or functions executed by the above-mentioned communication device 40, the transceiver 1002 is used to send a registration request message to the first network device of the second system; the transceiver 1002 is also used to receive a registration acceptance message from the first network device of the second system at a first moment; the transceiver 1002 is also used to send a service request to the first network device of the second system at a second moment; the service request is a request to establish one or more DRBs for a target session, and the difference between the first moment and the second moment is greater than or equal to a preset value.

[0284] It is understandable that the specific description of the processor and the transceiver can also refer to the above Figure 7 , Figure 8 , Fig. 9 or Fig.10 The description of the processing unit, receiving unit and sending unit shown will not be repeated here.

[0285] Optionally, the processor 1001 may include a transceiver for implementing the receiving and sending functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing the receiving and sending functions may be separate or integrated. The above-mentioned transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or the above-mentioned transceiver circuit, interface, or interface circuit may be used for transmitting or delivering signals.

[0286] Optionally, the processor 1001 may store instructions, which may be computer programs. The computer programs run on the processor 1001, and the communication device 50 may execute the method described in the above method embodiment. The computer program may be fixed in the processor 1001, in which case the processor 1001 may be implemented by hardware.

[0287] In one implementation, the communication device 50 may include a circuit that can implement the functions of sending or receiving or communicating in the aforementioned method embodiment. The processor and transceiver described in the present application can be implemented in an integrated circuit (IC), an analog IC, a radio frequency integrated circuit (RFIC), a mixed signal IC, an application specific integrated circuit (ASIC), a printed circuit board (PCB), an electronic device, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductor (CMOS), N-type metal oxide semiconductor (nMetal-oxide-semiconductor, NMOS), P-type metal oxide semiconductor (positive channel metal oxide semiconductor, PMOS), bipolar junction transistor (bipolar junction transistor, BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0288] It is understandable that the communication device shown in the embodiment of the present application may also have Fig.11 More components and parts are not limited in the embodiments of the present application. The method executed by the processor and transceiver described above is only an example, and the specific steps executed by the processor and transceiver can refer to the introduction of the method embodiment above.

[0289] In another possible implementation, Figure 7 , Figure 8 , Fig. 9 or Fig.10 In the communication device shown, the processing unit 100 or the processing unit 302 may be one or more logic circuits; the sending unit 101, the receiving unit 102, the receiving unit 200, the sending unit 201, the first sending unit 300, the receiving unit 301, the second sending unit 303, the first sending unit 400, the receiving unit 401 and the second sending unit 402 may be input-output interfaces, or also called communication interfaces, or interface circuits, or interfaces, etc. Alternatively, the sending unit may be an output interface, the receiving unit may be an input interface, and the sending unit and the receiving unit may be integrated into one unit, such as an input-output interface. See Fig.12 , Fig.12 is a schematic diagram of the structure of another communication device provided in an embodiment of the present application. Fig.12 As shown, the communication device 60 includes a logic circuit 901 and an interface 902. That is, the above-mentioned processing unit 100 or processing unit 302 can be implemented by the logic circuit 901, and the sending unit 101, the receiving unit 102, the receiving unit 200, the sending unit 201, the first sending unit 300, the receiving unit 301, the second sending unit 303, the first sending unit 400, the receiving unit 401 and the second sending unit 402 can be implemented by the interface 902. Among them, the logic circuit 901 can be a chip, a processing circuit, an integrated circuit or a system on chip (SoC) chip, etc., and the interface 902 can be a communication interface, an input and output interface, a pin, etc. Exemplarily, Fig.12 The communication device 60 is taken as an example of a chip, and the chip includes a logic circuit 901 and an interface 902 .

[0290] In the embodiment of the present application, the logic circuit and the interface may also be coupled to each other. The embodiment of the present application does not limit the specific connection method between the logic circuit and the interface.

[0291] Exemplarily, when the communication device 60 is used to execute the method, function or step executed by the above-mentioned communication device 10, the logic circuit 901 is used to release the DRB of all first sessions activated on the first system; the interface 902 is used to send a registration request message to the first network device of the second system; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all the first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and to initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems; the interface 902 is also used to receive a first message; the first message includes information of one or more DRBs established by the access network device of the second system for the one or more second sessions.

[0292] Exemplarily, when the communication device 60 is used to execute the steps, methods or functions executed by the above-mentioned communication device 20, the interface 902 is used to receive a registration request message sent by a terminal device; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and to initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems; the interface 902 is also used to send an indication message to an access network device of the second system; the indication message is used to instruct the access network device to establish one or more DRBs for the one or more second sessions.

[0293] Exemplarily, when the communication device 60 is used to execute the steps, methods or functions executed by the above-mentioned communication device 30, interface 902 is used to send a first service request to the first network device of the second system; the first service request is a request to establish one or more DRBs for a target session; interface 902 is also used to receive a session modification message from the second network device of the second system when a response message to the first service request is not received; the session modification message is used to instruct the terminal device to modify the target session; logic circuit 901 is used to modify the target session in response to the session modification message; interface 902 is also used to send a modification completion message to the second network device of the second system.

[0294] Exemplarily, when the communication device 60 is used to execute the steps, methods or functions executed by the above-mentioned communication device 40, interface 902 is used to send a registration request message to the first network device of the second system; interface 902 is also used to receive a registration acceptance message from the first network device of the second system at a first moment; interface 902 is also used to send a service request to the first network device of the second system at a second moment; the service request is a request to establish one or more DRBs for a target session, and the difference between the first moment and the second moment is greater than or equal to a preset value.

[0295] It is understood that for the specific description of the logic circuit 901 and the interface 902, reference can also be made to the above Figure 7 , Figure 8 , Fig. 9 or Fig.10 The description of the processing unit, sending unit and receiving unit shown will not be repeated here.

[0296] It can be understood that the communication device shown in the embodiment of the present application can implement the method provided in the embodiment of the present application in the form of hardware, or can implement the method provided in the embodiment of the present application in the form of software, etc., and the embodiment of the present application is not limited to this.

[0297] for Fig.12 The specific implementation methods of the various embodiments shown can also refer to the above embodiments, which will not be described in detail here.

[0298] The present application also provides a wireless communication system, which includes a communication device 10 and a communication device 20. The communication device 10 and the communication device 20 can be used to perform any of the above embodiments (such as Figure 4a , Figure 4b or Figure 4c ) in the method; or comprising a communication device 30, the communication device 30 can be used to perform any of the foregoing embodiments (such as Figure 5 ) in the method; or comprising a communication device 40, the communication device 40 can be used to perform any of the foregoing embodiments (such as Figure 6 ) in the method.

[0299] In addition, the present application also provides a computer program, which is used to implement the operations and / or processing performed by the communication device 10, the communication device 20, the communication device 30, or the communication device 40 in the method provided by the present application.

[0300] The present application also provides a readable storage medium, which stores computer code. When the computer code runs on a computer, the computer executes the operations and / or processing performed by the communication device 10, the communication device 20, the communication device 30, or the communication device 40 in the method provided by the present application.

[0301] The present application also provides a computer program product, which includes a computer code or a computer program. When the computer code or the computer program runs on a computer, the operations and / or processing performed by the communication device 10, the communication device 20, the communication device 30, or the communication device 40 in the method provided by the present application are executed.

[0302] The present application also provides a chip system, which includes a processor for supporting a device to implement any of the above embodiments (such as Figure 4a , Figure 4b , Figure 4c , Figure 5 or Figure 6 ) functions involved, for example, generating or processing the information involved in the above communication method. In one possible design, the chip system also includes a memory, which is used to store program instructions and data necessary for the device. The chip system can be composed of a chip or a chip and other discrete devices.

[0303] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0304] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the order of the actions described, because according to the present application, some steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0305] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0306] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the technical effects of the solutions provided in the embodiments of the present application.

[0307] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0308] 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 present application is essentially or partly contributed 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 readable storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned readable storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0309] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope 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 terminal device, the method comprises: releasing data radio bearers (DRBs) of all first sessions activated on the first system; Sending a registration request message to a first network device of a second system; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all the first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems; Receive a first message; the first message includes information about one or more DRBs established by the access network device of the second system for the one or more second sessions.

2. The method according to claim 1, characterized in that Before releasing the DRBs of all first sessions activated on the first system, the method further includes: Receive a redirection indication message from an access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system.

3. The method according to claim 1, characterized in that Before releasing the DRBs of all first sessions activated on the first system, the method further includes: Receive a switching indication message from an access network device of the first system, where the switching indication message is used to instruct the terminal device to switch from the first system to the second system.

4. The method according to any one of claims 1 to 3, characterized in that The session information of the one or more second sessions is carried in the uplink data status field or the reserved field of the registration request message.

5. The method according to any one of claims 1 to 4, characterized in that After receiving the first message, the method further includes: receiving a session modification message from a second network device of the second system; the session modification message is used to instruct the terminal device to modify a target second session, where the target second session is a session in the one or more second sessions; In response to the session modification message, the target second session is modified, and a modification completion message is sent to the second network device of the second system.

6. The method according to any one of claims 1 to 5, characterized in that The first system is a third-generation mobile communication system 3G, and the second system is a fourth-generation mobile communication system 4G; or, the first system is 4G, and the second system is 3G or a fifth-generation mobile communication system 5G; or, the first system is 5G, and the second system is 4G.

7. A communication method, characterized in that: Applied to a first network device, the method comprises: receiving a registration request message sent by a terminal device; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems; An indication message is sent to an access network device of the second system; the indication message is used to instruct the access network device to establish one or more DRBs for the one or more second sessions.

8. The method according to claim 7, characterized in that The first system is 3G and the second system is 4G; or, the first system is 4G and the second system is 3G or 5G; or, the first system is 5G and the second system is 4G.

9. A communication method, characterized in that: Applied to a terminal device, the method comprises: Sending a first service request to a first network device of a second system; the first service request is a request to establish one or more DRBs for a target session; In the case where a response message to the first service request is not received, receiving a session modification message from a second network device of the second system; the session modification message is used to instruct the terminal device to modify the target session; The target session is modified in response to the session modification message, and a modification completion message is sent to the second network device of the second system.

10. The method according to claim 9, characterized in that After sending the modification completion message to the second network device of the second system, the method further includes: A second service request is sent to the first network device of the second system, where the second service request is a request to establish one or more DRBs for the modified target session.

11. The method according to any one of claims 9 to 10, characterized in that: Before sending the first service request to the first network device of the second system, the method further includes: receiving a redirection indication message or a switching indication message from an access network device of a first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system, and the switching indication message is used to instruct the terminal device to switch from the first system to the second system; the first system and the second system are different communication systems; Sending a registration request message to the first network device of the second system; A registration acceptance message is received from the first network device of the second system.

12. The method according to claim 11, characterized in that The receiving a registration acceptance message from the first network device of the second system includes: receiving, at a first moment, a registration acceptance message from a first network device of the second system; The sending the first service request to the first network device of the second system includes: The first service request is sent to the first network device of the second system at a second moment; and the difference between the first moment and the second moment is greater than or equal to a preset value.

13. The method according to claim 12, characterized in that The preset value is greater than or equal to 10 milliseconds.

14. The method according to any one of claims 9 to 13, characterized in that The first system is 3G and the second system is 4G; or, the first system is 4G and the second system is 3G or 5G; or, the first system is 5G and the second system is 4G.

15. A communication method, characterized in that: Applied to a terminal device, the method comprises: Sending a registration request message to the first network device of the second system; receiving, at a first moment, a registration acceptance message from a first network device of the second system; Send a service request to the first network device of the second system at a second moment; the service request is a request to establish one or more DRBs for a target session, and the difference between the first moment and the second moment is greater than or equal to a preset value.

16. The method according to claim 15, characterized in that The preset value is greater than or equal to 10 milliseconds.

17. The method according to any one of claims 15 to 16, characterized in that Before sending the registration request message to the first network device of the second system, the method further includes: A redirection indication message or a switching indication message is received from an access network device of a first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system, and the switching indication message is used to instruct the terminal device to switch from the first system to the second system; the first system and the second system are different communication systems.

18. The method according to any one of claims 15 to 17, characterized in that The first system is 3G and the second system is 4G; or, the first system is 4G and the second system is 3G or 5G; or, the first system is 5G and the second system is 4G.

19. A communication device, characterized in that: include: A processing unit, configured to release the DRBs of all first sessions activated on the first system; A sending unit, configured to send a registration request message to a first network device of a second system; the registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all the first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems; A receiving unit, configured to receive a first message; The first message includes information of one or more DRBs established by the access network device of the second system for the one or more second sessions.

20. The device according to claim 19, characterized in that Before the processing unit releases the DRBs of all first sessions activated on the first system, the receiving unit is further used to receive a redirection indication message from an access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system.

21. The device according to claim 19, characterized in that Before the processing unit releases the DRBs of all first sessions activated on the first system, the receiving unit is further used to receive a switching indication message from an access network device of the first system, wherein the switching indication message is used to instruct the terminal device to switch from the first system to the second system.

22. The device according to any one of claims 19 to 21, characterized in that The session information of the one or more second sessions is carried in the uplink data status field or the reserved field of the registration request message.

23. The device according to any one of claims 19 to 22, characterized in that After the receiving unit receives the first message, the receiving unit is further used to receive a session modification message from a second network device of the second system; the session modification message is used to instruct the terminal device to modify a target second session, where the target second session is a session in the one or more second sessions; The processing unit is further configured to modify the target second session in response to the session modification message; The sending unit is further configured to send a modification completion message to the second network device of the second system.

24. The device according to any one of claims 19 to 23, characterized in that The first system is 3G and the second system is 4G; or, the first system is 4G and the second system is 3G or 5G; or, the first system is 5G and the second system is 4G.

25. A communication device, characterized in that: include: A receiving unit, configured to receive a registration request message sent by a terminal device; The registration request message includes session information of one or more second sessions, and the one or more second sessions are mapped one-to-one with all first sessions activated by the terminal device on the first system; the registration request message is used to initiate a registration request and initiate a request to establish a DRB for the one or more second sessions; the first system and the second system are different communication systems; A sending unit is used to send an indication message to the access network device of the second system; the indication message is used to instruct the access network device to establish one or more DRBs for the one or more second sessions.

26. The device as claimed in claim 25, characterized in that The first system is 3G and the second system is 4G; or, the first system is 4G and the second system is 3G or 5G; or, the first system is 5G and the second system is 4G.

27. A communication device, characterized in that: include: A first sending unit, configured to send a first service request to a first network device of a second system; The first service request is a request to establish one or more DRBs for a target session; a receiving unit, configured to receive a session modification message from a second network device of the second system when no response message to the first service request is received; the session modification message is used to instruct the terminal device to modify the target session; a processing unit, configured to modify the target session in response to the session modification message; The second sending unit is used to send a modification completion message to the second network device of the second system.

28. The device according to claim 27, characterized in that After the second sending unit sends a modification completion message to the second network device of the second system, the first sending unit is also used to send a second service request to the first network device of the second system, where the second service request is a request to establish one or more DRBs for the modified target session.

29. The device according to any one of claims 27-28, characterized in that Before the first sending unit sends the first service request to the first network device of the second system, the receiving unit is further used to receive a redirection indication message or a switching indication message from the access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system, and the switching indication message is used to instruct the terminal device to switch from the first system to the second system; the first system and the second system are different communication systems; The first sending unit is further configured to send a registration request message to the first network device of the second system; The receiving unit is further configured to receive a registration acceptance message from the first network device of the second system.

30. The device according to claim 29, characterized in that The receiving unit is specifically used for: receiving, at a first moment, a registration acceptance message from a first network device of the second system; The first sending unit is specifically configured to: The first service request is sent to the first network device of the second system at a second moment; and the difference between the first moment and the second moment is greater than or equal to a preset value.

31. The device according to claim 30, characterized in that The preset value is greater than or equal to 10 milliseconds.

32. The device according to any one of claims 27 to 31, characterized in that The first system is 3G and the second system is 4G; or, the first system is 4G and the second system is 3G or 5G; or, the first system is 5G and the second system is 4G.

33. A communication device, characterized in that: include: A first sending unit, configured to send a registration request message to a first network device of a second system; A receiving unit, configured to receive a registration acceptance message from a first network device of the second system at a first moment; The second sending unit is used to send a service request to the first network device of the second system at a second moment; the service request is a request to establish one or more DRBs for a target session, and the difference between the first moment and the second moment is greater than or equal to a preset value.

34. The device according to claim 33, characterized in that The preset value is greater than or equal to 10 milliseconds.

35. The device according to any one of claims 33 to 34, characterized in that Before the first sending unit sends a registration request message to the first network device of the second system, the receiving unit is also used to receive a redirection indication message or a switching indication message from the access network device of the first system; the redirection indication message is used to instruct the terminal device to redirect from the first system to the second system, and the switching indication message is used to instruct the terminal device to switch from the first system to the second system; the first system and the second system are different communication systems.

36. The device according to any one of claims 33 to 35, characterized in that The first system is 3G and the second system is 4G; or, the first system is 4G and the second system is 3G or 5G; or, the first system is 5G and the second system is 4G.

37. A communication device, characterized in that: It includes a processor and an interface circuit, wherein the interface circuit is used to receive signals from other communication devices and transmit them to the processor or send signals from the processor to other communication devices, and the processor is used to implement the method as described in any one of claims 1-18 through a logic circuit or executing code instructions.

38. A computer-readable storage medium, characterized in that: The storage medium stores a computer program or an instruction. When the computer program or the instruction is executed by the communication device, the method according to any one of claims 1 to 18 is implemented.

39. A computer program, characterized in that The computer program comprises instructions, and when the computer program is executed by a communication device, the method according to any one of claims 1 to 18 is implemented.

40. A chip system, characterized in that: The chip system includes a processor for supporting the device to implement the functions involved in the method as described in any one of claims 1-18.

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