Switching methods, apparatuses, storage medium and program product

Abstract

Switching methods, apparatuses, a storage medium, and a program product. A method comprises: a source access network device sends a switching request message to a target access network device, the switching request message being used to request switching a first terminal to the target access network device, wherein the first terminal is connected to the source access network device via a first path and a second path, the first path is a direct path between the first terminal and the source access network device, and the second path is an indirect path via which the first terminal is connected to the source access network device by means of a second terminal; and receiving a switching request response from the target access network device.

Description

Handover method, device, storage medium and program product

[0001] The present disclosure claims priority to Chinese Patent Application No. 202411332505.8, filed on September 20, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to the field of communication technology, and in particular to a handover method, device, storage medium and program product. BACKGROUND

[0003] Terminal aggregation (UE Aggregation) is a terminal cooperation technology that allows multiple terminals to share resources through a direct link, thereby improving the uplink capability of a single terminal. Here, a remote terminal (Remote UE) can connect to a base station (next generation node B, gNB) through a relay terminal (Relay UE) or an aggregated terminal (Aggregated UE), thereby accessing the network. In some scenarios, such as wireless transmission service load adjustment, active operation maintenance, device failure, terminal movement, etc., the remote terminal may need to switch from one base station to another. SUMMARY

[0004] In one aspect, the present disclosure provides a handover method applied to a source access network device, the method comprising:

[0005] sending a handover request message to a target access network device, the handover request message being used to request switching a first terminal to the target access network device; wherein the first terminal is connected to the source access network device through a first path and a second path, the first path being a direct path between the first terminal and the source access network device, and the second path being an indirect path through a second terminal for connecting the first terminal to the source access network device;

[0006] receiving a handover request response from the target access network device.

[0007] In another aspect, the present disclosure also provides a handover method applied to a target access network device, the method comprising:

[0008] receiving a handover request message from a source access network device, the handover request message being used to request switching a first terminal to the target access network device, and being used to request maintaining a direct path connected during a handover process, and / or maintaining an indirect path connected during the handover process;

[0009] sending a handover request response to the source access network device, the handover request response comprising second indication information, the second indication information being used to indicate whether to keep the direct path connected and / or whether to keep the indirect path connected during the handover process.

[0010] In another aspect, the disclosure also provides a handover method applied to a first terminal, the method comprising:

[0011] receiving second indication information from the source access network device, the second indication information being used to indicate that the first terminal is handed over to the target access network device and that at least one path between the first terminal and the source access network device is kept connected during the handover process;

[0012] establishing a connection with the target access network device based on the second indication information.

[0013] In another aspect, the disclosure also provides a handover method applied to a second terminal, the method comprising:

[0014] keeping data transmission of an indirect path between the first terminal and the source access network device or keeping data transmission of an indirect path between the first terminal and the target access network device during the process in which the first terminal is handed over from the source access network device to the target access network device.

[0015] In another aspect, the disclosure provides a communication apparatus applied to a source access network device, the apparatus comprising:

[0016] a sending module configured to send a handover request message to a target access network device, the handover request message being used to request that a first terminal is handed over to the target access network device; wherein the first terminal is connected to the source access network device through a first path and a second path, the first path being a direct path between the first terminal and the source access network device, and the second path being an indirect path through which the first terminal is connected to the source access network device via a second terminal;

[0017] a receiving module configured to receive a handover request response from the target access network device.

[0018] In another aspect, the disclosure also provides a communication apparatus applied to a target access network device, the apparatus comprising:

[0019] a receiving module configured to receive a handover request message from a source access network device, the handover request message being used to request that a first terminal is handed over to the target access network device, and being used to request that a direct path is kept connected during the handover process and / or that an indirect path is kept connected during the handover process;

[0020] The sending module is configured to send a handover request response to the source access network device, the handover request response comprising second indication information, the second indication information being used to indicate whether to keep the direct path connected and / or whether to keep the indirect path connected during the handover process.

[0021] In another aspect, the disclosure also provides a communication apparatus applied to the first terminal, the apparatus comprising:

[0022] The receiving module is configured to receive second indication information from the source access network device, the second indication information being used to indicate that the first terminal is handed over to the target access network device and at least one path between the first terminal and the source access network device is kept connected during the handover process.

[0023] The processing module is configured to establish a connection with the target access network device based on the second indication information.

[0024] In another aspect, the disclosure also provides a communication apparatus applied to the second terminal, the apparatus comprising:

[0025] The processing module is configured to keep the data transmission of the indirect path between the first terminal and the source access network device or keep the data transmission of the indirect path between the first terminal and the target access network device during the process that the first terminal is handed over from the source access network device to the target access network device.

[0026] In another aspect, the disclosure also provides a communication apparatus, comprising a processor and a memory, the memory storing instructions executable by the processor, and the processor is configured to execute the instructions to enable the communication apparatus to implement any of the above methods.

[0027] In another aspect, the disclosure also provides a computer readable storage medium storing computer instructions, and the computer instructions, when executed on a computer, enable the computer to implement any of the above methods.

[0028] In another aspect, the disclosure also provides a computer program product comprising computer instructions, and the computer instructions, when executed on a computer, enable the computer to implement any of the above methods. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the disclosure, the following will briefly introduce the drawings needed to be used in some embodiments of the disclosure. Obviously, the drawings described in the following description are only some drawings of the embodiments of the disclosure, and other drawings can also be obtained by those skilled in the art according to these drawings.

[0030] FIG. 1 is a schematic diagram of an architecture of a communication system according to an embodiment.

[0031] FIG. 2 is a schematic diagram of a connection mode according to an embodiment.

[0032] FIG. 3 is a flowchart of a switching method according to an embodiment.

[0033] FIG. 4 is a schematic diagram of another connection mode according to an embodiment.

[0034] FIG. 5 is a schematic diagram of yet another connection mode according to an embodiment.

[0035] FIG. 6 is a schematic diagram of yet another connection mode according to an embodiment.

[0036] FIG. 7 is a flowchart of another switching method according to an embodiment.

[0037] FIG. 8 is a flowchart of yet another switching method according to an embodiment.

[0038] FIG. 9 is a flowchart of yet another switching method according to an embodiment.

[0039] FIG. 10 is a block diagram of a communication apparatus according to an embodiment.

[0040] FIG. 11 is a block diagram of another communication apparatus according to an embodiment.

[0041] FIG. 12 is a block diagram of yet another communication apparatus according to an embodiment.

[0042] FIG. 13 is a block diagram of yet another communication apparatus according to an embodiment.

[0043] FIG. 14 is a block diagram of yet another communication apparatus according to an embodiment. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present disclosure.

[0045] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an open, inclusive sense as "including, but not limited to." As used throughout the description and the claims, the term "one embodiment," "some embodiments," "an exemplary embodiment," "example," "specific example," or "some examples" means that a particular feature, structure, material, or characteristic is included in at least one embodiment or example of the disclosure, but not necessarily all embodiments or examples. The appearance of the phrases "in one embodiment" or "in some embodiments" in various places in the specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0046] The terms "first", "second", etc. are used only to describe the purpose and are not to be construed as indicating or implying relative importance or a specific number of the technical features indicated. Thus, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the disclosure, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0047] In the embodiments of the disclosure, the words "exemplary" or "for example" are used to mean serving as an example, instance, or illustration. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of the disclosure should not be construed as being more preferred or advantageous than other embodiments or design schemes. Rather, the use of the words "exemplary" or "for example" is intended to present concepts in a concrete manner.

[0048] In addition, the use of "based on" means open and inclusive, because the process, step, calculation or other action "based on" one or more stated conditions or values can be based on additional conditions or values beyond those stated in practice.

[0049] The terminal (user equipment, UE) aggregation technology, also known as UE aggregation, Remote UE can be connected to the base station through a direct link, and connected to the network through another UE (Relay UE or Aggregated UE) using non-standardized UE-UE interconnection. UE aggregation can provide terminals with applications that require high uplink bit rates, for example, in the case of ordinary UEs at the edge of the cell being limited by uplink UE transmission power and unable to achieve the required bit rate, this technology can be used to improve. And UE aggregation can also improve the reliability, stability and reduce the delay of services. In the case of channel conditions deteriorating for a terminal, another terminal can also be used to reduce the degree of traffic performance instability caused by changes in channel conditions.

[0050] Due to the above-mentioned technology needs to make the Remote UE and the Relay UE under the same gNB, when the Remote UE performs cross-base station handover, the reliability, stability and delay of the service cannot be guaranteed. This problem is particularly prominent in high-demand scenarios such as wireless vehicle networking, because the terminals (such as vehicle terminals) in vehicle networking will frequently cross different base station coverage ranges during driving, resulting in frequent handovers. Each handover may cause a relatively long service interruption time, which poses a challenge to the real-time service requirements in vehicle networking. The service interruption time caused by handover in the actual network is at least 70ms, usually more than 100ms, and the interruption time is relatively long. Among the current technologies for reducing handover interruption time, dual active protocol stack (DAPS) is an effective method, but this technology has high requirements for terminals, especially when switching between same-frequency cells, which is not very suitable and has low universality. The UE aggregation technology provides a new way to solve the mobility problem by aggregating the resources of multiple UEs (including Remote UE and Relay UE), which can reduce the requirements on a single UE to some extent, while improving the overall reliability and stability. In the cross-base station handover process of terminal aggregation, how to reduce the network interruption time and improve service continuity is a technical problem that needs to be solved in the related field.

[0051] Therefore, the present disclosure provides a handover method. Based on the method, a source access network device can send a handover request message to a target access network device, the handover request message being used to request to hand over a first terminal to the target access network device; wherein the first terminal is connected to the source access network device through a first path and a second path, the first path being a direct path between the first terminal and the source access network device, and the second path being an indirect path through a second terminal for the first terminal to connect to the source access network device; and the source access network device receives a handover request response from the target access network device. In this way, the source access network device and the target access network device can determine, through signaling interaction, to maintain data transmission of the direct path during the handover process and / or to maintain data transmission of the indirect path during the handover process. Thus, during the terminal aggregation cross access network device handover process, the terminal can maintain data transmission with the source access network device during the process of being handed over to the target access network device based on the handover configuration of the access network device. Compared with completely disconnecting the connection with the source access network device and then being handed over to the target access network device, this can reduce the network interruption time of the terminal, thereby maintaining service continuity during cross access network device handover, and also applicable to terminal mobility scenarios.

[0052] The technical solutions provided by the embodiments of the present disclosure can be applied to various mobile communication networks, for example, a long term evolution (LTE) system, various versions based on LTE evolution, a 5th-generation mobile communication technology (5G) system (including but not limited to a new radio (NR) mobile communication system environment, an ambient internet of things (Ambient IoT), and the like). In addition, the signal transmission method provided by the embodiments of the present disclosure can also be applied to a future-oriented communication system (for example, a 6G communication system, and the like) or a network of a variety of communication fusion systems, and the like, which are not limited by the embodiments of the present disclosure.

[0053] FIG. 1 shows an architecture schematic diagram of a communication system provided by an embodiment of the present disclosure. As shown in FIG. 1, the communication system includes one or more terminals 10 and one or more access network devices 20.

[0054] In some embodiments, the terminal 10 can be a device with wireless transceiver function, which can be deployed on land, including indoor or outdoor, handheld, wearable or vehicle-mounted; can also be deployed on water surface (such as ships, etc.); can also be deployed in the air (such as airplanes, balloons and satellites, etc.). The terminal can be a mobile phone, a tablet computer (Pad), a computer with wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. The embodiments of the present disclosure do not limit the application scenarios. The terminal can also be referred to as a user, a user equipment (UE), an access terminal, a UE unit, a UE station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a UE terminal, a wireless communication device, a UE agent or a UE apparatus, etc. The embodiments of the present disclosure do not limit this.

[0055] In some embodiments, the access network device 20 is configured to provide wireless access services for a plurality of terminals, which can be a base station. Specifically, one base station provides a service coverage area (also referred to as a cell). The terminal entering the area can communicate with the base station through a wireless signal to accept the wireless access service provided by the base station.

[0056] In some embodiments, the access network device 20 can be a base station or an evolved node B (eNB or eNodeB) in long term evolution (LTE) or long term evolution advanced (LTEA), a base station device in a 5G network, or a base station in a future communication system, etc. The base station can include various macro base stations, micro base stations, home base stations, wireless remote, reconfigurable intelligent surface (RIS), routers, wireless fidelity (WIFI) devices, and various network side devices.

[0057] In some embodiments, the one or more terminals 10 described above can include Remote UEs and multi-purpose relay user equipments (MP Relay UEs). As shown in FIG. 2, with UE aggregation technology, a Remote UE can be indirectly connected with the access network device 20 through an MP Relay UE of non-standardized UE-UE interconnection (path 2), and directly connected with the access network device 20 through a Uu interface (path 1).

[0058] It should be noted that FIG. 1 is only an exemplary architecture diagram, the number of devices included in FIG. 1, and the names of the respective devices are not limited, and in addition to the devices shown in FIG. 1, the communication system can also include other devices, such as core network devices.

[0059] The application scenarios of the embodiments of the present disclosure are not limited. The system architecture and business scenarios described in the embodiments of the present disclosure are for more clearly illustrating the technical solutions of the embodiments of the present disclosure, and do not constitute a limitation on the technical solutions provided by the embodiments of the present disclosure. It is known to those skilled in the art that with the evolution of network architecture and the appearance of new business scenarios, the technical solutions provided by the embodiments of the present disclosure are also applicable to similar technical problems.

[0060] The embodiments provided by the present disclosure will be described in detail below with reference to the accompanying drawings.

[0061] As shown in FIG. 3, the present disclosure provides a switching method, which includes:

[0062] S101, the source access network device sends a switching request message to the target access network device.

[0063] Here, the switching request message is used to request switching the first terminal to the target access network device.

[0064] In some embodiments, the first terminal is connected with the source access network device through a first path and a second path, the first path is a direct path between the first terminal and the source access network device, and the second path is an indirect path through which the first terminal is connected with the source access network device through a second terminal. For example, taking FIG. 2 described above as an example, the first path here is path 1 in FIG. 2, the second path is path 2 in FIG. 2, the first terminal is a Remote UE, and the second terminal is an MP Relay UE.

[0065] In some embodiments, the switching request message is also used to request maintaining data transmission of the direct path during the switching process, and / or maintaining data transmission of the indirect path during the switching process.

[0066] In some embodiments, in the inter-access network device handover process of terminal aggregation, the Remote UE switches to the target access network device first, and then the Relay UE switches to the target access network device. Alternatively, the Relay UE switches to the target access network device first, and then the Remote UE switches to the target access network device.

[0067] S102, the target access network device sends a handover request response to the source access network device.

[0068] In some embodiments, the handover request response includes first indication information, which is used to indicate whether to keep the direct path data transmission and / or whether to keep the indirect path data transmission in the handover process.

[0069] S103, the source access network device sends second indication information to the first terminal.

[0070] Here, the second indication information is used to indicate that the first terminal switches to the target access network device and keeps the connection between the first terminal and the source access network device in the handover process.

[0071] In some embodiments, the second indication information includes at least one of the following: target cell information, indication information of whether to keep the direct path connection in the handover process, and indication information of whether to keep the indirect path connection.

[0072] Here, the target cell information includes related information of the target cell to which the first terminal is to switch, such as the identifier of the target cell, the target cell being the cell-radio network temporary identifier (C-RNTI) allocated for the first terminal, the handover timer (such as T304), and the random access resource configuration. Here, the T304 is used to control the time of the terminal in the handover process.

[0073] Exemplarily, the source access network device can send the handover related configuration information, i.e., the second indication information, to the first terminal through the radio resource control (RRC) reconfiguration message in the case of accepting the handover request response from the source access network device, so that the first terminal switches to the target access network device based on the second indication information.

[0074] In some embodiments, the second indication information is terminal-granularity indication information. Alternatively, the second indication information is data radio bearer (DRB)-granularity indication information. That is, the first indication information can be per UE configuration or per DRB configuration.

[0075] S104, the first terminal establishes a connection with the target access network device based on the second indication information.

[0076] In an example, in the case that the Remote UE switches to the target access network device first and then the Relay UE switches to the target access network device, the second indication information can specifically indicate the first terminal to stop data transmission of the first path and keep data transmission of the second path, and connect with the target access network device through a third path. Here, the third path is a path in which the first terminal directly connects with the target access network device.

[0077] Exemplarily, as shown in FIG. 4, based on the second indication information, the Remote UE can stop data transmission of the path 1 and keep data transmission between the path 2 and the source access network device (source gNB), and connect with the target access network device (target gNB) through a path 3 (i.e., the third path), the path 3 including: the first terminal <-> the target access network device.

[0078] In another example, in the case that the Remote UE switches to the target access network device first and then the Relay UE switches to the target access network device, the second indication information can specifically indicate to stop data transmission of the first path and keep data transmission of the second path, and access the target access network device through an indirect path. Exemplarily, the path of the first terminal to the target access network device can be: “the first terminal <-> the second terminal <-> the source access network device <-> the target access network device”, i.e., the first terminal connects with the second terminal, the second terminal also connects with the source access network device, and the source access network device also connects with the target access network device. Since the second terminal has not switched to the target access network device, it connects with the source access network device, and at this time, data transmission can be forwarded through the source access network device.

[0079] In yet another example, in the case that the Relay UE switches to the target access network device first and then the Remote UE switches to the target access network device, the second indication information can specifically indicate the first terminal to keep data transmission of the first path, and connect with the target access network device through a fourth path, the fourth path being a path in which the first terminal connects with the target access network device through a target terminal. Here, the target terminal includes an aggregated terminal that has switched to the target access network device, and the target terminal can also be the second terminal or other possible terminal.

[0080] Exemplarily, as shown in FIG. 5, the Relay UE has switched to the target access network device, at this time, the path 2 has been disconnected, based on the second indication information, the Remote UE can maintain the data transmission between the path 1 and the source access network device. In addition, the Remote UE can also connect with the target access network device through a path 4 (i.e., the fourth path), the path 4 includes: "first terminal <-> target terminal <-> target access network device", that is, the first terminal connects with the target terminal, and the target terminal also connects with the target access network device.

[0081] In another example, in the case that the Relay UE switches to the target access network device first, and then the Remote UE switches to the target access network device, the second indication information is specifically used to instruct the first terminal to stop the data transmission of the first path, and maintain the data transmission between the fifth path and the source access network device, and connect with the target access network device through the third path. Here, the fifth path is a path through which the first terminal indirectly connects with the source access network device through the target terminal and the target access network device. The target terminal includes the aggregated terminal that has switched to the target access network device, and the target terminal can also be the second terminal or other possible terminal.

[0082] Exemplarily, as shown in FIG. 6, the Relay UE has switched to the target access network device, at this time, the path 2 has been disconnected, based on the second indication information, the Remote UE can stop the data transmission between the path 1 and the source access network device. In addition, the Remote UE can also connect with the source access network device through a path 5 (i.e., the fifth path), and connect with the target access network device through a path 3. Here, the path 5 includes: "first terminal <-> target terminal <-> target access network device <-> source access network device", that is, the first terminal connects with the target terminal, the target terminal also connects with the target access network device, and the target access network device also connects with the source access network device. The path 3 includes: "first terminal <-> target access network device", that is, the first terminal connects with the target access network device.

[0083] Based on the technical solutions provided in the present disclosure, the source access network device and the target access network device can determine, through signaling interaction, to maintain the data transmission of the direct path in the switching process, and / or to maintain the data transmission of the indirect path in the switching process. Thus, in the terminal aggregation cross-access network device switching process, the terminal can maintain the data transmission with the source access network device in the process of switching to the target access network device based on the switching configuration of the access network device, compared with completely disconnecting the connection with the source access network device and then switching to the target access network device, this can reduce the network interruption time of the terminal, thereby maintaining the service continuity when switching across access network devices, and also applicable to the terminal mobility scenario.

[0084] In the case that the Remote UE switches to the target access network device first, and then the Relay UE switches to the target access network device, as shown in FIG. 7, the disclosure also provides another switching method, including:

[0085] S201, the first terminal sends a measurement report to the source access network device.

[0086] Exemplarily, the connection between the first terminal and the source access network device can refer to the example shown in FIG. 2, which will not be described here again. In the process that the first terminal and its aggregated terminal (the second terminal) gradually move away from the source access network device to the position of the target access network device, if the first terminal or the second terminal triggers the measurement report, the first terminal or the second terminal can perform measurement and send the obtained measurement report to the source access network device. Here, the measurement report can include the serving cell measurement result, the candidate cell measurement result, etc. Further, after receiving the measurement report, the source access network device can determine whether to switch the terminal (the first terminal and the second terminal).

[0087] S202, the source access network device sends a switching request message to the target access network device.

[0088] Here, the detailed description of step S202 can refer to the description in step S101 described above.

[0089] Exemplarily, in the case that the source access network device determines to switch the first terminal, the source access network device can send a switching request message (HANDOVER REQUEST) to the target access network device. In order to retain the data transmission of the original direct path (the first path) or the original indirect path (the second path) in the switching process, the source access network device can add indication information of whether to retain the path on the source access network device side in the switching request message, for example, at least one of the following: indication information of retaining the direct path (directPathMaintain), indication information of retaining the indirect path (indirectPathMaintain).

[0090] In the case that the Remote UE switches to the target access network device first, and then the Relay UE switches to the target access network device, the indication information can include the indication information of retaining the indirect path. At this time, the first terminal is configured to stop the data transmission of the second path, and / or the second terminal has been configured to switch to the target access network device.

[0091] In some embodiments, the information (the indication information of whether to keep the source access network device side path) in the handover request message described above is indication information in a terminal granularity, or indication information in a data radio bearer granularity. That is, the indication information of whether to keep the source access network device side path can be configured per UE or per DRB. For example, in the case where the information in the handover request message is indication information in a terminal granularity, all bearers of the terminal related to the direct path or the indirect path apply the indication information. In the case where the information in the handover request message is indication information in a DPB granularity, only the related DRB applies the indication information.

[0092] S203, the target access network device sends a handover request response to the source access network device.

[0093] Here, the detailed description of step S203 can refer to the description in step S102 described above.

[0094] Exemplarily, the target access network device receives the handover request message and can perform admission control on the first terminal, so as to determine whether to allow the first terminal to access the network, that is, whether to allow the first terminal to switch from the source access network device to the target access network device.

[0095] In the case where the target access network device allows the first terminal to switch, the target access network device can send a handover request response (HANDOVER REQUEST ACKNOWLEDGE) to the source access network device. Moreover, the target access network device can agree to keep the data transmission of part of the bearers in the original direct path or indirect path. Therefore, the handover request response sent by the target access network device to the source access network device can include indication information (that is, the first indication information in the present disclosure) of whether to keep the source access network device side path, which includes at least one of the following: indication information of agreeing to keep the data transmission of the direct path, indication information of disagreeing to keep the data transmission of the direct path, indication information of agreeing to keep the data transmission of the indirect path, and indication information of disagreeing to keep the data transmission of the indirect path.

[0096] In the case where the Remote UE switches to the target access network device first, and then the Relay UE switches to the target access network device, the indication information can include indication information of disagreeing to keep the data transmission of the direct path and indication information of agreeing to keep the data transmission of the indirect path.

[0097] In some embodiments, the first indication information is indication information in granularity of the terminal, or indication information in granularity of the data radio bearer. That is, the first indication information can be per UE configuration or per DRB configuration. In some embodiments, the source access network device and the target access network device can also negotiate to establish an Xn interface tunnel for forwarding the second terminal data during the related handover signaling interaction.

[0098] S204, the source access network device sends second indication information to the first terminal.

[0099] Here, the detailed description of step S204 can refer to the description in step S102 described above.

[0100] In some embodiments, the source access network device can send the handover related configuration information (that is, the second indication information) to the first terminal through the RRC reconfiguration message, including at least one of the target cell information and the indication information for maintaining the indirect path connection during the handover process.

[0101] Here, the target cell information includes related information of the target cell to which the first terminal is to be handed over, such as the identifier of the target cell, the cell radio network temporary identifier (C-RNTI) allocated to the first terminal, the handover timer (such as T304), and the random access resource configuration. Here, T304 is used to control the time of the terminal in the handover process.

[0102] Exemplarily, the source access network device can send the RRC reconfiguration message to the first terminal to reconfigure the RRC layer of the first terminal to adapt to the new network environment and the requirements of the target access network device after receiving the handover request response from the target access network device. Thus, the source access network device can send the second indication information to the first terminal through the RRC reconfiguration message.

[0103] At this time, the second indication information can specifically indicate the first terminal to stop the data transmission of the first path and maintain the data transmission of the second path, and connect with the target access network device through the third path. Here, the third path is the path directly connecting the first terminal and the target access network device.

[0104] The first terminal can stop Uu interface data transmission (first path) with the source access network device after receiving the second indication information. In the case that the second indication information includes indication information for maintaining the indirect path, the first terminal can continue data transmission on the N3 indirect path (second path) during the execution of the handover. Exemplarily, the uplink (UL) data transmission path: first terminal -> second terminal -> source access network device -> user plane function (UPF). The downlink (DL) data transmission path: 1) UPF -> source access network device -> second terminal -> first terminal, 2) UPF -> source access network device -> target access network device. At this time, after receiving the downlink data from the UPF, the source access network device can continue to send the data to the first terminal through the indirect path (second path) at the source access network device, and can also forward the data to the target access network device.

[0105] In some embodiments, the first terminal can also maintain independent security contexts and robust header compression (ROHC) contexts for data transmission of the second path and the third path, respectively, and maintain a common packet data convergence protocol (PDCP) sequence number allocation.

[0106] Exemplarily, during the execution of the handover, the first terminal can also maintain separate security contexts and robust header compression (ROHC) header decompression contexts for uplink transmission to the source access network device and the target access network device, respectively. The first terminal can also maintain a common uplink packet data convergence protocol (PDCP) sequence number allocation. Thus, the first terminal can receive downlink data sent by the source access network device or the target access network device using the security context and the ROHC header decompression function associated with the source access network device or the target access network device, respectively. In addition, the first terminal can also maintain the general functions of reordering, duplicate detection and discard, and delivery of PDCP service data units (SDUs) to upper layers in sequence.

[0107] S205, the first terminal sends an RRC reconfiguration complete message to the target access network device.

[0108] Exemplarily, after the first terminal successfully accesses the target access network device, the first terminal can send an RRC reconfiguration complete message to the target access network device.

[0109] In some embodiments, in the case of connecting with the target access network device through the third path, the uplink data of the first terminal can also be switched from being transmitted to the source access network device to being transmitted to the target access network device.

[0110] Illustratively, the first terminal can no longer send uplink data through the indirect path (the second path) on the source access network device side, and transfer the uplink data transmission to the target access network device. At this time, since the uplink data of the first terminal is transferred from the source access network device to the target access network device, the lossless transmission of the uplink data needs to be considered. Based on UE aggregation, it is assumed that the first terminal can determine the data packets successfully / unsuccessfully sent by the second terminal to the source access network device (for example, by receiving a radio link control (RLC) acknowledgement (ack) / negative acknowledgement (nack) on the Uu interface) according to the N3C ideal interface, so that the first terminal can transmit to the target access network device from the first data packet that is acknowledged by the source access network device RLC, thereby realizing the transfer of the uplink data transmission to the target access network device.

[0111] S206, the target access network device sends a handover success indication information to the source access network device.

[0112] Illustratively, after the target access network device receives the RRC reconfiguration complete message from the first terminal, the handover success indication information (HANDOVER SUCCESS) can be sent to the source access network device.

[0113] Further, after receiving the handover success indication information, the source access network device can stop sending downlink data on the indirect path (the second path) on the source access network device side, receive downlink data from the UPF and forward it to the target access network device. Moreover, the source access network device stops sending uplink data packets of the first terminal to the UPF, and instead forwards the uplink data packets to the target access network device.

[0114] In some embodiments, the source access network device sends a sequence number (SN) state transfer to the target access network device.

[0115] In the process of transferring downlink data from the source access network device to the target access network device, the lossless transmission of the downlink data also needs to be considered. Based on UE aggregation, it is assumed that the downlink data successfully sent by the source access network device to the second terminal is all successfully forwarded by the second terminal to the first terminal (N3C ideal interface), and thus the source access network device needs to forward the downlink data packets that are not successfully received by the second terminal to the target access network device. Alternatively, the source access network device forwards all the buffered downlink data packets of the first terminal (even if the data packets have been successfully received by the second terminal) to the target access network device.

[0116] In a case where the transmission paths of the uplink and downlink data of the first terminal are both completed to be switched, the target access network device can send an RRC reconfiguration message to the first terminal to instruct the first terminal to release the related configurations (such as security context, ROHC header compression, and the like) on the source access network device side. For example, the RRC reconfiguration message can include a source access network device side indirect path release indication and a source access network device side direct path release indication.

[0117] In some embodiments, for the aggregated terminal (the second terminal) on the source access network device side indirect path, the second terminal can continue to forward the uplink and downlink data of the first terminal until the Uu RLC channel is released or the indication information sent by the source access network device to release the first terminal is received.

[0118] In some embodiments, the second terminal is triggered to perform switching after the first terminal completes the switching. Further, after the second terminal is switched to the target access network device, the access network device can configure the first terminal to add an indirect path.

[0119] Based on the embodiment shown in FIG. 6, the Remote UE is switched to the target access network device first, and then the Relay UE is switched to the target access network device. In this case, the delay is less affected, and the data transmission of the first path is stopped and the data transmission of the second path is maintained during the switching process, and the third path is connected with the target access network device. In this way, the network interruption time of the terminal can be reduced, so that the service continuity can also be maintained when the access network devices are switched.

[0120] In a case where the Relay UE is switched to the target access network device first, and then the Remote UE is switched to the target access network device, as shown in FIG. 8, the disclosure also provides another switching method, including:

[0121] S301, the first terminal sends a measurement report to the source access network device.

[0122] Exemplarily, the connection between the first terminal and the source access network device can refer to the example shown in FIG. 2, which will not be described here again. In the process that the first terminal and its aggregated terminal (the second terminal) gradually move away from the source access network device to the position of the target access network device, if the first terminal or the second terminal triggers the measurement reporting, the first terminal or the second terminal can perform the measurement and send the obtained measurement report to the source access network device. Here, the measurement report can include the serving cell measurement result, the candidate cell measurement result, and the like. Further, after receiving the measurement report, the source access network device can determine whether to perform the switching for the terminal (the first terminal and the second terminal).

[0123] S302, the source access network device sends a handover request message to the target access network device.

[0124] Here, the detailed description of step S302 can refer to the description in step S101 described above.

[0125] Exemplarily, the Relay UE (the second terminal) switches to the target access network device first, at this time, the source access network device determines to send the handover request message to the target access network device in the case of sending the handover to the first terminal. In some embodiments, before performing step S302, the source access network device can send third indication information to the second terminal, the third indication information being used to instruct the second terminal to switch to the target access network device.

[0126] Here, during the switching of the second terminal, the first terminal can perform data transmission between the source access network device through the direct path. Before configuring the second terminal to switch, the source access network device can also configure the first terminal to release the split bearer and the indirect bearer transmitted through the indirect path, so as to configure the corresponding service data to use the Uu bearer on the direct path to transmit data.

[0127] In some embodiments, the handover request message comprises at least one of the following:

[0128] The wireless network temporary identifier of the candidate aggregation terminal, the serving cell identifier of the candidate aggregation terminal, the association relationship between the first terminal and the aggregation terminal that has switched to the target access network device, the association relationship between the first terminal and the second terminal, the identifier (such as F1AP UE ID) of the aggregation terminal that has switched to the target access network device, the identifier (such as F1AP UE ID) of the target terminal, the wireless network temporary identifier (C-RNTI) of the target terminal, and the indication information for maintaining the data transmission of the direct path in the handover process.

[0129] Exemplarily, the Relay UE switches to the target access network device first (the second path has ended the data transmission), when the source access network device decides to initiate the handover to the first terminal, if the source access network device hopes to still maintain the data transmission of the direct path (the first path) of the source access network device side during the handover of the first terminal, and connects to the target access network device through the indirect path (the fourth path), as shown in FIG. 5.

[0130] In some embodiments, the information (the indication information of whether to reserve the path of the source access network device side) in the handover request message described above is the indication information with the terminal as the granularity, or the indication information with the data radio bearer as the granularity. That is, the indication information of whether to reserve the path of the source access network device side can be per UE configuration or per DRB configuration.

[0131] S303, the target access network device sends an RRC reconfiguration message to the target terminal.

[0132] In the case where the target access network device allows the first terminal to switch, the target access network device can accept the first terminal to connect to itself through the target terminal (indicated by the source access network device), or the target access device itself can select a target terminal for the first terminal among the candidate aggregated terminals. Here, the target terminal includes an aggregated terminal that has switched to the target access network device, and the target terminal can also be a second terminal or other possible terminal.

[0133] It should be understood that FIG. 8 exemplarily illustrates the technical solutions of the embodiments of the present disclosure with the target terminal being a second terminal, and the target terminal can also be other possible aggregated terminal that has switched to the target access network device.

[0134] In some embodiments, the RRC reconfiguration message includes at least one of the following:

[0135] The wireless network temporary identifier (C-RNTI) of the first terminal, the N3C interface identifier of the first terminal, the mapping relationship between the signaling radio bearer (remote UE SRB, such as SRB0 / 1 / 2) of the first terminal and the wireless link control channel (relay UE Uu RLC channel) on the wireless interface of the target terminal, and the configuration information of the wireless link control channel on the wireless interface of the target terminal. Here, the N3C interface is an interface for control plane and user plane communication.

[0136] In some embodiments, the first terminal can also report its N3C interface to the source access network device.

[0137] S304, the target access network device sends a handover request response to the source access network device.

[0138] Here, the detailed description of step S304 can refer to the description in step S102 described above.

[0139] Exemplarily, the target access network device receives the handover request message, and can perform access control (Admission control) on the first terminal, so as to determine whether to allow it to access the network, that is, whether to allow the first terminal to switch from the source access network device to the target access network device.

[0140] If the target access network device allows the first terminal to handover, and both the target access network device and the target terminal are ready for handover, the target access network device can send a handover request response to the source access network device. For example, if the Relay UE first hands over to the target access network device, and then the Remote UE hands over to the target access network device, the first indication information in the handover request response may include indications agreeing to maintain data transmission along the direct path and indications disagreeing to maintain data transmission along the indirect path. Furthermore, this first indication information may also include the identifier of the target terminal, such as the C-RNTI / N3C interface identifier / F1AP UE ID of the target Relay UE. In this case, the first terminal is configured to stop data transmission along the second path, and / or the second terminal has been configured to handover to the target access network device.

[0141] In some embodiments, the first indication information is indication information at the terminal level, or indication information at the data radio bearer level. That is, the first indication information can be configured per UE or per DRB.

[0142] S305. The source access network device sends a second instruction message to the first terminal.

[0143] Here, for a detailed explanation of step S304, please refer to the description in step S102 above.

[0144] In some embodiments, the source access network device may send handover-related configuration information (i.e., second indication information) to the first terminal via an RRC reconfiguration message, including at least one of target cell information and indication information for maintaining direct path connectivity during handover. In this embodiment, the second indication information may further include the identifier of the target terminal, such as the target terminal's C-RNTI, the target terminal's serving cell identifier, etc.

[0145] At this time, the second instruction information can be specifically used to instruct the first terminal to maintain data transmission along the first path and to connect to the target access network device through the fourth path, whereby the fourth path is the path through which the first terminal connects to the target access network device via the target terminal.

[0146] In some embodiments, the first terminal may also maintain independent security contexts and robust header compression (ROHC) contexts for data transmission on the second and third paths, respectively, and maintain shared packet data aggregation protocol (PDCP) sequence number allocations.

[0147] Exemplarily, after receiving the second indication information, the first terminal can continue the data transmission of the direct path (first path) of the source access network device (in the case of receiving the indication information reserving the direct path). During the handover execution, the first terminal can maintain separate security contexts and ROHC header compressors for uplink transmission to the source access network device and the target access network device respectively; the UE maintains a common uplink PDCP SN allocation. And the first terminal receives the downlink data sent by the source access network device / target access network device using the security context and ROHC header decompression function associated with the source access network device / target access network device respectively, while maintaining the general functions of reordering, duplicate detection and discard, and sequentially delivering PDCP SDUs to the upper layer.

[0148] S306, the first terminal sends an RRC reconfiguration complete message to the target access network device.

[0149] Exemplarily, after the first terminal successfully accesses the target access network device, the first terminal can send an RRC reconfiguration complete message to the target access network device through the target terminal.

[0150] In some embodiments, the uplink data of the first terminal can also be switched from transmission to the source access network device to transmission to the target access network device.

[0151] Exemplarily, the target terminal can forward the signaling of the first terminal to the target access network device according to the configured mapping relationship between the signaling radio bearer (SRB) of the first terminal and the Uu RLC channel. When the target terminal successfully sends the RRC reconfiguration complete message of the first terminal to the target access network device (for example, receives the RLC ack feedback by the target access network device), the target terminal informs the first terminal through the N3C interface to stop sending uplink data to the source access network device. Thus, the first terminal transfers the uplink data to the target access network device through the target terminal.

[0152] S307, the target access network device sends a handover success indication information to the source access network device.

[0153] Exemplarily, after the target access network device receives the RRC reconfiguration complete message from the first terminal, the target access network device can send a handover success indication information to the source access network device.

[0154] Here, the detailed description of step S307 can refer to the description in step S206 described above, which will not be repeated here.

[0155] Based on the embodiment shown in FIG. 8, the Relay UE switches to the target access network device first, and then the Remote UE switches to the target access network device, and the data transmission of the first path is maintained during the switching process, and the fourth path is connected with the target access network device. In this way, the network interruption time of the terminal can be reduced, so that the service continuity can also be maintained when switching across access network devices.

[0156] In the case that the Relay UE switches to the target access network device first, and then the Remote UE switches to the target access network device, as shown in FIG. 9, the disclosure also provides another switching method, comprising:

[0157] S401, the first terminal sends a measurement report to the source access network device.

[0158] Exemplarily, the connection between the first terminal and the source access network device can refer to the example shown in FIG. 2, which will not be described here again. In the process that the first terminal and its aggregated terminal (the second terminal) gradually move away from the source access network device to the position of the target access network device, if the first terminal or the second terminal triggers the measurement reporting, the first terminal or the second terminal can perform measurement and send the obtained measurement report to the source access network device. Here, the measurement report can include the serving cell measurement result, the candidate cell measurement result, etc. Further, after receiving the measurement report, the source access network device can determine whether to switch the terminal (the first terminal and the second terminal).

[0159] S402, the source access network device sends a switching request message to the target access network device.

[0160] Here, the detailed description of step S402 can refer to the description in step S101 described above.

[0161] Exemplarily, in the case that the Relay UE (the second terminal) switches to the target access network device first, when the source access network device determines to send the switching to the first terminal, the switching request message can be sent to the target access network device. In some embodiments, before performing step S402, the source access network device can send third indication information to the second terminal, the third indication information being used to instruct the second terminal to switch to the target access network device.

[0162] Here, during the switching of the second terminal, the first terminal can perform data transmission between the source access network device through the direct path. Before configuring the second terminal to switch, the source access network device can also configure the first terminal to release the split bearer and the indirect bearer transmitted through the indirect path, so that the corresponding service data can be configured to use the Uu bearer on the direct path to transmit data.

[0163] In some embodiments, the handover request message comprises at least one of the following:

[0164] a wireless network temporary identifier of the candidate aggregation terminal, a serving cell identifier of the candidate aggregation terminal, an association relationship between the first terminal and the aggregation terminal that has been handed over to the target access network device, an association relationship between the first terminal and the second terminal, an identifier (e.g., F1AP UE ID) of the aggregation terminal that has been handed over to the target access network device, an identifier (e.g., F1AP UE ID) of the target terminal, a wireless network temporary identifier (C-RNTI) of the target terminal, and indication information for maintaining indirect path data transmission during the handover process.

[0165] Exemplarily, the Relay UE first switches to the target access network device (the second path ends data transmission), and when the source access network device decides to initiate handover of the first terminal, if the source access network device wants to stop data transmission of the direct path (the first path) on the source access network device side during the handover of the first terminal, data transmission is performed through the indirect path (the fifth path) with the source access network device side, and the direct path (the third path) is connected to the target access network device, as shown in FIG. 6. Here, the fifth path is a path in which the first terminal is indirectly connected to the source access network device through the target terminal and the target access network device.

[0166] In some embodiments, the information (indication information of whether to retain the path on the source access network device side) in the handover request message described above is indication information with terminal granularity, or indication information with data radio bearer granularity. That is, the indication information of whether to retain the path on the source access network device side can be configured per UE or per DRB.

[0167] S403, the target access network device sends an RRC reconfiguration message to the target terminal.

[0168] In the case where the target access network device allows the first terminal to hand over, the target access network device can accept that the first terminal is connected to itself through the target terminal (indicated by the source access network device), or the target access device itself can select a target terminal for the first terminal from the candidate aggregation terminal. Here, the target terminal includes the aggregation terminal that has been handed over to the target access network device, and the target terminal can also be the second terminal or other possible terminal.

[0169] It should be understood that FIG. 9 exemplarily illustrates the technical solutions of the embodiments of the present disclosure with the target terminal being the second terminal, and the target terminal can also be other possible aggregation terminal that has been handed over to the target access network device.

[0170] In some embodiments, the RRC reconfiguration message comprises at least one of the following:

[0171] a wireless network temporary identifier (C-RNTI) of the first terminal, an N3C interface identifier of the first terminal, a mapping relationship between a signaling radio bearer (remote UE SRB, for example, SRB0 / 1 / 2) of the first terminal and a wireless link control channel (relay UE Uu RLC channel) on a wireless interface of the target terminal, and configuration information of the wireless link control channel on the wireless interface of the target terminal. Here, the N3C interface is an interface used for control plane and user plane communication.

[0172] In some embodiments, the first terminal can also report its N3C interface to the source access network device.

[0173] S404. The target access network device sends a handover request response to the source access network device.

[0174] Here, the detailed description of step S404 can refer to the description in step S102 described above.

[0175] Illustratively, the target access network device receives the handover request message and can perform admission control on the first terminal, thereby determining whether to allow the first terminal to access the network, that is, whether to allow the first terminal to switch from the source access network device to the target access network device.

[0176] Illustratively, in the case where the target access network device allows the first terminal to switch, if both the target access network device and the target terminal are ready for switching, the target access network device can send a handover request response to the source access network device.

[0177] In this embodiment, in the case where the Relay UE switches to the target access network device first and then the Remote UE switches to the target access network device, the first indication information in the handover request response can include indication information of disapproving to maintain direct path data transmission and indication information of approving to maintain indirect path data transmission. In addition, the first indication information can also include an identifier of the target terminal, for example, a C-RNTI / N3C interface identifier / F1AP UE ID of the target Relay UE.

[0178] In some embodiments, the first indication information is indication information with terminal granularity or indication information with data radio bearer granularity. That is, the first indication information can be per UE configuration or per DRB configuration.

[0179] In some embodiments, the indirect path between the target access network device and the source access network device can establish a data channel for forwarding the first terminal data, i.e., can negotiate to establish an Xn interface for forwarding a tunnel of the data of the first terminal on the indirect path. The uplink data on the indirect path of the first terminal is forwarded by the target base station to the source base station through the Xn tunnel, and the downlink data on the indirect path of the first terminal is forwarded by the source base station to the target base station through the Xn tunnel.

[0180] S405, the source access network device sends second indication information to the first terminal.

[0181] Here, the detailed description of step S504 can refer to the description in step S102 described above.

[0182] In some embodiments, the source access network device can send the handover related configuration information (i.e., the second indication information) to the first terminal through the RRC reconfiguration message, including at least one of the target cell information and the indication information for maintaining the indirect path connection during the handover process. In this embodiment, the second indication information can further include the identifier of the target terminal, such as the C-RNTI of the target terminal, the serving cell identifier of the target terminal, etc.

[0183] At this time, the second indication information can specifically indicate the first terminal to stop the data transmission of the first path, and maintain the data transmission between the first terminal and the source access network device through the fifth path, the fifth path being the path through which the first terminal is indirectly connected with the source access network device through the target terminal and the target access network device, and connected with the target access network device through the third path.

[0184] For example, after receiving the second indication information, the first terminal can stop the Uu interface data transmission with the source access network device, and if the indication information of reserving the indirect path is received, the first terminal can also continue the data transmission on the N3C indirect path during the execution of the handover. At this time, the UL data transmission path is: first terminal -> target terminal -> target access network device -> source access network device -> UPF; the DL data transmission path is: 1) UPF -> source access network device -> target access network device -> target terminal -> first terminal.

[0185] In some embodiments, the first terminal can also maintain independent security context and robust header compression (ROHC) context for the data transmission of the second path and the third path, respectively, and maintain common packet data convergence protocol (PDCP) sequence number allocation.

[0186] Exemplarily, after receiving the second indication information, the first terminal can perform data transmission through the indirect path (the fifth path) between the source access network device (in the case of receiving the indication information reserving the indirect path). During the handover execution, the first terminal can maintain separate security context and ROHC header compressor context for uplink transmission to the source access network device and the target access network device respectively; the UE maintains a common uplink PDCP SN allocation. And the first terminal receives the downlink data sent by the source access network device / target access network device using the security context and ROHC header decompression function associated with the source access network device / target access network device respectively, while maintaining the general functions of reordering, duplicate detection and discard, and sequentially delivering PDCP SDU to the upper layer.

[0187] S406, the first terminal sends an RRC reconfiguration complete message to the target access network device.

[0188] Exemplarily, after the first terminal successfully accesses the target access network device, the first terminal can send an RRC reconfiguration complete message to the target access network device.

[0189] In some embodiments, the uplink data of the first terminal can also be switched from transmission to the source access network device to transmission to the target access network device.

[0190] Exemplarily, the first terminal no longer sends uplink data through the indirect path (the fifth path) on the source access network device side, and the uplink data transmission is transferred to the target access network device. When the uplink data of the first terminal is transferred from the source access network device to the target access network device, the lossless transmission of the uplink data needs to be considered. Under the UE aggregation, it can be assumed that the first terminal can determine which data packets are successfully / unsuccessfully sent by the target terminal to the target access network device (e.g. receiving RLC ack / nack of the Uu interface) according to the N3C ideal interface, so that when the first terminal transfers the uplink data transmission to the target access network device (using the security context and ROHC header compression configuration associated with the target access network device), it can start transmitting from the first data packet that is not confirmed by gNB2 RLC on the indirect path to the target access network device (through the direct Uu link between the target access network device).

[0191] Here, the data packet received by the target access network device on the indirect path (fifth path) usually needs to be further forwarded to the source access network device, and the source access network device needs to determine the time when the data forwarding of the target access network device is completed. In the embodiment of the present disclosure, the source access network device does not need to wait for the data packet of the first terminal forwarded by the target access network device any more. The first terminal can transmit an end marker indication (or an end marker for each bearer on the indirect path) on the indirect path (fifth path) when it is ready to transfer the uplink data transmission from the source access network device to the target access network device. Then, when the source access network device receives the end marker forwarded on the indirect path (fifth path) (or receives the end marker of all bearers on the indirect path), it can determine that the data forwarding of the target access network device is completed / there is no need to wait for the uplink data packet of the first terminal forwarded by the target access network device any more.

[0192] S407, the target access network device sends the handover success indication information to the source access network device.

[0193] Exemplarily, after the target access network device receives the RRC reconfiguration complete message from the first terminal, the handover success indication information can be sent to the source access network device.

[0194] Further, after receiving the handover success indication information, the source access network device can stop the downlink data transmission on the indirect path (fifth path) of the source access network device side, receive the downlink data from the UPF and forward it to the target access network device. Moreover, the source access network device stops sending the uplink data packet of the first terminal to the UPF, but forwards the uplink data packet to the target access network device.

[0195] In some embodiments, the source access network device sends the sequence number (SN) status transfer to the target access network device.

[0196] In the case where the transmission paths of the uplink and downlink data of the first terminal are both completed, the target access network device can send an RRC reconfiguration message to the first terminal to instruct the first terminal to release the related configurations (such as security context, ROHC header compression, etc. associated with the source access network device) on the source access network device side. For example, it can include the indirect path release indication on the source access network device side, the direct path release indication on the source access network device side, and the reconfiguration bearer.

[0197] In some embodiments, for the aggregated terminal (second terminal) on the indirect path between the source access network device, the second terminal can continue to forward the uplink and downlink data of the first terminal until the Uu RLC channel is released, or receiving the indication information sent by the source access network device to release the first terminal. The target access network device can also update / reconfigure the Uu RLC channel and the mapping relationship between the remote UE RB and the Uu RLC channel for the target terminal.

[0198] Based on the embodiment shown in FIG. 9, the Relay UE switches to the target access network device first, and then the Remote UE switches to the target access network device, and during the switching process, data transmission is performed with the source access network device through the fifth path, and the third path is connected with the target access network device. In this way, the network interruption time of the terminal can be reduced, so that the service continuity can also be maintained during the inter-access network device switching.

[0199] The above mainly introduces the scheme provided by the present disclosure from the perspective of interaction between various communication nodes. It can be understood that each communication node includes a hardware structure and / or software module for executing each function in order to achieve the above functions. Those skilled in the art should easily realize that, in combination with the algorithm steps of each example described in the embodiments disclosed herein, the present disclosure can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in hardware or computer software driven hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present disclosure.

[0200] FIG. 10 is a block diagram of a communication apparatus according to some embodiments. The communication apparatus 1000 can perform the switching method executed by the source access network device provided by the above method embodiments. As shown in FIG. 10, the communication apparatus 1000 includes a sending module 1001 and a receiving module 1002.

[0201] The sending module 1001 is configured to send a switching request message to the target access network device, the switching request message being used to request switching the first terminal to the target access network device; wherein the first terminal is connected with the source access network device through a first path and a second path, the first path being a direct path between the first terminal and the source access network device, and the second path being an indirect path through which the first terminal is connected with the source access network device via a second terminal.

[0202] The receiving module 1002 is configured to receive a switching request response from the target access network device.

[0203] In some embodiments, the handover request message is further used to request to maintain direct path data transmission during the handover process, and / or to maintain indirect path data transmission during the handover process.

[0204] In some embodiments, the handover request response comprises first indication information, the first indication information being used to indicate whether to agree to maintain direct path data transmission during the handover process, and / or to agree to maintain indirect path data transmission during the handover process.

[0205] In some embodiments, the sending module 1001 is further used to send second indication information to the first terminal, the second indication information being used to indicate that the first terminal switches to the target access network device and maintains the connection between the first terminal and the source access network device during the handover process. The receiving module 1002 is further used to receive indication information of the successful handover of the first terminal from the target access network device.

[0206] In some embodiments, the second indication information comprises at least one of the following: target cell information, indication information of whether to maintain direct path connection during the handover process, and indication information of whether to maintain indirect path connection.

[0207] In some embodiments, the second indication information is specifically used to indicate that the first terminal stops the data transmission of the first path and maintains the data transmission of the second path, and connects to the target access network device through a third path, the third path being a path directly connecting the first terminal and the target access network device.

[0208] In some embodiments, before sending the handover request message to the target access network device, the sending module 1001 is further used to send third indication information to the second terminal, the third indication information being used to indicate that the second terminal switches to the target access network device.

[0209] In some embodiments, the second indication information further comprises an identifier of a target terminal, the target terminal comprising an aggregated terminal that has switched to the target access network device.

[0210] In some embodiments, the handover request message comprises at least one of the following:

[0211] The wireless network temporary identifier of the candidate aggregated terminal, the serving cell identifier of the candidate aggregated terminal, the association relationship between the first terminal and the aggregated terminal that has switched to the target access network device, the association relationship between the first terminal and the second terminal, the identifier of the aggregated terminal that has switched to the target access network device, the identifier of the target terminal, the wireless network temporary identifier of the target terminal, and the indication information of maintaining direct path data transmission during the handover process.

[0212] In some embodiments, the second indication information is specifically used to indicate that the first terminal keeps data transmission of the first path, and connects with the target access network device through a fourth path, the fourth path being a path through which the first terminal connects with the target access network device through the target terminal.

[0213] In some embodiments, the handover request message comprises at least one of the following:

[0214] a wireless network temporary identifier of the candidate aggregation terminal, a serving cell identifier of the candidate aggregation terminal, an association relationship between the first terminal and the aggregation terminal that has been switched to the target access network device, an association relationship between the first terminal and the second terminal, an identifier of the aggregation terminal that has been switched to the target access network device, an identifier of the target terminal, a wireless network temporary identifier of the target terminal, and indication information for keeping data transmission of the indirect path during the handover process.

[0215] In some embodiments, the second indication information is specifically used to indicate that the first terminal stops data transmission of the first path, and maintains data transmission with the source access network device through a fifth path, the fifth path being an indirect path through which the first terminal connects with the source access network device through the target terminal and the target access network device, and the first terminal connects with the target access network device through a third path.

[0216] In some embodiments, the information in the handover request message, the first indication information in the handover request response, and the second indication information are indication information with terminal granularity or indication information with data radio bearer granularity.

[0217] For more details of the above sending module 1001 and receiving module 1002, and more details of each technical feature and beneficial effects, please refer to the corresponding method embodiment part above, which will not be repeated here.

[0218] FIG. 11 is a block diagram of another communication apparatus according to some embodiments. The communication apparatus 1100 can perform the handover method executed by the target access network device provided in the above method embodiments. As shown in FIG. 11, the communication apparatus 1100 comprises a receiving module 1101 and a sending module 1102.

[0219] The receiving module 1101 is configured to receive a handover request message from a source access network device, the handover request message being used to request to switch a first terminal to a target access network device; wherein the first terminal connects with the source access network device through a first path and a second path, the first path being a direct path between the first terminal and the source access network device, and the second path being an indirect path through which the first terminal connects with the source access network device through a second terminal.

[0220] The sending module 1102 is configured to send a handover request response to the source access network device, the handover request response comprising second indication information, the second indication information being used to indicate whether to agree to maintain direct path connectivity and / or to agree to maintain indirect path connectivity during the handover process.

[0221] In some embodiments, the handover request message is further used to request to maintain direct path data transmission during the handover process and / or to maintain indirect path data transmission during the handover process.

[0222] In some embodiments, the handover request response comprises first indication information, the first indication information being used to indicate whether to agree to maintain direct path data transmission and / or to agree to maintain indirect path data transmission during the handover process.

[0223] In some embodiments, the handover request message comprises at least one of the following:

[0224] The wireless network temporary identifier of the candidate aggregated terminal, the serving cell identifier of the candidate aggregated terminal, the association relationship between the first terminal and the aggregated terminal that has been handed over to the target access network device, the association relationship between the first terminal and the second terminal, the identifier of the aggregated terminal that has been handed over to the target access network device, the identifier of the target terminal, the wireless network temporary identifier of the target terminal, and the indication information of maintaining direct path or indirect path data transmission during the handover process; wherein the target terminal comprises the aggregated terminal that has been handed over to the target access network device.

[0225] In some embodiments, the sending module 1102 is further configured to send a radio resource control (RRC) reconfiguration message to the target terminal.

[0226] In some embodiments, the RRC reconfiguration message comprises at least one of the following:

[0227] The wireless network temporary identifier of the first terminal, the N3C interface identifier of the first terminal, the mapping relationship between the signaling radio bearer of the first terminal and the radio link control channel on the wireless interface of the target terminal, and the configuration information of the radio link control channel on the wireless interface of the target terminal.

[0228] In some embodiments, in the case where the first terminal completes the RRC reconfiguration, the sending module 1102 is further configured to send handover success indication information to the source access network device.

[0229] For more detailed descriptions of the above-mentioned receiving module 1101 and sending module 1102, and more detailed descriptions of various technical features and beneficial effects thereof, please refer to the above-mentioned corresponding method embodiment part, which will not be repeated here.

[0230] FIG. 12 is a block diagram of yet another communication apparatus according to some embodiments. The communication apparatus 1200 can perform the handover method performed by the first terminal provided by the above-mentioned method embodiments. As shown in FIG. 12, the communication apparatus 1200 includes a receiving module 1201 and a processing module 1202.

[0231] The receiving module 1201 is configured to receive second indication information from a source access network device, the second indication information being used to indicate that the first terminal is to be handed over to a target access network device and that at least one path between the first terminal and the source access network device is to be maintained during the handover.

[0232] The processing module 1202 is configured to establish a connection with the target access network device based on the second indication information.

[0233] In some embodiments, the first terminal is connected to the source access network device through a first path and a second path; the first path is a direct path between the first terminal and the source access network device; and the second path is an indirect path through a second terminal between the first terminal and the source access network device.

[0234] In some embodiments, the second indication information includes at least one of the following: target cell information, indication information about whether the direct path is to be maintained during the handover, and indication information about whether the indirect path is to be maintained.

[0235] In some embodiments, the second indication information is terminal-granularity indication information; or the second indication information is data radio bearer-granularity indication information.

[0236] In some embodiments, the processing module 1202 is specifically configured to, in a case where the second indication information includes the indication information about whether the indirect path is to be maintained, stop data transmission of the first path and maintain data transmission of the second path; and connect to the target access network device through a third path, the third path being a direct path between the first terminal and the target access network device.

[0237] In some embodiments, the processing module 1202 is further configured to maintain independent security contexts and robust header compression (ROHC) contexts for data transmission of the second path and the third path, respectively, and maintain common packet data convergence protocol (PDCP) sequence number allocation.

[0238] In some embodiments, the processing module 1202 is further configured to, in a case where the first terminal is connected to the target access network device through the third path, switch uplink data of the first terminal from being transmitted to the source access network device to being transmitted to the target access network device.

[0239] In some embodiments, the first terminal is configured to stop data transmission of the second path, and / or the second terminal has been configured to be handed over to the target access network device.

[0240] In some embodiments, the second indication information further comprises identification information of the target terminal, the target terminal comprising the aggregated terminal which has switched to the target access network device.

[0241] In some embodiments, the processing module 1202 is specifically configured to, in a case where the second indication information comprises the indication information of maintaining the direct path connection, maintain the data transmission of the first path; connect with the target access network device through a fourth path, the fourth path being a path through which the first terminal connects with the target access network device through the target terminal.

[0242] In some embodiments, the processing module 1202 is specifically configured to, in a case where the second indication information comprises the indication information of maintaining the indirect path connection, stop the data transmission of the first path, and maintain the data transmission between the first terminal and the source access network device through a fifth path, the fifth path being a path through which the first terminal indirectly connects with the source access network device through the target terminal and the target access network device; connect with the target access network device through the third path.

[0243] For more details of the above-mentioned receiving module 1201 and processing module 1202, and more details of the technical features and beneficial effects thereof, please refer to the above-mentioned corresponding method embodiment part, which will not be repeated here.

[0244] FIG. 13 is a block diagram of another communication apparatus according to some embodiments. The communication apparatus 1300 can perform the switching method executed by the second terminal provided by the above-mentioned method embodiments. As shown in FIG. 13, the communication apparatus 1300 comprises a processing module 1301 and a receiving module 1302.

[0245] The processing module 1301 is configured to, in a process of switching the first terminal from the source access network device to the target access network device, maintain the data transmission of an indirect path between the first terminal and the source access network device, or maintain the data transmission of an indirect path between the first terminal and the target access network device.

[0246] In some embodiments, the processing module 1301 is configured to, in a case where the second terminal does not switch to the target access network device, maintain the data transmission of the indirect path between the first terminal and the source access network device through the second terminal.

[0247] In some embodiments, the receiving module 1302 is further configured to, in a case where the first terminal has switched to the target access network device, receive indication information from the source access network device, the indication information being used to indicate that the second terminal switches to the target access network device.

[0248] In some embodiments, the processing module 1301 is configured to maintain data transmission of the path through which the first terminal is connected to the target access network device via the second terminal in a case where the second terminal has been handed over to the target access network device; or maintain data transmission of the path through which the first terminal is connected to the source access network device via the second terminal and the target access network device.

[0249] In some embodiments, the receiving module 1302 is further configured to receive an RRC reconfiguration message from the target access network device before maintaining data transmission of the indirect path between the first terminal and the target access network device.

[0250] In some embodiments, the RRC reconfiguration message comprises at least one of the following:

[0251] a radio network temporary identifier of the first terminal, an N3C interface identifier of the first terminal, a mapping relationship between a signaling radio bearer of the first terminal and a radio link control channel on a radio interface of the target terminal, and configuration information of the radio link control channel on the radio interface of the target terminal.

[0252] For more details of the processing module 1301 and the receiving module 1302, and more details of each technical feature and beneficial effects, please refer to the corresponding method embodiments described above, which will not be repeated here.

[0253] It should be noted that the modules in FIGS. 10-13 can also be referred to as units, for example, the sending module can be referred to as a sending unit. In addition, in the embodiments shown in FIGS. 10-13, the names of the various modules can not be the names shown in the figures, for example, the receiving module can also be referred to as a communication module, and the sending module can also be referred to as a communication module.

[0254] Each unit or module in FIGS. 10-13, if implemented in the form of a software function module and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present disclosure, essentially or in part, or all or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to perform all or part of the steps of the methods in the various embodiments of the present disclosure. The storage medium storing the computer software product includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, etc. Various media that can store program codes.

[0255] In the case of implementing the functions of the above-mentioned integrated modules in the form of hardware, the embodiments of the present disclosure provide a structural diagram of a communication device, which can be any of the communication devices in FIGS. 10-13. As shown in FIG. 14, the communication device 1400 includes a processor 1402, a communication interface 1403, and a bus 1404. In some embodiments, the communication device 1400 can further include a memory 1401.

[0256] The processor 1402 can be a central processing unit, a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array, or other programmable logic device, transistor logic, hardware components, or any combination thereof. It can implement or execute various exemplary logical blocks, modules, and circuits described in connection with the present disclosure. The processor 1402 can also be a combination of computing functions, such as a combination of one or more microprocessors, a combination of a digital signal processor (DSP) and a microprocessor, and the like.

[0257] The communication interface 1403 is used to connect with other devices through a communication network. The communication network can be an Ethernet, a wireless access network, a wireless local area network (WLAN), and the like.

[0258] The memory 1401 can be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited thereto.

[0259] In some embodiments, the memory 1401 can exist independently of the processor 1402, and the memory 1401 can be connected to the processor 1402 through the bus 1404 for storing instructions or program code. When the processor 1402 invokes and executes the instructions or program code stored in the memory 1401, the method provided by the embodiments of the present disclosure can be implemented.

[0260] In some embodiments, the memory 1401 can also be integrated in the processor 1402.

[0261] The bus 1404 can be an extended industry standard architecture (EISA) bus, an industry standard architecture (ISA) bus, a microchannel architecture (MCA) bus, an external bus, a proprietary bus, and the like. The bus 1404 can be a single bus or a combination of buses. The bus 1404 can be divided into an address bus and a data bus, for example. For the sake of brevity, only one bus is depicted in FIG. 14 as a thick line, but this is simply to simplify the diagram, and is not intended to indicate that there is only one bus or only one type of bus.

[0262] From the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of brevity and conciseness, only the division of the above functional modules is taken as an example, and in actual applications, the above functions can be completed by different functional modules according to needs, that is, the internal structure of the device or apparatus is divided into different functional modules to complete all or part of the functions described above.

[0263] The embodiments of the present disclosure further provide a computer readable storage medium. All or part of the processes in the above method embodiments can be instructed by computer instructions to complete relevant hardware, and the program can be stored in the above computer readable storage medium. When the program is executed, the processes of the above method embodiments can be included. The computer readable storage medium can be the memory of any of the preceding embodiments. The above computer readable storage medium can also be an external storage device of the device or apparatus, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, and the like. Further, the above computer readable storage medium can include both the internal storage unit of the device or apparatus and the external storage device. The above computer readable storage medium is used to store the above computer program and other programs and data required by the device or apparatus. The above computer readable storage medium can also be used to temporarily store data that has been output or will be output.

[0264] The embodiments of the present disclosure further provide a computer program product, which contains a computer program, and when the computer program product runs on a computer, the computer executes any method provided in the above embodiments.

[0265] Although the present disclosure has been described in connection with certain embodiments, it will be understood that the application is capable of further modifications and that this application is intended to cover any variations, uses or adaptations of the application following, in general, the principles of the application and including such further modifications as come within the four corners of the following claims and equivalents thereof. It will be understood that the application is capable of further modifications and that this application is intended to cover any variations, uses or adaptations of the application following, in general, the principles of the application and including such further modifications as come within the four corners of the following claims and equivalents thereof. In the claims, the term "including" does not exclude other components or steps. The indefinite articles "a" or "an" do not exclude a plurality. A single processor or other unit can fulfil the functions of several items recited in the claims. The terms "first", "second" and the like in the description do not necessarily imply that there are only two. The terms "including", "containing", "comprising" and similar terms are not to be construed as implying a quantitative or qualifying effect, and do not exclude other parts, components or steps.

[0266] Although the present disclosure has been described in connection with specific features thereof, it will be evident to an artisan of ordinary skill that various modifications and changes can be made to the application without departing from the spirit and scope thereof. Accordingly, it is intended that the present disclosure be viewed as exemplary only and that any and all modifications, changes, variations, or equivalents that fall within the scope of the present disclosure be covered by this disclosure. Obviously, numerous modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the disclosure and appended claims, the application can be practiced otherwise than as specifically described. Thus, the disclosure and examples set forth above are meant as illustrative only, rather than limiting, of the present disclosure. Accordingly, the disclosure is intended to embrace all such alterations, modifications, and variations which fall within the scope and spirit of the disclosure.

[0267] The above description is only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and any changes or replacements within the technical scope disclosed by the present disclosure should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A handover method, wherein, The method is applied to a source access network device, and the method comprises: sending a handover request message to a target access network device, the handover request message being used to request handover of a first terminal to the target access network device; wherein the first terminal is connected to the source access network device through a first path and a second path, the first path being a direct path between the first terminal and the source access network device, and the second path being an indirect path through a second terminal for connecting the first terminal to the source access network device; receiving a handover request response from the target access network device.

2. The method of claim 1, wherein, The handover request message is also used to request maintaining data transmission of the direct path during the handover process and / or maintaining data transmission of the indirect path during the handover process.

3. The method of claim 1 or 2, wherein, The handover request response comprises first indication information, the first indication information being used to indicate whether to agree to maintain data transmission of the direct path and / or to maintain data transmission of the indirect path during the handover process.

4. The method of any one of claims 1-3, wherein, The method further comprises: sending second indication information to the first terminal, the second indication information being used to indicate handover of the first terminal to the target access network device and maintaining connection of the first terminal to the source access network device during the handover process; receiving indication information of successful handover of the first terminal from the target access network device.

5. The method of claim 4, wherein, The second indication information comprises at least one of the following: target cell information, indication information of whether to maintain connection of the direct path during the handover process, and indication information of whether to maintain connection of the indirect path.

6. The method of claim 4 or 5, wherein, The second indication information is used to indicate that the first terminal stops data transmission of the first path and maintains data transmission of the second path, and is connected to the target access network device through a third path, the third path being a path for directly connecting the first terminal to the target access network device.

7. The method of any one of claims 4-6, wherein, Before the handover request message is sent to the target access network device, the method further comprises: sending third indication information to the second terminal, the third indication information being used to indicate handover of the second terminal to the target access network device.

8. The method of claim 7, wherein, The second indication information further comprises an identifier of a target terminal, the target terminal comprising an aggregated terminal that has been handed over to the target access network device.

9. The method of claim 7 or 8, wherein, The handover request message comprises at least one of the following: a radio network temporary identifier of a candidate aggregated terminal, a serving cell identifier of the candidate aggregated terminal, an association relationship between the first terminal and an aggregated terminal that has been handed over to the target access network device, an association relationship between the first terminal and the second terminal, an identifier of the aggregated terminal that has been handed over to the target access network device, an identifier of the target terminal, a radio network temporary identifier of the target terminal, and indication information of maintaining data transmission of the direct path during the handover process.

10. The method of claim 9, wherein, The second indication information is specifically used to indicate that the first terminal maintains data transmission of the first path and is connected to the target access network device through a fourth path, the fourth path being a path for connecting the first terminal to the target access network device through the target terminal.

11. The method of claim 7, wherein, The handover request message comprises at least one of the following: a radio network temporary identifier of the candidate aggregated terminal, a serving cell identifier of the candidate aggregated terminal, an association relationship between the first terminal and an aggregated terminal that has been switched to the target access network device, an association relationship between the first terminal and the second terminal, an identifier of the aggregated terminal that has been switched to the target access network device, an identifier of the target terminal, a radio network temporary identifier of the target terminal, and indication information for maintaining data transmission of an indirect path during the handover process.

12. The method of claim 11, wherein, The second indication information is specifically used to instruct the first terminal to stop data transmission of the first path and maintain data transmission between the first terminal and the source access network device through a fifth path, the fifth path being an indirect connection path between the first terminal, the target terminal, and the target access network device and the source access network device, and the third path being a direct connection path between the first terminal and the target access network device.

13. The method of claim 5, wherein, At least one of the information in the handover request message, the first indication information in the handover request response, and the second indication information is terminal-granularity indication information or data radio bearer-granularity indication information.

14. A handover method, wherein, The method is applied to a target access network device, and the method comprises: receiving a handover request message from a source access network device, the handover request message being used to request handover of a first terminal to the target access network device; wherein the first terminal is connected to the source access network device through a first path and a second path, the first path being a direct path between the first terminal and the source access network device, and the second path being an indirect path through a second terminal between the first terminal and the source access network device; sending a handover request response to the source access network device.

15. The method of claim 14, wherein, The handover request message is also used to request maintaining data transmission of the direct path during the handover process and / or maintaining data transmission of the indirect path during the handover process.

16. The method of claim 14, wherein, The handover request response comprises first indication information, the first indication information being used to indicate whether to agree to maintain data transmission of the direct path and / or whether to agree to maintain data transmission of the indirect path during the handover process.

17. The method of claim 14, wherein, The handover request message comprises at least one of the following: a radio network temporary identifier of the candidate aggregated terminal, a serving cell identifier of the candidate aggregated terminal, an association relationship between the first terminal and an aggregated terminal that has been switched to the target access network device, an association relationship between the first terminal and the second terminal, an identifier of the aggregated terminal that has been switched to the target access network device, an identifier of the target terminal, a radio network temporary identifier of the target terminal, and indication information for maintaining data transmission of an indirect path during the handover process; wherein the target terminal comprises the aggregated terminal that has been switched to the target access network device.

18. The method of claim 17, wherein, The method further comprises: sending a radio resource control connection (RRC) reconfiguration message to the target terminal.

19. The method of claim 18, wherein, The RRC reconfiguration message comprises at least one of the following: a radio network temporary identifier of the first terminal, an N3C interface identifier of the first terminal, a mapping relationship between a signaling radio bearer of the first terminal and a radio link control channel on a radio interface of the target terminal, configuration information of the radio link control channel on the radio interface of the target terminal.

20. The method of claim 17, wherein, In a case where the handover request message comprises indication information for maintaining data transmission of an indirect path during a handover procedure, the method further comprises: establishing a data channel with the source access network device for forwarding the first terminal data via an indirect path.

21. The method of claim 20, wherein, The method further comprises: forwarding uplink data of the first terminal to the source access network device via the data channel; and / or, receiving downlink data of the first terminal forwarded by the source access network device via the data channel.

22. The method of claim 14, wherein, The method further comprises: in a case where the first terminal RRC reconfiguration is completed, sending handover success indication information to the source access network device.

23. A handover method, wherein, The method applied to a first terminal, the method comprising: receiving second indication information from a source access network device, the second indication information being used to indicate that the first terminal is handed over to a target access network device and at least one path connection between the first terminal and the source access network device is maintained during a handover procedure; establishing a connection with the target access network device based on the second indication information.

24. The method of claim 23, wherein the first terminal is connected to the source access network device via a first path and a second path; the first path is a direct path between the first terminal and the source access network device; the second path is an indirect path via a second terminal between the first terminal and the source access network device.

25. The method of claim 24, wherein, The second indication information comprises at least one of the following: target cell information, indication information of whether to maintain a direct path connection during a handover procedure, and indication information of whether to maintain an indirect path connection.

26. The method of claim 24 or 25, wherein, The establishing a connection with the target access network device based on the second indication information comprises: in a case where the second indication information comprises indication information of maintaining an indirect path connection, stopping data transmission of the first path and maintaining data transmission of the second path; connecting to the target access network device via a third path, the third path being a direct path between the first terminal and the target access network device.

27. The method of claim 26, wherein, The method further comprises: maintaining independent security contexts and robust header compression (ROHC) contexts for data transmission of the second path and the third path respectively, and maintaining a common packet data convergence protocol (PDCP) sequence number allocation.

28. The method of claim 26, wherein, The method further comprises: in a case where the connecting to the target access network device via the third path, switching uplink data of the first terminal from being transmitted to the source access network device to being transmitted to the target access network device.

29. The method of claim 24, wherein, The first terminal is configured to stop data transmission of the second path, and / or the second terminal has been configured to be handed over to the target access network device.

30. The method of claim 29, wherein, The second indication information further comprises identification information of a target terminal, the target terminal comprising an aggregated terminal that has been handed over to the target access network device.

31. The method of claim 30, wherein, The second path stops data transmission, and the switching to the target access network device based on the second indication information comprises: In a case where the second indication information comprises indication information for maintaining direct path connectivity, maintaining data transmission of the first path; connecting to the target access network device through a fourth path, the fourth path being a path through which the first terminal connects to the target access network device through the target terminal.

32. The method of claim 30, wherein, The switching to the target access network device based on the second indication information comprises: In a case where the second indication information comprises indication information for maintaining indirect path connectivity, stopping data transmission of the first path, and maintaining data transmission between the first terminal and the source access network device through a fifth path, the fifth path being a path through which the first terminal indirectly connects to the source access network device through the target terminal and the target access network device; connecting to the target access network device through a third path.

33. A handover method, wherein, The method applied to a second terminal comprises: In a process in which a first terminal switches from a source access network device to a target access network device, maintaining data transmission of an indirect path between the first terminal and the source access network device, or maintaining data transmission of an indirect path between the first terminal and the target access network device.

34. The method of claim 33, wherein, The maintaining data transmission of the indirect path between the first terminal and the source access network device comprises: In a case where the second terminal does not switch to the target access network device, maintaining data transmission of an indirect path between the first terminal and the source access network device through the second terminal.

35. The method of claim 33 or 34, wherein, The method further comprises: In a case where the first terminal has switched to the target access network device, receiving indication information from the source access network device for indicating that the second terminal switches to the target access network device.

36. The method of claim 34, wherein, The maintaining data transmission of the indirect path between the first terminal and the target access network device comprises: In a case where the second terminal has switched to the target access network device, maintaining data transmission of a path between the first terminal and the target access network device through the second terminal; or maintaining data transmission of a path between the first terminal and the source access network device through the second terminal and the target access network device.

37. The method of claim 36, wherein, Before the maintaining data transmission of the indirect path between the first terminal and the target access network device, the method further comprises: receiving an RRC reconfiguration message from the target access network device.

38. The method of claim 37, wherein, The RRC reconfiguration message comprises at least one of the following: a radio network temporary identifier of the first terminal, an N3C interface identifier of the first terminal, a mapping relationship between a signaling radio bearer of the first terminal and a radio link control channel on a radio interface of the target terminal, and configuration information of the radio link control channel on the radio interface of the target terminal.

39. A communications device, wherein comprise: a memory and a processor; the memory and the processor are coupled; the memory is configured to store instructions executable by the processor; the processor executes the instructions to perform the method in any one of claims 1 to 38.

40. A computer readable storage medium, wherein, The computer readable storage medium has stored thereon computer instructions that, when executed at the processor, cause the processor to perform the method of any one of claims 1 to 38.

41. A computer program product, wherein, The computer program product comprises a computer program that, when executed at the computer, causes the computer to perform the method of any one of claims 1 to 38.

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