Access Method, Communication Device, Communication System, Computer-Readable Medium, and Computer Program

Abstract

An access method and a communication device are provided. The method includes a step in which a terminal device receives first indication information from a first network device, a step in which the terminal device receives access indication information from a second network device, and a step in which the terminal device starts accessing a target cell of the second network device based on the access indication information. The first indication information instructs the terminal device to start accessing the target cell of the second network device based on the access indication information from the second network device. After being instructed to receive the access indication information from the second network device, the terminal device starts accessing the target cell of the second network device. Thereby, the success rate of accessing the second network device by the terminal device can be improved.

Description

Technical Field

[0001] This It relates to the field of wireless communication technology, and in particular, to an access method and a communication device.

Background Art

[0002] When the serving base station of the terminal device stops providing communication services to the terminal device, the terminal device is handed over from the serving base station to another base station, for example, a target base station. There may be a plurality of terminal devices served by the serving base station. In this case, when all terminal devices need to be handed over, the plurality of terminal devices may access the target base station simultaneously. When a large number of terminal devices access the target base station simultaneously, if the terminal devices accessing the target base station simultaneously access the target base station in a contention access manner, the access success rate of each terminal device will decrease. When a plurality of terminal devices accessing the target base station simultaneously access the target base station in a non-contention access manner, the target base station needs to allocate a large number of resources to the accessed terminal devices, resulting in a large resource overhead.

Summary of the Invention

[0003] The present application provides an access method and a communication device to improve the success rate of a terminal device accessing a network and reduce resource overhead.

[0004] According to a first aspect, embodiments of the present application provide an access method. The method can be executed by a first communication device. The first communication device can be a communication device or a communication apparatus, such as a chip system, that can support a communication device in implementing functions required in the method. For example, the first communication device can be a terminal device, a chip disposed in the terminal device, or another component configured to implement functions of the terminal device. Hereinafter, an example in which the communication device is a terminal device is used for the purpose of explanation.

[0005] The access method includes a stage where the terminal device receives first indication information from a first network device, a stage where it receives access indication information from a second network device, and a stage where it starts accessing a target cell of the second network device based on the access indication information. The first indication information instructs the terminal device to start accessing the target cell of the second network device based on the access indication information from the second network device. The first network device may be regarded as a source base station, and the second network device may be regarded as a target base station. The first indication information from the first network device instructs the terminal device to start accessing the target cell of the second network device based on the access indication information from the second network device. In other words, the terminal device starts an access scheduled by the second network device. For example, when a small number of terminal devices access the target cell at a specific time, the second network device may instruct the terminal device to access the target cell. For example, when it is determined that a small number of terminal devices access the target cell within the same time or within the same time-frequency resource, the second network device instructs the terminal device to access the target cell. For the terminal device, after receiving the access indication information from the second network device, the terminal device starts accessing the target cell. For a terminal device accessing the second network device in a contention access mode, the success rate of the terminal device accessing the second network device can be improved. For a terminal device accessing the second network device in a non-contention access mode, the resource overhead can be reduced.

[0006] In a possible implementation, the first instruction information is included in the access rule information, and the access rule information further includes a first time period. The terminal device receiving the access instruction information from the second network device includes the terminal device receiving the access instruction information within the first time period. The access rule information may indicate the rules that the terminal device needs to comply with when accessing the network. For example, the access rule information includes the first instruction information. In addition, the access rule information may further include the first time period, and instruct the terminal device to receive the access instruction information within the first time period. That is, if the terminal device does not receive the access instruction information within the first time period, the terminal device may alternatively start accessing the target cell after the first time period. Therefore, the situation where the terminal device cannot access the network because it cannot receive the access instruction information is avoided, and as a result, the continuity of the communication executed by the terminal device is ensured.

[0007] In a possible implementation, the terminal device receiving the access instruction information within the first time period includes the terminal device receiving the access instruction information within the first time period after disconnecting the connection with the first network device. It can be understood that the start time of the first time period is the time when the terminal device disconnects the connection with the first network device. The terminal device receives the access instruction information within the first time period after disconnecting the connection with the first network device. Correspondingly, after the terminal device disconnects the connection with the first network device, the second network device transmits the access instruction information, avoiding transmitting unnecessary access instruction information, thereby reducing the signaling overhead.

[0008] In a possible implementation, the first instruction information is included in access rule information, and the access rule information further includes cell information. The cell information indicates a target cell, and the terminal device receives access instruction information in the target cell. When the terminal device is handed over from the first network device to the second network device, it can be understood that the cells configured in the network may remain unchanged or may change. When the cells configured in the network remain unchanged, the terminal device recognizes the cells in which the access instruction information can be received. When the cells configured in the network change, the terminal device does not recognize the target cell served by the second network device. Therefore, the first network device may provide the target cell served by the second network device for the terminal device, and as a result, the terminal device receives access instruction information in the target cell. In this way, the success rate of the terminal device receiving access instruction information from the second network device can be improved, and as a result, the terminal device can normally access the target cell of the second network device.

[0009] In a possible implementation, the terminal device starting to access the target cell of the second network device based on the access instruction information includes the terminal device starting to access the target cell based on the access instruction information after disconnecting the connection with the first network device.

[0010] In a possible implementation, the method further comprises a step in which the terminal device receives second indication information from the first network device or the second network device, and the second indication information instructs the terminal device to select a first reference signal. The first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam obstacle detection. The first network device or the second network device re-instructs the terminal device with the first reference signal corresponding to the target cell, so as to avoid inaccurate radio link detection results and / or inaccurate beam obstacle detection results that occur when the terminal device performs radio link detection and / or beam obstacle detection based on the originally configured reference signal due to the change of the beam where the terminal device is located.

[0011] In a possible implementation, the second indication information includes any one of the following.

[0012] (1) Configuration information of the first reference signal. That is, the configuration information of the reference signal under the target cell is directly provided to the terminal device.

[0013] (2) First information and second information. The first information indicates the configuration information of at least one reference signal corresponding to the target cell, and the second information includes the index of the configuration information of the first reference signal. The configuration information of all the reference signals under the target cell (that is, at least one reference signal) can be predefined, pre-configured, or indicated. In addition, the first network device or the second network device only needs to provide the index of the configuration information of the first reference signal, and does not need to provide the configuration information of the first reference signal separately each time, thereby reducing the signaling overhead.

[0014] (3) The mapping relationship between at least one reference signal corresponding to the source cell and at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device. The first network device or the second network device may provide the mapping relationship between at least one reference signal corresponding to the source cell and at least one reference signal corresponding to the target cell. As a result, the terminal device may determine the first reference signal based on the reference signal and the mapping relationship in the source cell.

[0015] (4) The mapping relationship between the configuration information of at least one reference signal corresponding to the target cell and the geographical location area. The geographical area covered by the target cell may be divided into a plurality of areas, and each area has a corresponding reference signal. In this case, there is a mapping relationship between the configuration of at least one reference signal corresponding to the target cell and one or more areas obtained by dividing the target cell. The location area of the terminal device belongs to one or more areas obtained by dividing the target cell. As a result, the terminal device may determine the first reference signal based on the location area of the terminal device and the mapping relationship.

[0016] In a possible implementation, the access indication information includes third indication information, and the third indication information indicates a second reference signal, and the second reference signal is used to determine an access opportunity. The second network device may further provide the second reference signal for the terminal device. As a result, the terminal device determines an appropriate access opportunity, thereby ensuring the success rate of network access.

[0017] In a possible implementation, the access indication information includes fourth indication information, and the fourth indication information includes a first time interval. The terminal device is instructed to start accessing the target cell after the first time interval from when the terminal device receives the access indication information. Different terminal devices correspond to different first time intervals. As a result, different terminal devices transmit accesses to the target cell at different times.

[0018] In a possible implementation, the method further comprises: a stage where the terminal device receives trigger rule information from a first network device, where the trigger rule information instructs the terminal device not to start accessing the target cell before a first time. Next, when the terminal device determines that the preset condition is satisfied, after the first time, the terminal device starts accessing the target cell. The first time is instructed by the first network device. The preset condition includes: the signal quality of the source cell being lower than a preset threshold, or the source cell stopping providing services. That the terminal device does not start accessing the target cell before the first time means that when the terminal device decides to start accessing the target cell, instead of starting to access the target cell immediately, the terminal device waits for a period, for example, for the first time, and then starts accessing the target cell. In this way, for different terminal devices, the network device can configure different first times to avoid multiple terminal devices accessing the network simultaneously.

[0019] In a possible implementation, the first time is carried in a radio resource control (RRC) message including conditional handover (CHO) configuration information or handover (HO) configuration information. The network side can provide the first time to the terminal device by using a handover command, thereby reducing signaling overhead.

[0020] In a possible implementation, the CHO configuration information includes a time-based trigger condition, and the time-based trigger condition includes a second time and a second time duration. The second time is the start time of the time-based trigger condition, and the second time duration is the time duration of the time-based trigger condition. The first time is the second time, or the first time is the sum of the second time and the second time duration. It can be understood that the CHO configuration information includes the time-based trigger condition, that is, the second time and the second time duration. The network side can reuse the time-based trigger condition in the CHO configuration information to indicate the first time. For example, the first time is the second time, or the first time is the sum of the second time and the second time duration. Therefore, the first time does not need to be indicated separately.

[0021] In a possible implementation, the method further includes: after accessing the second network device, the terminal device retains a first partial configuration of the media access control (MAC) layer and deletes a second partial configuration of the MAC layer. That is, after accessing the second network device, the terminal device deletes some configurations of the MAC layer and retains some configurations of the MAC layer. In this way, some configurations of the MAC layer can be inherited in subsequent access configurations, thereby simplifying the configuration procedure for accessing the network, ensuring configuration continuity, and improving system performance.

[0022] According to a second aspect, an embodiment of the present application provides an access method. The method can be executed by a first communication device. The first communication device can be a communication device or a communication apparatus that supports a communication device in implementing functions required in the method, for example, a chip system. For example, the first communication device can be a first network device, a chip disposed on the first network device, or another component configured to implement the functions of the first network device. Hereinafter, an example in which the communication device is a first network device is used for illustration. The first network device can also be understood as a base station currently providing services as a terminal device, and is also called a source base station.

[0023] The access method comprises the steps of: a first network device determining first instruction information and sending the first instruction information to a terminal device. The first instruction information instructs the terminal device to start accessing a target cell of a second network device based on access instruction information from the second network device. The first network device, by using the first instruction information, instructs the terminal device to start accessing the target cell of the second network device based on the access instruction information from the second network device. If the terminal device does not receive access instruction information from the second network device based on the instruction of the first instruction information, the terminal device may not start accessing the target cell of the second network device, avoiding time or time-frequency resource contention with another terminal device for starting the access. As a result, the success rate of the access by the terminal device to the second network device can be improved, and the resource overhead can be reduced.

[0024] In a possible implementation, the first instruction information is included in access rule information, and the access rule information further includes a first time duration, and the first time duration instructs the terminal device to receive access instruction information within the first time duration.

[0025] In a possible implementation, the first instruction information is included in access rule information, and the access rule information further includes cell information, and the cell information instructs the terminal device to receive access instruction information in the target cell.

[0026] In a possible implementation, the method further comprises the step of: the first network device sending second instruction information to the terminal device, where the second instruction information instructs the terminal device to select a first reference signal. The first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for wireless link detection and / or beam obstacle detection.

[0027] In a possible implementation, the second indication information is: configuration information of a first reference signal; first information and second information, where the first information indicates configuration information of at least one reference signal of a target cell, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to a source cell and at least one reference signal corresponding to a target cell, where the source cell is managed by a first network device; or any one of mapping relationships between configuration information of at least one reference signal corresponding to a target cell and a geographical location area.

[0028] In a possible implementation, the access indication information includes third indication information, and the third indication information indicates a second reference signal, and the second reference signal is used to determine an access opportunity.

[0029] In a possible implementation, the access indication information includes fourth indication information, and the fourth indication information includes a first time interval, and the terminal device is instructed to start accessing the target cell after the first time interval after receiving the access indication information.

[0030] In a possible implementation, the method further includes: a step in which a first network device transmits trigger rule information to the terminal device, where the trigger rule information instructs the terminal device not to start accessing the target cell before a first time, and the first time is indicated by the first network device.

[0031] In a possible implementation, the first time is carried in an RRC message including CHO configuration information.

[0032] In a possible implementation, the CHO configuration information includes a time-based trigger condition, and the time-based trigger condition includes a second time and a second time length. The second time is the start time of the time-based trigger condition, and the second time length is the time length of the time-based trigger condition. The first time is the second time, or the first time is the sum of the second time and the second time length.

[0033] For the technical effects achieved by the second aspect or possible implementations of the second aspect, reference may be made to the description of the technical effects of the first aspect or possible implementations of the first aspect.

[0034] According to a third aspect, embodiments of the present application provide an access method. The method may be executed by a third communication device. The third communication device may be a communication device or a communication apparatus that can support a communication device in implementing functions required in the method, for example, a chip system. For example, the third communication device may be a second network device, a chip disposed in the second network device, or another component configured to implement the functions of the second network device. Hereinafter, an example in which the communication device is a second network device will be used for the purpose of explanation. The second network device may also be understood as a network device to which a terminal device is handed over, and is also referred to as a target network device.

[0035] The access method includes: a step in which a second network device determines access indication information, and a step of separately transmitting the access indication information to one or more terminal devices to instruct the one or more terminal devices to separately start accessing a target cell of the second network device. After receiving first indication information from a first network device, the one or more terminal devices separately start accessing the target cell based on the access indication information. The second network device schedules each terminal device to access the target cell by using second indication information. For example, when a small number of terminal devices access the target cell at a specific time, the second network device may transmit the access indication information to the terminal devices to improve the success rate of access to the second network device by the terminal devices and reduce resource overhead.

[0036] In a possible implementation, for the second network device to separately send access indication information to one or more terminal devices may include: the second network device separately sending access indication information to a plurality of terminal devices, where the second network device sends the access indication information to the terminal devices at different transmission opportunities, or the second network device separately sending, to a plurality of terminal devices, access indication information that indicates time-frequency resources used to start access at different transmission opportunities, and different time-frequency resources are configured for the plurality of terminal devices. Since the terminal device starts access to the target cell only after receiving the access indication information, if the access indication information corresponding to different terminal devices has different transmission opportunities, the number of terminal devices accessing the second network device simultaneously can be reduced, thereby improving the success rate of access to the second network device by each terminal device. In addition, when the terminal device accesses the second network device in a contention mode, since a small number of terminal devices access the second network device simultaneously, a small number of resources need to be allocated to the second network device, and as a result, the resource overhead can be reduced. Alternatively, the access indication information corresponding to different terminal devices indicates different time-frequency resources, and as a result, the number of terminal devices contending simultaneously to access the second network device by using the same resource can be reduced, thereby improving the success rate of access to the second network device by each terminal device.

[0037] In a possible implementation, the method further includes: the second network device separately sending second indication information to one or more terminal devices, where the second indication information instructs the one or more terminal devices to select a first reference signal. The first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for wireless link detection and / or beam failure detection.

[0038] In a possible implementation, the second indication information is: configuration information of a first reference signal; first information and second information, where the first information indicates configuration information of at least one reference signal of a target cell, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to a source cell and at least one reference signal corresponding to a target cell, where the source cell is managed by a first network device; or, any one of mapping relationships between configuration information of at least one reference signal corresponding to a target cell and a geographical location area.

[0039] In a possible implementation, the access indication information includes third indication information, and the third indication information indicates a second reference signal, and the second reference signal is used to determine an access opportunity.

[0040] In a possible implementation, the access indication information includes fourth indication information, and the fourth indication information includes a first time interval, and the terminal device is instructed to start accessing the target cell after the first time interval since the terminal device receives the access indication information.

[0041] Regarding the technical effects achieved by the third aspect or possible implementations of the third aspect, please refer to the description of the technical effects of the first aspect or possible implementations of the first aspect.

[0042] According to a fourth aspect, embodiments of the present application provide an access method. The method can be executed by a second communication device. The second communication device can be a communication device or a communication apparatus that supports a communication device in implementing functions required in the method, for example, a chip system. For example, the second communication device can be a terminal device, a chip disposed in the terminal device, or another component configured to implement functions of the terminal device. Hereinafter, an example where the communication device is a terminal device is used for illustration.

[0043] The access method includes: the step in which the terminal device receives trigger rule information from the first network device, where the trigger rule information instructs the terminal device not to start accessing the target cell of the second network device before the first time. Next, when the terminal device determines that the preset condition is satisfied, after the first time, it starts accessing the target cell. The first time is instructed by the first network device. The preset condition includes: the signal quality of the source cell being lower than the preset threshold, or the source cell stopping providing services. That the terminal device does not start accessing the target cell before the first time means that when it decides to start accessing the target cell, the terminal device does not start accessing the target cell immediately, but waits for a period, for example, for the first time, and then starts accessing the target cell. Different first times are configured for different terminal devices to avoid multiple terminal devices accessing the second network device simultaneously.

[0044] In a possible implementation, the first time is carried in an RRC message including CHO configuration information.

[0045] In a possible implementation, the CHO configuration information includes a time-based trigger condition, and the time-based trigger condition includes a second time and a second time length. The second time is the start time of the time-based trigger condition, and the second time length is the time length of the time-based trigger condition. The first time is the second time, or the first time is the sum of the second time and the second time length.

[0046] In a possible implementation, the method further includes the step in which the terminal device receives second instruction information from the first network device or the second network device, and the second instruction information instructs the terminal device to select a first reference signal. The first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam obstacle detection.

[0047] In a possible implementation, the second indication information includes: configuration information of the first reference signal; the first information and the second information, where the first information indicates configuration information of at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to a source cell and at least one reference signal corresponding to a target cell, where the source cell is managed by a first network device; or any one of mapping relationships between configuration information of at least one reference signal corresponding to a target cell and a geographical location area.

[0048] In a possible implementation, the method further includes: after accessing a second network device, a terminal device retains a first partial configuration of a MAC layer and deletes a second partial configuration of the MAC layer.

[0049] For the technical effects achieved by the fourth aspect or possible implementations of the fourth aspect, please refer to the description of the technical effects of the first aspect or possible implementations of the first aspect.

[0050] According to a fifth aspect, embodiments of the present application provide an access method. The method may be executed by a second communication device. The second communication device may be a communication device or a communication apparatus that supports a communication device in implementing functions required in the method, for example, a chip system. For example, the second communication device may be a first network device, a chip disposed in the first network device, or another component configured to implement functions of the first network device. Hereinafter, an example in which the communication device is a first network device is used for illustration.

[0051] The access method includes: a step in which a first network device determines trigger rule information and transmits the trigger rule information to a terminal device. The trigger rule information instructs the terminal device not to start accessing a target cell of a second network device before a first time. The first time is indicated by the first network device. That the terminal device does not start accessing the target cell before the first time means that when determining to start accessing the target cell, the terminal device does not immediately start accessing the target cell, but waits for a period, for example, over the first time, and then starts accessing the target cell. In this way, for different terminal devices, the first network device can configure different first times to avoid multiple terminal devices accessing the network simultaneously.

[0052] In a possible implementation, different terminal devices correspond to different first times.

[0053] In a possible implementation, the first time is carried in an RRC message including CHO configuration information.

[0054] In a possible implementation, the CHO configuration information includes a time-based trigger condition, and the time-based trigger condition includes a second time and a second time length. The second time is the start time of the time-based trigger condition, and the second time length is the time length of the time-based trigger condition. The first time is the second time, or the first time is the sum of the second time and the second time length.

[0055] In a possible implementation, the method further includes: a step in which the first network device transmits second indication information to the terminal device, where the second indication information instructs the terminal device to select a first reference signal. The first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam failure detection.

[0056] In a possible implementation, the second indication information includes: configuration information of a first reference signal; first information and second information, where the first information indicates configuration information of at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to a source cell and at least one reference signal corresponding to a target cell, where the source cell is managed by a first network device; or any one of mapping relationships between configuration information of at least one reference signal corresponding to a target cell and a geographical location area.

[0057] For the technical effects achieved by the fifth aspect or possible implementations of the fifth aspect, please refer to the description of the technical effects of the first aspect or possible implementations of the first aspect.

[0058] According to the sixth aspect, embodiments of the present application provide a communication device. The communication device has a function of implementing behaviors in embodiments of any one of the methods of the first aspect to the fifth aspect. For beneficial effects, please refer to the descriptions of the first aspect to the fifth aspect. Details will not be described again here.

[0059] The communication device can be a terminal device in the first aspect (or the fourth aspect), or the communication device can be a device, such as a chip or a chip system, that can implement the method provided in the first aspect (or the fourth aspect). In a conceivable design, the communication device includes corresponding means or modules configured to execute the method in the first aspect (or the fourth aspect). For example, the communication device includes a processing unit (which may also be referred to as a processing module or a processor in some cases) and / or a transceiver unit (which may also be referred to as a transceiver module or a transceiver in some cases). The transceiver unit may include a transmission unit and a reception unit, or it can be understood that the transmission unit and the reception unit are the same functional module. Alternatively, the transceiver unit can also be understood as a general term for the transmission unit and the reception unit, and the transmission unit and the reception unit can be different functional modules. These units (modules) can execute the corresponding functions in the method example of the first aspect (or the fourth aspect). For details, please refer to the detailed description in the method example. Details will not be described again here.

[0060] The communication device can be the first network device in the second aspect (or the fifth aspect), or the communication device can be a device, such as a chip or a chip system, that can implement the method provided in the second aspect (or the fifth aspect). In a conceivable design, the communication device includes corresponding means or modules configured to execute the method in the second aspect (or the fifth aspect). For example, the communication device includes a processing unit (which may also be referred to as a processing module or a processor in some cases) and / or a transceiver unit (which may also be referred to as a transceiver module or a transceiver in some cases). The transceiver unit may include a transmission unit and a reception unit, or it can be understood that the transmission unit and the reception unit are the same functional module. Alternatively, the transceiver unit can also be understood as a general term for the transmission unit and the reception unit, and the transmission unit and the reception unit can be different functional modules. These units (modules) can execute the corresponding functions in the method example of the second aspect (or the fifth aspect). For details, please refer to the detailed description in the method example. Details will not be described again here.

[0061] The communication device can be the second network device in the third aspect, or the communication device can be a device that can implement the method provided in the third aspect, such as a chip or a chip system. In a conceivable design, the communication device includes corresponding means or modules configured to execute the method in the third aspect. For example, the communication device includes a processing unit (which may also be referred to as a processing module or a processor in some cases) and / or a transceiver unit (which may also be referred to as a transceiver module or a transceiver in some cases). The transceiver unit can include a transmission unit and a reception unit, or it can be understood that the transmission unit and the reception unit are the same functional module. Alternatively, the transceiver unit can also be understood as a general term for the transmission unit and the reception unit, and the transmission unit and the reception unit can be different functional modules. These units (modules) can execute the corresponding functions in the method example of the third aspect. For details, please refer to the detailed description of the method example. Details will not be described again here.

[0062] According to a seventh aspect, an embodiment of the present application provides a communication device. The communication device can be the communication device in the sixth aspect, or a chip or a chip system arranged in the communication device in the sixth aspect. The communication device can be a terminal device, a first network device, or a second network device. The communication device includes a communication interface and a processor, and optionally further includes a memory. The memory is configured to store a computer program. The processor is coupled to the memory and the communication interface. When the processor reads the computer program or instructions, the communication device can execute the method executed by the terminal device, the first network device, or the second network device in the aforementioned method.

[0063] According to an eighth aspect, an embodiment of the present application provides a communication device. The communication device includes an input / output interface and a logic circuit. The input / output interface is configured to input and / or output information. The logic circuit is configured to execute the method according to any one of the first aspect to the fifth aspect.

[0064] According to a ninth aspect, an embodiment of the present application provides a chip system. The chip system includes a processor, and may further include a memory and / or a communication interface configured to implement the method according to any one of the first aspect to the fifth aspect. In a possible implementation, the chip system may further include a memory configured to store a computer program. The chip system may include a chip, or may include a chip and other discrete devices.

[0065] According to a tenth aspect, an embodiment of the present application provides a communication system. The communication system includes a first network device and a second network device. The first network device is configured to execute the method executed by the first network device in the second aspect, and the second network device may be configured to execute the method executed by the second network device in the third aspect. Naturally, the communication system may further include a terminal device, and the terminal device may be configured to execute the method executed by the terminal device in the first aspect. It can be understood that the communication system may include more terminal devices or more network devices.

[0066] According to the 11th aspect, an embodiment of the present application provides a communication system. The communication system includes a first network device and a terminal device. The terminal device may be configured to execute the method executed by the terminal device in the 4th aspect, and the first network device is configured to execute the method executed by the first network device in the 5th aspect. Of course, the communication system may further include a second network device. It can be understood that the communication system may include more terminal devices or more network devices.

[0067] According to the 12th aspect, the present application provides a computer-readable storage medium. The computer-readable storage medium stores a computer program. When the computer program is executed, the method in any one of the 1st aspect to the 5th aspect is implemented.

[0068] According to the 13th aspect, a computer program product is provided. The computer program product includes computer program code. When the computer program code is executed, the method in any one of the 1st aspect to the 5th aspect is executed.

[0069] For the 6th aspect to the 13th aspect, and the beneficial effects of the implementation of the 6th aspect to the 13th aspect, please refer to the description of the beneficial effects of the 1st aspect to the 5th aspect and the implementation of the 1st aspect to the 5th aspect.

Brief Description of Drawings

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MODE FOR CARRYING OUT THE INVENTION

[0081] The technical solution provided in the embodiments of the present application can be applied to a long term evolution (LTE) system, a 5th generation (5G) mobile communication technology system, an NTN system, vehicle-to-everything (V2X), internet of vehicles, machine type communication (MTC), internet of things (IoT), machine-to-machine (M2M), or a future mobile communication system.

[0082] In a possible application scenario, the NTN system may include a satellite system. Based on the satellite altitude, i.e., the height of the satellite orbit, the satellite can be classified into a highly elliptical orbit (HEO) satellite, a geostationary earth orbit (GEO) satellite, a medium earth orbit (MEO) satellite, and a low earth orbit (LEO) satellite. In addition, the NTN system may further include an air network device, for example, a high altitude platform station (HAPS) communication system. The air network device in the present application is not limited to the foregoing examples.

[0083] In an example, FIG. 1 is a diagram of the architecture of an NTN network. The NTN network includes a non-terrestrial network device, a gateway, a terrestrial base station, a terrestrial core network, and a terminal device. The non-terrestrial network device can be a satellite, for example, a HEO satellite, a GEO satellite, a MEO satellite, or a LEO satellite. The non-terrestrial network device can alternatively be a HAPS. This is not limited in this specification. In this application, an example where the non-terrestrial network device is a satellite is used for illustration. However, in this application, the satellite can alternatively be replaced by another non-terrestrial network device (e.g., HAPS). The gateway (or also called a ground station, an earth station, a signal gateway station, or a gateway station) can be configured to connect a satellite and a base station. One or more satellites can be connected to one or more terrestrial base stations via one or more gateways. This is not limited in this specification. In FIG. 1, the communication mode of the satellite is the transparent mode. Specifically, the satellite can implement radio frequency conversion and amplification as an analog radio frequency repeater and transmit or replicate signals transparently between the base station and the terminal. For example, a signal transmitted by a terminal device can be transmitted transparently via the satellite, transferred via the gateway, and enter the terrestrial base station.

[0084] The communication mode of the satellite is not limited in this embodiment of this application. For example, the communication mode of the satellite can alternatively be the regenerative mode. FIG. 2 is a diagram of another architecture of the NTN network. In FIG. 2, the communication mode of the satellite is the regenerative mode. Specifically, the satellite can be used as a base station for wireless communication to regenerate signals received from the ground and can understand and process these signals. For example, the satellite can be an artificial earth satellite or a base station held on a high-altitude aircraft. The gateway can transfer signaling between the satellite (i.e., the base station) and the core network.

[0085] Note that FIG. 2 shows only one satellite and one gateway. In actual use, an architecture including multiple satellites and / or multiple gateways may be used based on requirements. Each satellite may provide services to one or more terminal devices, each gateway may correspond to one or more satellites, and each satellite may correspond to one or more gateways. This is not specifically limited in the present embodiment of the present application.

[0086] In an example, FIG. 3 is a diagram of another architecture of the NTN network. In FIG. 3, an example including two satellites (the first satellite and the second satellite) and two gateways (the first gateway and the second gateway) is used. The communication mode of the two satellites is the regeneration mode. That is, the two satellites can be used as base stations for wireless communication. As a difference from FIG. 2, an inter-satellite link (ISL) exists between the two satellites. In this network architecture, different satellites can communicate with each other or can be connected to the same terrestrial core network.

[0087] In an example, the satellite can alternatively be used as a distributed unit (DU) of the base station, which is separate from the central unit (CU) of the terrestrial base station, forming a CU-DU distributed architecture. For example, FIG. 4 is a diagram of another architecture of the NTN network. As a difference between FIG. 4 and FIG. 1, the satellite can understand, process, and regenerate signals from the ground as the DU of the base station, and not only transparently transmit or replicate the signals. The terrestrial base station is only used as the CU. In this network architecture, the NR-Uu radio interface signal can be transmitted between the terminal device and the satellite through the service link, the satellite radio interface (SRI) signal is transmitted between the satellite and the gateway through the feeder link, and the F1 interface signal between the DU and the CU is transmitted by using the SRI signal.

[0088] In an embodiment of the present application, the network device includes a non-terrestrial network device, such as a satellite, or a terrestrial access network (AN) device, such as a base station. The network device is an access device used by a terminal device to access a mobile communication system in a wireless manner. Alternatively, the network device can be a device that communicates with the terminal device through an air interface. The access network device in the present application includes an evolved NodeB (eNB, or e-NodeB) in an LTE system or a long term evolution-advanced (LTE-A) system; or a next generation NodeB (gNB) in a 5G system, an access node in a wireless fidelity (Wi-Fi (registered trademark)) system, or the like. Alternatively, the network device can be a relay station, an in-vehicle device, a future evolved Public Land Mobile Network (PLMN) device, a device in an M2M network, a device in an IoT network, a drone device, or the like. The access network device in a V2X system can be a road side unit (RSU). The specific technology and specific device form used by the network device are not limited in the embodiments of the present application.

[0089] In addition, the base station in the embodiments of the present application may include a CU and a DU, and a plurality of DUs may be controlled by one CU in a centralized manner. The CU and the DU may be split based on the protocol layer functions each of the CU and the DU has in a wireless network. For example, the functions of the packet data convergence protocol (PDCP) layer and the protocol layers above the PDCP layer are set on the CU, and the protocol layers below the PDCP layer, such as the functions of the radio link control (RLC) layer and the media access control (MAC) layer, are set on the DU. It should be noted that such a protocol layer split is merely an example, and there may be other protocol layer splits. The radio frequency device may be remotely deployed and may not be placed in the DU, may be integrated into the DU, or may be partially remotely deployed and partially integrated into the DU. This is not limited in the embodiments of the present application. In addition, in some embodiments, the control plane (CP)-user plane (UP) of the CU may alternatively be separately implemented in different entities, where the entities are a control plane CU entity (CU-CP entity) and a user plane CU entity (CU-UP entity), respectively. The control plane CU-CP of the CU may be further split into CU-CP1 and CU-CP2. CU-CP1 includes various radio resource management functions, and CU-CP2 includes the RRC function and the PDCP-C function (i.e., the basic function of control plane signaling in the PDCP layer). In this network architecture, the signaling generated by the CU may be transmitted to the terminal device via the DU, or the signaling generated by the terminal device may be transmitted to the CU via the DU. The DU may transparently transmit the signaling to the terminal device or the CU by directly encapsulating the signaling in the protocol layer without analyzing the signaling.

[0090] An example where the network device is a base station is used. The base station may communicate with the terminal device or may communicate with the terminal device via a relay station. The terminal device may communicate with a plurality of base stations in different access technologies. An example where the network device is a satellite is used. The satellite may be connected to the base station via a gateway. When the communication mode of the satellite is the transparent mode, the signal transmitted by the terminal device may be transparently transmitted via the satellite, transferred via the gateway, and enter the terrestrial base station. When the communication mode of the satellite is the regeneration mode, the satellite may be used as a base station and process the signal transmitted by the terminal device.

[0091] In an embodiment of the present application, a terminal device is a device having a wireless transceiver function and can transmit a signal to a network device or receive a signal from a network device. The terminal device may include a user equipment (UE) and, in some cases, is also referred to as a terminal, an access station, a UE station, a remote station, a wireless communication device, a user device, or the like. The terminal device is configured to connect people, objects, machines, and the like and can be widely used in various scenarios. For example, but not limited to, the following scenarios: cellular communication, D2D, V2X, machine-to-machine / machine-type communication (M2M / MTC), IoT, virtual reality (VR), augmented reality (AR), industrial control, self-driving, remote medical, smart grid, smart furniture, smart office, and smart wearable, smart transportation, smart city, unmanned aircraft, and robots. For example, the terminal device may be a mobile phone, a tablet computer, a computer having a wireless transceiver function, a VR terminal, an AR terminal, or the like. By way of non-limiting example, in an embodiment of the present application, the terminal device may alternatively be a wearable device. When various terminal devices described above are located in a vehicle (e.g., arranged or installed in the vehicle), all of the terminal devices may be regarded as in-vehicle terminal devices. The in-vehicle terminal device is also referred to as an on-board unit (OBU). Alternatively, the terminal device in the present application may be an in-vehicle module, an in-vehicle assembly, an in-vehicle component, an in-vehicle chip, or an in-vehicle unit built into the vehicle as one or more components or units. The vehicle may implement the method in the present application by using the built-in terminal device.

[0092] In the embodiments of the present application, a communication device configured to implement the functions of a network device or a terminal device may be the network device or the terminal device itself, or may be a device that can support the network device or the terminal device in implementing this function, such as a chip system. The device may be mounted on the network device or the terminal device. In the technical solutions provided in the embodiments of the present application, an example in which a device configured to implement the functions of a network device is the network device and a device configured to implement the functions of a terminal device is the terminal device is used to explain the technical solutions provided in the embodiments of the present application.

[0093] In the embodiments of the present application, unless otherwise specified, the number of nouns represents "singular noun or plural noun", that is, "one or more". "At least one" means one or more, and "a plurality of" means two or more. "And / or" explains the corresponding relationship between related objects and indicates that three relationships may exist. For example, A and / or B may indicate the following three cases: A exists alone, both A and B exist, and B exists alone, where A and B may be singular or plural. The character " / " usually indicates the "or" relationship between related objects. For example, A / B indicates A or B. "At least one of the following items" or a similar expression indicates any combination of these items and includes any combination of a single item or multiple items. For example, at least one of a, b, or c indicates a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be singular or plural.

[0094] The ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish a plurality of objects, but are not used to limit the size, content, order, time order, priority, importance, or the like of the plurality of objects. For example, the first network device and the second network device may be the same network device or different network devices. In addition, this name does not indicate that the priorities, importance, or the like of the two network devices are different.

[0095] In the above, a communication system to which the embodiments of the present application are applicable is briefly described. Hereinafter, related technical solutions in the embodiments of the present application will be described.

[0096] A satellite communication scenario, for example, the scenario shown in any one of FIGS. 1 to 4, is used as an example. A satellite that provides services to a terminal device (referred to as a source satellite in this specification) may stop providing services to the terminal device due to movement. The terminal device is handed over from the source satellite to another satellite (referred to as a target satellite in this specification) and accesses a base station connected to the target satellite (referred to as a target base station in this specification). The target base station and the base station connected to the source satellite (referred to as a source base station in this specification) may be the same base station or different base stations. There may be a plurality of terminal devices provided with services by the source satellite, and the plurality of terminal devices may simultaneously access the target satellite and access the target base station. When a plurality of terminal devices simultaneously access the target satellite in a contention mode, the success rate of each terminal device accessing the target base station is low, and an additional access delay occurs. When a plurality of terminal devices simultaneously access the network in a non-contention mode, the target base station needs to allocate resources used to access the target base station to the terminal devices. Since there are a large number of terminal devices, the target base station needs to allocate a large number of resources. That is, a large resource consumption occurs.

[0097] Similarly, in a non-satellite communication scenario, alternatively, there may be a plurality of terminal devices served by a source base station. When the source base station stops providing services, the plurality of terminal devices connected to the source base station are also handed over from the source base station to a target base station. In this case, the success rate of accessing the target base station by each terminal device is also low, or the resource overhead for accessing the target base station is also large.

[0098] It can be understood that a satellite (or base station) stopping providing services means that the satellite (or base station) stops or interrupts the services for terminal devices in the corresponding cell. For example, when a satellite connected to a base station is handed over between gateways, the connection with the terminal device is disconnected. In another example, the cell covered by the satellite connected to the base station reaches the service stop time. The service stop time is indicated by using the information element "t_service" in the broadcast message. "t_service" indicates the time information used when the NTN quasi-geostationary cell stops providing services to the current coverage.

[0099] In addition, when the terminal device is handed over from one satellite to another, the beam in which the terminal device is located may change. For example, FIG. 5 shows a scenario in which the satellite connected to the terminal device changes. The terminal device is handed over from satellite 1 to satellite 2. The beams of satellite 1 include beam 1, beam 2, and beam 3, and are shown by using the ellipses (shown by using thin lines) in FIG. 5. The beams of satellite 2 include beam 1, beam 2, and beam 3, and are shown by using the circles (shown by using thick lines) in FIG. 5. It can be seen from FIG. 5 that when the terminal device is connected to satellite 1, the beam in which the terminal device is located is beam 2. When the terminal device is connected to satellite 2, the beam in which the terminal device is located is beam 3. That is, when the satellite connected to the terminal device changes, the beam covering the terminal device may also change.

[0100] However, in a possible scenario, the terminal device may not determine the exact beam. For example, the satellite connected to the terminal device changes, but the base station connected to the terminal device does not change. In this case, the terminal device considers that the beam configuration does not change. FIG. 6 is a diagram showing the handover of the terminal device between satellites. In FIG. 6, an example where the terminal device is handed over from satellite 1 to satellite 2 is used. Satellite 1 and satellite 2 are connected to the same base station. Satellite 1 corresponds to cell 1 managed by the base station, and satellite 2 corresponds to cell 2 managed by the base station. Cell 1 and cell 2 have the same physical cell identifier (PCI), that is, both are PCI1. In this case, even when the terminal device is handed over from cell 1 (i.e., the source cell) to cell 2 (i.e., the target cell), the cell where the terminal device is located may be considered not to change. In other words, the source cell and the target cell having the same PCI may be considered the same cell. Therefore, the base station does not send a cell handover command to the terminal device. Therefore, the cell handover procedure is not triggered, and the beam is not reconfigured for the terminal device in the network. The cell handover command may be an RRC reconfiguration message that carries an indication indicating the cell accessed by the terminal device. It should be noted that in the present application, cells having the same PCI may be considered the same cell.

[0101] Generally, during access to a network or in the process of accessing a network, a terminal device measures a reference signal transmitted in a beam format, such as a synchronization signal and a physical broadcast channel block (SSB), a channel state information reference signal (CSI-RS), or another possible reference signal, to determine the radio link quality or to determine whether there is a beam obstruction. In this scenario shown in FIG. 5 or FIG. 6, if the terminal device still uses the original beam configuration or reference signal configuration, the terminal device may fail to detect (or receive) the reference signal. As a result, inaccurate radio link detection results occur, affecting the determination of radio link obstruction. Similarly, if the terminal device still uses the original beam configuration or reference signal configuration, inaccurate beam obstruction detection results may occur, affecting beam recovery.

[0102] In the present embodiment of the present application, the source network device may instruct access rules for the terminal device. For example, the terminal device starts accessing the target cell of the target network device only after receiving an access instruction from the target network device. For different terminal devices, the target network device may send access instructions at different times, or the time-frequency resources instructed for accessing the network are different. In this case, different terminal devices start accessing the target cell of the target network device at different times or on different time-frequency resources. Therefore, the number of terminal devices accessing the network within the same time can be reduced, the success rate of the terminal device accessing the network can be improved, or the resource overhead for accessing the network can be reduced. In addition, the source network device and / or the target network device may provide the terminal device with a reference signal corresponding to the target cell, so as to avoid inaccurate radio link detection results that occur when the terminal device performs radio link detection based on the originally configured reference signal due to changes in the beam where the terminal device is located. This affects the determination of radio link failures. Similarly, inaccurate beam failure detection results caused by the terminal device performing beam failure detection based on the originally configured reference signal can be avoided, and beam recovery can be prevented from being affected.

[0103] Hereinafter, with reference to the accompanying drawings, the technical solutions provided in the embodiments of the present application will be described.

[0104] Embodiments of the present application provide an access method. The method can be applied to a satellite (or base station) handover scenario. For example, the method can be applied to a scenario where a satellite in a quasi-earth fixed cell reaches the service stop time and the terminal device is handed over between satellites. In another example, the method can be applied to a scenario where a satellite in an earth moving cell is handed over between terrestrial gateways. An example where the terminal device is handed over from a first network device to a second network device is used. In a satellite handover scenario, the first network device can be a first satellite and the second network device can be a second satellite. The base station connected to the first satellite is the source base station, and the base station connected to the second satellite is the target base station. In a base station handover scenario, the first network device is the source base station and the second network device is the target base station. For example, regarding the architecture of the NTN network in FIG. 1, the first network device and the second network device are terrestrial base stations. Regarding the architecture of the NTN network in FIGS. 2 and 3, the first network device and the second network device are satellites, that is, the satellites have base station functions. Regarding the architecture of the NTN network in FIG. 4, the first network device or the second network device can be a satellite or a terrestrial base station.

[0105] The first network device and the second network device can be the same network device or different network devices. The first satellite and the second satellite can be two different satellites or the same satellite.

[0106] When the first network device and the second network device are the same network device, and the first satellite and the second satellite are two different satellites, the terminal device is handed over from the first satellite to the second satellite, and the network device connected to the terminal device remains unchanged. In this case, the communication method can be applied to the scenario where the first network device does not send or does not need to send a handover command, and the cell configured in the terminal device does not change. Of course, in this case, the communication method can alternatively be applied to the scenario where the first network device sends a handover command or the cell configured in the terminal device changes.

[0107] When the first network device and the second network device are different network devices, and the first satellite and the second satellite are two different satellites, the terminal device is handed over from the first network device to the second network device, and the network device connected to the terminal device changes. In this case, the communication method can be applied to the scenario where the first network device sends a handover command and the cell configured in the terminal device changes, or can be applied to the scenario where the first network device does not send or does not need to send a handover command and the cell configured in the terminal device does not change.

[0108] In addition, when the first network device and the second network device are different network devices, and the first satellite and the second satellite are the same satellite, the terminal device is handed over from the first network device to the second network device. Alternatively, the first network device and the second network device are the same network device, the first satellite and the second satellite are the same satellite, but the gateway connected to the first satellite or the second satellite changes. In these two cases, the communication method can be applied to scenarios where the first network device does not send or does not need to send a handover command, or the cell configured for the terminal device does not change. For example, the communication method can be applied to the scenario in FIG. 1. Due to the movement of the satellite, the gateway connected to the satellite needs to change. In this case, the cell corresponding to the satellite also needs to change.

[0109] In the present embodiment of the present application, starting access includes starting a random access process, or the terminal does not need to start a random access process and only needs to transmit information, and as a result, the target network device recognizes that the terminal device has accessed the cell managed by the network device. For example, the terminal device transmits a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) to the target network device to notify the network device that the terminal device has accessed the corresponding cell managed by the network device.

[0110] In the present embodiment of the present application, the handover of the terminal device from the first network device to the second network device can also be understood as the handover of the terminal device from the source cell to the target cell. When the first network device and the second network device are base stations, the first network device manages the source cell and the second network device manages the target cell. When the first network device and the second network device are satellites, the first satellite corresponds to the source cell and the second satellite corresponds to the target cell.

[0111] Unless otherwise specified, "case" and "assume" in the embodiments of the present application can be replaced, and unless otherwise specified, "when" and "in the case" can be replaced. The steps shown by using broken lines in the accompanying drawings are optional steps, that is, the steps are not necessarily executed. In this specification, "access the network", "access the target network device", "access the target base station" and "access the target cell" belong to the same concept and can be replaced with each other unless otherwise specified. "The cell constituted by the second network device does not change" and "the PCI constituted by the second network device does not change" belong to the same concept and can be replaced with each other unless otherwise specified. "The cell constituted by the second network device changes" and "the PCI constituted by the second network device changes" belong to the same concept and can be replaced with each other unless otherwise specified.

[0112] FIG. 7 is a schematic flowchart of a communication method according to an embodiment of the present application.

[0113] In the following description, an example in which a communication method is executed by using a first network device, a second network device, and a terminal device is used. In a non-NTN scenario (i.e., a terrestrial network scenario), the first network device may be a source base station in the terrestrial network, and the second network device may be a target base station in the terrestrial network. In an NTN scenario, the first network device may be a source base station connected to a first satellite, and the second network device may be a target base station connected to a second satellite. For example, refer to the architecture of the NTN network in FIG. 1. Alternatively, the first network device may be a first satellite having a base station function, and the second network device may be a second satellite having a base station function. Refer to the architecture of the NTN network in FIGS. 2, 3, and 4.

[0114] S701: The first network device transmits first indication information to at least one terminal device. Correspondingly, at least one terminal device receives the first indication information from the first network device.

[0115] The first indication information instructs the terminal device to start accessing the target cell of the second network device based on the access indication information from the second network device. The transmission of the first indication information from the first network device to the terminal device can also be understood as the first network device instructing the terminal device to start the access scheduled by the second network device. The first network device may separately transmit the first indication information to one or more terminal devices. Correspondingly, after receiving the access indication information from the second network device, one or more terminal devices start accessing the target cell of the second network device. Regarding the terminal device, it can also be understood that the first network device provides the terminal device with rules for accessing the network. That is, when deciding to start the access, the terminal device does not immediately start accessing the target cell of the second network device, but waits for the access indication information from the second network device, and then the terminal device starts accessing the target cell of the second network device. For example, after disconnecting the connection with the first network device, the terminal device does not immediately start accessing the target cell of the second network device, but waits for the access indication information from the second network device, and then the terminal device starts accessing the target cell of the second network device.

[0116] Considering the case of a large number of terminal devices, the access instruction information transmitted by the second network device is limited within a certain period. As a result, one or more terminal devices may not receive the access instruction information from the second network device. Therefore, one or more terminal devices do not initiate access and do not access the network either. Thus, in the present embodiment of the present application, the first network device may instruct the terminal device to receive the access instruction information from the second network device within the first time period. For example, the first network device may further instruct the first time period to one or more terminal devices. For any one terminal device, if the terminal device does not receive the access instruction information from the second network device within the first time period, the terminal device may alternatively start accessing the target cell after the first time period. Therefore, the situation where the terminal device cannot access the network due to the inability to receive the access instruction information is avoided as much as possible. Optionally, different terminal devices correspond to different first time periods, minimizing the number of competing terminal devices for accessing the network within the same time. Alternatively, terminal devices in different groups correspond to different first time periods, and terminal devices in the same group correspond to the same first time period, minimizing the delay for each terminal device to access the network.

[0117] The first indication information and the first time duration can be carried in the same signaling or in different pieces of signaling. For example, the first indication information and the first time duration can be included in access rule information, and the first network device can separately send the access rule information to one or more terminal devices. Optionally, the access rule information received by different terminal devices includes different first time durations. When the first network device multicasts the access rule information, the access rule information received by terminal devices in different groups can include different first time durations. It should be noted that the specific name of the access rule information is not limited in the present embodiment of the present application.

[0118] In another example, the first network device can broadcast or multicast the first indication information and multicast the first time duration. Terminal devices in different groups obtain different first time durations. Alternatively, the first network device can broadcast or multicast the first indication information. In addition, the first network device can separately send the first time duration to different terminal devices, and different terminal devices can obtain different first time durations.

[0119] It can be understood that when the terminal device is not disconnected from the first network device, the terminal device does not need to start access. Therefore, after the terminal device disconnects from the first network device, it can receive access indication information from the second network device within the first time duration. It can also be understood that the start time of the first time duration is the time when the terminal device disconnects from the first network device. Before the terminal device disconnects from the first network device, if the terminal device receives access indication information, the terminal device can ignore or discard the access indication information, or the terminal device can analyze the access indication information but does not start accessing the target cell of the second network device based on the access indication information. This can avoid the terminal device frequently starting unnecessary access.

[0120] Optionally, the terminal device disconnecting from the first network device includes the following multiple disconnections: The terminal device disconnects from the first network device via the first satellite; The terminal device disconnects from the first network device after recognizing that the first network device has stopped providing services to the terminal device. Here, for example, the terminal device disconnects from the first network device after the time when the first network device stops providing services to the terminal device, which is broadcast by the first network device; Or, the terminal device disconnects from the first network device after receiving a handover command from the first network device. Optionally, after the terminal device disconnects from the first network device and before the terminal device accesses the second network device, the terminal device does not trigger a wireless link failure due to the deterioration of the signal quality of the first network device.

[0121] When the first network device and the second network device correspond to different cells, that is, when the cell constituted by the second network device changes, the terminal device fails to recognize the cell managed by the second network device, or the terminal device fails to recognize the cell in which the access instruction information transmitted by the second network device is received. When the access instruction information transmitted by the second network device is still received in the source cell, it is clear that the terminal device cannot receive the access instruction information. Therefore, the first network device may provide the terminal device with the target cell managed by the second network device, and as a result, the terminal device receives the access instruction information from the second network device in the target cell, and thus, the terminal device can receive the access instruction information from the second network device. For example, the first network device may transmit cell information to the terminal device, where the cell information indicates the target cell. The terminal device receives the cell information and receives the access instruction information in the target cell. The cell information may be transmitted to the terminal device together with the first instruction information and / or the first time duration. For example, the access rule information may include the first instruction information, the first time duration, and the cell information. Of course, the first network device may alternatively transmit the cell information to the terminal device separately. That is, the cell information and the first instruction information (or the first time duration) are respectively carried in different pieces of signaling. Optionally, after the first network device provides the terminal device with the target cell managed by the second network device, the terminal device performs downlink synchronization with the target cell.

[0122] When the first network device and the second network device are the same network device, and the two satellites connected to the network device correspond to the same cell, that is, when the cell formed by the second network device does not change, the terminal device should note that it recognizes that the cell from which access instruction information can be received includes the source cell. In this case, the first network device does not need to provide the target cell to the terminal device, that is, the first network device does not need to send cell information to the terminal device. Of course, even when the cell formed by the second network device does not change, the first network device may provide the target cell to the terminal device. Optionally, the terminal device performs downlink synchronization with the source cell (i.e., the target cell) again.

[0123] Before the first network device stops the service, the access rule information can be sent by the first network device to the terminal device, that is, the first network device can send the access rule information to the terminal device before stopping the service. The present embodiment of the present application does not limit the interval at which the first network device sends the access rule information after the first network device stops the service. In addition, the signaling for carrying the access rule information is not limited in the present embodiment of the present application. For example, the access rule information can be carried in one or more of a media access control control element (MAC CE), a physical downlink control channel (PDCCH), a common (shared) RRC message, or a dedicated RRC message. The common RRC message may include a system message, for example, a system information block (SIB). The dedicated RRC message may include a cell handover message. For example, the dedicated RRC message is a CHO configuration message in the RRC reconfiguration message, or the dedicated RRC message is an HO configuration message in the RRC reconfiguration message. It should be noted that the access rule information may include first indication information, or the access rule information may include first indication information and a first time duration, or the access rule information may include first indication information and cell information. Alternatively, the access rule information includes first indication information, a first time duration, and cell information.

[0124] Optionally, when the first network device uses a CU-DU separation architecture, the first network device sends the access rule information to the terminal device in the following two ways.

[0125] Method 1: The CU generates access rule information and sends the access rule information to the terminal device via the DU. For example, the access rule information is carried in a common RRC message or a dedicated RRC message. The DU may transfer the access rule information received from the CU to the terminal device; or modify the access rule information received from the CU and then send the modified access rule information to the terminal device.

[0126] Method 2: The CU sends indication information to the DU, where the indication information instructs the DU to generate access rule information and send the access rule information to the terminal device. In this method, the indication information may be carried in terminal device level signaling or UE level signaling, or may be carried in cell level signaling. That is, the indication information takes effect for all terminal devices in the cell. The DU receives the indication information and sends the access rule information to the terminal device. The access rule information may be carried in a MAC CE or a PDCCH.

[0127] Optionally, when the CU is a CU-CP and CU-UP separation architecture and the CU-CP is further separated into two parts, for example, the CU-CP is separated into CU-CP1 and CU-CP2, the CU in Method 1 and Method 2 may be CU-CP2. That is, CU-CP2 generates access rule information and sends the access rule information to the terminal device via the DU. The access rule information is carried in a common RRC message or a dedicated RRC message. Alternatively, CU-CP2 sends indication information to the DU, where the indication information instructs the DU to generate access rule information and send the access rule information to the terminal device, and the access rule information may be carried in a MAC CE or a PDCCH.

[0128] S702: The second network device sends access indication information to at least one terminal device. Correspondingly, at least one terminal device receives the access indication information from the second network device.

[0129] The access instruction information can instruct the terminal device to start accessing the target cell of the second network device. After any one terminal device receives the access instruction information, it can send an access to the target cell of the second network device. In the present embodiment of the present application, the second network device can schedule the terminal device to access the target cell of the second network device. For example, when it is determined that a small number of terminal devices need to access the second network device within a specific time, the second network device schedules one or more terminal devices to access the target cell, thereby improving the success rate of access to the second network device by each terminal device.

[0130] In a possible implementation, the second network device can send the access instruction information to different terminal devices at different times. In this case, different terminal devices receive the access instruction information at different opportunities and start accessing the target cell at different times. Therefore, the number of terminal devices accessing the second network device simultaneously is reduced, thereby improving the success rate of access to the second network device by each terminal device. In addition, when the terminal device accesses the second network device in a contention mode, since a small number of terminal devices access the second network device simultaneously, a small number of resources need to be allocated to the second network device, and as a result, the resource overhead can be reduced.

[0131] Alternatively, the second network device separately transmits access indication information indicating time-frequency resources used by a plurality of terminal devices to start access at different transmission opportunities, where different time-frequency resources are configured for the plurality of terminal devices. That is, the access indication information received by different terminal devices indicates different time-frequency resources. Since different terminal devices receive the access indication information at different opportunities, the different terminal devices start access to the target cell at different times by using different time-frequency resources. Thereby, the number of terminal devices that simultaneously compete to access the second network device by using the same resource can be reduced, thereby improving the success rate of each terminal device accessing the network.

[0132] Optionally, access indication information corresponding to terminal devices in different groups is transmitted at different opportunities, and access indication information corresponding to terminal devices in the same group may be transmitted at the same opportunity, minimizing the delay for each terminal device to access the network. Similarly, the access indication information corresponding to terminal devices in different groups indicates different time-frequency resources, and the access indication information corresponding to terminal devices in the same group may indicate the same time-frequency resource.

[0133] Before accessing the target cell, the terminal device needs to determine the access opportunity based on the SSB of the target cell. If the target cell and the source cell have the same PCI and the second network device does not send a handover command to the terminal device, the second network device does not reconfigure the SSB for the terminal device through the handover procedure. In this case, if the terminal device still detects the SSB based on the original SSB configuration, the detected SSB may not be the SSB corresponding to the second network device. The access opportunity determined by the terminal device based on the SSB selected based on the original SSB configuration may also be inappropriate. This results in multiple access obstacles. Therefore, in the present embodiment of the present application, the second network device may further provide the found terminal device with a reference signal used to determine the access opportunity. For ease of explanation, the reference signal is referred to as the second reference signal.

[0134] For example, the access indication information includes third indication information, the third indication information indicates a second reference signal, and the second reference signal is used to determine an access opportunity. The second reference signal may be an SSB, and the third indication information may include an index of the SSB. The terminal device may select an appropriate SSB based on the index of the SSB to determine an access opportunity. In this way, a plurality of access obstacles caused by inappropriate access opportunities determined by the terminal device based on the selected SSB can be avoided. It can be understood that the second reference signal can be used to determine an opportunity to initiate a random access to a target cell. In this case, the second reference signal corresponds to the target cell, that is, the second reference signal belongs to at least one reference signal corresponding to the target cell. Therefore, the terminal device may perform radio link detection and / or beam obstacle detection by using the second reference signal. That is, the second reference signal can be used for radio link detection and / or beam obstacle detection. It may also be considered that the third indication information can further instruct the terminal device to select a reference signal used for radio link detection and / or beam obstacle detection. For the terminal device, when the access indication information includes the third indication information, in addition to determining an opportunity to start access based on the second reference signal, the terminal device can further perform radio link detection and / or beam obstacle detection based on the second reference signal. It should be noted that the second reference signal and the reference signal used for radio link detection and / or beam obstacle detection can be the same reference signal or different reference signals. For ease of explanation, in the present embodiment of the present application, the reference signal used for radio link detection and / or beam obstacle detection is referred to as a first reference signal and will be described below.

[0135] In a possible scenario, the first network device and the second network device may communicate with each other. In this case, the second network device may provide information about the second reference signal to the first network device. Alternatively, the first network device may obtain information about the second reference signal from the second network device. When the first network device recognizes the information about the second reference signal, the third indication information may alternatively be transmitted by the first network device to the terminal device. That is, the second network device transmits access indication information to the terminal device, and the first network device transmits the third indication information to the terminal device.

[0136] Optionally, the access indication information includes fourth indication information, which indicates the point in time when the terminal device starts accessing the target cell of the second network device. For example, the fourth indication information includes a time interval, and after the terminal device receives the access indication information, the terminal device is instructed to start accessing the target cell of the second network device within the time interval. The second network device may transmit different time intervals to different terminal devices, and as a result, different terminal devices start accessing the target cell of the second network device at different times.

[0137] The signaling that carries the access indication information is not limited in the present embodiment of the present application. For example, the access indication information may be carried in downlink control information (DCI) in PDCCH, for example, in trigger signaling specialized for accessing the network, where the trigger signaling may be a PDCCH order.

[0138] Optionally, when the first network device or the second network device uses a CU-DU separation architecture, the DU generates access indication information based on the indication information from the CU and sends the access indication information to the terminal device. For example, the CU sends the indication information to the DU, and the indication information instructs the DU to send the access indication information to the terminal device. The DU receives the indication information from the CU, generates the access indication information, and sends the access indication information to the terminal device. The indication information sent by the CU to the DU can be carried in UE-level signaling or can be carried in cell-level signaling. That is, the indication information takes effect for all terminal devices in the cell. Alternatively, in step 701, the DU may send the access indication information to the terminal device in method 2 based on the indication information from the CU. Optionally, when the CU is a CU-CP and CU-UP separation architecture and the CU-CP is further separated into two parts, for example, the CU-CP is separated into CU-CP1 and CU-CP2, the CU-CP2 may instruct the DU to send the access indication information to the terminal device, and the DU sends the access indication information to the terminal device based on the instruction of the CU-CP2. Alternatively, in step 701, the DU may send the access indication information to the terminal device in method 2 based on the indication information from the CU-CP2. After sending the access indication information, it can be understood that the second network device may send the third indication information to the terminal device as shown in FIG. 7.

[0139] S703: The terminal device starts accessing the target cell based on the access indication information.

[0140] The terminal device receives access instruction information from the second network device and starts accessing the target cell. Optionally, after disconnecting the connection to the first network device, the terminal device starts accessing the target cell of the second network device based on the access instruction information. Correspondingly, after the terminal device disconnects the connection to the first network device, the second network device may send the access instruction information to the terminal device, reducing unnecessary access instruction information and signaling overhead.

[0141] After starting to access the target cell, the terminal device may access the second network device via the second satellite. In this case, after accessing the second network device, the terminal device may delete some configurations of the MAC layer and retain other configurations of the MAC layer. For example, the terminal device may erase the uplink time alignment timer and / or cancel the beam failure detection timer. The terminal device may retain the value of the new data indicator (NDI) and / or retain the content in the soft buffer of all downlink hybrid automatic repeat request (HARQ) progresses. Compared with deleting all configurations of the MAC layer, this enables subsequent access configurations to inherit some configurations of the MAC layer, thereby simplifying the configuration procedure for accessing the network, improving configuration continuity, and improving system performance. Optionally, when the cell configured for the terminal device by the second network device changes, the terminal device may delete all configurations of the MAC layer. In addition, the configurations of the RLC layer and the PDCP layer may remain unchanged.

[0142] Optionally, after accessing the second network device, the terminal device may further update the configuration of the reference signal for wireless link detection and / or beam failure detection. For example, the terminal device notifies the MAC layer or the PHY layer of the update of the reference signal configuration via the RRC layer.

[0143] Before starting access to the target cell, it can be understood that the terminal device may obtain the ephemeris information of the second satellite. The ephemeris information of the second satellite may be transmitted by the second network device to the terminal device, or may be transmitted by the first network device to the terminal device via the first satellite. For example, after establishing a connection with the second satellite, the second network device may broadcast the ephemeris information of the second satellite. For example, the ephemeris information of the second satellite may be carried in a system message, such as SIB19. In another example, the first network device may transmit an RRC message carrying the ephemeris information of the second satellite to the terminal device via the first satellite. The RRC message may be an RRC reconfiguration message, and the ephemeris information of the second satellite may be carried in a CHO configuration message or an HO configuration message in the RRC reconfiguration message.

[0144] Optionally, when the first network device or the second network device uses a CU-DU separation architecture, the ephemeris information of the second satellite can be generated by the CU or the DU. For example, the DU generates the ephemeris information of the second satellite and transmits the ephemeris information of the second satellite to the terminal device. Alternatively, the DU generates the ephemeris information of the second satellite and transmits the ephemeris information of the second satellite to the CU, and the CU transmits the ephemeris information of the second satellite to the terminal device by using an RRC message. Optionally, the CU can receive the ephemeris information of the second satellite from the DU and execute control capabilities based on the ephemeris information of the second satellite. For example, when determining that the terminal device is to be handed over, the CU transmits the ephemeris information of the second satellite to the first network device. In another example, the CU generates the ephemeris information of the second satellite and transmits the ephemeris information of the second satellite to the terminal device via the DU. Alternatively, the CU generates the ephemeris information of the second satellite and transmits the ephemeris information of the second satellite to the DU, and the DU can transmit the ephemeris information of the second satellite to the terminal device. Optionally, the DU can modify and receive the ephemeris information of the second satellite and transmit the modified ephemeris information of the second satellite to the terminal device. The CU can further transmit indication information to the DU, where the indication information can indicate that the epoch time information corresponding to the ephemeris information of the second satellite is indicated in an explicit manner or an implicit manner. When the indication information indicates that the epoch time information corresponding to the ephemeris information of the second satellite is indicated in an implicit manner, the DU needs to decode the received epoch time information corresponding to the ephemeris information of the second satellite in an implicit manner, thereby obtaining the epoch time information corresponding to the ephemeris information of the second satellite. When the indication information indicates that the epoch time information corresponding to the ephemeris information of the second satellite is indicated in an explicit manner, the DU needs to decode the received epoch time information corresponding to the ephemeris information of the second satellite in an explicit manner, thereby obtaining the epoch time information corresponding to the ephemeris information of the second satellite.Therefore, by using the indication information, the CU instructs the DU that the epoch time information corresponding to the ephemeris information of the second satellite is indicated to the DU in an explicit or implicit manner. As a result, the DU can be avoided from performing unnecessary decoding, thereby simplifying the processing procedure of the DU, increasing the processing speed of the DU, and improving the system performance.

[0145] Optionally, when the CU has a CU-CP and CU-UP separation architecture and the CU-CP is further separated into two parts, for example, the CU-CP is separated into CU-CP1 and CU-CP2, the ephemeris information of the second satellite generated by the DU can be sent to CU-CP2. CU-CP2 uses a dedicated RRC message to send the ephemeris information of the second satellite to the terminal device via the DU. Optionally, CU-CP2 sends the ephemeris information to CU-CP1, and as a result, CU-CP1 can execute the control capability based on the ephemeris information.

[0146] Alternatively, CU-CP1 generates the ephemeris information of the second satellite, sends the ephemeris information of the second satellite to CU-CP2, and CU-CP2 sends the ephemeris information of the second satellite to the DU. The DU corrects the received ephemeris information of the second satellite and sends the corrected ephemeris information of the second satellite to the terminal device. CU-CP2 further sends indication information to the DU, where the indication information can indicate that the epoch time information corresponding to the ephemeris information of the second satellite is indicated in an explicit or implicit manner.

[0147] Alternatively, CU-CP1 generates the ephemeris information of the second satellite, sends the ephemeris information of the second satellite to CU-CP2, and CU-CP2 transfers the ephemeris information of the second satellite to the terminal device via the DU by using a dedicated RRC message.

[0148] When the target cell and the source cell have the same PCI and the second network device does not send a handover command to the terminal device, the second network device does not reconfigure a reference signal, such as an SSB or a CSI-RS, for the terminal device through the handover procedure. An example where the reference signal is an SSB is used. In this case, if the terminal device still detects the SSB based on the original SSB configuration, the detected SSB may not be the SSB corresponding to the second network device. Subsequently, the terminal device performs radio link detection based on the received SSB, and the obtained radio link detection may be inaccurate. That is, the terminal device performs radio link detection based on the configuration of the original reference signal, which affects the determination of radio link failure. Similarly, the terminal device performs beam failure detection based on the configuration of the original reference signal, which also affects the determination of beam failure.

[0149] Therefore, the second network device may instruct the terminal device to select a first reference signal corresponding to the target cell. In implementation, the access method may further include the following steps.

[0150] S704: The second network device separately sends second indication information to at least one terminal device. Correspondingly, at least one terminal device receives the second indication information from the second network device.

[0151] For one terminal device, the second indication information may instruct the terminal device to select a first reference signal, and the first reference signal corresponds to the target cell. That the first reference signal corresponds to the target cell may also be understood as the first reference signal belonging to at least one reference signal corresponding to the target cell. An example where one terminal device is used. That the second network device transmits the second indication information to the terminal device may be understood as the second network device instructing the terminal device to use a reference signal corresponding to the target cell. The first reference signal may be used for wireless link detection and / or beam failure detection. After accessing the target cell of the second network device, the terminal device selects the first reference signal based on the second indication information, and based on the first reference signal, may perform wireless link detection and / or beam failure detection corresponding to the connection between the terminal device and the second network device. Since the first reference signal is a reference signal corresponding to the target cell, the terminal device can perform wireless link detection by using the first reference signal, and as a result, inaccurate wireless link detection results can be avoided as much as possible, that is, the determination of wireless link failure can be avoided. Similarly, the terminal device can perform beam failure detection by using the first reference signal, and as a result, the influence on the determination of beam failure can be avoided.

[0152] The first network device and the second network device may communicate with each other. In this case, the second network device may provide the first network device with information about the first reference signal corresponding to the target cell. Alternatively, the first network device may obtain information about the first reference signal of the target cell from the second network device. When the first network device recognizes the information about the first reference signal, the second indication information may alternatively be transmitted by the first network device to the terminal device. In other words, S704 may be replaced by the first network device separately transmitting the second indication information to at least one terminal device. Correspondingly, as shown in FIG. 7, at least one terminal device receives the second indication information from the first network device.

[0153] The second indication information has multiple implementation forms. The specific implementation form for use is not limited in the present embodiment of this application. For example, the second indication information can be implemented in the following four possible implementation forms.

[0154] Implementation form 1: Configuration information of the first reference signal. Specifically, the first network device or the second network device directly provides the terminal device with the configuration information of the reference signal corresponding to the target cell. After accessing the target cell, the terminal device receives the first reference signal based on the configuration information of the first reference signal. It can be understood that the first network device can obtain the first reference signal of the target cell from the second network device. For example, the first network device can request the second network device to obtain information about the first reference signal of the target cell of the second network device, and the second network device responds to the request of the first network device and sends the information about the first reference signal of the target cell to the first network device. Alternatively, the second network device can actively send the information about the first reference signal of the target cell to the first network device without a request from the first network device.

[0155] Implementation form 2: First information and second information. The first information indicates the configuration information of at least one reference signal corresponding to the target cell, and the second information includes the index of the configuration information of the first reference signal. The configuration information of all reference signals (that is, at least one reference signal) corresponding to the target cell can be predefined, preconfigured, or indicated. In this case, the second network device only needs to provide the index of the configuration information of the first reference signal, and there is no need to provide the configuration information of the first reference signal separately each time, thereby reducing the signaling overhead.

[0156] Implementation Form 3: The mapping relationship between at least one reference signal corresponding to the source cell and at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device. The mapping relationship can be a mapping table or neural network parameters. The first network device or the second network device can provide the mapping relationship between at least one reference signal corresponding to the source cell and at least one reference signal corresponding to the target cell. As a result, the terminal device can determine the first reference signal based on the reference signal currently used for wireless link detection or beam obstacle detection in the source cell and the mapping relationship.

[0157] Implementation Form 4: The mapping relationship between the configuration information of at least one reference signal corresponding to the target cell and the geographical location area. The geographical area covered by the target cell can be divided into a plurality of location areas, and each area has a corresponding reference signal. In this case, there is a mapping relationship between the configuration of at least one reference signal corresponding to the target cell and the plurality of areas obtained by dividing the target cell. One reference signal can correspond to one or more location areas, or one location area can correspond to one or more reference signals. The terminal device determines the first reference signal based on the current location area and the mapping relationship. The location area of the terminal device can belong to one or more location areas obtained by dividing the target cell. As a result, it can be understood that the terminal device can determine the first reference signal based on the location area of the terminal device and the mapping relationship.

[0158] When the second indication information is implemented in the aforementioned Implementation Form 1, Implementation Form 3, or Implementation Form 4, the method by which the first network device or the second network device transmits the second indication information to the terminal device is the same as Method 1 by which the first network device transmits the access rule information to the terminal device. Optionally, when the first network device or the second network device uses a CU-DU separation architecture, or when the CU has a CU-CP and CU-UP separation architecture and the CU-CP can be further separated into CU-CP1 and CU-CP2, the method by which the first network device or the second network device transmits the second indication information to the terminal device is the same as Method 1 by which the first network device transmits the access rule information to the terminal device. For details, refer to the above method by which the first network device transmits the access rule information to the terminal device. Details will not be described again here.

[0159] When the second indication information is implemented in the aforementioned Implementation Form 2, the second indication information includes first information and second information. The first information may be carried in a dedicated RRC message or a common RRC message. The second information may be carried in a MAC CE, a PDCCH, a common RRC message, or a dedicated RRC message. For example, the first network device or the second network device may broadcast the first information by using an SIB message and transmit the second information to the terminal device by using a MAC CE.

[0160] Optionally, when the first network device uses a CU-DU separation architecture, the CU may transmit the first information to the terminal device via the DU, and the DU transmits the second information to the terminal device. The CU may further transmit to the DU auxiliary information used to determine the second information, for example, called first auxiliary information. The DU generates the second information based on the first auxiliary information and transmits the second information to the terminal device. The first auxiliary information may include the location information of the terminal device and / or the configuration information of at least one first reference signal. As a result, the DU may determine the index of the configuration information of the first reference signal based on the first auxiliary information. Optionally, when the CU is a CU-CP and CU-UP separation architecture and the CU-CP is further separated into two parts, for example, the CU-CP is separated into CU-CP1 and CU-CP2, the CU-CP2 transmits the first information to the terminal device via the DU, and the DU transmits the second information to the terminal device. The CU-CP2 may further transmit the first auxiliary information to the DU, and the DU generates the second information based on the first auxiliary information and transmits the second information to the terminal device.

[0161] Since the reference signals corresponding to the source cell and the target cell may be the same, S704 is not necessarily executed and is shown by using a dashed line in FIG. 7. In addition, the first network device transmitting the second indication information to the terminal device is the same as the second network device transmitting the second indication information to the terminal device. Details are not described again here. It can be understood that the second network device transmits the second indication information to the terminal device, which may be executed after the second network device is connected to the second satellite.

[0162] It should be noted that the execution order of S704, S702, and S703 is not limited in the present embodiment of the present application. For example, the second instruction information is broadcast by the first network device, and S704 can be executed before or after S702. In another example, the second instruction information is sent by the second network device to the terminal device, the second instruction information is implemented in Implementation Form 1 or Implementation Form 2, and S704 is executed after S702 or S703. In another example, the second instruction information is implemented in Implementation Form 3 or Implementation Form 4, and the second network device can broadcast the second instruction information before or after S702. That is, S704 can be executed before or after S702. In addition, the execution order of S704 and S701 is not limited in the present embodiment of the present application. That is, S701 can be executed after S704, or can be executed before S704. In the present procedure shown in FIG. 7, the first network device can instruct the terminal device of access rules. For example, the first network device starts accessing the target cell of the second network device only after receiving the access instruction information from the second network device. The terminal device starts accessing the target cell of the second network device based on the access instruction information from the second network device. In other words, if the terminal device does not receive the access instruction information from the second network device, the terminal device may not start accessing the target cell. For example, different terminal devices can receive the access instruction information at different times. As a result, different terminal devices start accessing the target cell of the second network device at different times, thereby improving the network access success rate of the terminal device and reducing the network access delay. In addition, the first network device can further provide the terminal device with a reference signal corresponding to the target cell, so as to avoid the terminal device from performing radio link detection and / or beam obstacle detection based on the originally configured reference signal due to the change of the beam where the terminal device is located. This affects the determination of radio link failure and / or beam recovery.

[0163] Embodiments of the present application further provide alternative solutions. The solutions will be described in detail below.

[0164] FIG. 8 is a schematic flowchart of another access method according to an embodiment of the present application. In the following description, an example in which a communication method is executed by using a first network device, a second network device, and a terminal device is used. In a non-NTN scenario, the first network device may be a source base station in a terrestrial network, and the second network device may be a target base station in a terrestrial network. In an NTN scenario, the first network device may be a first satellite having a base station function, and the second network device may be a second satellite having a base station function. Refer to the architecture of the NTN network in FIGS. 2, 3, and 4.

[0165] S801: The first network device transmits trigger rule information to at least one terminal device. Correspondingly, at least one terminal device receives the trigger rule information from the first network device.

[0166] For any one terminal device, the trigger rule information may instruct the terminal device not to start accessing the target cell of the second network device before the first hour. When determining to start accessing the target cell, it can also be understood that the terminal device does not start accessing the target cell immediately, but waits for a period, for example, the first hour, and then starts accessing the target cell. For example, when the terminal device determines that the conditions for starting access to the target cell are met, for example, when the terminal device determines that the signal quality of the source cell is lower than the preset threshold, or when the source cell stops providing services, the terminal device does not start accessing the target cell of the second network device before the first hour. Different terminal devices correspond to different first hours, avoiding multiple terminal devices accessing the second network device simultaneously. Optionally, terminal devices in different groups correspond to different first hours, and terminal devices in the same group may correspond to the same first hour, reducing the delay for each terminal device to access the network.

[0167] The first time can be configured or indicated by the first network device. Optionally, the first time is carried in an RRC message including HO configuration information. Alternatively, the first time is carried in an RRC message including CHO configuration information. It can also be understood that the first network device can send both the first time and the CHO configuration information to the terminal device. For example, the first network device sends an RRC reconfiguration message to the terminal device, where the RRC reconfiguration message includes the CHO configuration information and the first time. It can be seen that the CHO configuration information includes time-based trigger conditions, and the time-based trigger conditions include time information and time duration information. For example, the time-based trigger conditions include a second time and a second time duration. The second time can be regarded as the start time of the time-based trigger condition, or understood as the start time of the CHO. The second time duration is the time duration of the time-based trigger condition. Optionally, the time-based trigger condition in the CHO configuration information can be reused for the first time. For example, the first time can be the second time, or the first time is the sum of the second time and the second time duration, or the first time is any time from the second time to the sum of the second time and the second time duration. That is, the first network device sends an RRC reconfiguration message to the terminal device, where the RRC reconfiguration information includes the CHO configuration information, and the CHO configuration information includes the second time and the second time duration. The terminal device receives the RRC reconfiguration message and can determine that the second time is the first time, or the sum of the second time and the second time duration is the first time.

[0168] Optionally, when the first network device uses a CU-DU separation architecture, the CU may generate trigger rule information and transmit the trigger rule information to the terminal device via the DU. For example, the trigger rule information may be included in a common RRC message (e.g., an SIB message) or a dedicated RRC message (e.g., carried in a CHO configuration message in an RRC reconfiguration message or carried in HO configuration information in an RRC reconfiguration message). Optionally, when the CU includes CU-CP1 and CU-CP2, CU-CP2 may generate trigger rule information and transmit the trigger rule information to the terminal device via the DU.

[0169] Optionally, the first network device may transmit indication information to the terminal device, where the indication information may indicate whether the trigger rule information takes effect. The indication information may be carried in a MAC CE and / or a PDCCH. For example, when the first network device uses a CU-DU separation architecture, the CU may generate auxiliary information used by the DU to determine whether to trigger the terminal device to cause the effect of the trigger rule information, e.g., the so-called second auxiliary information. The second auxiliary information may include configuration information of the trigger rule information and / or third information, and the third information may indicate whether the CU transmits the trigger rule information to the terminal device. The CU transmits the second auxiliary information to the DU, and the DU may generate indication information based on the second auxiliary information and transmit the indication information to the terminal device. For example, the second auxiliary information includes third information, the third information indicates that the CU transmits the trigger rule information to the terminal device, and the indication information generated by the DU based on the second auxiliary information may indicate to the terminal device to cause the effect of the trigger rule information. In another example, the second auxiliary information includes configuration information of the trigger rule information, the configuration information indicates that the trigger rule information is enabled, and the indication information generated by the DU based on the second auxiliary information may indicate to the terminal device to cause the effect of the trigger rule information. Optionally, when the CU includes CU-CP1 and CU-CP2, CU-CP2 may generate the second auxiliary information and transmit the second auxiliary information to the DU.

[0170] When the terminal device determines that the preset condition is satisfied, after the first hour, it starts accessing the target cell of the second network device.

[0171] The preset conditions can also be understood as predefined conditions for starting access. For example, the signal quality of the source cell is lower than a preset threshold, or the source cell stops the service. Usually, when the signal quality of the source cell is lower than the preset threshold, or the source cell stops the service, the terminal device triggers a radio link failure (RLF) and then triggers an RRC reestablishment. The terminal device selects a target cell to start access in the target cell. From this perspective, the trigger rule information can also be understood as information indicating a rule for triggering an RLF. That the terminal device does not start access to the target cell before the first time may mean that the terminal device does not start access to the target cell even when the preset conditions are met. For example, before the first time, even if the terminal device meets the preset conditions, the terminal device does not trigger an RLF or an RRC reestablishment, and thus does not start access to the target cell; or, before the first time, even if the terminal device meets the preset conditions and triggers an RLF, the terminal device does not trigger an RRC reestablishment and does not start access to the target cell. Alternatively, before the first time, even if the terminal device meets the preset conditions and triggers an RLF and an RRC reestablishment, the terminal device is not triggered to start access to the target cell. Of course, even when the terminal device triggers an RLF or an RRC reestablishment, the terminal device needs to start access to the target cell after the first time. For example, the terminal device triggers an RRC reestablishment and selects a target cell in the RRC reestablishment process. However, before the first time, the terminal device does not start access to the target cell. The terminal device starts access to the target cell after the first time when it determines that the preset conditions are met. Alternatively, it should be noted that the terminal device may not determine whether the preset conditions are met, and the terminal device may start access to the target cell only after the first time.Therefore, even if the preset conditions are not satisfied, the terminal device may start accessing the target cell after the first hour.

[0172] S803: The second network device transmits the second instruction information to at least one terminal device. Correspondingly, at least one terminal device receives the second instruction information from the second network device.

[0173] In another implementation, S803 may alternatively be replaced with the first network device transmitting the second instruction information to at least one terminal device. Correspondingly, at least one terminal device receives the second instruction information from the second network device. The specific implementation of S803 is the same as the specific implementation of S704. For details, refer to the relevant content in S704. Details will not be described again here. It should be understood that S803 is not necessarily executed, and thus is indicated by using a dashed line in FIG. 8. The order of executing S802 and S803 is not limited in the present embodiment of the present application. S803 may be executed before S802 or after S802. For example, the first network device may broadcast the second instruction information before or after S802. When the second instruction information is implemented in the foregoing implementation forms 1 and 2, the second instruction information is transmitted to the terminal device by the second network device, and S803 is executed after S802. When the second instruction information is implemented in the foregoing implementation forms 3 and 4, the second instruction information is transmitted to the terminal device by the second network device, and S803 may be executed before or after S802. As shown in FIG. 8, when the second instruction information is transmitted to the terminal device by the second network device, after the second network device transmits the ephemeris information of the second satellite to the terminal device, the second network device may transmit the second instruction information to the terminal device. S803 may be executed before S801 or after S801.

[0174] In the procedure shown in FIG. 8, when it is determined that the terminal device needs to be handed over from the source cell to the target cell when the preset conditions are met, the terminal device does not immediately start accessing the target cell, but starts accessing the target cell after the first hour. For example, after determining the RLF, the terminal device does not immediately trigger the RLF or RRC re-establishment, but triggers the RLF and RRC re-establishment after reaching the first hour to start accessing the target cell. In another example, after determining the RLF, the terminal device does not immediately trigger the RLF or RRC re-establishment, and does not trigger the RLF or RRC re-establishment even after the first hour, but directly starts accessing the target cell. When receiving access indication information before the first hour, the terminal device may directly start accessing the target cell without triggering the RLF or RRC re-establishment. Different terminal devices correspond to different first hours, and as a result, the terminal devices that compete to access the target cell simultaneously can also be reduced, and the success rate of each terminal device accessing the network can be improved.

[0175] The procedures shown in FIGS. 7 and 8 can also be combined with each other. For example, FIG. 9 is a schematic flowchart of another access method according to an embodiment of the present application.

[0176] S901: The first network device transmits the first indication information of the terminal device. Correspondingly, the terminal device receives the first indication information from the first network device.

[0177] S902: The second network device transmits the second indication information to the terminal device. Correspondingly, the terminal device receives the second indication information from the second network device.

[0178] S903: The first network device transmits the trigger rule information to the terminal device. Correspondingly, the terminal device receives the trigger rule information from the first network device.

[0179] S904: The second network device transmits access instruction information to the terminal device. Correspondingly, the terminal device receives the access instruction information from the second network device.

[0180] S905: The terminal device starts accessing the target cell of the second network device based on the first instruction information.

[0181] For details about the steps in the procedure shown in FIG. 9, refer to the relevant content of the corresponding steps in FIGS. 7 and 8. Details will not be described again here. In the procedure shown in FIG. 9, both S902 and S903 are optional steps and are thus indicated by using dashed lines. In addition, S903 can be executed before S902 or after S902. S903 can be executed before S901 or after S901. S904 can be executed before S903 or after S903. S902 can be executed before S904 or after S904.

[0182] In the procedure shown in FIG. 9, the terminal device may start accessing the target cell of the second network device based on the access instruction information from the second network device. As a result, the success rate of the terminal device accessing the network can be improved, and the access delay can be reduced. When it is determined that the terminal device needs to be handed over from the source cell to the target cell when the preset conditions are met, the terminal device may not start accessing the target cell immediately, but may start accessing the target cell after the first hour. This can also improve the success rate of the terminal device accessing the network. Alternatively, when the preset conditions are met, the terminal device may still start accessing the target cell of the second network device after the first hour based on the access instruction information from the second network device. For example, during RRC re-establishment, when the terminal device selects a cell, it still selects the cell waiting for the reception of access instruction information as a candidate cell for access, listens to the access instruction information below the cell, and accesses the target cell.

[0183] In the embodiments provided in the present application, the method provided in the embodiments of the present application is separately described from the perspectives of the terminal device, the first network device, the second network device, and the interaction between the terminal device, the first network device, and the second network device. To implement the functions in the foregoing method provided in the embodiments of the present application, the terminal device, the first network device, and the second network device include a hardware structure and / or a software module, and may implement the foregoing functions in the form of a hardware structure, a software module, or a combination of a hardware structure and a software module. Whether the functions in the foregoing functions are executed in any of the ways of a hardware structure, a software module, or a combination of a hardware structure and a software module depends on specific applications and design constraints of technical solutions.

[0184] Hereinafter, with reference to the accompanying drawings, a communication device configured to implement the foregoing method in an embodiment of the present application will be described.

[0185] FIG. 10 is a block diagram of a communication device 1000 according to an embodiment of the present application. The communication device 1000 may include a processing module 1010 and a transceiver module 1020. Optionally, a storage unit may further be included. The storage unit may be configured to store instructions (codes or programs) and / or data. The processing module 1010 and the transceiver module 1020 may be connected to the storage unit. For example, the processing module 1010 may read instructions (codes or programs) and / or data in the storage unit and implement the corresponding method. The foregoing modules may be arranged independently, or may be partially or fully integrated.

[0186] In some possible implementations, the communication device 1000 may correspondingly implement the behavior and functions of the terminal device in the embodiment of the foregoing method. The communication device 1000 may be a terminal device, or may be a component (such as a chip or a circuit) used in the terminal device, or may be a chip or a chipset in the terminal device, or may be a part of the chip configured to execute the related method functions.

[0187] For example, the communication device 1000 implements the method executed by the terminal device in FIG. 7 or FIG. 9 in the embodiment of the present application. The transceiver module 1020 is configured to receive first indication information from a first network device, receive access indication information from a second network device, and start accessing a target cell of the second network device based on the access indication information. The first indication information instructs the communication device 1000 to start accessing the target cell of the second network device based on the access indication information from the second network device. The processing module 1010 is configured to determine the access indication information.

[0188] In an optional implementation, the first instruction information is included in the access rule information, and the access rule information further includes a first time duration. Specifically, the transceiver module 1020 is configured to receive the access instruction information within the first time duration.

[0189] In an optional implementation, specifically, the transceiver module 1020 is configured to receive the access instruction information within the first time duration after the communication device 1000 disconnects the connection with the first network device.

[0190] In an optional implementation, the first instruction information is included in the access rule information, and the access rule information further includes cell information, and the cell information indicates a target cell. Specifically, the transceiver module 1020 is configured to receive the access instruction information in the target cell.

[0191] In an optional implementation, specifically, the transceiver module 1020 is configured to start accessing the target cell based on the access instruction information after the communication device 1000 disconnects the connection with the first network device.

[0192] In an optional implementation, the transceiver module 1020 is further configured to receive second instruction information from the first network device or the second network device, where the second instruction information instructs the communication device 1000 to select a first reference signal. The first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for wireless link detection and / or beam failure detection.

[0193] In an optional implementation, the second indication information includes: configuration information of the first reference signal; the first information and the second information, where the first information indicates configuration information of at least one reference signal corresponding to the target cell, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to the source cell and at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or a mapping relationship between configuration information of at least one reference signal corresponding to the target cell and a geographical location area, including any one of them.

[0194] In an optional implementation, the access indication information includes third indication information, and the third indication information indicates a second reference signal, where the second reference signal is used to determine an access opportunity.

[0195] In an optional implementation, the access indication information includes fourth indication information, and the fourth indication information includes a first time interval, and the communication device 1000 is instructed to start accessing the target cell after the first time interval from when the terminal device receives the access indication information.

[0196] In an optional implementation, the transceiver module 1020 is further configured to receive trigger rule information from the first network device, where the trigger rule information instructs the communication device 1000 not to start accessing the target cell before the first time. The processing module 1010 is further configured to start accessing the target cell after the first time when it is determined that the preset condition is satisfied.

[0197] In an optional implementation, the first time is carried in an RRC message including CHO configuration information.

[0198] In an optional implementation, the CHO configuration information includes a time-based trigger condition, and the time-based trigger condition includes a second time and a second time length. The second time is the start time of the time-based trigger condition, and the second time length is the time length of the time-based trigger condition. The first time is the second time, or the first time is the sum of the second time and the second time length.

[0199] In an optional implementation, after the communication device 1000 accesses the second network device, the processing module 1010 is further configured to hold the first partial configuration of the MAC layer and delete the second partial configuration of the MAC layer.

[0200] In another example, the communication device 1000 implements the method executed by the terminal device in FIG. 8 or FIG. 9 in the embodiments of the present application. The transceiver module 1020 is configured to receive trigger rule information from the first network device, where the trigger rule information instructs the communication device 1000 not to start accessing the target cell of the second network device before the first time. The processing module 1010 is configured to start accessing the target cell after the first time when it is determined that the preset condition is satisfied. The first time is instructed by the first network device. The preset condition includes that the signal quality of the source cell is lower than the preset threshold, or the source cell stops providing services.

[0201] In an optional implementation, the first time is carried in an RRC message including the CHO configuration information.

[0202] In an optional implementation, the CHO configuration information includes a time-based trigger condition, and the time-based trigger condition includes a second time and a second time length. The second time is the start time of the time-based trigger condition, and the second time length is the time length of the time-based trigger condition. The first time is the second time, or the first time is the sum of the second time and the second time length.

[0203] In an optional implementation, the transceiver module 1020 is further configured to receive second indication information from the first network device or the second network device, where the second indication information instructs the communication device 1000 to select a first reference signal. The first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam failure detection.

[0204] In an optional implementation, the second indication information includes any one of: configuration information of the first reference signal; first information and second information, where the first information instructs configuration information of at least one reference signal corresponding to the target cell, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to a source cell and at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or a mapping relationship between configuration information of at least one reference signal corresponding to the target cell and a geographical location area.

[0205] In some possible implementations, the communication device 1000 may correspondingly implement the behaviors and functions of the network device in the foregoing method embodiments. The communication device 1000 may be a network device, or a component (such as a chip or a circuit) used in a network device, or a chip or a chipset in a network device, or a part of a chip configured to execute related method functions.

[0206] For example, communication device 1000 implements the method executed by the first network device in FIG. 7 in any embodiment of the present application. Processing module 1010 is configured to determine first instruction information, where the first instruction information is based on access instruction information from a second network device and instructs the terminal device to start accessing the target cell of the second network device. Transceiver module 1020 is configured to transmit the first instruction information to the terminal device.

[0207] In an optional implementation, the first instruction information is included in access rule information, and the access rule information further includes a first time period, and the first time period instructs the terminal device to receive access instruction information within the first time period.

[0208] In an optional implementation, the first instruction information is included in access rule information, and the access rule information further includes cell information, and the cell information instructs the terminal device to receive access instruction information in the target cell.

[0209] In an optional implementation, transceiver module 1020 is further configured to transmit second instruction information to the terminal device, where the second instruction information instructs the terminal device to select a first reference signal. The first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for wireless link detection and / or beam failure detection.

[0210] In an optional implementation, the second indication information is: configuration information of the first reference signal; the first information and the second information, where the first information indicates configuration information of at least one reference signal of the target cell, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to the source cell and at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or any one of the mapping relationships between the configuration information of at least one reference signal corresponding to the target cell and the geographical location area.

[0211] In an optional implementation, the access indication information includes third indication information, and the third indication information indicates a second reference signal, where the second reference signal is used to determine an access opportunity.

[0212] In an optional implementation, the access indication information includes fourth indication information, and the fourth indication information includes a first time interval, and the terminal device is instructed to start accessing the target cell after the first time interval after receiving the access indication information.

[0213] In an optional implementation, the transceiver module 1020 is further configured to send trigger rule information to the terminal device, where the trigger rule information instructs the terminal device not to start accessing the target cell before a first time, and the first time is indicated by the first network device.

[0214] In an optional implementation, the first time is carried in an RRC message including CHO configuration information.

[0215] In an optional implementation, the CHO configuration information includes time-based trigger conditions, and the time-based trigger conditions include a second time and a second time length. The second time is the start time of the time-based trigger conditions, and the second time length is the time length of the time-based trigger conditions. The first time is the second time, or the first time is the sum of the second time and the second time length.

[0216] For example, the communication device 1000 implements the method executed by the first network device in FIGS. 8 or 9 in any embodiment of the present application. The processing module 1010 is configured to determine trigger rule information, where the trigger rule information instructs the terminal device not to start accessing the target cell of the second network device before the first time. The first time is instructed by the communication device 1000. The transceiver module 1020 is configured to transmit the trigger rule information to the terminal device.

[0217] In an optional implementation, different terminal devices correspond to different first times.

[0218] In an optional implementation, the first time is carried in an RRC message including CHO configuration information.

[0219] In an optional implementation, the CHO configuration information includes a time-based trigger condition, the time-based trigger condition includes a second time and a second time length, the second time is the start time of the time-based trigger condition, and the second time length is the time length of the time-based trigger condition. The first time is the second time, or the first time is the sum of the second time and the second time length.

[0220] In an optional implementation, the transceiver module 1020 is further configured to transmit second instruction information to the terminal device, where the second instruction information instructs the terminal device to select a first reference signal. The first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam obstacle detection.

[0221] In an optional implementation, the second indication information is: configuration information of the first reference signal; the first information and the second information, where the first information indicates configuration information of at least one reference signal of the target cell, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to the source cell and at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or, any one of mapping relationships between configuration information of at least one reference signal corresponding to the target cell and location information of the terminal device.

[0222] For example, the communication device 1000 implements a method executed by the second network device in FIGS. 7 or 9 in any embodiment of the present application. The processing module 1010 is configured to determine access indication information, where the access indication information instructs one or more terminal devices to separately start accessing the target cell of the communication device 1000. The transceiver module 1020 is further configured to separately transmit the access indication information to one or more terminal devices.

[0223] In an optional implementation, specifically, the transceiver module 1020 is configured to separately transmit the access indication information to a plurality of terminal devices, where the transceiver module 1020 transmits the access indication information to the terminal devices at different transmission opportunities, or the transceiver module 1020 separately transmits, to a plurality of terminal devices, access indication information indicating time-frequency resources used by the plurality of terminal devices to start access at different transmission opportunities, and different time-frequency resources are configured for the plurality of terminal devices.

[0224] In an optional implementation, the transceiver module 1020 is further configured to separately transmit the second indication information to one or more terminal devices, where the second indication information instructs the one or more terminal devices to select a first reference signal. The first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for wireless link detection and / or beam failure detection.

[0225] In an optional implementation, the second indication information includes: configuration information of the first reference signal; first information and second information, where the first information instructs configuration information of at least one reference signal of the target cell, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to the source cell and at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or any one of mapping relationships between configuration information of at least one reference signal corresponding to the target cell and location information of the terminal device.

[0226] In the embodiment of the present application, it should be understood that the processing module 1010 may be implemented by a processor or a processor-related circuit component, and the transceiver module 1020 may be implemented by a transceiver, a transceiver-related circuit component, or a communication interface.

[0227] FIG. 11 is a block diagram of a communication device 1100 according to an embodiment of the present application. The communication device 1100 can be a terminal device and can implement the functions of the terminal device in the method provided in the embodiment of the present application. Alternatively, the communication device 1100 can be a device that can support the terminal device in implementing the corresponding functions in the method provided in the embodiment of the present application. The communication device 1100 can be a chip system. In the present embodiment of the present application, the chip system can include a chip or can include a chip and another discrete device. For specific functions, refer to the description of the method embodiments above. Alternatively, the communication device 1100 can be a first network device and can implement the functions of the first network device in the method provided in the embodiment of the present application. Alternatively, the communication device 1100 can be a device that can support the first network device in implementing the corresponding functions in the method provided in the embodiment of the present application. The communication device 1100 can be a chip system. In the present embodiment of the present application, the chip system can include a chip or can include a chip and another discrete device. For specific functions, refer to the description of the method embodiments above. Alternatively, the communication device 1100 can be a second network device and can implement the functions of the second network device in the method provided in the embodiment of the present application. Alternatively, the communication device 1100 can be a device that can support the first network device in implementing the corresponding functions in the method provided in the embodiment of the present application. The communication device 1100 can be a chip system. In the present embodiment of the present application, the chip system can include a chip or can include a chip and another discrete device. For specific functions, refer to the description of the method embodiments above.

[0228] The communication device 1100 includes one or more processors 1101 that may be configured to implement the functions of the terminal device in the method provided in the embodiments of the present application or to support the communication device 1100 in such implementation. For details, refer to the detailed description in the method example. Details will not be described again here. The one or more processors 1101 may alternatively be configured to implement the functions of the first network device or the second network device in the method provided in the embodiments of the present application or to support the communication device 1100 in such implementation. For details, refer to the detailed description in the method example. Details will not be described again here. The processor 1101 may also be referred to as a processing unit or a processing module and may implement specific control functions. The processor 1101 may be a general-purpose processor or a dedicated processor, etc. For example, the processor may include a central processing unit, an application processor, a modem processor, a graphics processing unit, an image signal processor, a digital signal processor, a video codec processor, a controller, a memory, and / or a neural network processor. The central processing unit may be configured to control the communication device 1100, execute software programs, and / or process data. Different processors may be independent devices or may be integrated into one or more processors, for example, integrated into one or more application-specific integrated circuits.

[0229] Optionally, the communication device 1100 includes one or more memories 1102 configured to store instructions 1104. The instructions can be executed on the processor 1101 to enable the communication device 1100 to execute the methods described in the embodiments of the foregoing methods. The memory 1102 and the processor 1101 can be separately arranged, or integrated together, or the memory 1102 can be considered to be coupled to the processor 1101. The connection in the present embodiment of the present application can be an indirect connection or a communication connection between devices, units, or modules in an electrical form, a mechanical form, or another form, and is used for information exchange between devices, units, or modules. The processor 1101 can cooperate with the memory 1102 in operation. At least one of the at least one memory can be included in the processor. It should be noted that the memory 1102 is not essential, and thus is shown by using a dashed line in FIG. 11.

[0230] Optionally, the memory 1102 can further store data. The processor and the memory can be separately arranged or integrated. In the present embodiment of the present application, the memory 1102 can be a non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), or a volatile memory, such as a random-access memory (RAM). The memory is any other medium that can carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory in the present embodiment of the present application can alternatively be a circuit or any other device capable of implementing a storage function and configured to store program instructions and / or data.

[0231] Optionally, communication device 1100 may include an instruction 1103 (which may also be referred to as a code or, in some cases, a program), and the instruction 1103 can be executed on a processor. As a result, communication device 1100 executes the methods described in the foregoing embodiments. Processor 1101 can store data.

[0232] Optionally, communication device 1100 may further include a transceiver 1105 and an antenna 1106. The transceiver 1105 may be referred to as a transceiver unit, transceiver module, transceiver device, transceiver circuit, transceiver, input / output interface, or the like, and is configured to implement the transceiver function of communication device 1100 through antenna 1106.

[0233] Processor 1101 and transceiver 1105 described in this application may be implemented in an integrated circuit (IC), analog IC, radio frequency integrated circuit (RFID), mixed-signal IC, ASIC, printed circuit board (PCB), or electronic device, etc. The communication device described in this specification may be an independent device (e.g., an independent integrated circuit or a mobile phone), or may be a part of a larger device (e.g., a module that can be incorporated into another device). For details, please refer to the foregoing descriptions of terminal devices and network devices. Details will not be described again here.

[0234] Optionally, the communication device 1100 may further include one or more of the following components, namely, a wireless communication module, an audio module, an external memory interface, an internal memory, a universal serial bus (USB) interface, a power management module, an antenna, a speaker, a microphone, an input / output module, a sensor module, a motor, a camera, or a display, etc. In some embodiments, it can be understood that the communication device 1100 may include more or fewer components, or some components may be integrated, or some components may be separated. These components may be implemented by hardware, software, or a combination of software and hardware.

[0235] The communication device in the foregoing embodiment can be a terminal device (or a network device), a circuit, a chip used in a terminal device (or a network device), or another combined device, component, or the like having the functions of a terminal device (or a network device). It should be noted that when the communication device is a terminal device (or a network device), the transceiver module can be a transceiver and may include an antenna, a radio frequency circuit, and the like, and the processing module can be a processor, for example, a central processing unit (CPU). When the communication device is a component having the functions of a terminal device (or a network device), the transceiver module can be a radio frequency unit, and the processing module can be a processor. When the communication device is a chip system, the communication device can be a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a system on chip (SoC), a CPU, a network processor (NP), a digital signal processing circuit (DSP), a microcontroller unit (MCU), a programmable logic device (PLD), or another integrated chip. The processing module can be a processor of the chip system. The transceiver module or the communication interface can be an input / output interface or an interface circuit of the chip system. For example, the interface circuit can be a code / data read / write interface circuit. The interface circuit can be configured to receive a code instruction (where the code instruction can be stored in a memory, directly read from the memory, or read from the memory via another device) and transmit the code instruction to the processor.The processor may be configured to execute code instructions to perform the methods in the embodiments of the foregoing methods. In another example, the interface circuit may alternatively be a signal transmission interface circuit between a communication processor and a transceiver device.

[0236] When the communication device is a chip-type device or circuit, the device may include a transceiver unit and a processing unit. The transceiver unit may be an input / output circuit and / or a communication interface. The processing unit may be an integrated processor, a microprocessor, or an integrated circuit.

[0237] Some embodiments of the present application further provide a communication system. Specifically, the communication system includes at least one first network device and at least one second network device. For example, the communication system includes a first network device and a second network device configured to implement related functions in any of the procedures in FIGS. 7 to 9. For details, refer to the related descriptions of the method embodiments. Details will not be described again here. The communication system may further include a terminal device, and the terminal device is a terminal device configured to implement related functions in any of the procedures in FIGS. 7 to 9.

[0238] Some embodiments of the present application further provide a computer-readable storage medium including instructions. When the instructions are executed on a computer, the computer can execute the methods executed by the terminal device in any of the procedures in FIGS. 7 to 9. Alternatively, when the instructions are executed on a computer, the computer can execute the methods executed by the first network device in any of the procedures in FIGS. 7 to 9; or when the instructions are executed on a computer, the computer can execute the methods executed by the second network device in any of the procedures in FIGS. 7 to 9.

[0239] Embodiments of the present application further provide a computer program product including instructions. When the instructions are executed on a computer, the computer can execute the method executed by the terminal device in any of the procedures in FIGS. 7 to 9. Alternatively, when the instructions are executed on a computer, the computer can execute the method executed by the first network device in any of the procedures in FIGS. 7 to 9; or, when the instructions are executed on a computer, the computer can execute the method executed by the second network device in any of the procedures in FIGS. 7 to 9.

[0240] Some embodiments of the present application provide a chip system. The chip system includes a processor and may further include a memory configured to implement the function of the first network device or the function of the second network device in the foregoing method, or configured to implement the function of the terminal device in the foregoing method. This chip system may include a chip or may include a chip and other discrete devices.

[0241] It should be understood that the sequence numbers of the foregoing processes do not mean the execution sequence in various embodiments of the present application. The execution order of the processes should be determined based on the functions and internal logics of the processes and should not be construed as any limitation to the implementation process of the embodiments of the present application.

[0242] One skilled in the art can recognize that the various illustrative logical blocks and steps described with reference to the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed by hardware or software depends on specific applications and design constraints of the technical solution. One skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered as exceeding the scope of this application.

[0243] For the purpose of a concise and brief description, one skilled in the art can clearly understand that for the detailed operation processes of the aforementioned systems, devices, and units, the corresponding processes in the embodiments of the aforementioned methods are referred to. Details will not be described again here.

[0244] In some embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in another manner. For example, the described device embodiments are merely examples. For example, the division into units is merely a logical function division, and in actual implementation, it can be in another division manner. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the indicated or described interconnection, direct connection, or communication connection may be implemented through some interfaces. The indirect coupling or communication connection between devices or units can be implemented in an electronic, mechanical, or other form.

[0245] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, and may be arranged in one place, or may be distributed across multiple network units. Some or all of these units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

[0246] When these functions are implemented in the form of software function units and sold or used as independent products, such functions may be stored in a computer-readable storage medium. Based on such understanding, the parts that essentially contribute to the technical solutions of the present application or parts of the technical solutions may be embodied in the form of software products. The computer software products are stored in a storage medium and include a plurality of instructions for enabling a computer device (which may be a personal computer, a server, a network device, or the like) to execute all or some of the steps of the methods in the embodiments of the present application. The aforementioned storage medium includes any medium that can store program codes, such as a USB flash drive, a removable hard disk, a read-only memory (ROM), a RAM, a magnetic disk, or an optical disk.

[0247] It is obvious to those skilled in the art that various modifications and variations can be made to the present application without departing from the scope of the present application. Thus, when these modifications and variations to the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is intended to cover these modifications and variations as well. 。 [Other possible items] [Item 1] An access method, comprising: a step of receiving, by a terminal device, first instruction information from a first network device, where the first instruction information is based on access instruction information from a second network device and instructs the terminal device to start accessing a target cell of the second network device; a step of receiving, by the terminal device, the access instruction information from the second network device; and a step of starting, by the terminal device, the access to the target cell based on the access instruction information The method comprising the above steps. [Item 2] The first instruction information is included in access rule information, the access rule information further includes a first time duration, and the step of receiving, by the terminal device, the access instruction information from the second network device is: a step of receiving, by the terminal device, the access instruction information within the first time duration The method according to item 1, including the above step. [Item 3] The step of receiving, by the terminal device, the access instruction information within the first time duration is: a step of receiving, by the terminal device, the access instruction information within the first time duration after disconnecting the connection with the first network device The method according to item 1 or 2, including the above step. [Item 4] The first instruction information is included in the access rule information, the access rule information further includes cell information, the cell information indicates the target cell, and the terminal device receives the access instruction information in the target cell. The method according to any one of items 1 to 3. [Item 5] The step of starting, by the terminal device, the access to the target cell based on the access instruction information is: a step of starting, by the terminal device, the access to the target cell based on the access instruction information after disconnecting the connection with the first network device The method according to any one of items 1 to 4, including the above step. [Item 6] The method further comprises: The step of receiving, by the terminal device, second indication information from the first network device or the second network device, where the second indication information instructs the terminal device to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam failure detection. The method according to any one of items 1 to 5, comprising. [Item 7] The second indication information is: Configuration information of the first reference signal; First information and second information, where the first information instructs configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; A mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or A mapping relationship between configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of the following. The method according to item 6. [Item 8] The access indication information includes third indication information, the third indication information instructs a second reference signal, and the second reference signal is used for determining an access opportunity. The method according to any one of items 1 to 7. [Item 9] The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the fourth indication information instructs the terminal device to start the access to the target cell after the first time interval after the terminal device receives the access indication information. The method according to any one of items 1 to 8. [Item 10] The method further includes: The step of receiving, by the terminal device, trigger rule information from the first network device, where the trigger rule information instructs the terminal device not to start the access to the target cell before a first time, and the first time is indicated by the first network device; and When it is determined by the terminal device that preset conditions are satisfied, starting to access the target cell after the first time, where the preset conditions include that the signal quality of the source cell is less than a preset threshold, or that the source cell stops providing services The method according to any one of items 1 to 9, comprising the above. [Item 11] The method according to item 10, wherein the first time is carried in a radio resource control (RRC) message including conditional handover (CHO) configuration information. [Item 12] The method according to item 11, wherein the CHO configuration information includes a time-based trigger condition, the time-based trigger condition includes a second time and a second time length, the second time is the start time of the time-based trigger condition, and the second time length is the time length of the time-based trigger condition, where the first time is the second time, or the first time is the sum of the second time and the second time length. [Item 13] The method further comprises: After accessing the second network device, the terminal device retains a first partial configuration of the medium access control (MAC) layer and deletes a second partial configuration of the MAC layer. The method according to any one of items 1 to 12, comprising the above. [Item 14] An access method, comprising: Determining, by a first network device, first indication information, where the first indication information is used to instruct the terminal device to start accessing a target cell of the second network device based on access indication information from the second network device; and Transmitting, by the first network device, the first indication information to the terminal device The method comprising the above. [Item 15] The method according to item 14, wherein the first indication information is included in access rule information, and the access rule information further includes a first time length, and the first time length is used to instruct the terminal device to receive the access indication information within the first time length. [Item 16] The method according to item 14 or 15, wherein the first indication information is included in the access rule information, and the access rule information further includes cell information, and the cell information is used to instruct the terminal device to receive the access indication information in the target cell. [Item 17] The method further comprises: The step of transmitting second indication information to the terminal device by the first network device, where the second indication information instructs the terminal device to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam failure detection. The method according to any one of items 14 to 16, comprising. [Item 18] The second indication information is: Configuration information of the first reference signal; First information and second information, where the first information instructs configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; A mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or A mapping relationship between configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of the following. The method according to item 17. [Item 19] The access indication information includes third indication information, the third indication information instructs a second reference signal, and the second reference signal is used to determine an access opportunity. The method according to any one of items 14 to 18. [Item 20] The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the terminal device is instructed to start the access to the target cell after the first time interval from receiving the access indication information. The method according to any one of items 14 to 19. [Item 21] The method further includes: The step of transmitting trigger rule information to the terminal device by the first network device, where the trigger rule information instructs the terminal device not to start the access to the target cell before a first time, and the first time is indicated by the first network device. The method according to any one of items 14 to 20, comprising. [Item 22] The first time is carried in a radio resource control (RRC) message including conditional handover (CHO) configuration information. The method according to item 21. [Item 23] The CHO configuration information includes time-based trigger conditions, the time-based trigger conditions include a second time and a second time duration, the second time is the start time of the time-based trigger conditions, the second time duration is the time duration of the time-based trigger conditions, where the first time is the second time, or the first time is the sum of the second time and the second time duration, the method according to item 22. [Item 24] An access method, comprising: Determining, by a second network device, access instruction information; and Transmitting, by the second network device, the access instruction information separately to one or more terminal devices, thereby instructing the one or more terminal devices to separately start access to a target cell of the second network device, where the one or more terminal devices separately start the access to the target cell based on the access instruction information after receiving first instruction information from a first network device. A method comprising the above. [Item 25] The step of transmitting, by the second network device, the access instruction information separately to the one or more terminal devices is: Transmitting, by the second network device, the access instruction information separately to the plurality of terminal devices, where the second network device transmits the access instruction information to the terminal devices at different transmission opportunities, or the second network device transmits, at different transmission opportunities, the access instruction information for instructing the time-frequency resources used by the plurality of terminal devices to start the access separately to the plurality of terminal devices, and different time-frequency resources are configured for the plurality of terminal devices, the method according to item 24. Including the above, the method according to item 24. [Item 26] The method further comprises: Transmitting, by the second network device, second instruction information separately to the one or more terminal devices, where the second instruction information instructs the one or more terminal devices to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam failure detection, the method according to item 24 or 25. Comprising the above, the method according to item 24 or 25. [Item 27] The second instruction information is: Configuration information of the first reference signal; First information and second information, where the first information indicates configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; A mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or A mapping relationship between configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of the above; The method according to item 26. [Item 28] The access indication information includes third indication information, the third indication information indicates a second reference signal, and the second reference signal is used by the terminal device to determine an access opportunity. The method according to any one of items 24 to 27. [Item 29] The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the terminal device is instructed to start the access to the target cell after the first time interval after receiving the access indication information. The method according to any one of items 24 to 28. [Item 30] A communication device comprising: A transceiver module configured to receive first indication information from a first network device, where the first indication information instructs the communication device to start accessing a target cell of the second network device based on access indication information from the second network device; where the transceiver module is further configured to receive the access indication information from the second network device; and A processing module configured to start the access to the target cell based on the access indication information The device comprising the above. [Item 31] The first indication information is included in access rule information, and the access rule information further includes a first time duration; Specifically, the transceiver module is configured to receive the access indication information within the first time duration; The device according to item 30. [Item 32] The transmission / reception module is specifically configured to receive the access instruction information within the first time period after the communication device disconnects the connection with the first network device, for the device according to item 30 or 31. [Item 33] The first instruction information is included in the access rule information, the access rule information further includes cell information, the cell information indicates the target cell, and the communication device receives the access instruction information in the target cell, for the device according to any one of items 30 to 32. [Item 34] The processing module is specifically configured to start the access to the target cell based on the access instruction information after disconnecting the connection with the first network device, for the device according to any one of items 30 to 33. [Item 35] The transmission / reception module is further: configured to receive second instruction information from the first network device or the second network device, where the second instruction information instructs the communication device to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for wireless link detection and / or beam failure detection. for the device according to any one of items 30 to 34. [Item 36] The second instruction information is: configuration information of the first reference signal; first information and second information, where the first information instructs configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or a mapping relationship between configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of them, for the device according to item 35. [Item 37] The access instruction information includes third instruction information, the third instruction information instructs a second reference signal, and the second reference signal is used to determine an access opportunity, for the device according to any one of items 30 to 36. [Item 38] The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the communication device is instructed to start the access to the target cell after the first time interval after receiving the access indication information. The device according to any one of items 30 to 37. [Item 39] The transceiver module is further configured to: Receive trigger rule information from the first network device, where the trigger rule information instructs the communication device not to start the access to the target cell before the first time, and the first time is indicated by the first network device; Specifically, when the processing module determines that a preset condition is satisfied, it is configured to start the access to the target cell after the first time, where the preset condition includes: the signal quality of the source cell is smaller than a preset threshold, or the source cell stops providing services. The device according to any one of items 30 to 38. [Item 40] The first time is carried in a radio resource control (RRC) message including conditional handover (CHO) configuration information. The device according to item 39. [Item 41] The CHO configuration information includes a time-based trigger condition, the time-based trigger condition includes a second time and a second time length, the second time is the start time of the time-based trigger condition, and the second time length is the time length of the time-based trigger condition. Here, the first time is the second time, or the first time is the sum of the second time and the second time length. The device according to item 40. [Item 42] The processing module is further configured to: After accessing the second network device, retain a first partial configuration of the media access control (MAC) layer and delete a second partial configuration of the MAC layer. The device according to any one of items 30 to 41. [Item 43] A communication device, A processing module configured to determine first indication information, where the first indication information instructs the terminal device to start accessing a target cell of the second network device based on access indication information from the second network device; and A transceiver module configured to transmit the first indication information to the terminal device The device comprising. [Item 44] The first indication information is included in the access rule information, the access rule information further includes a first time duration, and the first time duration is for instructing the terminal device to receive the access indication information within the first time duration. The apparatus according to item 43. [Item 45] The first indication information is included in the access rule information, the access rule information further includes cell information, and the cell information is for instructing the terminal device to receive the access indication information in the target cell. The apparatus according to item 43 or 44. [Item 46] The transceiver module further: is configured to transmit second indication information to the terminal device, where the second indication information instructs the terminal device to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for wireless link detection and / or beam obstacle detection. The apparatus according to any one of items 43 to 45. [Item 47] The second indication information is: configuration information of the first reference signal; first information and second information, where the first information instructs configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, where the source cell is managed by the communication device; or a mapping relationship between configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of them. The apparatus according to item 46. [Item 48] The access indication information includes third indication information, the third indication information instructs a second reference signal, and the second reference signal is used for determining an access opportunity. The apparatus according to any one of items 43 to 47. [Item 49] The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the fourth indication information instructs the terminal device to start the access to the target cell after the first time interval from when the terminal device receives the access indication information. The apparatus according to any one of items 43 to 48. [Item 50] The transceiver module further: configured to send trigger rule information to the terminal device, where the trigger rule information instructs the terminal device not to start accessing the target cell before the first hour, and the first hour is the device according to any one of items 43 to 49 instructed by the communication device. [Item 51] The device according to item 50, wherein the first hour is carried in a radio resource control (RRC) message including conditional handover (CHO) configuration information. [Item 52] The CHO configuration information includes a time-based trigger condition, the time-based trigger condition includes a second hour and a second hour length, the second hour is the start time of the time-based trigger condition, and the second hour length is the time length of the time-based trigger condition, where the first hour is the second hour, or the first hour is the sum of the second hour and the second hour length. The device according to item 51. [Item 53] A communication device, a processing module configured to determine access instruction information; and a transceiver module configured to separately send the access instruction information to one or more terminal devices to instruct the one or more terminal devices to separately start accessing the target cell of the communication device, where after receiving first instruction information from a first network device, the one or more terminal devices separately start accessing the target cell based on the access instruction information. The device comprising. [Item 54] Specifically, the transceiver module is: configured to separately send the access instruction information to the plurality of terminal devices, where the second network device sends the access instruction information to the terminal devices at different transmission opportunities, or the second network device separately sends the access instruction information instructing the time-frequency resources used by the plurality of terminal devices to start the access at different transmission opportunities to the plurality of terminal devices, and different time-frequency resources are configured for the plurality of terminal devices. The device according to item 53. [Item 55] The transceiver module further: configured to separately transmit the second indication information to the one or more terminal devices, where the second indication information instructs the one or more terminal devices to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam obstacle detection The apparatus according to item 53 or 54 [Item 56] The second indication information is: configuration information of the first reference signal; first information and second information, where the first information instructs configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or a mapping relationship between configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of The apparatus according to item 55 [Item 57] The access indication information includes third indication information, the third indication information instructs a second reference signal, and the second reference signal is used by the terminal device to determine an access opportunity. The apparatus according to any one of items 53 to 56 [Item 58] The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the fourth indication information instructs the terminal device to start the access to the target cell after the first time interval from when the terminal device receives the access indication information. The apparatus according to any one of items 53 to 57 [Item 59] A communication device comprising a processor and a memory, the memory is configured to store a computer program, the processor is configured to execute the computer program stored in the memory, and the communication device is capable of executing the method according to any one of items 1 to 13, the method according to any one of items 14 to 23, or the method according to any one of items 24 to 29. A communication device [Item 60] A communication system comprising a first network device and a second network device, wherein the first network device is configured to execute the method according to any one of items 14 to 23, and the second network device is configured to execute the method according to any one of items 24 to 29. [Item 61] The communication system according to item 60, further comprising a terminal device, wherein the terminal device is configured to execute the method according to any one of items 1 to 13. [Item 62] A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a computer, the computer is capable of executing the method according to any one of items 1 to 13, the method according to any one of items 14 to 23, or the method according to any one of items 24 to 29. [Item 63] A computer program product storing a computer program, wherein when the computer program is executed by a computer, the computer is capable of executing the method according to any one of items 1 to 13, the method according to any one of items 14 to 23, or the method according to any one of items 24 to 29.

Claims

1. An access method, comprising: receiving, by a terminal device, first instruction information from a first network device, where the first instruction information is based on access instruction information from a second network device and instructs the terminal device to start accessing a target cell of the second network device; receiving, by the terminal device, the access instruction information from the second network device; and starting, by the terminal device, the access to the target cell based on the access instruction information A method comprising the above steps.

2. The first instruction information is included in access rule information, the access rule information further includes a first time duration, and the step of receiving, by the terminal device, the access instruction information from the second network device is: receiving, by the terminal device, the access instruction information within the first time duration The method according to claim 1, including the above step.

3. The step of receiving, by the terminal device, the access instruction information within the first time duration is: after disconnecting the connection between the terminal device and the first network device, receiving, by the terminal device, the access instruction information within the first time duration The method according to claim 1 or 2, including the above step.

4. The first instruction information is included in the access rule information, the access rule information further includes cell information, the cell information indicates the target cell, and the terminal device receives the access instruction information in the target cell. The method according to any one of claims 1 to 3.

5. The step of starting, by the terminal device, the access to the target cell based on the access instruction information is: after disconnecting the connection between the terminal device and the first network device, starting, by the terminal device, the access to the target cell based on the access instruction information The method according to any one of claims 1 to 4, including the above step.

6. The method further comprises: The step of receiving, by the terminal device, second indication information from the first network device or the second network device, where the second indication information instructs the terminal device to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam failure detection. The method according to any one of claims 1 to 5, comprising the above.

7. The second indication information is: Configuration information of the first reference signal; First information and second information, where the first information instructs configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; A mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or A mapping relationship between configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of the above. The method according to claim 6.

8. The access indication information includes third indication information, the third indication information instructs a second reference signal, and the second reference signal is used for determining an access opportunity. The method according to any one of claims 1 to 7.

9. The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the fourth indication information instructs the terminal device to start the access to the target cell after the first time interval from when the terminal device receives the access indication information. The method according to any one of claims 1 to 8.

10. The method further includes: The step of receiving, by the terminal device, trigger rule information from the first network device, where the trigger rule information instructs the terminal device not to start the access to the target cell before a first time, and the first time is indicated by the first network device; and When it is determined by the terminal device that preset conditions are satisfied, starting to access the target cell after the first time, where the preset conditions include that the signal quality of the source cell is less than a preset threshold or the source cell stops providing services The method according to any one of claims 1 to 9, comprising the above

11. The method according to claim 10, wherein the first time is carried in a radio resource control (RRC) message including conditional handover (CHO) configuration information

12. The CHO configuration information includes a time-based trigger condition, the time-based trigger condition includes a second time and a second time length, the second time is the start time of the time-based trigger condition, and the second time length is the time length of the time-based trigger condition. Here, the first time is the second time or the first time is the sum of the second time and the second time length. The method according to claim 11

13. The method further comprises: After accessing the second network device, the terminal device retains a first partial configuration of the media access control (MAC) layer and deletes a second partial configuration of the MAC layer. The method according to any one of claims 1 to 12

14. An access method, comprising: Determining, by a first network device, first indication information, where the first indication information is based on access indication information from a second network device and instructs the terminal device to start accessing a target cell of the second network device; and Transmitting, by the first network device, the first indication information to the terminal device The method comprising the above

15. The first indication information is included in access rule information, and the access rule information further includes a first time length, and the first time length instructs the terminal device to receive the access indication information within the first time length. The method according to claim 14

16. The first indication information is included in the access rule information, and the access rule information further includes cell information, and the cell information instructs the terminal device to receive the access indication information in the target cell. The method according to claim 14 or 15

17. The method further comprises: The step of transmitting second indication information to the terminal device by the first network device, where the second indication information instructs the terminal device to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam failure detection. The method according to any one of claims 14 to 16, comprising the above.

18. The second indication information is: Configuration information of the first reference signal; First information and second information, where the first information instructs configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; A mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or A mapping relationship between configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of the above. The method according to claim 17.

19. The access indication information includes third indication information, the third indication information instructs a second reference signal, and the second reference signal is used for determining an access opportunity. The method according to any one of claims 14 to 18.

20. The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the fourth indication information instructs the terminal device to start the access to the target cell after the first time interval since the terminal device receives the access indication information. The method according to any one of claims 14 to 19.

21. The method further includes: The step of transmitting trigger rule information to the terminal device by the first network device, where the trigger rule information instructs the terminal device not to start the access to the target cell before a first time, and the first time is indicated by the first network device. The method according to any one of claims 14 to 20, comprising the above.

22. The first time is carried in a radio resource control (RRC) message including conditional handover (CHO) configuration information. The method according to claim 21.

23. The CH0 composition information includes time-based trigger conditions, the time-based trigger conditions include a second time and a second time length, the second time is the start time of the time-based trigger conditions, the second time length is the time length of the time-based trigger conditions, wherein the first time is the second time, or the first time is the sum of the second time and the second time length, the method according to claim 22.

24. An access method, comprising: determining, by a second network device, access instruction information; and separately transmitting, by the second network device, the access instruction information to one or more terminal devices, thereby instructing the one or more terminal devices to separately start accessing a target cell of the second network device, wherein the one or more terminal devices separately start the access to the target cell based on the access instruction information after receiving first instruction information from a first network device. A method comprising the above.

25. The step of separately transmitting, by the second network device, the access instruction information to the one or more terminal devices is: separately transmitting, by the second network device, the access instruction information to the plurality of terminal devices, wherein the second network device transmits the access instruction information to the terminal devices at different transmission opportunities, or the second network device separately transmits the access instruction information for instructing time-frequency resources used by the plurality of terminal devices to start the access at different transmission opportunities, and different time-frequency resources are configured for the plurality of terminal devices. The method according to claim 24, comprising the above.

26. The method further comprises: separately transmitting, by the second network device, second instruction information to the one or more terminal devices, wherein the second instruction information instructs the one or more terminal devices to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam failure detection. The method according to claim 24 or 25, comprising the above.

27. The second instruction information is: Configuration information of the first reference signal; First information and second information, where the first information indicates configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; A mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or A mapping relationship between configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of them; The method according to claim 26.

28. The access indication information includes third indication information, the third indication information indicates a second reference signal, and the second reference signal is used by the terminal device to determine an access opportunity. The method according to any one of claims 24 to 27.

29. The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the terminal device is instructed to start the access to the target cell after the first time interval after receiving the access indication information. The method according to any one of claims 24 to 28.

30. A communication device comprising: A transceiver module configured to receive first indication information from a first network device, where the first indication information instructs the communication device to start accessing a target cell of the second network device based on access indication information from the second network device; where the transceiver module is further configured to receive the access indication information from the second network device; and A processing module configured to start the access to the target cell based on the access indication information The device comprising.

31. The first indication information is included in access rule information, and the access rule information further includes a first time duration; Specifically, the transceiver module is configured to receive the access indication information within the first time duration. The device according to claim 30.

32. The transmitting and receiving module is specifically configured to receive the access instruction information within the first time period after the communication device disconnects the connection with the first network device, according to the apparatus of claim 30 or 31.

33. The first instruction information is included in the access rule information, the access rule information further includes cell information, the cell information indicates the target cell, and the communication device receives the access instruction information in the target cell, according to the apparatus of any one of claims 30 to 32.

34. The processing module is specifically configured to start the access to the target cell based on the access instruction information after disconnecting the connection with the first network device, according to the apparatus of any one of claims 30 to 33.

35. The transmitting and receiving module is further configured to: Receive second instruction information from the first network device or the second network device, where the second instruction information instructs the communication device to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for wireless link detection and / or beam obstacle detection. According to the apparatus of any one of claims 30 to 34.

36. The second instruction information includes: Configuration information of the first reference signal; First information and second information, where the first information instructs the configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; A mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, where the source cell is managed by the first network device; or A mapping relationship between the configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of them. According to the apparatus of claim 35.

37. The access instruction information includes third instruction information, the third instruction information instructs a second reference signal, and the second reference signal is used to determine an access opportunity, according to the apparatus of any one of claims 30 to 36.

38. The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the communication device is instructed to start the access to the target cell after the first time interval after receiving the access indication information. The device according to any one of claims 30 to 37.

39. The transceiver module is further configured to: Receive trigger rule information from the first network device, where the trigger rule information instructs the communication device not to start the access to the target cell before the first time, and the first time is instructed by the first network device; Specifically, when the processing module determines that a preset condition is satisfied, it is configured to start the access to the target cell after the first time, where the preset condition includes: the signal quality of the source cell is smaller than a preset threshold, or the source cell stops providing services. The device according to any one of claims 30 to 38.

40. The first time is carried in a radio resource control (RRC) message including conditional handover (CHO) configuration information. The device according to claim 39.

41. The CHO configuration information includes a time-based trigger condition, the time-based trigger condition includes a second time and a second time length, the second time is the start time of the time-based trigger condition, and the second time length is the time length of the time-based trigger condition. Here, the first time is the second time, or the first time is the sum of the second time and the second time length. The device according to claim 40.

42. The processing module is further configured to: After accessing the second network device, retain a first partial configuration of the media access control (MAC) layer and delete a second partial configuration of the MAC layer. The device according to any one of claims 30 to 41.

43. A communication device, A processing module configured to determine first indication information, where the first indication information instructs a terminal device to start access to a target cell of a second network device based on access indication information from the second network device; and A transmitting and receiving module configured to transmit the first indication information to the terminal device A device comprising the same. **Claim 44** The first indication information is included in access rule information, the access rule information further includes a first time duration, and the first time duration instructs the terminal device to receive the access indication information within the first time duration. The device according to claim 43. **Claim 45** The first indication information is included in the access rule information, the access rule information further includes cell information, and the cell information instructs the terminal device to receive the access indication information in the target cell. The device according to claim 43 or 44. **Claim 46** The transmitting and receiving module is further configured to: Transmit second indication information to the terminal device, where the second indication information instructs the terminal device to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for wireless link detection and / or beam obstacle detection. The device according to any one of claims 43 to 45. **Claim 47** The second indication information includes: Configuration information of the first reference signal; First information and second information, where the first information instructs configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; A mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, where the source cell is managed by the communication device; or A mapping relationship between configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of the above. The device according to claim 46. **Claim 48** The access indication information includes third indication information, the third indication information indicates a second reference signal, and the second reference signal is used to determine an access opportunity. The device according to any one of claims 43 to 47. **Claim 49** The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the fourth indication information instructs the terminal device to start the access to the target cell after the first time interval from when the terminal device receives the access indication information. The device according to any one of claims 43 to 48.

50. The transceiver module is further configured to: Transmit trigger rule information to the terminal device, where the trigger rule information instructs the terminal device not to start the access to the target cell before the first time, and the first time is indicated by the communication device. The device according to any one of claims 43 to 49.

51. The first time is carried in a radio resource control (RRC) message including conditional handover (CHO) configuration information. The device according to claim 50.

52. The CHO configuration information includes a time-based trigger condition, the time-based trigger condition includes a second time and a second time length, the second time is the start time of the time-based trigger condition, and the second time length is the time length of the time-based trigger condition. Here, the first time is the second time, or the first time is the sum of the second time and the second time length. The device according to claim 51.

53. A communication device, comprising: A processing module configured to determine access indication information; and A transceiver module configured to separately transmit the access indication information to one or more terminal devices and instruct the one or more terminal devices to separately start access to a target cell of the communication device. After receiving first indication information from a first network device, the one or more terminal devices separately start the access to the target cell based on the access indication information. The device comprising the above.

54. Specifically, the transceiver module is configured to: configured to separately transmit the access indication information to the plurality of terminal devices, wherein the second network device transmits the access indication information to the terminal devices at different transmission opportunities, or the second network device separately transmits the access indication information indicating time-frequency resources used by the plurality of terminal devices to start the access to the plurality of terminal devices at different transmission opportunities, and different time-frequency resources are configured for the plurality of terminal devices. The apparatus according to claim 53. **Claim 55** The transceiver module is further configured to: separately transmit second indication information to the one or more terminal devices, wherein the second indication information instructs the one or more terminal devices to select a first reference signal, the first reference signal belongs to at least one reference signal corresponding to the target cell, and the first reference signal is used for radio link detection and / or beam failure detection. The apparatus according to claim 53 or 54. **Claim 56** The second indication information is: configuration information of the first reference signal; first information and second information, wherein the first information indicates configuration information of the at least one reference signal, and the second information includes an index of the configuration information of the first reference signal; a mapping relationship between at least one reference signal corresponding to a source cell and the at least one reference signal corresponding to the target cell, wherein the source cell is managed by the first network device; or a mapping relationship between configuration information of the at least one reference signal corresponding to the target cell and a geographical location area including any one of the above. The apparatus according to claim 55. **Claim 57** The access indication information includes third indication information, the third indication information indicates a second reference signal, and the second reference signal is used by the terminal device to determine an access opportunity. The apparatus according to any one of claims 53 to 56. **Claim 58** The access indication information includes fourth indication information, the fourth indication information includes a first time interval, and the terminal device is instructed to start the access to the target cell after the first time interval after receiving the access indication information. The apparatus according to any one of claims 53 to 57. **Claim 59** A communication device comprising a processor and a memory, wherein the memory is configured to store a computer program, and the processor is configured to execute the computer program stored in the memory, and the communication device is capable of executing the method according to any one of claims 1 to 13, the method according to any one of claims 14 to 23, or the method according to any one of claims 24 to 29.

60. A communication system comprising a first network device and a second network device, wherein the first network device is configured to execute the method according to any one of claims 14 to 23, and the second network device is configured to execute the method according to any one of claims 24 to 29.

61. The communication system according to claim 60, further comprising a terminal device, wherein the terminal device is configured to execute the method according to any one of claims 1 to 13.

62. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a computer, the computer is capable of executing the method according to any one of claims 1 to 13, the method according to any one of claims 14 to 23, or the method according to any one of claims 24 to 29.

63. A computer program product storing a computer program, wherein when the computer program is executed by a computer, the computer is capable of executing the method according to any one of claims 1 to 13, the method according to any one of claims 14 to 23, or the method according to any one of claims 24 to 29.

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