Communication method and device

Abstract

The embodiment of the invention discloses a communication method and device. The method comprises: a first access network device receiving a first request sent by a second access network device, the first request being used for requesting to switch from a cell of the second access network device to a cell of the first access network device, the first request comprising first indication information, the first indication information is used for indicating transmission layer information inheriting data transfer to candidate access network equipment, and establishing a data forwarding tunnel with the candidate access network equipment based on the transmission layer information. By adopting the embodiment of the invention, the process of applying for switching resources can be reduced, the switching time is shortened, and the switching efficiency is improved.

Description

Technical Field

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

[0002] Since the traditional terrestrial network (TN) cannot provide seamless coverage for user equipment (UE), especially in places where base stations cannot be deployed such as the sea, desert, and air, non-terrestrial network (NTN) has been introduced into the Internet of Things (IoT) and the fifth-generation mobile communication technology (5G) system and subsequent evolved system architectures such as 6G. By deploying base stations or part of the base station functions on non-ground network devices such as high-altitude platforms or satellites, seamless coverage is provided for UE, thereby improving the reliability of the system.

[0003] In the networking of NTN and TN, the XN interface between NTN and TN is very likely to not exist. Therefore, if switching is required between NTN and TN, switching preparation must be performed through the NG interface. The switching preparation of the NG interface may require multiple satellites, gateway stations and core networks. The entire process may take up to several hundred milliseconds (ms), resulting in a long switching preparation time. Summary of the invention

[0004] The embodiments of the present application provide a communication method and device, which can reduce the process of applying for switching resources, reduce switching time, and improve switching efficiency.

[0005] In a first aspect, an embodiment of the present application provides a communication method, which is applied to a first access network device, or a chip or circuit configured in the first access network device includes:

[0006] receiving a first request sent by a second access network device, where the first request is used to request switching from a cell of the second access network device to a cell of the first access network device, where the first request includes first indication information, where the first indication information is used to indicate inheritance of transport layer information for data transfer to a candidate access network device;

[0007] Based on the transport layer information, a data forwarding tunnel is established with the candidate access network device.

[0008] By applying for the transport layer information for data transfer to the candidate access network device in advance, in the process of switching from the cell of the second access network device to the cell of the first access network device, the second access network device indicates to inherit the transport layer information for data transfer to the candidate access network device, so that after the terminal device switches from the cell of the second access network device to the cell of the first access network device, the first access network device can switch from the cell of the first access network device to the cell of the candidate access network device without applying for the transport layer information for data transfer to the candidate access network device. This reduces the process of applying for switching resources, reduces the switching time, and improves the switching efficiency.

[0009] In one possible design, the first request includes the transport layer information. The transport layer information for data transfer to the candidate access network device included in the first request may be first indication information. That is, if the first request includes the transport layer information for data transfer to the candidate access network device, it may implicitly indicate inheritance of the transport layer information for data transfer to the candidate access network device. After receiving the first request, the first access network device determines that the first request includes the transport layer information for data transfer to the candidate access network device, and then inherits the transport layer information for data transfer to the candidate access network device.

[0010] In a possible design, the first request also includes second indication information, where the second indication information is used to indicate that pre-configuration information of the cell of the candidate access network device is retained, and the pre-configuration information is used to access the cell of the candidate access network device.

[0011] By applying for the pre-configuration information of the cell of the candidate access network device in advance, in the process of switching from the cell of the second access network device to the cell of the first access network device, the second access network device indicates to retain the pre-configuration information of the cell of the candidate access network device, so that after the terminal device switches from the cell of the second access network device to the cell of the first access network device, the first access network device can switch from the cell of the first access network device to the cell of the candidate access network device without applying for the pre-configuration information of the cell of the candidate access network device. This reduces the process of applying for switching resources, reduces the switching time, and improves the switching efficiency.

[0012] In one possible design, the first request includes pre-configuration information of a cell of a candidate access network device. The pre-configuration information of a cell of a candidate access network device included in the first request may be second indication information. That is, if the first request includes pre-configuration information of a cell of a candidate access network device, it may implicitly indicate that the pre-configuration information of the cell of the candidate access network device is retained. After receiving the first request, the first access network device determines that the first request includes pre-configuration information of a cell of a candidate access network device, and then retains the pre-configuration information of the cell of the candidate access network device.

[0013] In one possible design, the preconfiguration information includes preconfiguration information based on conditional switching CHO, and / or preconfiguration information based on L1 / L2 triggered mobility LTM switching. That is, the second access network device can apply for the preconfiguration information of the cell of the candidate access network device through the CHO switching process or the LTM switching process, and send the preconfiguration information of the cell of the candidate access network device to the terminal device and the first access network device. The terminal device can determine whether to access the cell of the candidate access network device according to the CHO switching trigger condition of the cell of the candidate access network device evaluated by itself in the CHO switching process. Alternatively, the first access network device determines whether to switch to the cell of the candidate access network device according to the measurement report based on the cell of the candidate access network device in the LTM switching process. If the terminal device or the first access network device determines to switch to the cell of the candidate access network device, the cell of the candidate access network device is accessed based on the preconfiguration information.

[0014] In one possible design, the first access network device sends first information to the second access network device, where the first information is used to indicate confirmation of inheriting the transport layer information for transferring data to the candidate access network device.

[0015] In one possible design, the transport layer information includes the transport layer information on the core network side. For example, when the switching with the cell of the candidate access network device is Ng switching, the transport layer information is the transport layer information on the core network side.

[0016] In one possible design, the transport layer information includes the transport layer information of the candidate access network device side. For example, when the switching with the cell of the candidate access network device is an Xn switching, the transport layer information is the transport layer information of the candidate access network device side.

[0017] In one possible design, the first access network device or the second access network device is a non-terrestrial network NTN base station, and the candidate access network device is a terrestrial network NT base station; or, the first access network device or the second access network device is a NT base station, and the candidate access network device is an NTN base station.

[0018] In a second aspect, an embodiment of the present application provides a communication method, which is applied to a second access network device, or a chip or circuit configured in the second access network device includes:

[0019] Obtaining transport layer information for transferring data to a candidate access network device;

[0020] A first request is sent to a first access network device, where the first request is used to request switching from a cell of the second access network device to a cell of the first access network device, and the first request includes first indication information, where the first indication information is used to indicate inheritance of transport layer information for data transfer to the candidate access network device.

[0021] By applying for the transport layer information for data transfer to the candidate access network device in advance, in the process of switching from the cell of the second access network device to the cell of the first access network device, the second access network device indicates to inherit the transport layer information for data transfer to the candidate access network device, so that after the terminal device switches from the cell of the second access network device to the cell of the first access network device, the first access network device can switch from the cell of the first access network device to the cell of the candidate access network device without applying for the transport layer information for data transfer to the candidate access network device. This reduces the process of applying for switching resources, reduces the switching time, and improves the switching efficiency.

[0022] In one possible design, the first request includes the transport layer information. The transport layer information for data transfer to the candidate access network device included in the first request may be first indication information. That is, if the first request includes the transport layer information for data transfer to the candidate access network device, it may implicitly indicate inheritance of the transport layer information for data transfer to the candidate access network device. After receiving the first request, the first access network device determines that the first request includes the transport layer information for data transfer to the candidate access network device, and then inherits the transport layer information for data transfer to the candidate access network device.

[0023] In a possible design, the first request also includes second indication information, where the second indication information is used to indicate that pre-configuration information of the cell of the candidate access network device is retained, and the pre-configuration information is used to access the cell of the candidate access network device.

[0024] By applying for the pre-configuration information of the cell of the candidate access network device in advance, in the process of switching from the cell of the second access network device to the cell of the first access network device, the second access network device indicates to retain the pre-configuration information of the cell of the candidate access network device, so that after the terminal device switches from the cell of the second access network device to the cell of the first access network device, it is not necessary to apply for the pre-configuration information of the cell of the candidate access network device, and can execute the switching from the cell of the first access network device to the cell of the candidate access network device. Thereby reducing the process of applying for switching resources, reducing the switching time, and improving the switching efficiency.

[0025] In one possible design, the first request includes pre-configuration information of a cell of a candidate access network device. The pre-configuration information of a cell of a candidate access network device included in the first request may be second indication information. That is, if the first request includes pre-configuration information of a cell of a candidate access network device, it may implicitly indicate that the pre-configuration information of the cell of the candidate access network device is retained. After receiving the first request, the first access network device determines that the first request includes pre-configuration information of a cell of a candidate access network device, and then retains the pre-configuration information of the cell of the candidate access network device.

[0026] In one possible design, the preconfiguration information includes preconfiguration information based on conditional switching CHO, and / or preconfiguration information based on L1 / L2 triggered mobility LTM switching. That is, the second access network device can apply for the preconfiguration information of the cell of the candidate access network device through the CHO switching process or the LTM switching process, and send the preconfiguration information of the cell of the candidate access network device to the terminal device and the first access network device. The terminal device can determine whether to access the cell of the candidate access network device according to the CHO switching trigger condition of the cell of the candidate access network device evaluated by itself in the CHO switching process. Alternatively, the first access network device determines whether to switch to the cell of the candidate access network device according to the measurement report based on the cell of the candidate access network device in the LTM switching process. If the terminal device or the first access network device determines to switch to the cell of the candidate access network device, the cell of the candidate access network device is accessed based on the preconfiguration information.

[0027] In one possible design, first information sent by the first access network device is received, and the first information is used to indicate confirmation of inheritance of the transport layer information for transferring data to the candidate access network device.

[0028] In one possible design, the second access network device sends second information to the terminal device, the second information is used to indicate switching from the cell of the second access network device to the cell of the first access network device, and the second information includes third indication information, the third indication information is used to indicate retaining the pre-configuration information of the cell of the candidate access network device. By instructing the terminal device to retain the pre-configuration information of the cell of the candidate access network device, during the process of switching from the cell of the first access network device to the cell of the candidate access network device, the cell of the candidate access network device is accessed through the pre-configuration information of the cell of the candidate access network device, thereby ensuring successful switching.

[0029] In one possible design, the second access network device sends pre-configuration information of the cell of the candidate access network device to the terminal device.

[0030] In one possible design, the first access network device sends first information to the second access network device, where the first information is used to indicate confirmation of inheriting the transport layer information for transferring data to the candidate access network device.

[0031] In one possible design, the transport layer information includes the transport layer information on the core network side. For example, when the switching with the cell of the candidate access network device is Ng switching, the transport layer information is the transport layer information on the core network side.

[0032] In one possible design, the first access network device or the second access network device is a non-terrestrial network NTN base station, and the candidate access network device is a terrestrial network NT base station; or, the first access network device or the second access network device is a NT base station, and the candidate access network device is an NTN base station.

[0033] In a third aspect, an embodiment of the present application provides a communication method, which is applied to a terminal device, or a chip or circuit configured in the terminal device includes:

[0034] receiving second information sent by a second access network device, where the second information includes third indication information, where the third indication information is used to indicate that pre-configuration information of a cell of a candidate access network device is retained;

[0035] After switching from the cell of the second access network device to the cell of the first access network device, the pre-configuration information of the cell of the candidate access network device is retained, and the pre-configuration information is used to access the cell of the candidate access network device.

[0036] By instructing the terminal device to retain the pre-configuration information of the cell of the candidate access network device, during the process of switching from the cell of the first access network device to the cell of the candidate access network device, the cell of the candidate access network device is accessed through the pre-configuration information of the cell of the candidate access network device, thereby ensuring successful switching.

[0037] In one possible design, pre-configuration information of the cell of the candidate access network device sent by the second access network device is received.

[0038] In a possible design, the pre-configuration information includes pre-configuration information based on conditional switching CHO and / or pre-configuration information based on L1 / L2 triggered mobility LTM switching.

[0039] In one possible design, the first access network device or the second access network device is a non-terrestrial network NTN base station, and the candidate access network device is a terrestrial network NT base station; or, the first access network device or the second access network device is a NT base station, and the candidate access network device is an NTN base station.

[0040] In a fourth aspect, an embodiment of the present application provides a communication device, the communication device comprising:

[0041] a receiving module, configured to receive a first request sent by a second access network device, the first request being used to request switching from a cell of the second access network device to a cell of the first access network device, the first request comprising first indication information, the first indication information being used to indicate inheritance of transport layer information for data transfer to a candidate access network device;

[0042] A processing module is used to establish a data forwarding tunnel with the candidate access network device based on the transport layer information.

[0043] In one possible design, the first request includes the transport layer information.

[0044] In a possible design, the first request also includes second indication information, where the second indication information is used to indicate that pre-configuration information of the cell of the candidate access network device is retained, and the pre-configuration information is used to access the cell of the candidate access network device.

[0045] In one possible design, the first request includes the preconfiguration information.

[0046] In a possible design, the pre-configuration information includes pre-configuration information based on conditional switching CHO and / or pre-configuration information based on L1 / L2 triggered mobility LTM switching.

[0047] In one possible design, the device further includes:

[0048] A sending module is used to send first information to the second access network device, where the first information is used to indicate confirmation of inheriting the transport layer information for data transfer to the candidate access network device.

[0049] In one possible design, the transport layer information includes transport layer information on the core network side.

[0050] In one possible design, the transport layer information includes transport layer information on the candidate access network device side.

[0051] In one possible design, the first access network device or the second access network device is a non-terrestrial network NTN base station, and the candidate access network device is a terrestrial network NT base station; or, the first access network device or the second access network device is a NT base station, and the candidate access network device is an NTN base station.

[0052] The operations and beneficial effects performed by the communication device can refer to the method and beneficial effects described in the first aspect above, and the repeated parts will not be repeated.

[0053] In a fifth aspect, an embodiment of the present application provides a communication device, the communication device comprising:

[0054] A receiving module, used to obtain transport layer information for transferring data to a candidate access network device;

[0055] A sending module is used to send a first request to a first access network device, wherein the first request is used to request switching from a cell of a second access network device to a cell of the first access network device, and the first request includes first indication information, and the first indication information is used to indicate inheritance of transport layer information for data transfer to the candidate access network device.

[0056] In one possible design, the first request includes the transport layer information.

[0057] In a possible design, the first request also includes second indication information, where the second indication information is used to indicate that pre-configuration information of the cell of the candidate access network device is retained, and the pre-configuration information is used to access the cell of the candidate access network device.

[0058] In one possible design, the first request includes the preconfiguration information.

[0059] In a possible design, the pre-configuration information includes pre-configuration information based on conditional switching CHO and / or pre-configuration information based on L1 / L2 triggered mobility LTM switching.

[0060] In one possible design, the receiving module is also used to receive first information sent by the first access network device, and the first information is used to indicate confirmation of inheritance of the transport layer information for data transfer to the candidate access network device.

[0061] In one possible design, the sending module is also used to send second information to the terminal device, the second information is used to indicate switching from the cell of the second access network device to the cell of the first access network device, the second information includes third indication information, and the third indication information is used to indicate retaining pre-configuration information of the cell of the candidate access network device.

[0062] In a possible design, the sending module is also used to send pre-configuration information of the cell of the candidate access network device to the second access network device and the terminal device.

[0063] In one possible design, the transport layer information includes address information on the core network side.

[0064] In one possible design, the transport layer information includes transport layer information on the candidate access network device side.

[0065] In one possible design, the first access network device or the second access network device is a non-terrestrial network NTN base station, and the candidate access network device is a terrestrial network NT base station; or, the first access network device or the second access network device is a NT base station, and the candidate access network device is an NTN base station.

[0066] The operations and beneficial effects performed by the communication device can refer to the method and beneficial effects described in the second aspect above, and the repeated parts will not be repeated.

[0067] In a sixth aspect, an embodiment of the present application provides a communication device, the communication device comprising:

[0068] A receiving module, configured to receive second information sent by a second access network device, where the second information includes third indication information, where the third indication information is used to indicate pre-configuration information of a cell of a candidate access network device;

[0069] The processing module is used to retain the pre-configuration information of the cell of the candidate access network device after switching from the cell of the second access network device to the cell of the first access network device, wherein the pre-configuration information is used to access the cell of the candidate access network device.

[0070] In one possible design, the receiving module is also used to receive pre-configuration information of the cell of the candidate access network device sent by the second access network device.

[0071] In a possible design, the pre-configuration information includes pre-configuration information based on conditional switching CHO and / or pre-configuration information based on L1 / L2 triggered mobility LTM switching.

[0072] In one possible design, the first access network device or the second access network device is a non-terrestrial network NTN base station, and the candidate access network device is a terrestrial network NT base station; or, the first access network device or the second access network device is a NT base station, and the candidate access network device is an NTN base station.

[0073] The operations and beneficial effects performed by the communication device can refer to the method and beneficial effects described in the third aspect above, and the repeated parts will not be repeated.

[0074] In a seventh aspect, the present application provides a communication device, comprising a processor and a memory, wherein the memory is used to store a computer program; the processor is used to execute the computer program stored in the memory so that the communication device performs a method as described in any one of the first aspects.

[0075] In an eighth aspect, the present application provides a communication device, comprising a processor and a memory, wherein the memory is used to store a computer program; the processor is used to execute the computer program stored in the memory so that the communication device performs a method as described in any one of the second aspects.

[0076] In a ninth aspect, the present application provides a communication device, comprising a processor and a memory, wherein the memory is used to store a computer program; the processor is used to execute the computer program stored in the memory so that the communication device performs a method as described in any one of the third aspects.

[0077] In the tenth aspect, the present application provides a communication device, which may be a first access network device, or a device in the first access network device, or a device that can be used in combination with the first access network device. Among them, the communication device may also be a chip system. The communication device may execute the method described in the first aspect. The functions of the communication device may be implemented by hardware, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules corresponding to the above functions. The module may be software and / or hardware. The operations and beneficial effects performed by the communication device may refer to the methods and beneficial effects described in the first aspect above, and the repeated parts will not be repeated.

[0078] In the eleventh aspect, the present application provides a communication device, which may be a second access network device, or a device in the second access network device, or a device that can be used in combination with the second access network device. Among them, the communication device may also be a chip system. The communication device may execute the method described in the second aspect. The functions of the communication device may be implemented by hardware, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules corresponding to the above functions. The module may be software and / or hardware. The operations and beneficial effects performed by the communication device may refer to the methods and beneficial effects described in the second aspect above, and the repetitive parts will not be repeated.

[0079] In the twelfth aspect, the present application provides a communication device, which may be a terminal device, or a device in a terminal device, or a device that can be used in combination with a terminal device. Among them, the communication device may also be a chip system. The communication device may execute the method described in the third aspect. The functions of the communication device may be implemented by hardware, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules corresponding to the above functions. The module may be software and / or hardware. The operations and beneficial effects performed by the communication device may refer to the methods and beneficial effects described in the third aspect above, and the repetitive parts will not be repeated.

[0080] In a thirteenth aspect, the present application provides a computer-readable storage medium for storing a computer program. When the computer program is executed, the method described in any one of the first to third aspects is implemented.

[0081] In a fourteenth aspect, the present application provides a computer program product comprising a computer program, which, when executed, enables the method described in any one of the first to third aspects to be implemented.

[0082] In the fifteenth aspect, an embodiment of the present application provides a communication system, which includes at least one terminal device and at least one access network device, the access network device is used to execute the steps in the above-mentioned first aspect or second aspect, and the terminal device is used to execute the steps in the above-mentioned third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the accompanying drawings required in the embodiments of the present application or the background technology will be described below.

[0084] Figure 1 is a schematic diagram of a communication system provided in an embodiment of the present application;

[0085] Figure 2 It is a schematic diagram of a CU-DU network structure;

[0086] Figure 3 It is a schematic diagram of the architecture of a transparent satellite;

[0087] Figure 4 It is a schematic diagram of the architecture of a regenerative satellite;

[0088] Figure 5 This is a schematic diagram of LTM switching;

[0089] Figure 6 This is another schematic diagram of LTM switching;

[0090] Figure 7 It is a schematic diagram of a CHO process;

[0091] Figure 8 It is a schematic diagram of switching between NTN and TN;

[0092] Fig. 9 It is a flow chart of a communication method provided in an embodiment of the present application;

[0093] Fig.10 It is a flowchart of another communication method provided in an embodiment of the present application;

[0094] Fig.11It is a flowchart of another communication method provided in an embodiment of the present application;

[0095] Fig.12 is a structural diagram of a communication device provided in an embodiment of the present application;

[0096] Fig.13 It is a structural diagram of an access network device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0097] like Figure 1 As shown, Figure 1 1 is a schematic diagram of a communication system provided in an embodiment of the present application. The communication system mainly includes terminal equipment, core network equipment and access network equipment. Among them:

[0098] Terminal equipment, also known as user equipment (UE), mobile station (MS), mobile terminal (MT), etc., refers to equipment that provides voice and / or data connectivity to users. For example, handheld devices with wireless connection functions, vehicle-mounted devices, etc. At present, some examples of terminals are: mobile phones, tablet computers, laptops, PDAs, mobile Internet devices (MID), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, etc.

[0099] Access network equipment refers to the radio access network (RAN) node (or device) that connects the terminal to the wireless network, which can also be called a base station. At present, some examples of RAN nodes are: evolved Node B (gNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved NodeB, or home Node B, HNB), base band unit (BBU), or wireless fidelity (Wifi) access point (AP).

[0100] The access network equipment and terminal equipment can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on the water surface; they can also be deployed on airplanes, balloons and satellites in the air. The embodiments of the present application do not limit the application scenarios of the access network equipment and terminal equipment.

[0101] like Figure 2 As shown, Figure 2It is a schematic diagram of the network structure of CU-DU. The access network equipment may include a centralized unit (CU) node, a distributed unit (DU) node, or a RAN device including a CU node and a DU node. The RAN device including the CU node and the DU node splits the protocol layer of the gNB in ​​the NR system, places the functions of some protocol layers under the centralized control of the CU, and distributes the functions of the remaining part or all of the protocol layers in the DU, which is centrally controlled by the CU. Furthermore, the centralized unit CU can also be divided into a control plane (CU-CP) and a user plane (CU-UP). Among them, the CU-CP is responsible for the control plane function, mainly including the packet data convergence protocol (PDCP) corresponding to the RRC and the control plane, namely PDCP-C. PDCP-C is mainly responsible for the encryption and decryption, integrity protection, data transmission, etc. of the control plane data. CU-UP is responsible for the user plane function, mainly including SDAP and the PDCP corresponding to the user plane, namely PDCP-U. Among them, SDAP is mainly responsible for processing the data of the core network and mapping the flow to the bearer. PDCP-U is mainly responsible for encryption and decryption, integrity protection, header compression, sequence number maintenance, data transmission, etc. of the data plane. Among them, CU-CP and CU-UP are connected through the E1 interface. CU-CP represents the gNB connected to the core network through the NG interface. The control plane through the F1 interface, i.e., F1-C, is connected to the DU. CU-UP is connected to the DU through the user plane of the F1 interface, i.e., F1-U. Of course, another possible implementation is that PDCP-C is also in CU-UP.

[0102] Core network equipment refers to equipment in the core network (CN) that provides service support for terminals. At present, some examples of core network equipment are: access and mobility management function (AMF) entity, session management function (SMF) entity, user plane function (UPF) entity, etc., which are not listed here one by one. Among them, the AMF entity can be responsible for terminal access management and mobility management; the SMF entity can be responsible for session management, such as user session establishment, etc.; the UPF entity can be a functional entity of the user plane, mainly responsible for connecting to the external network. It should be noted that the entity in this application can also be referred to as a network element or a functional entity. For example, the AMF entity can also be referred to as an AMF network element or an AMF functional entity. For another example, the SMF entity can also be referred to as an SMF network element or an SMF functional entity, etc.

[0103] The communication system can be applicable to a long term evolution (LTE) system, a universal mobile telecommunications system (UMTS) system, a code division multiple access (CDMA) system, a wireless local area network (WLAN) or a fifth generation mobile communication system (5G) or a next generation wireless communication system, etc.

[0104] NTN is a communication achieved with the help of non-terrestrial network equipment. NTN systems can include satellite systems, drones, and high altitude platform stations (HAPS). NTN communication has the advantages of wide coverage, long communication distance, high reliability, high flexibility, and high throughput. It is not affected by geographical environment, climatic conditions, and natural disasters, and has been widely used in aviation communications, maritime communications, military communications, and other fields. Introducing NTN into the future fifth-generation mobile network (5G) can greatly improve user experience. On the one hand, NTN can provide communication services for areas that are difficult to cover by terrestrial networks, such as oceans, forests, deserts, or remote areas; on the other hand, NTN can enhance the reliability of 5G communications, such as providing more stable communication services for users in high-speed mobile scenarios such as trains and airplanes; in addition, NTN can also provide more data transmission resources and support a larger number of connections. Thanks to the concept of "any time, any place" communication, the status of NTN will be further improved in the future.

[0105] Generally speaking, the higher the satellite's orbit, the larger its coverage area, but the longer the communication delay. According to the orbital altitude, satellites can be divided into: low-orbit satellites (LEO), with an orbital altitude of 160 to 2000 km; medium-orbit satellites (MEO), with an orbital altitude of 2000 to 35,786 km; high-orbit satellites, also known as geostationary orbit (GEO) satellites, with an orbital altitude of 35,786 km; among them, GEO is a synchronous earth satellite orbit, and satellites operating in this orbit are stationary relative to the ground; LEO and MEO are collectively referred to as non-geostationary orbits (NGSO), and satellites operating in such orbits move at high speed relative to the ground.

[0106] For NGSO, it can be further divided into Earth Moving Cell and Earth Fixed Cell according to whether the satellite beam moves with the satellite. For Earth Moving Cell, the cell moves relative to the ground, and the satellite beam points to follow the satellite movement; for Earth Fixed Cell, the cell is fixed relative to the ground for a certain period of time, and the satellite antenna can use its beamforming capability to point the beam to a certain area fixed on the ground for a certain period of time.

[0107] According to the satellite's working mode, satellites can generally be divided into two categories. They include:

[0108] like Figure 3 As shown, Figure 3 It is a schematic diagram of the architecture of a transparent satellite. The satellite forwards the cell information of ground network equipment (such as base stations) in a transparent forwarding form. The role of the satellite is wireless frequency filtering, frequency conversion and amplification, that is, the satellite mainly acts as an L1 relay to regenerate the physical layer signal and does not have other higher protocol layers.

[0109] like Figure 4 As shown, Figure 4 This is a schematic diagram of the architecture of a regenerative satellite. In a regenerative form, the satellite has the processing function of a base station. In the regenerative working mode, it can be divided into a regenerative satellite without an intersatellite link, that is, there is no intersatellite link (ISL) between satellites; a regenerative satellite with an intersatellite link, that is, there is an interface between satellites to directly exchange data, where the intersatellite link is an Xn port; there is also an architecture in which the satellite has the DU processing function of a base station, and the satellite can act as a DU in this scenario.

[0110] It should be noted that Figure 3 and Figure 4 Only one satellite and one NTN gateway are shown. In actual use, a plurality of satellites and / or a plurality of NTN gateways may be used as required. Each satellite may provide services to one or more terminal devices, each NTN gateway may correspond to one or more satellites, and each satellite may correspond to one or more NTN gateways, which are not specifically limited in the embodiments of the present application.

[0111] It should be noted that Figure 3 and Figure 4 It is only an example of an NTN scenario. The NTN scenario may also include other specific scenarios, which are not limited in this application.

[0112] It should be noted that the embodiments of the present application can be used in transparent satellite architecture and regenerative satellite architecture, and can also be used in Earth Moving Cell and Quasi-Earth Fixed Cell scenarios.

[0113] L1 / L2 triggered mobility (LTM) switching is mainly a switching involving L1 and / or L2, and switching-related operations are mainly performed in L1 and L2. Among them, L1 refers to the physical layer, and L2 refers to one or more layers of the media access control (MAC) layer, the radio link control (RLC) layer, the packet data convergence protocol (PDCP), and the service data adaptation protocol (SDAP) layer. L1 / L2 can also be understood as L1 and / or L2. For example, the terminal device sends the L1 measurement result to the access network device through the physical layer control signaling, wherein the physical layer control signaling is carried on the physical uplink control channel (PUCCH). The access network device reads the L1 measurement result, makes a switching decision based on the L1 measurement result, and sends the switching decision to the terminal device through L1 / L2 signaling. The L1 / L2 signaling may be carried on a physical downlink control channel (PDCCH) or a media access control protocol control element (MAC CE).

[0114] LTM switching refers to switching-related operations mainly performed at the physical layer and MAC layer, but it should be understood that LTM switching also involves the participation of other protocol layers, such as the RRC layer (also known as L3). This application document does not limit the specific name of the switching technology, and L1 / L2 switching can also be called bottom layer switching, or lower layer switching, etc.

[0115] L1 / L2 switching is applicable to: (1) cell switching across DUs within the same CU (i.e., the source cell and the target cell belong to different DUs under the same CU); (2) cell switching within the same DU (i.e., the source cell and the target cell belong to the same DU). It may be introduced into NTN in the future, NTN to TN switching, or NTN to NTN switching, and may also be introduced into more scenarios. In the above different scenarios, although the specific signaling interaction content of L1 / L2 switching is different, the basic idea is the same.

[0116] like Figure 5 As shown, Figure 5 This is a schematic diagram of LTM switching. In the cell switching scenario within the same DU under the CU-DU separation architecture, the UE switches from the source cell (cell1) to the target cell (cell2) through LTM switching. It mainly includes the following steps:

[0117] S501, CU sends configuration information of LTM candidate cells to UE. It should be understood that CU sends configuration information to UE via DU.

[0118] S502, the UE sends the measurement result to the access network device (DU in the figure) to which the source cell belongs.

[0119] Specifically, the UE measures the reference signal of the source cell and / or the candidate cell according to the configuration information, obtains the measurement result, and then reports the measurement result to the DU.

[0120] The measurement result includes at least one of the following: an L1 measurement result of a source cell, and an L1 measurement result of at least one candidate cell. The L1 measurement result of the source cell and / or the candidate cell may be a cell-level measurement result, such as a cell-level reference signal received power (RSRP). It may also be a beam-level measurement result, such as a beam-level RSRP.

[0121] S503: The DU sends a handover command to the UE.

[0122] Specifically, after receiving the measurement result, the DU determines whether to switch according to the measurement result. If the switch is determined, a switching command is sent to the UE.

[0123] For example, when the signal quality of a candidate cell is better than that of the source cell, it is determined to switch to the candidate cell, and the candidate cell can also be called the target cell. The DU sends a handover command to the UE. The handover command is an LTM handover command, and the LTM handover command is an L1 / L2 signaling.

[0124] The handover command may include the identity information of the target cell, or the identity information associated with the target cell. Furthermore, the handover command may also carry indication information, which is used to indicate the beam information that the UE should use when communicating with the target cell.

[0125] S504, the UE accesses the target cell in the DU.

[0126] Specifically, the UE performs handover according to the configuration information of the target cell received in S501, accesses the target cell of the DU, and starts uplink and downlink data transmission with the target cell after successful access. Further, the UE can use the beam information indicated in S503 to perform uplink and downlink data transmission with the target cell. In this application document, the communication between the UE and the target cell can be understood as the communication between the UE and the access network device to which the target cell belongs.

[0127] Furthermore, the UE may access the target cell using a random access channel (RACH), or access the target cell using a RACH-less method.

[0128] S505, the DU sends notification information to the CU, where the notification information is used to indicate that the UE has successfully completed the LTM switching.

[0129] The notification information may include identification information associated with the target cell identity.

[0130] like Figure 6 As shown, Figure 6 This is another schematic diagram of LTM switching. In the CU-DU separation architecture, in the cell switching scenario between different DUs under the same CU, the UE switches from the source DU to the target DU through LTM switching. Figure 5 The steps shown are different in that: in S601, the CU establishes a UE context with the target DU, obtains the configuration information of the cell of the target DU as the configuration information of the candidate cell, and sends the configuration information of the candidate cell to the UE in S602. Finally, the UE accesses the target cell of the target DU in S605. For other steps, please refer to Figure 5 , I will not go into details here.

[0131] It should be understood that the target DU may also be referred to as a candidate DU before switching. When it is determined to switch to a target cell of a candidate DU, the candidate DU may be referred to as a target DU.

[0132] In the traditional new radio (NR) basic handover, the signal of the base station can be measured during the movement of the terminal device. If the signal quality of the target base station is measured to be better than that of the source base station, the cell covered by the source base station can be switched to the cell covered by the target base station. However, due to the deterioration of the wireless environment between the UE and the source base station, the UE's measurement report may not reach the base station, resulting in a handover failure. At this time, the UE will recognize the failure of the wireless link and initiate the RRC reconstruction process.

[0133] In order to reduce the probability of NR basic handover, the 3rd generation partnership project (3GPP) R16 introduced conditional handover (CHO), which is an enhancement of NR basic handover. CHO can be understood as: before the wireless environment between the UE and the source base station further deteriorates, the source base station sends the handover command (carrying the CHO configuration of the candidate target base station and the CHO trigger condition) to the UE in advance, so that the UE knows how to access the target base station in advance. After the UE finds a base station that meets the CHO trigger condition among the candidate target base stations, it can decide to initiate the handover independently, which increases the chance of successful message transmission and can greatly improve the success rate of the handover. Figure 7 As shown, Figure 7 This is a schematic diagram of the CHO process. It mainly includes the following steps:

[0134] S701. The source base station sends a measurement configuration to a UE.

[0135] S702, the UE measures one or more candidate base stations (including candidate base station 1 and candidate base station 2) based on the measurement configuration, obtains measurement reports of the one or more candidate base stations, and sends the measurement reports to the source base station.

[0136] S703 : The source base station sends a first handover request to the candidate base station 1 . The first handover request is used to request CHO configuration of one or more candidate cells of the candidate base station 1 .

[0137] S704 , candidate base station 1 sends first handover confirmation information to the source base station. The first handover confirmation information includes CHO configuration of one or more candidate cells of candidate base station 1 .

[0138] S705 : The source base station sends a second handover request to the candidate base station 2 , where the second handover request is used to request CHO configuration of one or more candidate cells of the candidate base station 2 .

[0139] S706 , the candidate base station 2 sends second handover confirmation information to the source base station, where the second handover confirmation information includes the CHO configuration of one or more candidate cells of the candidate base station 2 .

[0140] S703-S704 and S705-S706 are in no particular order.

[0141] S707, the source base station sends CHO configuration information (pre-configuration information of candidate cells) to the UE when the source link quality is good. The CHO configuration information may include CHO switching trigger conditions and related information of one or more candidate cells (information required for the UE to access the candidate cells).

[0142] The relevant information of the candidate cell may include at least one of the following: a cell-radio network temporary identifier (C-RNTI) allocated by the candidate cell to the UE, resource information of a random access channel (RACH) required to access the candidate cell, index information corresponding to the candidate cell (for example, a measurement identifier measID corresponding to the cell and / or a CHO-ConfigId corresponding to the cell), a cell global identity (CGI) of the candidate cell, a physical cell identifier (PCI) of the candidate cell, and frequency information corresponding to the candidate cell, physical layer configuration parameters corresponding to the candidate cell, MAC layer configuration parameters, RLC layer configuration parameters, PDCP layer configuration parameters, SDAP layer configuration parameters, RRC layer configuration parameters, etc. Among them, the frequency information corresponding to the candidate cell includes one or more of the following: the absolute frequency of the synchronization signal block SSB (absolute frequency SSB), the absolute frequency position (absolute Frequency pointA) of the reference resource module (common RB0), a frequency bandwidth list (frequency band list), and an SCS-specific carrier list (scs-specific carrier list).

[0143] The CHO switching trigger condition may include a CHO execution event type and a corresponding threshold value. The CHO execution event type may include event A3, event A4, event A5, event B1, event B2 or other execution event types. A candidate cell may be configured with one or more CHO switching trigger conditions. For example, a candidate cell may be configured with an execution event type, but may be configured with at least two different threshold values ​​and / or at most two different trigger qualities (triggerquantity). The trigger quality may include reference signal received power (reference signal received power, RSRP), reference signal received quality (reference signal received quality, RSRQ), and signal to interference plus noise ratio (signal to interference plus noise ratio, SINR). Alternatively, a candidate cell may be configured with at least two different execution event types and threshold values ​​corresponding to each execution event type. The CHO execution event types corresponding to different candidate cells may be the same or different. The threshold values ​​corresponding to different candidate cells may be the same or different, without limitation.

[0144] S708: The UE determines whether the candidate cell meets the handover triggering condition according to the CHO configuration information, and selects a candidate cell that meets the handover triggering condition as the target cell.

[0145] For example, for candidate cell A, the configured CHO execution event type is an A3 event, and the configured corresponding threshold value is a first threshold value. When the cell signal quality of candidate cell A is higher than the first threshold value of the cell signal quality of the serving cell, it can be considered that candidate cell A meets the CHO switching trigger condition, and the candidate cell A can be determined as the target cell. Specifically, for example, for candidate cell A, an A3 event is configured, and two trigger qualities are configured, such as RSRP and RSRQ, and the configured first threshold value corresponding to RSRP is E, and the configured first threshold value corresponding to RSRQ is F. Then, when the RSRP of candidate cell A is higher than the RSRP of the serving cell by E, and the RSRQ of candidate cell A is higher than the RSRQ of the serving cell by F, it can be considered that candidate cell A meets the CHO switching trigger condition, and the candidate cell A can be determined as the target cell. For another example, corresponding to candidate cell B, if the configured CHO execution event type is an A5 event, a trigger quality is configured, such as RSRP, and the corresponding threshold values ​​are configured as the second threshold and the third threshold. Then, when the RSRP of candidate cell B is higher than the second threshold and the RSRP of the serving cell is lower than the third threshold, it can be considered that candidate cell B meets the CHO switching trigger condition, and the candidate cell B can be determined as the target cell.

[0146] S709, the UE accesses the target cell, for example, by performing a random access process.

[0147] S710, the UE sends an RRC message (such as an RRC reconfiguration completion message) to the base station to which the target cell belongs (ie, the target base station), where the RRC message is used to notify the target base station that the conditional handover is completed.

[0148] like Figure 8 As shown, Figure 8 This is a schematic diagram of switching between NTN and TN. In the networking of NTN and TN, the Xn interface between the NTN network and the TN network is very likely to not exist. Therefore, switching between NTN and TN requires switching preparation through the Ng interface, and the Ng interface switching preparation may pass through multiple satellites, satellite gateways and core networks. The whole process may take up to hundreds of milliseconds (ms), resulting in a long switching preparation time.

[0149] Taking the switching from NTN (where NTN is a satellite) to TN as an example, when the pre-configuration information of the candidate TN cell is sent to the UE but the UE does not switch to the candidate TN cell, due to the rapid movement of the satellite, the source satellite switches the UE to the target satellite. In the prior art, the pre-configuration information of the candidate TN cell needs to be released when the switch occurs or after the switch is completed. However, after the switch is successful, the target satellite is likely to re-apply for the pre-configuration information of the candidate TN cell for the UE to switch to the candidate TN cell. The re-application process wastes time and is not conducive to the UE switching to the candidate TN target cell in a timely manner.

[0150] In order to solve the above technical problems, the embodiments of the present application provide the following solutions.

[0151] The embodiments of the present application involve Ng switching and Xn switching. The Ng switching and Xn switching are explained below:

[0152] Xn switching: Xn is the interface between two access network devices. When there is an Xn interface between two access network devices, the two access network devices can directly complete the switching through the Xn interface, that is, the source access network device sends a switching request to the target access network device and receives the switching confirmation information sent by the target access network device. When transferring data, it does not need to pass through the core network, so only the transport layer information of the candidate access network device needs to be known.

[0153] Ng switching: When the switching cannot be completed through the Xn interface, the switching is completed through the Ng interface. When the source access network device needs to apply for the switching resources of a certain terminal device from the target access network device, the source access network device sends a switching request to the core network device. After receiving the switching request, the core network device sends a switching request to the target access network device. The core network device may need to forward during this process. When transferring data, the source access network device is also required to send the transferred data to the core network device, and then the core network device sends the transferred data to the target access network device. Therefore, for the source access network device, it is necessary to know the transport layer information of the next-hop core network side when transferring data. For the core network side, it is necessary to know the transport layer information of the candidate access network device.

[0154] like Fig. 9 As shown, Fig. 9 1 is a flow chart of a communication method provided in an embodiment of the present application. The method in the embodiment of the present application comprises the following steps:

[0155] S901, a first access network device receives a first request sent by a second access network device, where the first request is used to request switching from a cell of the second access network device to a cell of the first access network device, and the first request includes first indication information, where the first indication information is used to indicate inheritance of transport layer information for data transfer to a candidate access network device.

[0156] The first request may be a handover request. The transport layer information may include transport layer information on the core network side or transport layer information on the candidate access network device side. When the handover with the cell of the candidate access network device is an Xn handover, the transport layer information is the transport layer information on the candidate access network device side; when the handover with the cell of the candidate access network device is an Ng handover, the transport layer information is the transport layer information on the core network side. Further, the transport layer information may include an IP address and a port number.

[0157] Optionally, the first request may include transport layer information for transferring data to the candidate access network device (i.e., when the first access network device transfers data to the candidate access network device through the core network, the transport layer information on the core network side or the transport layer information on the candidate access network device side).

[0158] It should be understood that the transport layer information for data transfer to the candidate access network device included in the first request may be the first indication information. That is, if the first request includes the transport layer information for data transfer to the candidate access network device, it may implicitly indicate the inheritance of the transport layer information for data transfer to the candidate access network device. After receiving the first request, the first access network device determines that the first request includes the transport layer information for data transfer to the candidate access network device, and then inherits the transport layer information for data transfer to the candidate access network device.

[0159] Optionally, the first request may also include second indication information, the second indication information being used to indicate that the pre-configuration information allocated to the terminal device by the cell of the candidate access network device is retained, and the pre-configuration information is used for the terminal device to access the cell of the candidate access network device. Optionally, the second indication information may also be the first indication information. That is, if the first request includes the second indication information, it may implicitly indicate the inheritance of the transport layer information for data transfer to the candidate access network device.

[0160] Optionally, the first request includes pre-configuration information of a cell of the candidate access network device.

[0161] It should be understood that the pre-configuration information of the cell of the candidate access network device included in the first request may be the second indication information. That is, if the first request includes the pre-configuration information of the cell of the candidate access network device, it may implicitly indicate to retain the pre-configuration information of the cell of the candidate access network device. After receiving the first request, the first access network device determines that the first request includes the pre-configuration information of the cell of the candidate access network device, and then retains the pre-configuration information of the cell of the candidate access network device.

[0162] The pre-configuration information includes information required for accessing a cell of a candidate access network device, and the pre-configuration information may include one or more of the following: a cell ID of the candidate access network device, a cell-radionetwork temporary identifier (C-RNTI), a security algorithm ID, a key, etc. The pre-configuration information may also include dedicated random access channel (RACH) resources, an association between RACH resources and synchronization signals and PBCH blocks (synchronization signal and PBCH block synchronization signal and PBCH block, SSB), an association between RACH resources and a terminal device-specific channel state information reference signal (CSI-RS) configuration, public RACH resources, system information of the cell of the candidate access network device, etc.

[0163] Wherein, the preconfiguration information includes preconfiguration information based on conditional switching CHO, and / or preconfiguration information based on LTM switching. That is, the second access network device can apply for the preconfiguration information of the cell of the candidate access network device through the CHO switching process or the LTM switching process, and send the preconfiguration information of the cell of the candidate access network device to the terminal device and the first access network device. The terminal device can determine whether to access the cell of the candidate access network device according to the CHO switching trigger condition of the cell of the candidate access network device evaluated by itself in the CHO switching process. Alternatively, the first access network device determines whether to switch to the cell of the candidate access network device according to the measurement report based on the cell of the candidate access network device in the LTM switching process. If the terminal device or the first access network device determines to switch to the cell of the candidate access network device, the cell of the candidate access network device is accessed based on the preconfiguration information.

[0164] Optionally, before the second access network device sends the first request to the first access network device, the second access network device may obtain the transport layer information for transferring data to the candidate access network device and the pre-configuration information of the cell of the candidate access network device. Specifically, the following methods may be included:

[0165] In one implementation, when Xn switching is adopted, the second access network device may send a switching request to one or more candidate access network devices, and after receiving the switching request, the candidate access network device allocates pre-configuration information (also called switching configuration) to the terminal device and sends switching confirmation information to the second access network device. The switching confirmation information includes the pre-configuration information of the candidate access network device and the transport layer information on the candidate access network device side.

[0166] In another implementation, when Ng switching is adopted, the second access network device may send a first switching request to the core network device. After receiving the first switching request, the core network device sends a second switching request to one or more candidate access network devices. The candidate access network device allocates pre-configuration information (also called switching configuration) to the terminal device, and then sends a first switching confirmation message to the core network device. The first switching confirmation message may include the pre-configuration information of the candidate access network device and the transport layer information on the candidate access network device side. After receiving the first switching confirmation message, the core network device sends a second switching confirmation message to the second access network device. The second switching confirmation message may include the pre-configuration information of the candidate access network device and the transport layer information on the core network side.

[0167] In another implementation, when Ng switching is adopted, the second access network device may send a first switching request to the core network device. After receiving the first switching request, the core network device sends a second switching request to one or more candidate access network devices. The candidate access network device allocates pre-configuration information (also called switching configuration) to the terminal device, and then sends a first switching confirmation message to the core network device. The first switching confirmation message may include the pre-configuration information of the candidate access network device and the transport layer information on the candidate access network device side. After receiving the first switching confirmation message, the core network device sends a second switching confirmation message to the second access network device. The second switching confirmation message may include the pre-configuration information of the candidate access network device and the transport layer information on the candidate access network device side.

[0168] Optionally, after acquiring the pre-configuration information of the cell of the candidate access network device, the second access network device may send the pre-configuration information of the cell of the candidate access network device to the terminal device.

[0169] S902: The first access network device sends a handover confirmation message to the second access network device. The handover confirmation message is used to indicate confirmation of handover from the cell of the second access network device to the cell of the first access network device or to indicate that the first access network device has prepared resources for handover.

[0170] Optionally, the switching confirmation information carries configuration information allocated by the first access network device to the terminal device.

[0171] Optionally, the switching confirmation information includes first information, where the first information is used to indicate confirmation of inheriting the transport layer information for transferring data to the candidate access network device.

[0172] Optionally, the first information may further include fourth indication information, and the fourth indication information is used to indicate confirmation of retaining the pre-configuration information of the cell of the candidate access network device. Based on the first information, the second access network device may determine that the first access network device inherits the transport layer information for data transfer to the candidate access network device, or determine that the first access network device retains the pre-configuration information of the cell of the candidate access network device.

[0173] S903: The first access network device establishes a data forwarding tunnel with the candidate access network device based on the transport layer information.

[0174] It can be understood that: the first access network device transfers data to the candidate access network device based on the transport layer information.

[0175] It should be noted that if the transport layer information is the transport layer information on the candidate access network device side, the first access network device can directly establish a data forwarding tunnel with the candidate access network device. If the transport layer information is the transport layer information on the core network side, the first access network device establishes a data forwarding tunnel with the core network based on the transport layer information on the core network side. The core network establishes a data forwarding tunnel with the candidate access network device based on the transport layer information on the candidate access network device side. In this way, the first access network device establishes a data forwarding tunnel with the core network, and the core network establishes a data forwarding tunnel with the candidate access network device. Among them, the data forwarding tunnel is used to forward data.

[0176] S904, the second access network device sends second information to the terminal device, where the second information is used to indicate switching from the cell of the second access network device to the cell of the first access network device.

[0177] Optionally, the second information includes third indication information, and the third indication information is used to indicate that pre-configuration information of the cell of the candidate access network device is retained.

[0178] The second information may be a switching command. Optionally, the switching command carries configuration information allocated by the first access network device to the terminal device.

[0179] Optionally, if the terminal device has saved the pre-configuration information of the source cell (eg, the cell of the second access network device), the terminal device may retain the pre-configuration information of the cell of the candidate access network device and the pre-configuration information of the source cell.

[0180] Optionally, the second information also includes pre-configuration information of the cell of the candidate access network device. Optionally, the pre-configuration information of the cell of the candidate access network device included in the second information may be incremental configuration information. If the terminal device has saved the reference configuration information of the cell of the candidate access network device, the terminal device may synthesize the reference configuration information of the cell of the candidate access network device (the basic configuration information common to the cells of multiple candidate access network devices) and the incremental configuration information to obtain the synthesized pre-configuration information of the cell of the candidate access network device, and the terminal device retains the synthesized pre-configuration information of the cell of the candidate access network device.

[0181] Optionally, after the terminal device switches from the cell of the second access network device to the cell of the first access network device, the terminal device and the first access network device retain the pre-configuration information of the cell of the candidate access network device. If the pre-configuration information is pre-configuration information based on conditional switching CHO, the terminal device evaluates whether the cell of the candidate access network device satisfies the CHO switching trigger condition by itself. If a candidate access network device satisfies the CHO switching trigger condition, it switches from the cell of the first access network device to the cell of the candidate access network device that satisfies the CHO switching trigger condition based on the pre-configuration information. If the pre-configuration information is pre-configuration information based on LTM, the first access network device determines whether to switch to the cell of the candidate access network device based on the measurement report of the cell of the candidate access network device, and the terminal device waits for the switching instruction of the first access network device.

[0182] In the embodiment of the present application, by applying in advance for the pre-configuration information of the cell of the candidate access network device and the transport layer information for data transfer to the candidate access network device, in the process of switching from the cell of the second access network device to the cell of the first access network device, the second access network device indicates to inherit the transport layer information for data transfer to the candidate access network device and retain the pre-configuration information of the cell of the candidate access network device, so that after the terminal device switches from the cell of the second access network device to the cell of the first access network device, the first access network device can switch from the cell of the first access network device to the cell of the candidate access network device without applying for the transport layer information for data transfer to the candidate access network device and the pre-configuration information of the cell of the candidate access network device. Thereby reducing the process of applying for switching resources, reducing the switching time, and improving the switching efficiency.

[0183] In an embodiment of the present application, the first access network device or the second access network device is a non-terrestrial network NTN base station, and the candidate access network device is a terrestrial network NT base station; or, the first access network device or the second access network device is an NT base station, and the candidate access network device is an NTN base station. The following is an example of switching from NTN to TN. Among them, the first access network device is the first NTN base station, the second access network device is the second NTN base station, the candidate access network device is the candidate NT base station, and the terminal device is the UE. For the scenario of switching from TN to NTN, it is similar to this and will not be repeated here.

[0184] like Fig.10 As shown, Fig.10 It is a flow chart of another communication method provided in an embodiment of the present application. In an embodiment of the present application, the NTN base station and the candidate TN base station are switched via the Xn interface. It mainly includes the following steps:

[0185] S1001: A second NTN base station sends a first handover request to a candidate TN base station, where the first handover request is used to request handover from a cell of the second NTN base station to a cell of the candidate TN base station.

[0186] S1002: The candidate TN base station sends first switching confirmation information to the second NTN base station, where the first switching confirmation information includes transmission layer information of the candidate TN base station and pre-configuration information of the cell of the candidate TN base station.

[0187] In the above S1001-S1002, the second NTN base station may apply for the transport layer information of the candidate TN base station and the pre-configuration information of the cell of the candidate TN base station through the CHO switching process or the LTM switching process.

[0188] S1003: The second NTN base station sends pre-configuration information of the cell of the candidate TN base station to the UE.

[0189] The preconfiguration information includes preconfiguration information based on conditional switching CHO, and / or preconfiguration information based on LTM switching. That is, the second NTN base station can apply for the preconfiguration information of the cell of the candidate TN base station through the CHO switching process or the LTM switching process, and send the preconfiguration information of the cell of the candidate TN base station to the UE and the first NTN base station. The UE can determine whether to access the cell of the candidate TN base station according to the CHO switching trigger condition of the cell of the candidate TN base station in the CHO switching process. Alternatively, the first NTN base station determines whether to switch to the cell of the candidate TN base station according to the measurement report based on the cell of the candidate TN base station in the LTM switching process. If the UE or the first NTN base station determines to switch to the cell of the candidate TN base station, the cell of the candidate TN base station is accessed based on the preconfiguration information.

[0190] The above S1001 - S1003 completes the pre-configuration of the candidate TN base station.

[0191] S1004: The second NTN base station sends a second handover request to the first NTN base station, where the second handover request is used to request handover from the cell of the second NTN base station to the cell of the first NTN base station.

[0192] The second handover request includes first indication information, and the first indication information is used to indicate to inherit the transport layer information of the candidate TN base station side. Optionally, the first request may include the transport layer information of the candidate TN base station.

[0193] Optionally, the second handover request may further include second indication information, where the second indication information is used to indicate to retain the pre-configuration information allocated by the cell of the candidate TN base station to the UE. Optionally, the first request includes the pre-configuration information of the cell of the candidate TN base station.

[0194] S1005, the first NTN base station sends second handover confirmation information to the second NTN base station. The second handover confirmation information is used to indicate confirmation of handover from the cell of the second NTN base station to the cell of the first NTN base station or to indicate that the first NTN base station has prepared resources for handover.

[0195] Optionally, the second switching confirmation information carries configuration information allocated by the first NTN base station to the UE.

[0196] Optionally, the second switching confirmation information includes first information, where the first information is used to indicate confirmation of inheriting the transmission layer information of the candidate TN base station.

[0197] Optionally, the first information may further include fourth indication information, and the fourth indication information is used to indicate confirmation of retaining the pre-configuration information of the cell of the candidate TN base station. The second NTN base station may determine, based on the first information, that the first NTN base station inherits the transport layer information of the candidate TN base station, or determine that the first NTN base station retains the pre-configuration information of the cell of the candidate TN base station.

[0198] It should be noted that the second NTN base station and the first NTN base station can also be switched through the Xn interface. That is, the information exchange between the second NTN base station and the first NTN base station does not need to pass through the core network. The second NTN base station and the first NTN base station can also be switched through the Ng interface. That is, the information exchange between the second NTN base station and the first NTN base station needs to pass through the core network.

[0199] S1006: The first NTN base station establishes a data forwarding tunnel with the candidate TN base station based on the transport layer information of the candidate TN base station.

[0200] It can be understood that: the first access network device transfers data to the candidate TN base station based on the transport layer information.

[0201] S1007: The second NTN base station sends a handover command to the UE, where the handover command may be used to indicate to retain the pre-configuration information of the cell of the candidate TN base station.

[0202] Optionally, the handover command carries configuration information allocated by the first NTN base station to the UE.

[0203] Optionally, after the UE switches from the cell of the second NTN base station to the cell of the first NTN, the pre-configuration information of the cell of the candidate TN base station is retained. If the pre-configuration information is pre-configuration information based on conditional switching CHO, the UE evaluates whether the cell of the candidate TN base station meets the CHO switching trigger condition by itself, and if a candidate TN base station meets the CHO switching trigger condition, it switches from the cell of the first NTN base station to the cell of the candidate TN base station that meets the CHO switching trigger condition. If the pre-configuration information is pre-configuration information based on LTM, the first NTN base station determines whether to switch to the cell of the candidate TN base station based on the measurement report of the cell of the candidate access network base station, and the UE waits for the switching instruction of the first NTN base station.

[0204] like Fig.11 As shown, Fig.11 It is a flow chart of another communication method provided in an embodiment of the present application. In an embodiment of the present application, the NTN base station and the candidate TN base station are switched through the Ng interface. It mainly includes the following steps:

[0205] S1101, a second NTN base station sends a first handover request to a core network, where the first handover request is used to request handover from a cell of the second NTN base station to a cell of a candidate TN base station.

[0206] S1102: The core network sends a second handover request to the candidate TN base station, where the second handover request is used to request handover from a cell of the second NTN base station to a cell of the candidate TN base station.

[0207] S1103, the candidate TN base station sends first switching confirmation information to the core network, where the first switching confirmation information includes transmission layer information of the candidate TN base station and pre-configuration information of the cell of the candidate TN base station.

[0208] S1104: The core network sends second switching confirmation information to the second NTN base station, where the second switching confirmation information includes the transport layer information on the core network side and pre-configuration information of the cell of the candidate TN base station.

[0209] In the above S1101-S1104, the second NTN base station can apply for the transport layer information of the core network side and the pre-configuration information of the cell of the candidate TN base station through the CHO switching process or the LTM switching process.

[0210] S1105: The second NTN base station sends pre-configuration information of the cell of the candidate TN base station to the UE.

[0211] The preconfiguration information includes preconfiguration information based on conditional switching CHO, and / or preconfiguration information based on LTM switching. That is, the second NTN base station can apply for the preconfiguration information of the cell of the candidate TN base station through the CHO switching process or the LTM switching process, and send the preconfiguration information of the cell of the candidate TN base station to the UE and the first NTN base station. The UE can determine whether to access the cell of the candidate TN base station according to the CHO switching trigger condition of the cell of the candidate TN base station in the CHO switching process. Alternatively, the first NTN base station determines whether to switch to the cell of the candidate TN base station according to the measurement report based on the cell of the candidate TN base station in the LTM switching process. If the UE or the first NTN base station determines to switch to the cell of the candidate TN base station, the cell of the candidate TN base station is accessed based on the preconfiguration information.

[0212] The above S1101 - S1105 complete the pre-configuration of the candidate TN base station.

[0213] S1106: The second NTN base station sends a third handover request to the first NTN base station, where the third handover request is used to request handover from the cell of the second NTN base station to the cell of the first NTN base station.

[0214] The third handover request includes first indication information, and the first indication information is used to indicate inheritance of the transport layer information on the core network side. Optionally, the first request may include the transport layer information on the core network side.

[0215] Optionally, the third handover request may further include second indication information, where the second indication information is used to indicate to retain the pre-configuration information allocated by the cell of the candidate TN base station to the UE. Optionally, the first request includes the pre-configuration information of the cell of the candidate TN base station.

[0216] S1107, the first NTN base station sends third handover confirmation information to the second NTN base station. The third handover confirmation information is used to indicate confirmation of handover from the cell of the second NTN base station to the cell of the first NTN base station, or to indicate that the first NTN base station has prepared resources for handover.

[0217] Optionally, the third switching confirmation information carries configuration information allocated by the first NTN base station to the UE.

[0218] Optionally, the third switching confirmation information includes first information, where the first information is used to indicate confirmation of inheriting the transport layer information on the core network side.

[0219] Optionally, the first information may further include fourth indication information, and the fourth indication information is used to indicate confirmation of retaining the pre-configuration information of the cell of the candidate TN base station. The second NTN base station may determine, based on the first information, that the first NTN base station inherits the transport layer information on the core network side, or determine that the first NTN base station retains the pre-configuration information of the cell of the candidate TN base station.

[0220] It should be noted that the second NTN base station can be switched with the first NTN base station through the Xn interface. That is, the information exchange between the second NTN base station and the first NTN base station does not need to pass through the core network. The second NTN base station can also be switched with the first NTN base station through the Ng interface. That is, the information exchange between the second NTN base station and the first NTN base station needs to pass through the core network.

[0221] S1108, the first NTN base station establishes a data forwarding tunnel with the candidate TN base station based on the transport layer information of the core network.

[0222] It can be understood that: the first access network device transfers data to the candidate TN base station based on the transport layer information.

[0223] Specifically, the data forwarding tunnel includes a first data forwarding tunnel and a second data forwarding tunnel. The first NTN base station establishes the first data forwarding tunnel with the core network based on the transport layer information on the core network side in S1106; the core network establishes the second data forwarding tunnel with the cell of the candidate TN base station based on the transport layer information of the candidate TN base station in S1103.

[0224] S1109: The second NTN base station sends a handover command to the UE, where the handover command may be used to indicate to retain the pre-configuration information of the cell of the candidate TN base station.

[0225] Optionally, the handover command carries configuration information allocated by the first NTN base station to the UE.

[0226] Optionally, after the UE switches from the cell of the second NTN base station to the cell of the first NTN, the pre-configuration information of the cell of the candidate TN base station is retained. If the pre-configuration information is pre-configuration information based on conditional switching CHO, the UE evaluates whether the cell of the candidate TN base station meets the CHO switching trigger condition by itself. If a candidate TN base station meets the CHO switching trigger condition, it switches from the cell of the first NTN base station to the cell of the candidate TN base station that meets the CHO switching trigger condition. If the pre-configuration information is pre-configuration information based on LTM, the first NTN base station determines whether to switch to the cell of the candidate TN base station based on the measurement report of the cell of the candidate access network base station. The UE waits for the switching indication from the first NTN base station.

[0227] Fig.10 and Fig.11The embodiment shown is Fig. 9 An illustration of the embodiment shown. Fig.10 and Fig.11 The specific implementation of the embodiment shown can refer to Fig. 9 The specific implementation of the illustrated embodiment will not be described in detail here.

[0228] It can be understood that in the above-mentioned method embodiments, the methods and operations implemented by the terminal device can also be implemented by components that can be used for the terminal device (such as chips or circuits), and the methods and operations implemented by the access network device can also be implemented by components that can be used for the access network device (such as chips or circuits).

[0229] The embodiment of the present application can divide the functional modules of the terminal device or access network device according to the above method example. For example, each functional module can be divided corresponding to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation. The following is an example of dividing each functional module corresponding to each function.

[0230] Above, combined Figure 9-11 The method provided by the embodiment of the present application is described in detail. Fig.12 The communication device provided in the embodiment of the present application is described in detail. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment, so the contents not described in detail can be referred to the method embodiment above, and will not be repeated here for the sake of brevity.

[0231] See also Fig.12 , Fig.12 12 is a schematic diagram of a communication device provided in an embodiment of the present application. The communication device may include a receiving module 1201, a processing module 1202 and a sending module 1203.

[0232] Optionally, the communication device may implement the steps or processes executed by the access network device in the above method embodiment, for example, it may be an access network device, or a chip or circuit configured in the access network device. The receiving module 1201 and the sending module 1203 are used to perform the sending and receiving related operations on the access network device side in the above method embodiment, and the processing module 1202 is used to perform the processing related operations of the access network device in the above method embodiment.

[0233] In one embodiment:

[0234] A receiving module 1201 is configured to receive a first request sent by a second access network device, where the first request is used to request switching from a cell of the second access network device to a cell of the first access network device, where the first request includes first indication information, where the first indication information is used to indicate inheritance of transport layer information for data transfer to a candidate access network device;

[0235] The processing module 1202 is used to establish a data forwarding tunnel with the candidate access network device based on the transport layer information.

[0236] Optionally, the first request includes the transport layer information.

[0237] Optionally, the first request also includes second indication information, where the second indication information is used to indicate that pre-configuration information of the cell of the candidate access network device is retained, and the pre-configuration information is used to access the cell of the candidate access network device.

[0238] Optionally, the first request includes the pre-configuration information.

[0239] Optionally, the pre-configuration information includes pre-configuration information based on conditional handover CHO and / or pre-configuration information based on L1 / L2 triggered mobility LTM handover.

[0240] Optionally, the sending module 1203 is used to send first information to the second access network device, where the first information is used to indicate confirmation of inheriting the transport layer information for transferring data to the candidate access network device.

[0241] Optionally, the transport layer information includes transport layer information on the core network side.

[0242] Optionally, the transport layer information includes transport layer information on the candidate access network device side.

[0243] Optionally, the first access network device or the second access network device is a non-terrestrial network NTN base station, and the candidate access network device is a terrestrial network NT base station; or, the first access network device or the second access network device is a NT base station, and the candidate access network device is an NTN base station.

[0244] In another embodiment:

[0245] The receiving module 1201 is used to obtain the transport layer information for transferring data to the candidate access network device;

[0246] The sending module 1203 is used to send a first request to the first access network device, where the first request is used to request switching from the cell of the second access network device to the cell of the first access network device, and the first request includes first indication information, where the first indication information is used to indicate inheritance of transport layer information for data transfer to the candidate access network device.

[0247] Optionally, the first request includes the transport layer information.

[0248] Optionally, the first request also includes second indication information, where the second indication information is used to indicate that pre-configuration information of the cell of the candidate access network device is retained, and the pre-configuration information is used to access the cell of the candidate access network device.

[0249] Optionally, the first request includes the pre-configuration information.

[0250] Optionally, the pre-configuration information includes pre-configuration information based on conditional handover CHO and / or pre-configuration information based on L1 / L2 triggered mobility LTM handover.

[0251] Optionally, the receiving module 1201 is further used to receive first information sent by the first access network device, where the first information is used to indicate confirmation of inheriting the transport layer information for transferring data to the candidate access network device.

[0252] Optionally, the sending module 1203 is also used to send second information to the terminal device, the second information is used to indicate switching from the cell of the second access network device to the cell of the first access network device, the second information includes third indication information, and the third indication information is used to indicate retaining pre-configuration information of the cell of the candidate access network device.

[0253] Optionally, the sending module 1203 is further used to send pre-configuration information of the cell of the candidate access network device to the second access network device and the terminal device.

[0254] Optionally, the transport layer information includes address information on the core network side.

[0255] Optionally, the transport layer information includes transport layer information on the candidate access network device side.

[0256] Optionally, the first access network device or the second access network device is a non-terrestrial network NTN base station, and the candidate access network device is a terrestrial network NT base station; or, the first access network device or the second access network device is a NT base station, and the candidate access network device is an NTN base station.

[0257] It should be noted that the implementation of each module can also refer to Figures 9 to 11 The corresponding description of the method embodiment shown executes the method and functions performed by the first access network device and the second access network device in the above-mentioned embodiment.

[0258] Fig.13 Schematic diagram of the structure of an access network device provided in an embodiment of the present application. The access network device can be applied to Figures 1 to 4 In the system shown, the functions of the first access network device and the second access network device in the above method embodiment are executed, or the steps or processes executed by the first access network device and the second access network device in the above method embodiment are realized.

[0259] like Fig.13 As shown, the access network device includes a processor 1301 and a transceiver 1302. Optionally, the access network device also includes a memory 1303. The processor 1301, the transceiver 1302 and the memory 1303 can communicate with each other through an internal connection path to transmit control and / or data signals. The memory 1303 is used to store a computer program, and the processor 1301 is used to call and run the computer program from the memory 1303 to control the transceiver 1302 to send and receive signals. Optionally, the access network device may also include an antenna for sending the uplink data or uplink control signaling output by the transceiver 1302 through a wireless signal.

[0260] The processor 1301 and the memory 1303 may be combined into a processing device, and the processor 1301 is used to execute the program code stored in the memory 1303 to implement the above functions. In specific implementation, the memory 1303 may also be integrated into the processor 1301, or independent of the processor 1301. Fig.10 Corresponding to the processing module in.

[0261] The transceiver 1302 can be used with Fig.10 The receiving module and the sending module in the embodiment correspond to each other, and may also be referred to as a transceiver unit or a transceiver module. The transceiver 1302 may include a receiver (or receiver, receiving circuit) and a transmitter (or transmitter, transmitting circuit). The receiver is used to receive signals, and the transmitter is used to transmit signals.

[0262] It should be understood that Fig.13 The access network equipment shown can achieve Figures 9 to 11 The method embodiment shown involves various processes of the access network device. The operations and / or functions of each module in the access network device are respectively to implement the corresponding processes in the above method embodiment. For details, please refer to the description in the above method embodiment. To avoid repetition, the detailed description is appropriately omitted here.

[0263] The processor 1301 can be used to execute the actions implemented by the access network device in the previous method embodiment, and the transceiver 1302 can be used to execute the actions of the access network device sending to or receiving from the access network device described in the previous method embodiment. Please refer to the description in the previous method embodiment for details, which will not be repeated here.

[0264] Among them, the processor 1301 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 devices, transistor logic devices, hardware components or any combination thereof. It can implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the contents disclosed in this application. The processor 1301 can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a digital signal processor and a microprocessor, and so on. The communication bus 1304 can be a peripheral component interconnect standard PCI bus or an extended industrial standard structure EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig.13 Only one thick line is used to represent it, but it does not mean that there is only one bus or one type of bus. The communication bus 1304 is used to realize the connection and communication between these components. Among them, the transceiver 1302 in the embodiment of the present application is used to communicate signaling or data with other node devices. The memory 1303 may include volatile memory, such as nonvolatile dynamic random access memory (NVRAM), phase change random access memory (PRAM), magnetoresistive random access memory (MRAM), etc., and may also include non-volatile memory, such as at least one disk storage device, electrically erasable programmable read-only memory (EEPROM), flash memory devices, such as NOR flash memory or NAND flash memory, semiconductor devices, such as solid state disk (SSD), etc. The memory 1303 may also be at least one storage device located away from the aforementioned processor 1301. The memory 1303 may optionally store a set of computer program codes or configuration information. Optionally, the processor 1301 may also execute a program stored in the memory 1303. The processor may cooperate with the memory and the transceiver to execute any one of the methods and functions of the first access network device or the second access network device in the above-mentioned application embodiment.

[0265] An embodiment of the present application also provides a chip system, which includes a processor for supporting a terminal device or an access network device to implement the functions involved in any of the above embodiments, such as generating or processing the transport layer information involved in the above method.

[0266] In one possible design, the chip system may also include a memory, which is used for computer programs and data necessary for the terminal device or access network device. The chip system may be composed of a chip, or may include a chip and other discrete devices. The input and output of the chip system correspond to the receiving and sending operations of the terminal device or access network device of the method embodiment, respectively.

[0267] According to the method provided in the embodiment of the present application, the present application also provides a computer program product, the computer program product comprising: a computer program, when the computer program is run on a computer, causes the computer to execute Figures 9 to 11 A method according to any one of the embodiments shown.

[0268] According to the method provided in the embodiment of the present application, the present application also provides a computer-readable medium, which stores a computer program, and when the computer program is run on a computer, the computer executes Figures 9 to 11 A method according to any one of the embodiments shown.

[0269] According to the method provided in the embodiment of the present application, the present application also provides a communication system, which includes one or more terminal devices and one or more access network devices mentioned above.

[0270] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a high-density digital video disc (DVD)), or a semiconductor medium (eg, a solid state disc (SSD)).

[0271] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A communication method, characterized in that: The method comprises: A first access network device receives a first request sent by a second access network device, where the first request is used to request switching from a cell of the second access network device to a cell of the first access network device, and the first request includes first indication information, where the first indication information is used to indicate inheritance of transport layer information for data transfer to a candidate access network device; The first access network device establishes a data forwarding tunnel with the candidate access network device based on the transport layer information.

2. The method according to claim 1, characterized in that The first request includes the transport layer information.

3. The method according to claim 1 or 2, characterized in that The first request also includes second indication information, where the second indication information is used to indicate that pre-configuration information of the cell of the candidate access network device is retained, and the pre-configuration information is used to access the cell of the candidate access network device.

4. The method according to claim 3, characterized in that The first request includes the pre-configuration information.

5. The method according to claim 3 or 4, characterized in that The pre-configuration information includes pre-configuration information based on conditional handover CHO and / or pre-configuration information based on L1 / L2 triggered mobility LTM handover.

6. The method according to any one of claims 1 to 5, characterized in that: The method comprises: The first access network device sends first information to the second access network device, where the first information is used to indicate confirmation of inheriting the transport layer information for transferring data to the candidate access network device.

7. The method according to any one of claims 1 to 6, characterized in that: The transport layer information includes the transport layer information on the core network side.

8. The method according to any one of claims 1 to 6, characterized in that: The transport layer information includes the transport layer information on the candidate access network device side.

9. The method according to any one of claims 1 to 8, characterized in that The first access network device or the second access network device is a non-terrestrial network NTN base station, and the candidate access network device is a terrestrial network NT base station; or, the first access network device or the second access network device is a NT base station, and the candidate access network device is a NTN base station.

10. A communication method, characterized in that: The method comprises: The second access network device acquires transport layer information for transferring data to the candidate access network device; The second access network device sends a first request to the first access network device, where the first request is used to request switching from the cell of the second access network device to the cell of the first access network device, and the first request includes first indication information, where the first indication information is used to indicate inheritance of transport layer information for data transfer to the candidate access network device.

11. The method according to claim 10, characterized in that The first request includes the transport layer information.

12. The method according to claim 10 or 11, characterized in that The first request also includes second indication information, where the second indication information is used to indicate that pre-configuration information of the cell of the candidate access network device is retained, and the pre-configuration information is used to access the cell of the candidate access network device.

13. The method according to claim 12, characterized in that The first request includes the pre-configuration information.

14. The method according to claim 12 or 13, characterized in that The pre-configuration information includes pre-configuration information based on conditional handover CHO and / or pre-configuration information based on L1 / L2 triggered mobility LTM handover.

15. The method according to any one of claims 10 to 14, characterized in that: The method comprises: The second access network device receives first information sent by the first access network device, where the first information is used to indicate confirmation of inheriting the transport layer information for transferring data to the candidate access network device.

16. The method according to any one of claims 9 to 15, characterized in that: The method comprises: The second access network device sends second information to the terminal device, the second information is used to indicate switching from the cell of the second access network device to the cell of the first access network device, the second information includes third indication information, and the third indication information is used to indicate retaining the pre-configuration information of the cell of the candidate access network device.

17. The method according to claim 16, characterized in that The method comprises: The second access network device sends pre-configuration information of the cell of the candidate access network device to the terminal device.

18. The method according to any one of claims 10 to 17, characterized in that: The transport layer information includes address information on the core network side.

19. The method according to any one of claims 10 to 17, characterized in that: The transport layer information includes the transport layer information on the candidate access network device side.

20. The method according to any one of claims 10 to 19, characterized in that: The first access network device or the second access network device is a non-terrestrial network NTN base station, and the candidate access network device is a terrestrial network NT base station; or, the first access network device or the second access network device is a NT base station, and the candidate access network device is a NTN base station.

21. A communication device, characterized in that: The communication device comprises a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the communication device to perform the method according to any one of claims 1 to 9.

22. A communication device, characterized in that: The communication device comprises a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the communication device to perform the method according to any one of claims 10 to 20.

23. A communication system, characterized in that: The system includes a first access network device and a second access network device, the first access network device is used to execute the method according to any one of claims 1-9, and the second access network device is used to execute the method according to any one of claims 10-20.

24. A computer-readable storage medium, characterized in that: The computer-readable storage medium comprises a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 20 is implemented.

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