Communication method and apparatus

Abstract

A communication method and apparatus, relating to the technical field of communications, and used for reducing the measurement overhead of terminal devices and improving the measurement efficiency. A network device sends a candidate cell list and first indication information to a terminal device. The first indication information indicates a range of candidate cells in the candidate cell list to be measured by the terminal device. Then, the terminal device only measures candidate cells in a first range. Thus, the number of cells to be measured can be reduced, the measurement overhead is reduced, and the measurement efficiency is improved.

Description

Communication method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on October 27, 2023, with application number 202311418907.5 and application name "A Communication Method and Device", the entire contents of which are incorporated by reference into this application. Technical Field

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

[0004] Cell switching is a very important feature in communication systems. It is mainly triggered by the movement of the terminal device when the terminal device is in the radio resource control (RRC) connection state, so as to switch the terminal device to a neighboring cell with better signal quality before the signal quality of the serving cell becomes unavailable for communication, thereby providing continuous and uninterrupted communication services.

[0005] In layer 1 / layer 2-triggered mobility (LTM), after the network side configures a candidate cell list for a terminal device, the terminal device measures all cells, which is inefficient.

[0006] Summary of the Invention

[0007] Embodiments of the present application provide a communication method and apparatus for improving cell measurement efficiency.

[0008] In a first aspect, an embodiment of the present application provides a communication method. The method is applied to a terminal device. The method can be executed by the terminal device or by a module (such as a chip or circuit) in the terminal device. Taking execution by the terminal device as an example. In this method, the terminal device receives a candidate cell list and first indication information from a first network device, where the first indication information is used to indicate a first range, where the first range is a range for measuring candidate cells in the candidate cell list; and performs measurement on the candidate cells within the first range.

[0009] Using the above method, after the terminal device receives the first indication information, it can determine the first measurement range and only perform measurements on candidate cells within the first range without performing measurements on all cells, thereby reducing the measurement overhead of the terminal device and improving measurement efficiency to improve switching efficiency.

[0010] In one possible design, the first network device may only send a candidate cell list to the terminal device, where the candidate cell list includes candidate cells within the first range. After receiving the candidate cell list, the terminal device measures the candidate cells in the candidate cell list, that is, measures the candidate cells within the first range.

[0011] In one possible design, the method further includes: sending a moving path of the terminal device to the first network device. The moving path of the terminal device can be used to determine the first range.

[0012] In one possible design, the first range may be a position range. The first indication information is used to indicate the first range, including: the first indication information is used to indicate the starting position and the ending position corresponding to the first range; or the first indication information is used to indicate the starting position corresponding to the first range.

[0013] In one possible design, when the first indication information indicates the starting position corresponding to the first range, the end position may be the position where the moving path is updated, or the moving end point of the moving path, etc. The end position may also be the position where the cell switching instruction is received.

[0014] By adopting the above method, the terminal device obtains the starting position and the ending position of the measurement, so that there is no need to perform measurement on the candidate cell list at positions outside the interval, which can reduce the measurement overhead of the terminal device.

[0015] In one possible design, the starting position is: the waypoint where the terminal device starts to perform the measurement; or the geographical location where the terminal device starts to perform the measurement; or a position whose distance from the first position is less than or equal to a first distance threshold.

[0016] In one possible design, the end location is: a waypoint where the terminal device ends the measurement; or a geographic location where the terminal device ends the measurement; or a location whose distance from the second location is greater than or equal to a second distance threshold. For example, the second location can be a waypoint or a geographic location. For example, the geographic location can be latitude and longitude coordinates or a geographic identifier.

[0017] In one possible design, the first range may be a time range. The first indication information is used to indicate the first range, including: the first indication information is used to indicate the start time and end time corresponding to the first range; or, the first indication information is used to indicate the start time corresponding to the first range. The start time and end time may be in Coordinated Universal Time (UTC). UTC may also be called Universal Time, World Standard Time, or International Coordinated Time.

[0018] In one possible design, the starting time is: the moment when the terminal device starts to perform the measurement; or the moment when the time difference with the first moment is less than or equal to a first time threshold.

[0019] In one possible design, the end time is: the moment when the terminal device ends the measurement; or the moment when the time difference with the second moment is greater than or equal to a second time threshold.

[0020] In one possible design, the first range may be a location range + a time range. The first indication information is used to indicate the first range, and the first indication information is used to indicate the starting location, starting time, ending time, and ending location corresponding to the first range; or the first indication information is used to indicate the starting location and starting time corresponding to the first range; or the first indication information indicates the starting location, starting time, and ending location corresponding to the first range; or the first indication information indicates the starting time, starting location, and ending time corresponding to the first range.

[0021] In one possible design, the method also includes: the terminal device receives second indication information from the first network device, the second indication information is used to indicate a trigger point (or timing) for deleting configuration information of at least one second candidate cell, and the second candidate cell is a candidate cell in the candidate cell list.

[0022] In one possible scenario, the number of the at least one second candidate cell may be the number of all candidate cells in the candidate cell list, that is, the at least one second candidate cell includes N second candidate cells, the candidate cell list also includes N candidate cells, and the N second candidate cells are the same as the N candidate cells in the candidate cell list. In this case, it can be understood that the second indication information is used to instruct deletion of configuration information of all candidate cells in the candidate cell list.

[0023] In another possible scenario, the number of the at least one second candidate cell is the number of all candidate cells corresponding to the first range in the candidate cell list. For example, the at least one second candidate cell includes N second candidate cells. The candidate cell list includes M candidate cells. M and N are both positive integers, and M is greater than N. The number of candidate cells within the first range measured by the terminal device is N. The N second candidate cells are the same as the N candidate cells within the first range of the candidate cell list. In this case, it can be understood that the second indication information is used to instruct the deletion of the configuration information of the candidate cells within the first range in the candidate cell list.

[0024] In some embodiments, the second indication information may further indicate a second range of candidate cells to be deleted. The second range may be indicated in a list, a set, or other manners, which are not limited in the embodiments of the present application. The second range may include all candidate cells included in the candidate cell list for which measurements have been completed, or may include a portion of the candidate cells included in the candidate cell list for which measurements have been completed.

[0025] In one possible design, the second indication information is used to indicate a trigger point for deleting the configuration information of at least one second candidate cell, including: the second indication information is used to indicate the location for deleting the configuration information of the at least one second candidate cell; or, the second indication information is used to indicate the time for deleting the configuration information of the at least one second candidate cell.

[0026] In one possible design, the location at which the configuration information of the at least one second candidate cell is deleted is: the first waypoint at which the configuration information of the at least one second candidate cell is deleted; or, the first geographical location at which the configuration information of the at least one second candidate cell is deleted; or, the location between the second waypoint and the third waypoint; or, the location between the second geographical location and the third geographical location; or, the location between the fourth geographical location and the fourth waypoint, where the fourth geographical location is a location that is less than a third distance threshold from the fourth waypoint.

[0027] In one possible design, the second indication information is used to indicate a trigger point for deleting the configuration information of at least one second candidate cell, including: the second indication information is used to indicate a time range for deleting the configuration information of at least one second candidate cell, or the second indication information is used to indicate a moment for deleting the configuration information of at least one second candidate cell.

[0028] In one possible design, after completing the switch to the target cell, when it is determined based on the moving path of the terminal device that the second path passed after flying away from the first path corresponding to the first range includes some or all of the candidate cells corresponding to the first range, the configuration information of some or all of the candidate cells in the candidate cell list corresponding to the first range can be retained.

[0029] In one possible design, after completing the switch to the target cell, when it is determined based on the moving path of the terminal device that the second path passed after flying away from the first path corresponding to the first range does not include some or all of the candidate cells corresponding to the first range, the configuration information of some or all of the candidate cells in the candidate cell list corresponding to the first range can be deleted.

[0030] In one possible design, after completing the switch to the target cell, the second path passed after flying away from the first path corresponding to the first range is determined according to the moving path of the terminal device to include the second range, and the shortest distance between the second range and the first range is less than or equal to the set threshold, then the configuration information of some or all candidate cells in the candidate cell list corresponding to the first range continues to be saved.

[0031] In one possible design, third indication information may be sent to the first network device, where the third indication information is used to indicate that some or all cells in the candidate cell list have been deleted.

[0032] In one possible design, if the terminal device enters the second path from the first path corresponding to the first range and the configuration information of the cell measured in the second path has been applied, the saved measurement results of the cell can be cleared.

[0033] In one possible design, if a terminal device enters a second path from a first path corresponding to a first range and configuration information of cells measured within the second path has been applied, only measurement results of overlapping cells may be saved. Overlapping cells are cells included in the candidate cell list corresponding to the first path and included in the candidate cell list corresponding to the second path.

[0034] In one possible design, the first range may be a height range. The first indication information is used to indicate the first range, including: the first indication information is used to indicate a starting height and an ending height corresponding to the first range; or, the first indication information is used to indicate an ending height corresponding to the first range; or, the first indication information is used to indicate a starting height corresponding to the first range.

[0035] In one possible design, the first range may be a height range + a position. The first indication information is used to indicate the first range, including: the first indication information is used to indicate the starting height, ending height, and position corresponding to the first range; or, the first indication information is used to indicate the ending height and position corresponding to the first range; or, the first indication information is used to indicate the starting height and position corresponding to the first range.

[0036] In one possible design, the receiving of the candidate cell list and the first indication information from the first network device includes: receiving first configuration information from the first network device, the first configuration information including the candidate cell list and the first indication information.

[0037] In one possible design, fourth indication information is received from the first network device, where the fourth indication information is used to instruct the terminal device to use the same configuration information (using the first configuration information) in the ascending phase and the descending phase.

[0038] In one possible design, fifth indication information is received from the first network device, where the fifth indication information is used to instruct the terminal device to use different configuration information during the ascending phase and the descending phase. Second configuration information is received from the first network device, where the second configuration information includes sixth indication information and a second candidate cell list.

[0039] In a second aspect, an embodiment of the present application provides a communication method, which is applied to a first network device. The method can be executed by the first network device or by a module (such as a chip or circuit) in the first network device. Take the method being executed by the first network device as an example. The method includes: the first network device determines a candidate cell list and first indication information; the first indication information is used to indicate a first range, and the first range is the range in which the terminal device measures the candidate cells in the first candidate cell list; and the candidate cell list and the first indication information are sent to the terminal device.

[0040] In one possible design, the first network device may only send a candidate cell list to the terminal device, where the candidate cell list includes candidate cells within the first range. After receiving the candidate cell list, the terminal device measures the candidate cells in the candidate cell list, that is, measures the candidate cells within the first range.

[0041] In one possible design, the method further includes: the first network device receiving a movement path from the terminal device. The movement path of the terminal device can be used to determine the first range.

[0042] In one possible design, the first range may be a position range. The first indication information is used to indicate the first range, including: the first indication information is used to indicate the starting position and the ending position corresponding to the first range; or the first indication information is used to indicate the starting position corresponding to the first range.

[0043] In one possible design, when the first indication information indicates the starting position corresponding to the first range, the end position may be the position where the moving path is updated, or the moving end point of the moving path, etc. The end position may also be the position where the cell switching instruction is received.

[0044] By adopting the above method, the terminal device obtains the starting position and the ending position of the measurement, so that there is no need to perform measurement on the candidate cell list at positions outside the interval, which can reduce the measurement overhead of the terminal device.

[0045] In one possible design, the starting position is: the waypoint where the terminal device starts to perform the measurement; or the geographical location where the terminal device starts to perform the measurement; or a position whose distance from the first position is less than or equal to a first distance threshold.

[0046] In one possible design, the end location is: a waypoint where the terminal device ends the measurement; or a geographic location where the terminal device ends the measurement; or a location whose distance from the second location is greater than or equal to a second distance threshold. For example, the second location can be a waypoint or a geographic location. For example, the geographic location can be latitude and longitude coordinates or a geographic identifier.

[0047] In one possible design, the first range may be a time range. The first indication information is used to indicate the first range, including: the first indication information is used to indicate the start time and end time corresponding to the first range; or, the first indication information is used to indicate the start time corresponding to the first range. The start time and end time may be in Coordinated Universal Time (UTC). UTC may also be called Universal Time, World Standard Time, or International Coordinated Time.

[0048] In one possible design, the starting time is: the moment when the terminal device starts to perform the measurement; or the moment when the time difference with the first moment is less than or equal to a first time threshold.

[0049] In one possible design, the end time is: the moment when the terminal device ends the measurement; or the moment when the time difference with the second moment is greater than or equal to a second time threshold.

[0050] In one possible design, the first range may be a location range + a time range. The first indication information is used to indicate the first range, and the first indication information is used to indicate the starting location, starting time, ending time, and ending location corresponding to the first range; or the first indication information is used to indicate the starting location and starting time corresponding to the first range; or the first indication information indicates the starting location, starting time, and ending location corresponding to the first range; or the first indication information indicates the starting time, starting location, and ending time corresponding to the first range.

[0051] In one possible design, the method also includes: the terminal device receives second indication information from the first network device, the second indication information is used to indicate a trigger point (or timing) for deleting configuration information of at least one second candidate cell, and the second candidate cell is a candidate cell in the candidate cell list.

[0052] In one possible design, the second indication information is used to indicate a trigger point for deleting the configuration information of at least one second candidate cell, including: the second indication information is used to indicate the location for deleting the configuration information of the at least one second candidate cell; or, the second indication information is used to indicate the time for deleting the configuration information of the at least one second candidate cell.

[0053] In one possible design, the location at which the configuration information of the at least one second candidate cell is deleted is: the first waypoint at which the configuration information of the at least one second candidate cell is deleted; or, the first geographical location at which the configuration information of the at least one second candidate cell is deleted; or, the location between the second waypoint and the third waypoint; or, the location between the second geographical location and the third geographical location; or, the location between the fourth geographical location and the fourth waypoint, where the fourth geographical location is a location that is less than a third distance threshold from the fourth waypoint.

[0054] In one possible design, the second indication information is used to indicate a trigger point for deleting the configuration information of at least one second candidate cell, including: the second indication information is used to indicate a time range for deleting the configuration information of at least one second candidate cell, or the second indication information is used to indicate a moment for deleting the configuration information of at least one second candidate cell.

[0055] In one possible design, third indication information is received from the terminal device, where the third indication information is used to indicate that configuration information of some or all cells in the candidate cell list has been deleted.

[0056] In one possible design, the first range may be a height range. The first indication information is used to indicate the first range, including: the first indication information is used to indicate a starting height and an ending height corresponding to the first range; or, the first indication information is used to indicate an ending height corresponding to the first range; or, the first indication information is used to indicate a starting height corresponding to the first range.

[0057] In one possible design, the first range may be a height range + a position. The first indication information is used to indicate the first range, including: the first indication information is used to indicate the starting height, ending height, and position corresponding to the first range; or, the first indication information is used to indicate the ending height and position corresponding to the first range; or, the first indication information is used to indicate the starting height and position corresponding to the first range.

[0058] In one possible design, sending a candidate cell list and first indication information includes: sending first configuration information, where the first configuration information includes the candidate cell list and the first indication information.

[0059] In one possible design, fourth indication information is sent, and the fourth indication information is used to instruct the terminal device to use the same configuration information (using the first configuration information) in the rising phase and the falling phase.

[0060] In one possible design, fifth indication information is sent, where the fifth indication information is used to instruct the terminal device to use different configuration information in the ascending phase and the descending phase. Second configuration information is sent, where the second configuration information includes sixth indication information and a second candidate cell list.

[0061] In one possible design, the method further includes: sending a movement path of the terminal device to a second network device; and receiving a cell list from the second network device, the cell list including an identifier of at least one cell through which the movement path passes. The second network device may be a candidate network device to be switched.

[0062] In one possible design, the method further includes: sending a mobile path of the terminal device to a second network device; sending first information to the second network device, the first information being used to indicate at least one cell; and receiving second information from the second network device, the second information being used to indicate whether the mobile path passes through the at least one cell. For example, the at least one cell may be a cell belonging to the second network device.

[0063] In a third aspect, an embodiment of the present application provides a communication method, applied to a first network device, including: sending a mobile path of a terminal device to a second network device; the first network device is a network device that provides services for the terminal device, and the second network device is a candidate network device to be switched; receiving an eighth indication information sent by the second network device, the eighth indication information being used to indicate the timing (or trigger point) for the terminal device to send a preamble code.

[0064] In one possible design, the eighth indication information is used to indicate the timing when the terminal device sends the preamble code, including: the eighth indication information is used to indicate the position where the terminal device sends the preamble code; or, the eighth indication information is used to indicate the time when the terminal device sends the preamble code.

[0065] In one possible design, the location where the terminal device sends the preamble code is: the waypoint where the terminal device sends the preamble code; the fifth geographical location where the terminal device sends the preamble code; or, the location between the fifth waypoint and the sixth waypoint; or, the location between the sixth geographical location and the seventh geographical location; or, the location whose distance from the third location is less than or equal to a fourth distance threshold.

[0066] In one possible design, the time when the terminal device sends the preamble code is: the moment when the terminal device sends the preamble code; or, the moment between the third moment and the fourth moment; the moment when the time difference with the fifth moment is less than or equal to the third time threshold.

[0067] In one possible design, the method further includes:

[0068] Sending the eighth indication information to the terminal device; or,

[0069] The timing of sending the PDCCH command is determined according to the eighth indication information, and the PDCCH command is sent to the terminal device according to the timing of the PDCCH command, where the PDCCH command is used to instruct the terminal device to send a preamble code.

[0070] In a fourth aspect, an embodiment of the present application provides a communication method, applied to a second network device, comprising: receiving a mobile path of a terminal device from a first network device, where the first network device is a network device providing a service for the terminal device, and the second network device is a candidate network device to be switched; and sending eighth indication information to the first network device, where the eighth indication information is used to indicate a timing (or trigger point) for the terminal device to send a preamble code.

[0071] In one possible design, the eighth indication information is used to indicate the timing when the terminal device sends the preamble code, including: the eighth indication information is used to indicate the position where the terminal device sends the preamble code; or, the eighth indication information is used to indicate the time when the terminal device sends the preamble code.

[0072] In one possible design, the location where the terminal device sends the preamble code is: the waypoint where the terminal device sends the preamble code; the fifth geographical location where the terminal device sends the preamble code; or, the location between the fifth waypoint and the sixth waypoint; or, the location between the sixth geographical location and the seventh geographical location; or, the location whose distance from the third location is less than or equal to a fourth distance threshold.

[0073] In one possible design, the time when the terminal device sends the preamble code is: the moment when the terminal device sends the preamble code; or, the moment between the third moment and the fourth moment; the moment when the time difference with the fifth moment is less than or equal to the third time threshold.

[0074] In a fifth aspect, the present application provides a communication device, which has the ability to implement the functions involved in the first to fourth aspects above. For example, the communication device includes modules or units or means corresponding to the operations involved in the first to fourth aspects above. The functions or units or means can be implemented through software, or through hardware, or the corresponding software can be implemented through hardware.

[0075] In one possible design, the communication device includes a processing unit and a communication unit. The communication unit can be used to send and receive signals to enable communication between the communication device and other devices, for example, the communication unit is used to send system information to a terminal. The processing unit can be used to perform certain internal operations of the communication device. The functions performed by the processing unit and the communication unit can correspond to the operations described in the first to fourth aspects above.

[0076] In one possible design, the communication device includes a processor, which can be coupled to a memory. The memory can store the necessary computer programs or instructions for implementing the functions of the first to third aspects described above. The processor can execute the computer programs or instructions stored in the memory. When the computer programs or instructions are executed, the communication device implements the method of any possible design or implementation of the first to fourth aspects described above.

[0077] In one possible design, the communication device includes a processor and a memory, and the memory may store the necessary computer programs or instructions for implementing the functions of the first to fourth aspects described above. The processor may execute the computer program or instructions stored in the memory. When the computer program or instructions are executed, the communication device implements the method of any possible design or implementation of the first to fourth aspects described above.

[0078] In one possible design, the communication device includes a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and execute the method in any possible design or implementation of the first to fourth aspects above.

[0079] It can be understood that in the fifth aspect above, the processor can be implemented by hardware or by software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software, the processor can be a general-purpose processor, which is implemented by reading the software code stored in the memory. In addition, the above processors can be one or more, and the memories can be one or more. The memory can be integrated with the processor, or the memory and the processor can be set separately. In the specific implementation process, the memory can be integrated with the processor on the same chip, or can be set on different chips respectively. The embodiment of the present application does not limit the type of memory and the setting method of the memory and the processor.

[0080] In a sixth aspect, the present application provides a communication system, which may include a first communication device and a second communication device; wherein the first communication device is used to execute the method described in the first aspect above, and the second communication device is used to execute the method described in the second aspect above.

[0081] In a seventh aspect, the present application provides a communication system, which may include a first communication device and a second communication device; wherein the first communication device is used to execute the method described in the third aspect above, and the second communication device is used to execute the method described in the fourth aspect above.

[0082] In an eighth aspect, the present application provides a computer-readable storage medium having computer-readable instructions stored therein. When a computer reads and executes the computer-readable instructions, the computer executes the method in any possible design of the first to fourth aspects above.

[0083] In a ninth aspect, the present application provides a computer program product, which, when read and executed by a computer, enables the computer to execute the method in any possible design of the first to fourth aspects above.

[0084] In a tenth aspect, the present application provides a chip, comprising a processor, wherein the processor is coupled to a memory and is configured to read and execute a software program stored in the memory to implement a method in any possible design of the first to fourth aspects above.

[0085] Based on the implementations provided in the above aspects, this application can also be further combined to provide more implementations. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] FIG1 is a schematic diagram of a communication system applicable to an embodiment of the present application;

[0087] FIG2A is a schematic diagram of another communication system provided in an embodiment of the present application;

[0088] FIG2B is a schematic diagram of another communication system provided in an embodiment of the present application;

[0089] FIG3 is a schematic diagram of the flight path of a UAV provided in an embodiment of the present application;

[0090] FIG4 is a flow chart of a network switching method provided in an embodiment of the present application;

[0091] FIG5 is a flow chart of another network switching method provided in an embodiment of the present application;

[0092] FIG6 is a flow chart of a communication method provided in an embodiment of the present application;

[0093] FIG7 is a flow chart of another communication method provided in an embodiment of the present application;

[0094] FIG8 is a flow chart of another communication method provided in an embodiment of the present application;

[0095] FIG9 is a flow chart of another communication method provided in an embodiment of the present application;

[0096] FIG10 is a schematic structural diagram of a communication device 1000 provided in an embodiment of the present application;

[0097] FIG11 is a schematic structural diagram of a communication device 1100 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0098] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings in the embodiments of the present application. The technical solutions in the embodiments of the present application can be applied to various communication systems, such as universal mobile telecommunications system (UMTS), wireless local area network (WLAN), wireless fidelity (Wi-Fi) system, 4th generation (4G) mobile communication system, such as long term evolution (LTE) system, fifth generation (5G) mobile communication system, such as new radio (NR) system, and future evolved communication systems, such as sixth generation (6G) mobile communication system.

[0099] This application will present various aspects, embodiments or features around a system that may include multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and / or may not include all the devices, components, modules, etc. discussed in conjunction with the accompanying drawings. In addition, combinations of these schemes may also be used. In addition, in the embodiments of this application, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described in this application as an "example" should not be interpreted as being more preferred or more advantageous than other embodiments or design schemes. Specifically, the use of the word "example" is intended to present concepts in a concrete way. In the embodiments of this application, "of", "corresponding, relevant" and "corresponding" can sometimes be used interchangeably. It should be noted that when the distinction is not emphasized, the meanings to be expressed are consistent.

[0100] FIG1 is a schematic diagram of the architecture of a communication system used in an embodiment of the present application. As shown in FIG1 , the communication system includes a wireless access network 100. The wireless access network 100 may include at least one network device (such as 110a and / or 110b in FIG1 ) and may also include at least one terminal device (such as at least one of 120a-120j in FIG1 ). The terminal device is connected to the access network device wirelessly, and the access network device is connected to the core network device wirelessly or by wire. Terminal devices and network devices may be connected to each other by wire or by wireless. FIG1 is only a schematic diagram, and the communication system may also include other network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in FIG1 .

[0101] A network device is a network-side device with wireless transceiver capabilities. A network device can be a device in a radio access network (RAN) that provides wireless communication capabilities for terminal devices, and is called a RAN device. For example, a network device can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB) in a fifth-generation (5G) mobile communication system, a next-generation base station in a sixth-generation (6G) mobile communication system, a base station in a future mobile communication system, or an access node in a WiFi system. It can also be a module or unit that performs some of the functions of a base station, such as a centralized unit (CU) or a distributed unit (DU). The CU here completes the functions of the radio resource control protocol and the packet data convergence protocol (PDCP) of the base station, and can also complete the function of the service data adaptation protocol (SDAP); the DU completes the functions of the radio link control layer and the medium access control (MAC) layer of the base station, and can also complete the functions of part of the physical layer or all of the physical layer. For the specific description of the above-mentioned various protocol layers, please refer to the relevant technical specifications of the 3rd Generation Partnership Project (3GPP). The network device can be a macro base station (such as 110a in Figure 1), a micro base station or an indoor station (such as 110b in Figure 1), or a relay node or a donor node, etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the network device. In the embodiments of the present application, the network device is taken as a base station as an example for explanation.

[0102] In another possible scenario, multiple RAN nodes collaborate to assist the terminal in achieving wireless access, and different RAN nodes implement part of the functions of the base station respectively. For example, the RAN node can be a CU, DU, CU-control plane (CP), CU-user plane (UP), or radio unit (RU). The CU and DU can be set separately, or they can be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0103] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called O-CU (Open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module. Optionally, the operations of updating the random seed and securely processing the data in the secure communication method provided in the embodiment of the present application may be performed by the RU, and the sending and receiving operations may be performed by the DU.

[0104] A terminal device is a user-side device with wireless transceiver capabilities. A terminal device may also be referred to as user equipment (UE), a mobile station, a mobile terminal, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), the Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, etc. The terminal device may be a mobile phone, a tablet computer, a computer with wireless transceiver capabilities, a wearable device, a vehicle, a drone, a helicopter, an airplane, a ship, a robot, etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal device. The terminal device in the embodiments of the present application may be a mobile device.

[0105] Network devices and terminal devices can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water; and in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of network devices and terminal devices.

[0106] The roles of network devices and terminal devices can be relative. For example, the helicopter or drone 120i in Figure 1 can be configured as a mobile network device. To terminal devices 120j accessing the wireless access network 100 via 120i, terminal device 120i is a network device. However, to network device 110a, 120i is a terminal device, meaning that communication between 110a and 120i occurs via a wireless air interface protocol. Of course, communication between 110a and 120i can also occur via an interface protocol between network devices. In this case, 120i is also a network device relative to 110a. Therefore, both network devices and terminal devices can be collectively referred to as communication devices. 110a and 110b in Figure 1 can be referred to as communication devices with network device functionality, while 120a-120j in Figure 1 can be referred to as communication devices with terminal device functionality.

[0107] In the embodiments of the present application, the functions of the network device may also be performed by a module (such as a chip) in the network device, or by a control subsystem that includes the network device functions. The control subsystem that includes the network device functions here may be a control center in the above-mentioned application scenarios such as smart grid, industrial control, smart transportation, and smart city. The functions of the terminal device may also be performed by a module (such as a chip or a modem) in the terminal device, or by a device that includes the terminal device functions.

[0108] Take the example of a mobile terminal device, a drone. As a new type of aircraft, uncrewed aerial vehicles (UAVs) are becoming increasingly popular due to their flexibility and convenience. Cellular networks can also provide drones with important features such as wide coverage, high reliability, high security, and continuous mobility, as well as oversight by regulators. The communication environment of a drone differs significantly from that of an ordinary terminal. It primarily flies above network devices and connects to them via the Uu port, primarily communicating in line of sight (LOS). Therefore, the drone can receive signals from more network devices, as shown in Figure 2A. Network devices can be connected to each other via the Xn port to exchange signaling. Logically, the Xn port is a point-to-point interface between two network devices. Even if there is no direct physical connection between the two network devices, signaling exchange can still be achieved using the point-to-point interface, as shown in Figure 2B.

[0109] When performing corresponding tasks, drones may fly along a fixed route, such as conducting power network inspections. This route can be called the flight path of the drone, as shown in Figure 3. The flight path includes at least one waypoint information. The first waypoint information in the flight path can include the location information corresponding to the drone's take-off point and the current time point, or include the location information that the drone will fly through in the future and the time point corresponding to the arrival at the location. For other waypoint information in the flight path except the first waypoint information, it can include the location information that the drone will fly through in the future and the time point corresponding to the arrival at the location information. Each waypoint information can also include the number of the waypoint information in the flight path. For example, the number included in the first waypoint information in the flight path is 1. It should be understood that the location information can be location information in a latitude and longitude coordinate system, location information in a city coordinate system, location information in a rectangular coordinate system, etc., and is not limited here. For example, each waypoint in the flight path is the location information that the drone will fly over in the future and the time point corresponding to the arrival at the location information. For example, the flight path determined by the drone is Shanghai (10:00:00)-Suzhou (12:00:00)-Beijing (16:00:00). The flight path includes 3 waypoints. The first waypoint is Shanghai (10:00:00). The drone will arrive in Shanghai at 10:00:00. The understanding of the second and third waypoints is similar to that of the first waypoint, and will not be repeated in the following text.

[0110] The following example uses the network device (i.e., gNB) in the NR network as the network device and the drone as the terminal device. The same applies to the network device being the eNodeB in the 4G network or other devices in the 6G network, and this application does not limit this. The NR protocol supports the reporting of the flight path of the drone. Among them, the maximum number of waypoints in the flight path currently specified by the NR protocol is 20. In addition, the standard also supports the update of the drone's flight path. For example, when the flight path of the drone changes, it can first send a flight path update indication message to the network device to notify the network device that the flight path has been updated. If the network device needs to update the flight path, it can send a flight path request message to the drone, requesting the drone to send the flight path to the network device.

[0111] During flight, a drone will pass through the coverage areas of different network devices. Therefore, the drone needs to communicate with different network devices within the coverage areas of different network devices. The drone is currently flying within the coverage area of ​​a source network device. The drone communicates with the source network device and uploads the drone's flight path to the source network device, which then configures the network based on the flight path. When the drone leaves the coverage area of ​​the source network device and enters the coverage area of ​​a target network device, the network device connected to the drone switches from the source network device to the target network device, and the drone then communicates with the target network device.

[0112] Specifically, the network device switching process, as shown in Figure 4, the network device switching method is interactively performed by the user equipment UE, the source network device, the target network device, the AMF network element and the UPF network element, and may include the following steps:

[0113] Before the handover is completed, the user device interacts with the UPF through the source network device for user data.

[0114] S401: The source network device sends measurement control information to the user equipment.

[0115] In the embodiment of the present application, the measurement control information is determined by the source network device according to information such as roaming and access restrictions.

[0116] After receiving the measurement control information, the user equipment generates a measurement report based on the measurement control information.

[0117] S402: The user equipment sends a measurement report to the source network equipment.

[0118] S403, the source network device determines whether to switch the network device based on the measurement report and radio resource measurement (RMM) information. If yes, execute S404; otherwise, end.

[0119] S404: The source network device sends a handover request message to the target network device.

[0120] In the embodiment of the present application, the handover request message includes information such as the target cell identification (ID).

[0121] S405: The target network device performs access control.

[0122] S406: The target network device sends a switching request confirmation message to the source network device.

[0123] In the embodiment of the present application, the handover request confirmation message includes an RRC reconfiguration (radio resource control reconfiguration, RRC Reconfiguration) message that the target network device needs to send to the user equipment.

[0124] After receiving the handover request confirmation message, the source network device obtains the RRC reconfiguration message from the handover request confirmation message.

[0125] S407: The source network device sends an RRC reconfiguration message to the user equipment.

[0126] In the embodiment of the present application, the RRC reconfiguration message also includes information such as the target cell ID.

[0127] Optionally, if the source network device's data radio bearers (DRBs) are configured with a dual active protocol stack (DAPS), the source network device can also send an early status transfer message to the target network device. The early status transfer message instructs the target network device to clear the stored data packets that the source network device has already sent.

[0128] S408: The source network device sends a sequence number status transfer (SN status transfer) message to the target network device.

[0129] In an embodiment of the present application, the sequence number status transmission information is used to inform the target network device of the packet data convergence protocol (PDCP) sequence number.

[0130] S409: The user equipment sends an RRC reconfiguration complete (Radio Resource Control Reconfiguration Complete, RRC Reconfiguration Complete) message to the target network device.

[0131] S410: The target network device sends a handover completion message to the source network device.

[0132] S411: The source network device sends SN status transfer information to the target network device.

[0133] S412, the target network device sends a path switching request message to the AMF network.

[0134] S413, the AMF network element performs path switching in the UPF network element.

[0135] S414, the AMF network element sends a path switching request confirmation message to the target network device.

[0136] S415: The target network device sends a context release message to the source network device.

[0137] Currently, cell handovers can be divided into two types: one is cell handover based on Layer 1 / Layer 2, which can be called Layer 1 / Layer 2 handover or Layer 1 / Layer 2 triggered mobility (LTM); the other is cell handover based on Layer 3, which can be called Layer 3 handover (L3 handover). Layer 1 can refer to the physical layer, Layer 2 can refer to any one or more of the media access control (MAC) layer, radio link control (RLC) layer, packet data convergence protocol (PDCP), and service data adaptation protocol (SDAP) layer, and Layer 3 can refer to the RRC layer. It can be understood that Layer 1 / Layer 2 handover can also be understood as Layer 1 and / or Layer 2 handover. When the relationship is "and", operations related to the handover process are primarily performed by both Layer 1 and Layer 2; when the relationship is "or", operations related to the handover process are primarily performed by either Layer 1 or Layer 2. Since Layer 1 and Layer 2 are located at a lower level of the protocol stack than the RRC layer (Layer 3), Layer 1 / Layer 2 handover may also be referred to as a lower layer handover, a bottom layer handover, or a lower layer handover.

[0138] For Layer 3 handover, as shown in Figure 4 , the source network device receives a measurement report from the terminal device, which includes Layer 3 measurement results. Based on the Layer 3 measurement results, the source network device can select a candidate neighboring cell, such as the target cell in Figure 4 . The source network device then sends a handover request message to the target network device to which the candidate neighboring cell belongs, executing S406 . Subsequent operations continue, as shown in Figure 4 .

[0139] For layer 1 / layer 2 switching, the source network device selects the target cell based on the L3 measurement results. The subject that performs the target cell selection can be the CU of the source network device, and the switching configuration information of LTM is sent to the terminal device through the RRC reconfiguration message. The difference between layer 1 / layer 2 switching and layer 3 switching is that the switching on the source network device is performed at L1 / L2. Specifically, the terminal device reports the L1 measurement results to the source network device, the DU of the source network device makes a switching decision based on the L1 measurement results, and sends a switching command to the terminal device through the MAC control unit (CE). After the switching is completed, the terminal device does not delete the configuration information of the target cell. The next time the terminal device switches to the target cell, it can directly send a switching command, which eliminates the switching configuration process and reduces the switching delay.

[0140] Specifically, the layer 1 / layer 2 switching process, as shown in FIG5 , may include the following steps:

[0141] LTM preparation phase:

[0142] S501: A terminal device sends a measurement report to a source network device. Based on the measurement report, the source network device determines to use LTM handover and triggers candidate cell preparation, thereby generating a candidate cell list. The candidate cell list can contain one or more candidate cells. The measurement report can be understood as a Layer 3 measurement report.

[0143] S502. The source network device sends an RRC reconfiguration message to the terminal device. The RRC reconfiguration message includes the configuration of each candidate cell in the candidate cell list.

[0144] S503: The terminal device saves the configuration information of the candidate cell sent by the source network device, and sends an RRC reconfiguration completion message to the source network device.

[0145] Early synchronous phase:

[0146] S504. Optionally, before the source network device receives the handover command, the terminal device may obtain timing advance (TA) in advance and synchronize to the candidate cell.

[0147] LTM execution phase:

[0148] S505: The terminal device measures each configured candidate cell and reports the L1 measurement result to the source network device.

[0149] S506: The source network device determines whether to perform LTM handover based on the L1 measurement results. If LTM handover is performed, it sends a cell switch command to the terminal device. For example, the handover can be triggered to the terminal device via a MAC CE. The MAC CE can carry an identifier of the target cell configuration, and the terminal device uses the corresponding target cell configuration based on the identifier.

[0150] S507: The terminal device determines whether a random access process needs to be performed, and the UE initiates a random access process to the target network device to which the target cell belongs.

[0151] LTM completion stage:

[0152] S508. The UE sends an RRC reconfiguration complete message to the target cell to indicate to the target network device that the handover is completed.

[0153] As shown in FIG5 , in the current LTM measurement, after the network device configures the candidate cell list for the terminal device, the terminal device attempts to measure all candidate cells, resulting in low efficiency.

[0154] In conjunction with the foregoing description, an embodiment of the present application provides a communication method, which can be applied to the network switching process of Figure 5. The terminal device can execute the steps executed by the terminal device in Figure 5. The network device can execute the steps executed by the source network device in Figure 5. Specifically, as shown in Figure 6, the communication method may include the following steps:

[0155] S601: The network device sends a candidate cell list and first indication information to the terminal device. Correspondingly, the terminal device receives the candidate cell list and the first indication information.

[0156] The first indication information is used to indicate a first range, and the first range may be a range for measuring candidate cells in the candidate cell list.

[0157] In some embodiments, the network device may also send only a candidate cell list to the terminal device, where the candidate cell list includes candidate cells that the terminal device needs to measure within a first range. For example, in this case, the first range may be a default range for the terminal device and the network device. For example, the first range may be the interval between two waypoints currently located by the terminal device.

[0158] In one possible implementation, the candidate cell list and the first indication information may be carried in configuration information, and the network device may send the configuration information to the terminal device. For example, the candidate cell list and the first indication information may be carried in an RRC reconfiguration message. In another possible implementation, the candidate cell list and the first indication information may be sent separately, carried in different messages, and sent by the network device to the terminal device.

[0159] It should be noted that the candidate cell list includes one or more candidate cells. If the network device configures multiple candidate cells for the terminal device, it can also be sent to the terminal device in a non-list form, such as in a collection or grouping manner. The embodiments of the present application do not limit this.

[0160] Regarding the first range indicated by the first indication information, embodiments of the present application may include the following possible implementation methods.

[0161] In a first possible implementation, the first range indicated by the first indication information may be a position or a position range. It may also be understood that the range in which the terminal device measures the candidate cells in the candidate cell list may be determined by the position or position range indicated by the first indication information.

[0162] In mode 1, the first indication information may indicate a location range for measuring the candidate cells in the candidate cell list, and the location range may include a start location and an end location.

[0163] Mode 2: The first indication information may indicate the starting position for measuring the candidate cells in the candidate cell list. In some embodiments, the end position may be the starting position of the updated moving path or the end position of the moving path (such as the last waypoint in the moving path). The terminal device may stop (or end) the measurement of the candidate cells in the candidate cell list when updating the moving path. In some other embodiments, the end position may be the position or time when the switching command is received. The terminal device may also stop measuring the candidate cell list when receiving the switching command.

[0164] The starting location can be a waypoint on the terminal device's movement path, a geographic location, or a location interval. The movement path is the terminal device's planned movement route. Alternatively, the route of the drone's flight can be referred to as the flight path. The ending location can be a waypoint on the terminal device's movement path, a geographic location, or a location interval. For example, the location interval can be represented by a location point and a distance threshold, or other forms can be used. The location point can be a waypoint or a geographic location.

[0165] The following describes an implementation scheme when the first indication information adopts mode 1 by way of example.

[0166] In Example 1-1, the starting and ending locations can be represented by waypoints. For example, the first indication information includes waypoint 1 and waypoint 2, i.e., (waypoint 1, waypoint 2). Thus, when the terminal device arrives at waypoint 1, it starts measuring the candidate cells in the candidate cell list, and when the terminal device leaves waypoint 2, it stops (or ends) measuring the candidate cells in the candidate cell list.

[0167] In Example 1-2, both the starting and ending locations are indicated by geographic location. The geographic location can be in latitude and longitude coordinates. For example, the first indication information includes geographic location 1 and geographic location 2, i.e., (geographic location 1, geographic location 2). Thus, when the terminal device reaches geographic location 1, it starts to perform measurements on the candidate cells in the candidate cell list, and when the terminal device leaves geographic location 2, it stops performing measurements on the candidate cells in the candidate cell list.

[0168] In example 1-3, the starting location is a location interval, and the ending location is a geographic location or waypoint. Alternatively, the starting location is a geographic location or waypoint, and the ending location is a location interval.

[0169] For example, the starting position is a position at a distance less than or equal to a first distance threshold from the first position, and the ending position is waypoint 2. The first indication information may include the first position, the first distance threshold, and waypoint 2. The first position may be a waypoint or a geographic location. For example, the first position is waypoint 1, so that the terminal device starts performing measurements on the candidate cell list at a position less than the first distance threshold from waypoint 1, and may end the measurement of the candidate cell list when it reaches waypoint 2. Exemplarily, the position less than the first distance threshold from waypoint 1 may be a position where the measurement on the candidate cell list is started when the distance from waypoint 1 is less than or equal to the first distance threshold during the process of flying to waypoint 1, and the position interval of the starting position may be a range from (waypoint 1-first distance threshold) to waypoint 1. The position less than or equal to the first distance threshold from waypoint 1 may also be a position where the measurement on the candidate cell list is started when the distance from waypoint 1 is less than or equal to the first distance threshold after flying away from waypoint 1, and the position interval of the starting position may be a range from waypoint 1 to (waypoint 1+first distance threshold).

[0170] For another example, the starting position is waypoint 1, and the ending position is a position at a distance from the second position that is greater than or equal to a second distance threshold. The first indication information may include waypoint 1, the second position, and the second distance threshold. The second position may be a waypoint or a geographic location. For example, the second position is waypoint 2, so that when the terminal device arrives at waypoint 1, it starts to perform measurements on the candidate cell list, and the measurement of the candidate cell list may be ended at a position where the distance from waypoint 2 is greater than or equal to the second distance threshold. Exemplarily, the position where the distance from waypoint 2 is greater than or equal to the second distance threshold may be a position where the measurement of the candidate cell list is ended when the distance from waypoint 2 is greater than or equal to the second distance threshold during the process of flying away from waypoint 2.

[0171] In Examples 1-4, the starting position is a location interval, and the ending position is a location interval. The starting position is a location whose distance from the first location is less than or equal to a first distance threshold, and the ending position can be a location whose distance from the second location is greater than or equal to a second distance threshold. The first location can be a waypoint or a geographic location. The second location can be a waypoint or a geographic location. For example, the first location is waypoint 1, and the second location is waypoint 2. The first indication information may include waypoint 1, a first distance threshold, waypoint 2, and a second distance threshold. Thus, the terminal device begins performing measurements on the candidate cell list at a location less than or equal to the first distance threshold from waypoint 1, and may end measuring the candidate cell list at a location greater than or equal to the second distance threshold from waypoint 2. In some possible scenarios, the first distance threshold and the second distance threshold are the same. The first indication information may include waypoint 1, the first distance threshold (or the second distance threshold), and waypoint 2. Thus, the terminal device begins performing measurements on the candidate cell list at a location less than or equal to the first distance threshold from waypoint 1, and may end measuring the candidate cell list at a location greater than or equal to the first distance threshold from waypoint 2.

[0172] The following describes an implementation scheme when the first indication information adopts mode 2 by way of example.

[0173] In Example 2-1, the starting position can be represented by a waypoint. For example, the first indication information includes waypoint 1. Thus, the terminal device starts to perform measurements on the candidate cells in the candidate cell list when it arrives at waypoint 1. In some embodiments, the terminal device can stop (or end) measuring the candidate cells in the candidate cell list when it flies away from the movement path. In some other embodiments, the terminal device can also stop measuring the candidate cell list when it receives a handover command.

[0174] In Example 2-2, the starting location can be represented by a geographic location. For example, the first indication information includes geographic location 1. Thus, the terminal device begins to perform measurements on the candidate cells in the candidate cell list when it reaches geographic location 1. In some embodiments, the terminal device can stop (or end) measuring the candidate cells in the candidate cell list when it flies away from the movement path. In some other embodiments, the terminal device can also stop measuring the candidate cell list when it receives a handover command.

[0175] Example 2-3, the starting position can be represented by a position interval. The starting position is a position whose distance from the first position is less than or equal to the first distance threshold. Taking the first position as waypoint 1 as an example, the first indication information includes waypoint 1 and the first distance threshold. Thus, the terminal device starts to perform measurements on the candidate cell list at a position less than the first distance threshold from waypoint 1. In some embodiments, the terminal device can stop (or end) the measurement of the candidate cell in the candidate cell list when it flies away from the moving path. In some other embodiments, the terminal device can also stop measuring the candidate cell list when receiving a switching command.

[0176] In a second possible implementation, the first range indicated by the first indication information may be a time or a time range. It can also be understood that the range in which the terminal device measures the candidate cells in the candidate cell list may be determined by the time or time range indicated by the first indication information.

[0177] Mode 3: The first indication information may indicate a time range for measuring the candidate cells in the candidate cell list, and the time range may include a start time and an end time.

[0178] In mode 4, the first indication information may indicate the start time for measuring the candidate cells in the candidate cell list. In some embodiments, the terminal device may stop (or end) measuring the candidate cells in the candidate cell list when the terminal device leaves the mobile path. In still other embodiments, the terminal device may also stop measuring the candidate cell list upon receiving a handover command.

[0179] The start time can be a moment or a time interval. The end time can be a moment or a time interval.

[0180] The following describes an implementation scheme when the first indication information adopts mode 3 by way of example.

[0181] In Example 3-1, the start time is the moment when the terminal device starts to perform measurements, and the end time is the moment when the terminal device ends the measurements. Taking the start time as moment 1 and the end time as moment 2 as an example, the first indication information instructs the terminal device to start measuring the candidate cell list at moment 1 and end the measurement of the candidate cell list at moment 2. Exemplarily, the first indication information may include moment 1 and moment 2, i.e., (moment 1, moment 2).

[0182] Example 3-2, the start time is a time interval, and the end time is a moment. Alternatively, the start time is a moment, and the end time is a time interval. For example, take the moment when the time difference between the start time and the first moment is less than or equal to the first time threshold, and the end time is moment 2. The first indication information instructs the terminal device to start measuring the candidate cell list at a moment when the time difference from the first moment is less than the first time threshold, and end the measurement of the candidate cell list at moment 2. Exemplarily, the first indication information may include the first moment, the first time threshold, and moment 2. The moment when the time difference from the first moment is less than the first time threshold may be the time interval from the first moment - the first time threshold to the first moment. Alternatively, the moment when the time difference from the first moment is less than the first time threshold may be the time interval from the first moment to the first moment + the first time threshold.

[0183] For another example, take the starting time moment 1 and the ending time as a moment when the time difference from the second moment is greater than or equal to the second time threshold. The first indication information instructs the terminal device to start measuring the candidate cell at moment 1 and end the measurement of the candidate cell list at a moment when the time difference from the second moment is greater than or equal to the second time threshold. Exemplarily, the first indication information may include moment 1, moment 2, and the second time threshold.

[0184] Example 3-3, the start time and the end time can both be time intervals. For example, take the start time as the moment when the time difference from the first moment is less than or equal to the first time threshold, and the end time as the moment when the time difference from the second moment is greater than or equal to the second time threshold. The first indication information instructs the terminal device to start measuring the candidate cell list at a moment when the time difference from the first moment is less than the first time threshold, and to end the measurement of the candidate cell list at a moment when the time difference from the second moment is greater than or equal to the second time threshold. Exemplarily, the first indication information may include the first moment, the first time threshold and the second moment, the second time threshold.

[0185] The time 1, first time, time 2 and second time mentioned above can be the estimated arrival time of the waypoint in the flight path, or can be any time in the time interval corresponding to the movement path.

[0186] In a third possible implementation manner, the first range indicated by the first indication information may be location (range)+time (range).

[0187] Mode 5, the first indication information may indicate the starting point where the candidate cells in the candidate cell list are measured. The starting point may include the starting time and the starting position. For the methods adopted for the starting time and the starting position, please refer to the description of Modes 1 to 4, which will not be repeated here. For example, the first indication information may include waypoint 1 and time 1. The terminal device starts measuring the candidate cells in the candidate cell list at time 1 and when it arrives at waypoint 1. For another example, the first indication information may include waypoint 1, the first distance threshold, time 1 and the first time threshold. The terminal device starts measuring the candidate cells in the candidate cell list at a moment when the time difference from time 1 is less than or equal to the first time threshold and the distance from waypoint 1 is less than or equal to the first distance threshold.

[0188] Mode 6, the first indication information may indicate the starting point and the ending point of the measurement of the candidate cells in the candidate cell list. The starting point may include the starting time and the starting position, and the ending point may include the ending position and the ending time. For the methods adopted for the starting time, the starting position, the ending time and the ending position, please refer to the description of Modes 1 to 4, which will not be repeated here. For example, the first indication information may include waypoint 1 and time 1, as well as waypoint 1 and time 2. The terminal device starts measuring the candidate cells in the candidate cell list at time 1 and when it arrives at waypoint 1, and ends measuring the candidate cells in the candidate cell list at time 2 and when it leaves waypoint 2. For another example, the first indication information may include waypoint 1, the first distance threshold, time 1 and the first time threshold, as well as waypoint 1, the second distance threshold, time 2 and the second time threshold. The terminal device starts measuring the candidate cells in the candidate cell list at a time when the time difference from time 1 is less than or equal to the first time threshold and the distance from waypoint 1 is less than or equal to the first distance threshold. The terminal device starts measuring the candidate cells in the candidate cells at a time when the time difference from time 2 is greater than or equal to the second time threshold and the distance from waypoint 2 is greater than or equal to the second distance threshold.

[0189] In a fourth possible implementation manner, the first indication information indicates a height range corresponding to the first range.

[0190] Mode 7: The first indication information indicates the starting altitude and ending altitude corresponding to the first range. For example, the starting altitude can be the minimum altitude value, and the ending altitude can be understood as the maximum altitude value. That is, the altitude range is represented by the minimum altitude value and the maximum altitude value. For another example, the starting altitude and / or ending altitude can be indicated by altitude information relative to a reference plane, such as altitude information relative to sea level or ground level, or altitude information relative to the maximum flight altitude.

[0191] Mode 8, the first indication information can indicate the altitude range for performing the measurement by indicating the starting altitude or the ending altitude. The starting altitude or the ending altitude can be indicated by the altitude information relative to the reference plane. For another example, the starting altitude and the ending altitude are indicated by an altitude threshold. For example, the first indication information includes an altitude threshold. Then the terminal device can be instructed to end the measurement when it is lower than the altitude threshold, that is, the altitude range for performing the measurement is 0 to the altitude corresponding to the altitude threshold. For another example, if the first indication information includes an altitude threshold, then the terminal device can be instructed to start performing the measurement when it is higher than the altitude threshold, that is, the altitude range for performing the measurement can be the altitude corresponding to the altitude threshold to the maximum flight altitude.

[0192] In the fifth possible implementation, the first indication information indicates the height (or height range) + position (or position range) corresponding to the first range. Taking into account that the ascending position and the descending position of the drone may be different. Different candidate cell lists are configured for different positions and different height ranges. For example, the first indication information includes a height threshold and a position point, which instructs the terminal device to measure the candidate cells in the candidate cell list at position point 1 and within a height range lower than the height threshold. For another example, the first indication information includes a height threshold and a position range, which instructs the terminal device to measure the candidate cells in the candidate cell list within the position range and within a height range lower than the height threshold. The position range can be the coverage range of the cell, or it can be represented by two position points. The position point can be a latitude and longitude coordinate. The position range can be represented by a waypoint + distance threshold.

[0193] S602: The terminal device performs measurement on candidate cells within the first range.

[0194] In the first possible application scenario, the above-mentioned first possible implementation method to the third possible implementation method can be applied to non-UAV (or non-aircraft) terminal devices, and can also be applied to non-take-off and non-landing phases of UAVs (or aircraft).

[0195] In the second possible application scenario, the fourth and fifth possible implementations can be applied to the takeoff or landing phase of the drone (or aircraft). Of course, if the flight altitude (or altitude range) corresponding to different positions of the drone (or aircraft) on the flight path is different, the fourth and fifth possible implementations can also be applied to the non-takeoff or non-landing phase of the drone (or aircraft).

[0196] The following first describes the solution provided by the embodiment of the present application in the first possible application scenario.

[0197] FIG7 is a flow chart of a communication method according to an embodiment of the present application. The method includes:

[0198] S701, see S601. The first indication information adopts any possible implementation manner from the first possible implementation manner to the third possible implementation manner.

[0199] In an embodiment of the present application, the network device can configure different candidate cell lists and first ranges associated with the candidate cell lists for the terminal device. For example, the network device segments the movement path of the terminal device according to the movement path, configures multiple candidate cell lists and first indication information corresponding to each candidate cell list. The terminal device then moves to the corresponding position (or position range) or time (or time range) according to the first indication information to measure the candidate cell in the candidate cell list corresponding to the first indication information.

[0200] Exemplarily, before step S701, in S701a, the terminal device may send the mobile path of the terminal device to the network device, and accordingly, the network device receives the mobile path of the terminal device, as shown in Figure 7. Further, the network device may configure at least one candidate cell list and first indication information corresponding to (or associated with) each candidate cell list for the terminal device based on the mobile path.

[0201] From the perspective of cell handover, the network devices in S701a-S701 can be understood as source network devices. Figure 7 describes the process from the perspective of cell handover. Figure 7 involves terminal devices, source network devices, and target network devices.

[0202] Optionally, the source network device may also instruct the terminal device on a timing to delete the configuration information of the candidate cell that has been configured. This may also be understood as a trigger point or execution point at which the source network device instructs the terminal device to perform a deletion operation on the configuration information of the candidate cell that has been configured.

[0203] In some possible implementations, before step S701, S7011 may be performed, where the source network device may further send the terminal device's mobile path to the candidate network devices (including the target network device). For example, the terminal device's mobile path may be carried in a handover request (HO request) message. In S7012, the candidate network device may send a cell list to the source network device, where the cell list includes cells that the terminal device's mobile path passes through. Furthermore, the source network device may determine the candidate cell list and the first indication information based on the received cell list of the candidate target network device.

[0204] In some other possible implementations, before step S701, S7013 may be further executed, and the source network device may further send the mobile path of the terminal device to the candidate network device (including the target network device). S7014, the source network device sends first information to the candidate network device, and the first information is used to indicate at least one cell, such as the at least one cell belonging to the candidate network device. S7015, the candidate network device sends second information to the source network device. The second information is used to indicate whether the mobile path of the terminal device passes through the at least one cell. Furthermore, the source network device may determine the candidate cell list and the first indication information based on the second information received from the candidate target network device. Figure 7 takes the candidate network device as the target network device as an example. If the mobile path of the terminal device passes through the at least one cell, the second information may be HO ACK. If the mobile path of the terminal device does not pass through the at least one cell, the second information may be HO prepartion failure.

[0205] S702, the source network device sends second indication information to the terminal device. In some embodiments, the source network device may carry the second indication information and the first indication information in the same message and send them to the terminal device, that is, S702 and S701 may be combined into one step. The source network device may also carry the second indication information and the first indication information separately in different messages and send them to the terminal device. The embodiments of the present application do not limit the order of S701 and S702.

[0206] The second indication information is used to indicate a trigger point for deleting configuration information of at least one second candidate cell, where the second candidate cell is a candidate cell in the candidate cell list.

[0207] In one possible scenario, the number of the at least one second candidate cell may be the number of all candidate cells in the candidate cell list, that is, the at least one second candidate cell includes N second candidate cells, the candidate cell list also includes N candidate cells, and the N second candidate cells are the same as the N candidate cells in the candidate cell list. In this case, it can be understood that the second indication information is used to instruct deletion of configuration information of all candidate cells in the candidate cell list.

[0208] In another possible scenario, the number of the at least one second candidate cell is the number of all candidate cells corresponding to the first range in the candidate cell list. For example, the at least one second candidate cell includes N second candidate cells. The candidate cell list includes M candidate cells. M and N are both positive integers, and M is greater than N. The number of candidate cells within the first range measured by the terminal device is N. The N second candidate cells are the same as the N candidate cells within the first range of the candidate cell list. In this case, it can be understood that the second indication information is used to instruct the deletion of the configuration information of the candidate cells within the first range in the candidate cell list.

[0209] In some embodiments, the second indication information may further indicate a second range of candidate cells to be deleted. The second range may be indicated in a list, a set, or other manners, which are not limited in the embodiments of the present application. The second range may include all candidate cells included in the candidate cell list for which measurements have been completed, or may include a portion of the candidate cells included in the candidate cell list for which measurements have been completed.

[0210] In a possible implementation manner, the second indication information indicates a trigger point for deleting configuration information of at least one second candidate cell, and the trigger point may be a position.

[0211] The trigger point can be a location point or a location range. The location point can be a waypoint or a geographic location.

[0212] For example, taking the trigger point as the first waypoint as an example, the second indication information indicates the first waypoint at which the configuration information of the at least one second candidate cell is deleted. That is, when the terminal device reaches the first waypoint, the configuration information of the at least one second candidate cell is deleted. For another example, taking the trigger point as the first geographic location as an example, the second indication information indicates the first geographic location at which the configuration information of the at least one second candidate cell is deleted. That is, when the terminal device reaches the first geographic location, the configuration information of the at least one second candidate cell is deleted.

[0213] For another example, take the trigger point as an example of a location range. The location range can be a range between two waypoints. Taking the second waypoint and the third waypoint as an example, the location where the configuration information of at least one second candidate cell is deleted is the location between the second waypoint and the third waypoint. For another example, the location range is a range between two geographical locations. Taking the second geographical location and the third geographical location as an example, the location where the configuration information of at least one second candidate cell is deleted is the location between the second geographical location and the third geographical location. For another example, the location range is a range between a geographical location and a waypoint. Taking the fourth geographical location and the fourth waypoint as an example, the fourth geographical location is a location that is less than the third distance threshold from the fourth waypoint. The location where the configuration information of at least one second candidate cell is deleted is the location between the fourth geographical location and the fourth waypoint.

[0214] In another possible implementation, the second indication information indicates a trigger point for deleting the configuration information of at least one second candidate cell. The trigger point may be a time. The time used as the trigger point may be a moment or a time range. The time range may be represented by two moments or by a moment and a time threshold.

[0215] In another possible implementation, the second indication information indicates the trigger point for deleting the configuration information of at least one second candidate cell, and the trigger point may be a time + location point. For example, the trigger point includes time 3 and time 4, and a third location. The third location may be a waypoint or a geographic location. The second indication information then indicates that the terminal device is between time 3 and time 4 and reaches the third location, and deletes the configuration information of at least one second candidate cell. For another example, the trigger point includes the third location, the fourth location, and time 3. The second indication information then indicates that the terminal device is at time 3 and reaches the range between the third location and the fourth location, and deletes the configuration information of at least one second candidate cell.

[0216] It should be noted that the location or time of the trigger point is the location or time point after the measurement of the candidate cells in the candidate cell list is completed. For example, the flight path of the terminal device is Shanghai (10:00:00)-Suzhou (12:00:00)-Beijing (16:00:00). The terminal device configures two candidate cell lists and the first indication information corresponding to each candidate cell list. The two candidate cell lists include Candidate Cell List 1 and Candidate Cell List 2, respectively. The first indication information associated with Candidate Cell List 1 indicates the path segment from Shanghai (10:00:00) to Suzhou (12:00:00). The first indication information associated with Candidate Cell List 2 indicates the path segment from Suzhou (12:00:00) to Beijing (16:00:00). The trigger point for deleting the configuration information of the candidate cells included in Candidate Cell List 1 can be the location or time after flying away from Suzhou.

[0217] In another possible implementation, the network device may instruct the terminal device to delete the configuration information of the configured candidate cell after completing the handover.

[0218] S703, the terminal device sends an RRC reconfiguration completion message to the source network device. After receiving the first indication information and / or the second indication information, the terminal device may store the first indication information and / or the second indication information.

[0219] S704: The terminal device measures the candidate cells in the candidate cell list according to the first indication information. The measurement performed by the terminal device in this step may be L1 measurement.

[0220] S705: The terminal device sends an L1 measurement report to the source network device.

[0221] S706: The source network device sends a cell switch command to the terminal device, instructing the terminal device to switch to a target cell. The target cell may be a cell in the candidate cell list.

[0222] Optionally, when the source network device sends the second indication information to the terminal device, the second indication information may also be carried in the handover command. The step of sending the second indication information to the terminal device may also be after the source network device sends the handover command to the terminal device.

[0223] S707, the terminal device executes handover to the target cell and sends an RRC reconfiguration completion message to the target network device to which the target cell belongs.

[0224] In one possible implementation, when the network device sends second indication information to the terminal device, the terminal device may perform a deletion operation on the configuration information of all or part of the candidate cells in the candidate cell list according to the second indication information after receiving the second indication information. Optionally, after performing the deletion operation, the terminal device may send third indication information to the source network device, where the third indication information is used to indicate that the configuration information of some or all cells in the candidate cell list has been deleted. In some possible implementations, the source network device may also send a deletion indication to the network device to which the cell whose configuration information has been deleted belongs. The deletion indication is used to indicate that one or more candidate cells managed by the network device have been deleted.

[0225] In another possible implementation, when the network device does not send the second indication information to the terminal device, the terminal device may determine whether to delete the configuration information of all or part of the candidate cells in the candidate cell list based on the mobile path. For example, after the terminal device completes handover to the target cell in the candidate cell list, it may determine whether it will subsequently pass through the candidate cells in the candidate cell list based on the mobile path. If it passes through the candidate cell, the configuration information of the candidate cell may be saved. If it does not pass through the candidate cell again, the configuration information of the candidate cell may be deleted.

[0226] In one possible example, after completing the handover to the target cell, when it is determined based on the movement path of the terminal device that the second path passed after leaving the first path corresponding to the first range includes some or all of the candidate cells corresponding to the first range, the configuration information of some or all of the candidate cells in the candidate cell list corresponding to the first range can be retained. For example, the first path corresponding to the first range is the range between waypoint 1 and waypoint 2. If after leaving the range between waypoint 1 and waypoint 2, any waypoint between waypoint 1 and waypoint 2 is subsequently passed, the terminal device can retain the configuration information of the candidate cells covering the range between waypoint 1 and waypoint 2, for example, the configuration information of the candidate cells in the candidate target cell list can be saved first.

[0227] After completing the switch to the target cell, when it is determined based on the moving path of the terminal device that the second path passed after flying away from the first path corresponding to the first range does not include some or all of the candidate cells corresponding to the first range, the configuration information of some or all of the candidate cells in the candidate cell list corresponding to the first range can be deleted.

[0228] In another possible example, after completing the handover to the target cell, if it is determined based on the movement path of the terminal device that the second path traversed after leaving the first path corresponding to the first range includes the second range, and the shortest distance between the second range and the first range is less than or equal to a set threshold, the configuration information of some or all candidate cells in the candidate cell list corresponding to the first range continues to be saved. If it is determined based on the movement path that the second path traversed after leaving the first path corresponding to the first range includes the second range, and the shortest distance between the second range and the first range is greater than a set threshold, the configuration information of some or all candidate cells in the candidate cell list corresponding to the first range is deleted.

[0229] For example, the first path corresponding to the first range is the range between waypoint 1 and waypoint 2. If after flying out of the range between waypoint 1 and waypoint 2, the distance between the subsequently passed waypoints and waypoint 1 or waypoint 2 is less than or equal to the set threshold, the terminal device can retain the configuration information of the candidate cells covering the range of waypoint 1 and waypoint 2. For example, the configuration information of the candidate cells in the candidate target cell list can be saved first.

[0230] Optionally, after deleting the configuration information of some or all candidate cells in the candidate target cell list, the terminal device may send a third indication message to the source network device, where the third indication message is used to indicate that some or all cells in the candidate cell list have been deleted. In some possible implementations, the source network device may also send a deletion indication to the network device to which the cell whose configuration information has been deleted belongs. The deletion indication is used to indicate that one or more candidate cells managed by the network device have been deleted. Exemplarily, the third indication information may be carried in an RRC reconfiguration complete message. For example, the third indication information may include an identifier of the cell whose configuration information has been deleted, such as an ID.

[0231] In a possible implementation, if the terminal device enters the second path from the first path corresponding to the first range, and the configuration information of the cell measured in the second path has been applied, the measurement results of the saved cell can be cleared. Optionally, the terminal device can also end the current measurement, such as currently measuring the candidate cell list corresponding to the second path, and then end the measurement of the candidate cell list corresponding to the second path. In some embodiments, before clearing the measurement results of the saved cell, the terminal device can also report to the source network device and indicate the source network device the location (or location range) or time (or time range) corresponding to the measurement result. Exemplarily, when the terminal device reports the L1 measurement result to the source network device, it can indicate the location (or location range) or time (or time range) corresponding to the L1 measurement result.

[0232] In a possible implementation, if the terminal device enters the second path from the first path corresponding to the first range, and the configuration information of the cell measured in the second path has been applied, only the measurement results of the overlapping cells can be saved. Overlapping cells are cells included in the candidate cell list corresponding to the first path and included in the candidate cell list corresponding to the second path. It can be understood that the overlapping cells are the same cells in the candidate cell list corresponding to the first path and the candidate cell list corresponding to the second path. Optionally, the terminal device can also continue the current measurement, such as currently measuring the candidate cell list corresponding to the second path, and then continue the measurement of the candidate cell list corresponding to the second path. In some embodiments, the terminal device can report the measured L1 measurement result to the source network device, and indicate the source network device to the location (or location range) or time (or time range) corresponding to the measurement result. Exemplarily, when the terminal device reports the L1 measurement result to the source network device, it can indicate the location (or location range) or time (or time range) corresponding to the L1 measurement result.

[0233] In an embodiment of the present application, the first indication information is used to indicate the measurement range of the terminal device for the candidate cell list, so that the terminal device only needs to measure the cells within the measurement range, which can reduce the measurement overhead of the terminal device and improve switching efficiency.

[0234] The following describes the solution provided by the embodiment of the present application in the second possible application scenario, taking the takeoff and landing phases as an example.

[0235] FIG8 is a flow chart of a communication method according to an embodiment of the present application. The method includes:

[0236] S801, see S601. The first indication information adopts any one of the fourth possible implementation manner to the fifth possible implementation manner.

[0237] In an embodiment of the present application, the source network device may configure different candidate cell lists and first ranges associated with the candidate cell lists for the terminal device. The source network device may segment the flight altitude of the terminal device and configure multiple candidate cell lists and first indication information corresponding to each candidate cell list. The terminal device then moves to the corresponding altitude (or altitude range) according to the first indication information to measure the candidate cell in the candidate cell list corresponding to the first indication information.

[0238] In some embodiments, the source network device may further send a fourth indication message to the terminal device, and the fourth indication message is used to instruct the terminal device to use the same configuration information in the ascending phase and the descending phase. In some possible scenarios, the terminal device is in the same position in the ascending phase and the descending phase, and the source network device may send the fourth indication message to the terminal device. For example, when the source network device sends a candidate cell list and a first indication message to the terminal device, the candidate cell list and the first indication message may be included in the first configuration message, and then the first configuration information is sent to the terminal device. If the ascending phase and the descending phase of the terminal device are in the same position, the source network device may send the fourth indication message to the terminal device to instruct the terminal device to use the first configuration information in both the ascending phase and the descending phase.

[0239] In other embodiments, the terminal device is located at different positions in the ascending phase and the descending phase, and the source network device may send a fifth indication message to the terminal device. The fifth indication message is used to instruct the terminal device to use different configuration information in the ascending phase and the descending phase. In some scenarios, the source network device may also send a second configuration message to the terminal device, and the second configuration information includes the sixth indication information and the second candidate cell list. For ease of distinction, the candidate cell list in the first configuration information may be referred to as the first candidate cell list. Optionally, the range indicated by the sixth indication message and the first indication message sent by the source network device both include an altitude range and a position (or position range). The terminal device may determine, based on the position and the moving path, whether the first configuration information is used in the ascending phase or the descending phase, and whether the second configuration information is used in the descending phase or the ascending phase. Exemplarily, the source network device may carry the first configuration information and the second configuration information in the same message, or may carry them in different messages and send them to the terminal device.

[0240] In some possible scenarios, the source network device may also adopt a direct indication method, such as sending seventh indication information to the terminal device, where the seventh indication information indicates the usage phase of the first configuration information and the second configuration information. The first configuration information is used in the rising phase, and the second configuration information is used in the falling phase, or the first configuration information is used in the falling phase, and the second configuration information is used in the rising phase. Exemplarily, the source network device may carry the seventh indication information and the first configuration information and the second configuration information in the same message, or may carry them in different messages and send them to the terminal device.

[0241] Optionally, before configuring the candidate cell list and the first indication information for the terminal device, the source network device may execute S8011 to obtain the height coverage range (or height coverage range and position) of the candidate network device from the candidate network device (such as the neighbor's network device, including the target network device). Exemplarily, the source network device may send a handover request message to the neighbor's network device and obtain the height coverage range of the neighbor's network device through the handover request message. The candidate cell list and the first indication information may then be determined based on the height coverage range of each neighbor. Figure 8 takes the candidate network device as the target network device as an example.

[0242] In one possible implementation, before executing S801, the source network device may further send a mobile path to a candidate network device (which may be a neighboring network device). The candidate network device may determine a list of cells belonging to the candidate network device that the mobile path passes through. At least one cell in the cell list is a cell that the mobile path passes through. In some embodiments, the mobile path may be the path that the terminal device passes through during the ascent phase and / or the path that the terminal device passes through during the descent phase. Furthermore, the source network device may determine the candidate cell list and the first indication information based on the cell list of the candidate network device.

[0243] In other possible implementations, before step S801, the source network device may further send the terminal device's mobile path to candidate network devices (including the target network device). The source network device sends first information to the candidate network devices, where the first information indicates at least one cell. The candidate network devices send second information to the source network device. The second information indicates whether the terminal device's mobile path passes through the at least one cell. Furthermore, the source network device may determine the candidate cell list and the first indication information based on the second information received from the candidate target network device.

[0244] Optionally, before configuring the candidate cell list and the first indication information for the terminal device, the source network device may also determine the current location information of the terminal device, or determine that the terminal device is in an ascending phase, or obtain ascending information of the terminal device, thereby configuring the candidate cell list and the first indication information for the terminal device. In some embodiments, the terminal device may proactively report its current flight location, or notify the source network device (i.e., the network device currently providing service to the terminal device) after takeoff.

[0245] S802, the terminal device sends an RRC configuration completion message to the source network device.

[0246] S803: The terminal device measures the candidate cells in the candidate cell list according to the first indication information to obtain an L1 measurement report, and sends the L1 measurement report to the source network device.

[0247] S804: The source network device sends a cell switch command to the terminal device. For example, the cell switch command may carry a configuration information index of the target cell.

[0248] In one possible implementation, when the terminal device enters the second altitude range from the first altitude range during flight and applies the configuration information of the target cell, the saved cell measurement results can be cleared. Optionally, the measurement of the candidate cells in the candidate cell list corresponding to the first altitude range can be stopped.

[0249] In another possible implementation, when the terminal device enters the second altitude range from the first altitude range during flight and applies the configuration information of the target cell, the terminal device continues to measure the candidate cells in the candidate cell list corresponding to the first altitude range. Optionally, when completing the cell measurement for the candidate cell list corresponding to the second altitude range and sending the L1 measurement result to the source network device, the L1 measurement result sent indicates that it corresponds to the second altitude range. The target cell is a cell in the candidate cell list corresponding to the first altitude range.

[0250] S805, after the terminal device switches to the target cell, it sends an RRC reconfiguration completion message to the target network device to which the target cell belongs.

[0251] In some possible implementations, after a terminal device switches to a target cell during an ascent, the terminal device may determine whether to delete the configuration information of candidate cells in the candidate cell list for which measurements were performed during the ascent based on the distance between the ascent location and the descent location. If the distance is close, the candidate cell configuration information may be saved for subsequent use, saving the step of re-acquisition and reducing resource waste.

[0252] In one possible example, after completing handover to the target cell during the ascent process, if it is determined that the distance between the location associated with the candidate cell list used during the descent process and the location associated with the candidate cell list to which the target cell belongs is greater than or equal to a set distance threshold, the configuration information of the candidate cell list to which the target cell belongs is deleted. Exemplarily, the terminal device may delete the configuration information of the candidate cells in the candidate cell list sequentially according to the order in which the candidate cells were measured. The terminal device may also delete the configuration information of the candidate cells in the candidate cell list used during the ascent process after completing the ascent phase. If it is determined that the distance between the location associated with the candidate cell list used during the descent process and the location associated with the candidate cell list to which the target cell belongs is less than a set distance threshold, the configuration information of the candidate cell list used during the ascent process may continue to be stored. In some scenarios, candidate cell lists corresponding to different altitude ranges are configured during the ascent phase. After completing the measurement of the first altitude range and switching to the target cell in the candidate cell list corresponding to the first altitude range, if it is determined that the distance between the location associated with the descent process and the location associated with the candidate cell list to which the target cell belongs is greater than or equal to the set distance threshold, the terminal device may delete the configuration information of the candidate cell list corresponding to the first altitude range. The terminal device can perform a deletion operation on the candidate cell configuration information in different height intervals according to the height range.

[0253] In another possible example, after completing the handover to the target cell during the ascending process, when it is determined that the position associated with the candidate cell list used in the descending process does not cover the position associated with the candidate cell list to which the target cell belongs, the configuration information of the candidate cell list used in the ascending process is deleted. Exemplarily, the terminal device may delete the configuration information of the candidate cells in the candidate cell list in sequence according to the measurement order of the candidate cells in the candidate cell list. The terminal device may also uniformly delete the configuration information of the candidate cells in the candidate cell list used in the ascending process after completing the ascending stage. If it is determined that the position associated with the candidate cell list used in the descending process covers the position associated with the candidate cell list to which the target cell belongs, the configuration information of the candidate cell list used in the ascending process may continue to be retained.

[0254] Optionally, after deleting the configuration information of some or all candidate cells in the candidate target cell list used in the ascending phase, the terminal device may send a third indication message to the source network device, where the third indication message is used to indicate that some or all cells in the candidate cell list have been deleted. In some possible implementations, the source network device may also send a deletion indication to the network device to which the cell whose configuration information has been deleted belongs. The deletion indication is used to indicate that one or more candidate cells managed by the network device have been deleted. Exemplarily, the third indication information may be carried in an RRC reconfiguration completion message. For example, the third indication information may include an identifier of the cell whose configuration information has been deleted, such as an ID. The deletion indication may include an identifier of the cell whose configuration information has been deleted.

[0255] In an embodiment of the present application, the first indication information is used to indicate the height measurement range of the candidate cell list to the terminal device, so that the terminal device only needs to measure the cells within the height measurement range, which can reduce the measurement overhead of the terminal device and improve switching efficiency.

[0256] Currently, when a terminal device performs early random access, the time at which the preamble is sent affects the accuracy of the TA. Based on this, the embodiment of the present application determines the timing of sending the preamble (the trigger point for sending the preamble) according to the moving path of the terminal device.

[0257] FIG9 is a flow chart of a communication method according to an embodiment of the present application. The communication method includes the following steps:

[0258] S901: A first network device sends a mobile path of a terminal device to a second network device. The first network device is a network device providing services for the terminal device, and the second network device is a candidate target network device to be switched. The mobile path of the terminal device may be sent by the terminal device to the first network device.

[0259] Exemplarily, the first network device may carry the mobile path of the terminal device in a handover request (HO request) message and send it to the second network device.

[0260] S902, the second network device sends eighth indication information to the first network device, where the eighth indication information is used to indicate a trigger point (or timing) for the terminal device to send a preamble code.

[0261] Exemplarily, the second network device may carry the eighth indication information in a handover request confirmation (HO request ACK) message and send it to the first network device.

[0262] Exemplarily, the second network device may determine the time and / or location when the terminal device passes through the coverage area of ​​the second network device based on the moving path of the terminal device, thereby determining the trigger point for the terminal device to send the preamble code.

[0263] In a possible implementation, the trigger point may be a position. For example, the eighth indication information is used to indicate the position where the terminal device sends the preamble.

[0264] The location used by the trigger point can be a location point or a location range. The location point can be a waypoint or a geographic location. Taking the trigger point as waypoint 2-1 as an example, the eighth indication information indicates the waypoint where the preamble is sent, and the eighth indication information may include waypoint 2-1. When the terminal device arrives at waypoint 2-1, it can send a preamble to the source network device. For another example, taking the trigger point as the fifth geographic location as an example, the eighth indication information indicates the fifth geographic location where the terminal device sends the preamble. When the terminal device arrives at the fifth geographic location, it can send a preamble to the source network device.

[0265] For another example, take the trigger point as an example of a location range. The location range can be a range between two waypoints. Taking the fifth waypoint and the sixth waypoint as an example, the location where the terminal device sends the preamble is the location between the fifth waypoint and the sixth waypoint. For another example, the location range can be a range between two geographic locations. Taking the sixth geographic location and the seventh geographic location as an example. The location where the terminal device sends the preamble is the location between the sixth geographic location and the seventh geographic location. For another example, the location range is represented by a third location and a fourth distance threshold. The location where the terminal device sends the preamble is a location whose distance from the third location is less than or equal to the fourth distance threshold.

[0266] In another possible implementation, the trigger point may be a time. For example, the eighth indication information is used to indicate the time at which the terminal device transmits the preamble. The time used as the trigger point may be a moment or a time range. The time range may be represented by two moments, such as the third moment and the fourth moment. The time range may also be represented by a moment and a time threshold, such as the fifth moment and the third time threshold.

[0267] In another possible implementation, the trigger point may be time + location. For example, the eighth indication information is used to indicate the time and location at which the terminal device sends the preamble. For example, the trigger points include time 5 and time 6, and location 5. Location 5 may be a waypoint or a geographic location. Then the eighth indication information instructs the terminal device to send the preamble between time 5 and time 6 and when it reaches location 5. For another example, the trigger points include location 5, location 6, and time 5. Then the eighth indication information instructs the terminal device to send the preamble at time 5 and when it reaches the range between location 5 and location 6.

[0268] S903: The first network device sends the ninth indication information to the terminal device.

[0269] S904, the terminal device sends a preamble code according to the ninth indication information.

[0270] In some possible embodiments, the ninth indication information may be the eighth indication information, and the terminal device sends the preamble according to the ninth indication information. For example, the terminal device determines the timing of sending the preamble according to the ninth indication information, and then sends the preamble.

[0271] In some other possible embodiments, the ninth indication information is determined based on the eighth indication information. For example, the first network device may determine the timing of sending a physical downlink control channel (PDCCH) order based on the eighth indication information, and then send the PDCCH order to the terminal device. For example, the ninth indication information may be a PDCCH order, which is used to instruct the terminal device to send a preamble. Thus, the terminal device sends the preamble.

[0272] In an embodiment of the present application, a candidate network device is used to determine the time or location for sending a preamble code for a terminal device to improve the accuracy of the TA.

[0273] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of the interaction between the terminal device and the network device (and between the network devices). It is understandable that in order to achieve the above functions, the terminal device and the network device may include hardware structures and / or software modules that perform the corresponding functions. Those skilled in the art should easily appreciate that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the embodiments of the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in a hardware or computer software driven hardware manner depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0274] In the embodiments of the present application, the network device can be divided into functional units according to the above method examples. For example, each functional unit can be divided according to each function, or two or more functions can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or software functional units.

[0275] In the case of adopting an integrated unit, Figure 10 shows a possible exemplary block diagram of the device involved in the embodiments of the present application. As shown in Figure 10, the device 1000 may include: a processing unit 1002 and a communication unit 1003. The processing unit 1002 is used to control and manage the actions of the device 1000. The communication unit 1003 is used to support the communication between the device 1000 and other devices. Optionally, the communication unit 1003 is also called a transceiver unit, and may include a receiving unit and / or a sending unit, which are used to perform receiving and sending operations respectively. The device 1000 may also include a storage unit 1001 for storing program code and / or data of the device 1000.

[0276] (1) The apparatus 1000 may be a terminal device in the aforementioned embodiments. The processing unit 1002 may support the apparatus 1000 in executing the actions of the terminal device in the aforementioned method examples. Alternatively, the processing unit 1002 may primarily execute the internal actions of the terminal device in the method examples, and the communication unit 1003 may support communication between the apparatus 1000 and other devices.

[0277] For example, in one embodiment, the communication unit 1003 is configured to receive a candidate cell list and first indication information from a first network device; and the processing unit 1002 is configured to perform measurement on candidate cells within the first range.

[0278] (2) The apparatus 1000 may be the first network device (or source network device) in the above-described embodiments. The processing unit 1002 may support the apparatus 1000 in executing the actions of the first network device (or source network device) in each of the above-described method examples. Alternatively, the processing unit 1002 may primarily execute the internal actions of the first network device (or source network device) in the method examples, and the communication unit 1003 may support communication between the apparatus 1000 and other devices.

[0279] For example, in one embodiment, the processing unit 1002 is configured to determine a candidate cell list and first indication information. The communication unit 1003 is configured to send the candidate cell list and the first indication information to the terminal device.

[0280] For example, in another embodiment, the communication unit 1003 is configured to: send the moving path of the terminal device to the second network device, and receive the eighth indication information sent by the second network device.

[0281] (3) The apparatus 1000 may be the second network device (or candidate network device or target network device) in the above-described embodiments. The processing unit 1002 may support the apparatus 1000 in executing the actions of the second network device (or candidate network device or target network device) in each of the above-described method examples. Alternatively, the processing unit 1002 may primarily execute the internal actions of the second network device (or candidate network device or target network device) in the method examples, and the communication unit 1003 may support communication between the apparatus 1000 and other devices.

[0282] For example, in one embodiment, the communication unit 1003 is configured to: receive the moving path of the terminal device from the first network device, and send eighth indication information to the first network device.

[0283] It should be understood that the division of units in the above device is merely a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or they can be physically separated. Moreover, the units in the device can all be implemented in the form of software calling through processing elements; or they can all be implemented in the form of hardware; or some units can be implemented in the form of software calling through processing elements, and some units can be implemented in the form of hardware. For example, each unit can be a separately established processing element, or it can be integrated into a certain chip of the device. In addition, it can also be stored in the memory in the form of a program, called by a certain processing element of the device and execute the function of the unit. In addition, all or part of these units can be integrated together, or they can be implemented independently. The processing element described here can also be a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, each operation of the above method or each unit above can be implemented by the integrated logic circuit of the hardware in the processor element or in the form of software calling through the processing element.

[0284] In one example, the unit in any of the above devices may be one or more integrated circuits configured to implement the above method, such as one or more application specific integrated circuits (ASICs), one or more digital singnal processors (DSPs), one or more field programmable gate arrays (FPGAs), or a combination of at least two of these integrated circuit forms. For another example, when the unit in the device can be implemented in the form of a processing element scheduler, the processing element can be a processor, such as a general-purpose central processing unit (CPU), or other processor that can call a program. For another example, these units can be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0285] The above-mentioned receiving unit is an interface circuit of the device, which is used to receive signals from other devices. For example, when the device is implemented as a chip, the receiving unit is the interface circuit of the chip used to receive signals from other chips or devices. The above-mentioned sending unit is an interface circuit of the device, which is used to send signals to other devices. For example, when the device is implemented as a chip, the sending unit is the interface circuit of the chip used to send signals to other chips or devices.

[0286] Figure 11 shows a schematic diagram of the structure of a communication device provided in an embodiment of the present application. The communication device 1100 may be the circuit system of the terminal device described in any of the above embodiments, and is used to implement the method corresponding to the terminal device in the above method embodiment. Alternatively, the communication device 1100 may be the circuit system of the first network device (or source network device) in any of the above embodiments, and is used to implement the method corresponding to the first network device in the above method embodiment. Alternatively, the communication device 1100 may be the circuit system of the second network device (or candidate network device or target network device) in any of the above embodiments, and is used to implement the method corresponding to the second network device (or candidate network device or target network device) in the above method embodiment.

[0287] For specific functions, please refer to the description in the above method embodiment. For example, a circuit system is a chip system.

[0288] The communication device 1100 includes at least one processor 1101. Processor 1101 can be used for internal processing of the device to implement certain control processing functions. Optionally, processor 1101 includes instructions. Optionally, processor 1101 can store data. Optionally, different processors can be independent devices, located in different physical locations, or on different integrated circuits. Optionally, different processors can be integrated into one or more processors, for example, on one or more integrated circuits.

[0289] Optionally, the communication device 1100 includes one or more memories 1103 for storing instructions. Optionally, data may also be stored in the memories 1103. The processor and memory may be provided separately or integrated together.

[0290] Optionally, the communication device 1100 includes a communication line 1102 and at least one communication interface 1104. Since the memory 1103, the communication line 1102 and the communication interface 1104 are all optional, they are indicated by dotted lines in FIG11 .

[0291] Optionally, the communication device 1100 may further include a transceiver and / or an antenna. The transceiver may be used to send information to or receive information from other devices. The transceiver may be referred to as a transceiver, a transceiver circuit, an input / output interface, etc., and is used to implement the transceiver function of the communication device 1100 via an antenna. Optionally, the transceiver includes a transmitter and a receiver. For example, the transmitter may be used to generate a radio frequency signal from a baseband signal, and the receiver may be used to convert the radio frequency signal into a baseband signal.

[0292] The processor 1101 may include a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present application.

[0293] The communication link 1102 may include a pathway for transmitting information between the aforementioned components.

[0294] The communication interface 1104 uses any transceiver or other device for communicating with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area network (WLAN), wired access network, etc.

[0295] The memory 1103 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 1103 may exist independently and be connected to the processor 1101 via the communication line 1102. Alternatively, the memory 1103 may be integrated with the processor 1101.

[0296] Among them, the memory 1103 is used to store computer-executable instructions for executing the solution of the present application, and the execution is controlled by the processor 1101. The processor 1101 is used to execute the computer-executable instructions stored in the memory 1103, thereby implementing the steps performed by the terminal device described in any of the above embodiments, or implementing the steps performed by the first network device (or source network device) described in any of the above embodiments, or implementing the steps performed by the second network device (or candidate network device or target network device) described in any of the above embodiments.

[0297] Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application code, which is not specifically limited in the embodiments of the present application.

[0298] In a specific implementation, as an embodiment, the processor 1101 may include one or more CPUs, such as CPU0 and CPU1 in FIG11 .

[0299] In a specific implementation, as an embodiment, the communication device 1100 may include multiple processors, such as the processor 1101 and the processor 1105 in FIG11 . Each of these processors may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. The processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0300] When the device shown in FIG11 is a chip, for example, a chip of a terminal device, or a chip of a first network device (or a source network device), or a second network device (or a candidate network device or a target network device), the chip includes a processor 1101 (and may also include a processor 1105), a communication line 1102, and a communication interface 1104. Optionally, the chip may include a memory 1103. Specifically, the communication interface 1104 may be an input interface, a pin, or a circuit. The memory 1103 may be a register, a cache, or the like. The processor 1101 and the processor 1105 may be a general-purpose CPU, a microprocessor, an ASIC, or one or more integrated circuits for controlling the execution of a program of the communication method of any of the above embodiments.

[0301] The terms "system" and "network" in the embodiments of the present application can be used interchangeably. "At least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, "at least one of A, B and C" includes A, B, C, AB, AC, BC or ABC. And, unless otherwise specified, the ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, timing, priority or importance of multiple objects.

[0302] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0303] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the present application. It should be understood that each flow and / or box in the flow chart and / or block diagram, as well as the combination of the flow chart and / or box in the flow chart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more flow charts and / or one or more boxes in the block diagram.

[0304] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0305] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0306] Obviously, those skilled in the art may make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include these modifications and variations.

Claims

1. A communication method, characterized in that: Applied to terminal equipment, including: receiving a candidate cell list and first indication information from a first network device, where the first indication information is used to indicate a first range, where the first range is a range for measuring candidate cells in the candidate cell list; Perform measurement on candidate cells within the first range.

2. The method according to claim 1, characterized in that The first indication information is used to indicate the first range, including: The first indication information is used to indicate the starting position and the ending position corresponding to the first range; or, The first indication information is used to indicate a starting position corresponding to the first range.

3. The method according to claim 2, characterized in that The starting position is: The terminal device starts to perform the measured waypoint; or, The geographical location where the terminal device starts to perform the measurement; or A position whose distance from the first position is less than or equal to a first distance threshold.

4. The method according to claim 2 or 3, characterized in that The end position is: The terminal device ends the measured waypoint; or, The geographical location where the terminal device ends the measurement; or A position whose distance from the second position is greater than or equal to a second distance threshold.

5. The method according to any one of claims 1 to 4, characterized in that: The first indication information is used to indicate the first range, including: The first indication information is used to indicate the start time and end time corresponding to the first range; or, The first indication information is used to indicate a start time corresponding to the first range.

6. The method according to claim 5, characterized in that The starting time is: The time when the terminal device starts to perform the measurement; or A moment whose time difference from the first moment is less than or equal to the first time threshold.

7. The method according to claim 5 or 6, characterized in that The end time is: The time when the terminal device ends the measurement; or A moment whose time difference from the second moment is greater than or equal to the second time threshold.

8. The method according to any one of claims 1 to 7, characterized in that: The method further comprises: Second indication information is received from the first network device, where the second indication information is used to indicate a trigger point for deleting configuration information of at least one second candidate cell, where the second candidate cell is a candidate cell in the candidate cell list.

9. The method according to claim 8, characterized in that The second indication information is used to indicate a trigger point for deleting configuration information of at least one second candidate cell, including: The second indication information is used to indicate a location where the configuration information of the at least one second candidate cell is deleted; or, The second indication information is used to indicate a time for deleting the configuration information of the at least one second candidate cell.

10. The method according to claim 9, characterized in that The location where the configuration information of the at least one second candidate cell is deleted is: The first waypoint at which the configuration information of the at least one second candidate cell is deleted; or, a first geographical location where the configuration information of the at least one second candidate cell is deleted; or, A position between the second waypoint and the third waypoint; or, a location between the second geographic location and the third geographic location; or, A position between a fourth geographical position and a fourth waypoint, wherein the fourth geographical position is a position whose distance from the fourth waypoint is less than a third distance threshold.

11. The method according to claim 9, characterized in that The second indication information is used to indicate a trigger point for deleting configuration information of at least one second candidate cell, including: The second indication information is used to indicate a time range for deleting configuration information of at least one second candidate cell, or, The second indication information is used to indicate a time to delete configuration information of at least one second candidate cell.

12. The method according to any one of claims 1 to 4, characterized in that: The first indication information is used to indicate the first range, including: The first indication information is used to indicate the starting height and the ending height corresponding to the first range; or, The first indication information is used to indicate the end height corresponding to the first range; or, The first indication information is used to indicate a starting height corresponding to the first range.

13. The method according to claim 12, characterized in that The receiving the candidate cell list and the first indication information from the first network device includes: First configuration information is received from the first network device, where the first configuration information includes the candidate cell list and the first indication information.

14. A communication method, characterized in that: Applied to the second network device, comprising: Determine a candidate cell list and first indication information; The candidate cell list and the first indication information are sent to a terminal device, where the first indication information is used to indicate a first range, and the first range is a range for measuring the candidate cells in the candidate cell list.

15. The method according to claim 14, characterized in that The first indication information is used to indicate the first range, including: The first indication information is used to indicate the starting position and the ending position corresponding to the first range; or, The first indication information is used to indicate a starting position corresponding to the first range.

16. The method according to claim 15, characterized in that The starting position is: The terminal device starts to perform the measured waypoint; or, The geographical location where the terminal device starts to perform the measurement; or A position whose distance from the first position is less than or equal to a first distance threshold.

17. The method according to claim 14 or 15, characterized in that The end position is: The terminal device ends the measured waypoint; or, The geographical location where the terminal device ends the measurement; or A position whose distance from the second position is greater than or equal to a second distance threshold.

18. The method according to any one of claims 14 to 17, characterized in that: The first indication information is used to indicate the first range, including: The first indication information is used to indicate the start time and end time corresponding to the first range; or, The first indication information is used to indicate a start time corresponding to the first range.

19. The method according to claim 18, characterized in that The starting time is: The time when the terminal device starts to perform the measurement; or A moment whose time difference from the first moment is less than or equal to the first time threshold.

20. The method according to claim 18 or 19, characterized in that The end time is: The time when the terminal device ends the measurement; or A moment whose time difference from the second moment is greater than or equal to the second time threshold.

21. The method according to any one of claims 14 to 20, characterized in that: The method further comprises: Sending second indication information to the terminal device, where the second indication information is used to indicate a trigger point for deleting configuration information of at least one second candidate cell, where the second candidate cell is a candidate cell in the candidate cell list.

22. The method according to claim 21, characterized in that The second indication information is used to indicate a trigger point for deleting configuration information of at least one second candidate cell, including: The second indication information is used to indicate a location where the configuration information of the at least one second candidate cell is deleted; or, The second indication information is used to indicate a time for deleting the configuration information of the at least one second candidate cell.

23. The method of claim 22, wherein: The location where the configuration information of the at least one second candidate cell is deleted is: The first waypoint at which the configuration information of the at least one second candidate cell is deleted; or, a first geographical location where the configuration information of the at least one second candidate cell is deleted; or, A position between the second waypoint and the third waypoint; or, a location between the second geographic location and the third geographic location; or, A position between a fourth geographical position and a fourth waypoint, wherein the fourth geographical position is a position whose distance from the first waypoint is less than a third distance threshold.

24. The method of claim 22, wherein: The second indication information is used to indicate a trigger point for deleting configuration information of at least one second candidate cell, including: The second indication information is used to indicate a time range for deleting configuration information of at least one second candidate cell, or, The second indication information is used to indicate a time to delete configuration information of at least one second candidate cell.

25. The method according to any one of claims 14 to 17, characterized in that: The first indication information is used to indicate the first range, including: The first indication information is used to indicate the starting height and the ending height corresponding to the first range; or, The first indication information is used to indicate the end height corresponding to the first range; or, The first indication information is used to indicate a starting height corresponding to the first range.

26. The method according to any one of claims 14 to 25, characterized in that The method further comprises: Sending the moving path of the terminal device to the second network device; A cell list is received from a second network device, wherein the cell list includes an identifier of at least one cell passed by the moving path.

27. The method according to any one of claims 14 to 25, characterized in that The method further comprises: Sending the moving path of the terminal device to the second network device; Sending first information to the second network device, where the first information is used to indicate at least one cell; Second information is received from a second network device, where the second information is used to indicate whether the moving path passes through the at least one cell.

28. A communication device, characterized in that: The invention comprises a processor and a memory, wherein the processor and the memory are coupled, and the processor is used to implement the method according to any one of claims 1 to 13, or to implement the method according to any one of claims 14 to 27.

29. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and the instructions are executed on a computer to enable the computer to execute the method of any one of claims 1 to 13, or the method of any one of claims 14 to 27.

30. A computer program product, characterized in that The device comprises a computer program or an instruction, and when the computer program or the instruction is executed by the device, the method according to any one of claims 1 to 13 is executed, or the method according to any one of claims 14 to 27 is executed.

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