Communication method and communication apparatus

Abstract

The present application provides a communication method and a communication apparatus. In the method, a second apparatus sends a first condition and a second condition to a first apparatus, so as to indicate to the first apparatus a trigger condition that needs to be satisfied when performing handover; correspondingly, the first apparatus receives the first condition and the second condition, and can trigger handover to a first cell or a second cell on the basis of the first condition and / or the second condition without additional signaling indication, thereby reducing signaling overhead. In addition, when the first apparatus triggers the handover on the basis of the conditions, a terminal can be automatically handed over to different cells on the basis of different conditions, realizing LTM-based conditional handover, thereby reducing the mobility interruption delay.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application with application number 202410257777.X filed with the State Intellectual Property Office of China on March 6, 2024, and priority to the Chinese patent application with the invention name “A Communication Method and Communication Device”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a communication method and a communication device. Background Art

[0003] Non-terrestrial networks (NTNs) include nodes such as satellite networks, high-altitude platforms, and drones, and have the advantages of global coverage, long-distance transmission, flexible networking, easy deployment, and no geographical restrictions. In satellite networks and / or satellite-ground integrated networks, the movement of satellite nodes can cause group switching or group reselection problems for users within a certain area. In one possible implementation, layer 3 (L3)-triggered switching can be used to implement mobility management in NTN networks. However, since the L3 switching-related configuration information needs to go through the radio resource control (RRC) layer, the mobility interruption time is relatively long. In another possible implementation, the existing layer 1 / layer 2 triggered mobility (L1 / L2 triggered mobility, LTM) switching (also known as bottom layer switching, etc.) can effectively reduce the mobility interruption delay, but the terminal needs to periodically report the L1 measurement results, and the LTM switching needs to be instructed by the serving cell before it is performed, which results in a large signaling overhead. Summary of the Invention

[0004] The present application provides a communication method and a communication device, which can reduce signaling overhead and reduce mobile interruption delay.

[0005] In the first aspect, the present application provides a communication method, which is performed by a first device. For example, the first device can be a terminal, or a terminal or a communication module in the terminal, or a circuit or chip in the terminal responsible for the communication function (such as a modem chip, also known as a baseband chip, or a system on chip (SoC) chip or system in package (SIP) chip containing a modem core). The first device receives a first condition and a second condition. When the first condition is met, the first device switches to the first cell; when the second condition is met, the first device switches to the second cell.

[0006] In this method, the first device can receive the first condition and the second condition to determine the conditions that need to be met when subsequently performing a handover. For example, the first device can subsequently trigger a handover based on the first condition and / or the second condition without requiring additional signaling instructions, thereby reducing signaling overhead. Furthermore, when the first device triggers a handover based on the conditions, the terminal can automatically switch to different cells based on different conditions, implementing LTM-based conditional handover (CHO), thereby reducing mobile interruption delay.

[0007] In one possible implementation, the first condition is that the distance between the first device and the first reference location is greater than a first threshold and / or the distance between the first device and the second reference location is less than a second threshold, and the layer 1 (L1) signal quality of the first reference signal is greater than a first signal quality threshold. The first reference location, the second reference location, the first threshold, the second threshold, and the first signal quality threshold are predefined parameters.

[0008] In one possible implementation, when the distance between the position of the first device and the reference position is greater than a first threshold and / or the distance between the position of the first device and the second reference position is less than a second threshold, and the first device measures the L1 signal quality of the first reference signal of the first cell to be greater than the first signal quality threshold, the first device switches to the first cell.

[0009] In the above embodiments, the meaning of the first condition and the meaning of satisfying the first condition are specifically described. For example, when the distance between the first device and the first reference location is greater than a first threshold, and the L1 signal quality of the first reference signal is greater than a first signal quality threshold, the first condition is satisfied, and the first device can perform LTM handover to the first cell, thereby reducing mobility interruption time. For another example, when the distance between the first device and the second reference location is less than a second threshold, and the L1 signal quality of the first reference signal is greater than the first signal quality threshold, the first condition is satisfied, and the first device can perform LTM handover to the first cell, thereby reducing mobility interruption time. For another example, when the distance between the first device and the reference location is greater than the first threshold, the distance between the first device and the second reference location is less than a second threshold, and the L1 signal quality of the first reference signal is greater than the first signal quality threshold, the first condition is satisfied, and the first device can perform LTM handover to the first cell, thereby reducing mobility interruption time.

[0010] In one possible implementation, the second condition is that the local clock of the first device is in a first time period and the L1 signal quality of the second reference signal is greater than a second signal quality threshold, wherein the first time period and the second signal quality threshold are predefined parameters.

[0011] In a possible implementation, when the local clock of the first device is in the first time period and the first device measures that the L1 signal quality of the second reference signal of the second cell is greater than a second signal quality threshold, the first device switches to the second cell.

[0012] In the above implementation, the meaning of the second condition and the meaning of satisfying the second condition are specifically described; for example, when the local clock of the first device is in the first time period, and the first device measures that the L1 signal quality of the second reference signal of the second cell is greater than the second signal quality threshold, it means that the second condition is satisfied, then the first device can perform LTM switching and switch to the second cell, which can reduce the mobile interruption time.

[0013] In a possible implementation, when the first device has no timing advance information, the first device obtains the timing advance information through an access procedure.

[0014] In this implementation, if the first device has no available timing advance (TA) information, it needs to re-access to obtain a valid TA, thereby improving the timeliness of TA acquisition in LTM communication.

[0015] In one possible implementation, when a first condition is met, the first device switches access based on a first random access resource associated with a first reference signal to obtain first timing advance information; when a second condition is met, the first device switches access based on a second random access resource associated with a second reference signal to obtain second timing advance information.

[0016] In this implementation, when the first condition or the second condition is met, the first device can re-access through different random access resources to obtain a valid TA, thereby improving the timeliness of TA acquisition in LTM communication.

[0017] In one possible implementation, when a first condition is met, the first device detects a first control resource associated with the first reference signal to determine a first physical downlink control channel associated with the first control resource. The first device demodulates the first physical downlink control channel and switches access based on the demodulated resources of the first physical downlink control channel to obtain first timing advance information.

[0018] In one possible implementation, when the second condition is met, the first device detects a second control resource associated with the second reference signal to determine a second physical downlink control channel associated with the second control resource. The first device demodulates the second physical downlink control channel and switches access based on the demodulated resources of the second physical downlink control channel to obtain the second timing advance information.

[0019] In the above implementation, when the first condition or the second condition is met, the first device can detect the physical downlink control channel based on different control resource sets to obtain scheduling information, thereby achieving re-access, obtaining a valid TA, and improving the timeliness of TA acquisition in LTM communication.

[0020] In a possible implementation, when the first device has timing advance information, the first device communicates through pre-configured uplink transmission resources.

[0021] In one possible implementation, when a first condition is met, the first device communicates through a first preconfigured uplink transmission resource associated with a first reference signal; when a second condition is met, the first device communicates through a second preconfigured uplink transmission resource associated with a second reference signal.

[0022] In the above implementation, if the first device has available TA information, the first device may communicate through the preconfigured uplink transmission resource (eg, the first preconfigured uplink transmission resource or the second preconfigured uplink transmission resource).

[0023] In one possible implementation, a first device sends an L1 measurement report, where the L1 measurement report includes an identifier of a candidate cell and / or a type of the candidate cell, where the candidate cells include a first cell and a second cell. The first device receives first indication information, where the first indication information is used to indicate a timing advance acquisition method; the timing advance acquisition method is determined by the second device based on a first delay, where the first delay is determined by the second device based on the identifier of the candidate cell or the type of the candidate cell in the L1 measurement report. The first device completes uplink synchronization with the candidate cell based on the timing advance acquisition method.

[0024] In one possible implementation, the timing advance acquisition method includes a first acquisition method and a second acquisition method; the first acquisition method is to obtain timing advance information from the serving cell of the first device; the second acquisition method is to obtain timing advance information from the random access response of the candidate cell.

[0025] In the above implementation, the TA acquisition method of the first device is dynamically configured in LTM communication. The specific acquisition methods include acquiring from the serving cell (called the first acquisition method) or acquiring from the random access response of the candidate cell (called the second acquisition method).

[0026] In one possible implementation, the first device receives LTM configuration information, which includes at least one of the following: an identifier of the first cell, an identifier of the second cell, an identifier of the LTM configuration information, a reference signal resource configuration, a reference signal measurement configuration, a random access resource configuration, a control resource configuration, a pre-configured uplink transmission resource configuration, and a transmission configuration indication status.

[0027] In this implementation, the first device may receive LTM configuration information, thereby obtaining information about a candidate cell (such as the first cell or the second cell), LTM configuration, resource configuration, and other information to implement LTM communication.

[0028] In a possible implementation, the period of the first reference signal is a first period, the second reference signal is a non-periodic signal, or the period of the second reference signal is a second period, and the second period is greater than the first period.

[0029] In this implementation, the first reference signal is defined as a periodic signal, and the period is relatively short (usually at the millisecond (ms) level, with typical values ​​of 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms); the second reference signal is defined as a non-periodic signal or a periodic signal, and when the second reference signal is a periodic signal, the period is relatively long (usually at the second (s) level, with typical values ​​of 1s, 2s, 4s, 8s, 16s, 32s, or 64s, etc.), that is, the second period is greater than the first period, so that these two different types of reference signals can be distinguished.

[0030] In a possible implementation manner, the first reference signal and the second reference signal are reference signals of different types.

[0031] In this embodiment, it is defined that the first reference signal and the second reference signal can be different types of reference signals. For example, assuming that the first reference signal is an existing SSB synchronization signal, the second reference signal is a switching-dedicated SSB signal, or the second reference signal is other types of reference signals (such as a tracking reference signal (TRS), a channel state information reference signal (CSI-RS), etc.), so that the two different types of reference signals can be distinguished.

[0032] In a possible implementation manner, the first reference signal and the second reference signal satisfy a quasi co-location (QCL) relationship.

[0033] In this embodiment, it is defined that the first reference signal and the second reference signal can satisfy the QCL relationship. For example, the properties of the second reference signal (such as the large-scale characteristics of the channel and the spatial receiver parameters, etc., the channel characteristics include Doppler frequency shift, Doppler spread, average delay, delay spread) can be inferred from the first reference signal. The first reference signal and the second reference signal can be reference signals of the same type or different types, so that the two different types of reference signals can be distinguished.

[0034] In one possible implementation, the first reference signal and the second reference signal differ in at least one of their time domain positions, frequency domain positions, or polarization modes. For example, the first reference signal and the second reference signal may have different time domain positions, but may have the same or different frequency domain positions or polarization modes; or, the first reference signal and the second reference signal may have different frequency domain positions, but may have the same or different time domain positions or polarization modes; or, the first reference signal and the second reference signal may have different polarization modes, but may have the same or different time domain positions or frequency domain positions.

[0035] In this implementation, two different types of reference signals can be distinguished through different designs of time domain positions, frequency domain positions, or polarization modes.

[0036] In a possible implementation, the first reference signal corresponds to a predefined time domain position, and the time domain position of the second reference signal is variable.

[0037] In this embodiment, the difference between the time domain positions corresponding to the first reference signal and the second reference signal is defined. For example, the resource pattern of the first reference signal (i.e., the predefined time domain position) and the resource pattern of the second reference signal are different, so that two different types of reference signals can be distinguished.

[0038] In a possible implementation, one second reference signal is associated with one transmission configuration indication state; or one second reference signal is associated with one first reference signal, and one first reference signal is associated with one transmission configuration indication state.

[0039] In this embodiment, the second reference signal needs to be associated with a transmission configuration indicator state (TCI state) to implement LTM communication. For example, the second reference signal can be directly associated with the TCI state, or the second reference signal can be associated with the first reference signal, which is pre-configured with the corresponding TCI state, thereby achieving the association between the second reference signal and the TCI state.

[0040] In one possible implementation, the first reference signal and the second reference signal are SSB synchronization signals, the first reference signal is mapped to a first type of time domain position, and the second reference signal is mapped to a second type of time domain position. The first type of time domain position satisfies a first periodicity, and the second type of time domain position is aperiodic or satisfies a second periodicity, where the second periodicity is greater than the first periodicity.

[0041] In one possible implementation, the first type of time domain position and the second type of time domain position multiplex the same SSB index.

[0042] In the above implementation, the first reference signal and the second reference signal may be reference signals of the same type, or may be a single reference signal. However, the same type, or the same reference signal, is mapped to different types of time domain positions, and thus may be considered two different types of reference signals. For example, the different types of time domain positions may be time domain positions of the first type and time domain positions of the second type, and the two types of time domain positions may have different periods.

[0043] In a second aspect, the present application provides a communication method, which is performed by a second device. For example, the second device can be a network device (such as a satellite, base station, etc.), or a component of a network device (such as a processor, chip, or chip system, etc.), or a logic module that can implement all or part of the functions of the network device. The second device determines a first condition and a second condition, and the second device sends the first condition and the second condition; the first condition is used to trigger the first device to switch to the first cell; the second condition is used to trigger the first device to switch to the second cell.

[0044] In this method, the second device can send the first condition and the second condition, thereby indicating to the first device the conditions that need to be met when performing the switch; for example, the first device subsequently triggers the switch based on the first condition and / or the second condition, and the second device does not need to send the switching signaling to the first device again, which can reduce signaling overhead.

[0045] In one possible implementation, the first condition is that the distance between the first device and the first reference location is greater than a first threshold and / or the distance between the first device and the second reference location is less than a second threshold, and the L1 signal quality of the first reference signal is greater than a first signal quality threshold. The first reference location, the second reference location, the first threshold, the second threshold, and the first signal quality threshold are predefined parameters.

[0046] In the above embodiment, the meaning of the first condition and the meaning of satisfying the first condition are specifically described; for example, when the distance between the position of the first device and the first reference position is greater than the first threshold, and the L1 signal quality of the first reference signal is greater than the first signal quality threshold, the first condition is satisfied. For another example, when the distance between the position of the first device and the second reference position is less than the second threshold, and the L1 signal quality of the first reference signal is greater than the first signal quality threshold, the first condition is satisfied. For another example, when the distance between the position of the first device and the reference position is greater than the first threshold, and the distance between the position of the first device and the second reference position is less than the second threshold, and the L1 signal quality of the first reference signal is greater than the first signal quality threshold, the first condition is satisfied.

[0047] In one possible implementation, the second condition is that the local clock of the first device is in a first time period and the L1 signal quality of the second reference signal is greater than a second signal quality threshold, wherein the first time period and the second signal quality threshold are predefined parameters.

[0048] In the above embodiment, the meaning of the second condition and the meaning of satisfying the second condition are specifically described; for example, when the local clock of the first device is in the first time period and the first device measures that the L1 signal quality of the second reference signal of the second cell is greater than the second signal quality threshold, it indicates that the second condition is satisfied.

[0049] In one possible implementation, a second device receives an L1 measurement report, the L1 measurement report including an identifier of a candidate cell and / or a type of the candidate cell; the candidate cells include a first cell and a second cell. The second device determines a first delay based on the identifier of the candidate cell or the type of the candidate cell in the L1 measurement report. The second device determines a timing advance acquisition method based on the first delay. The second device sends first indication information, the first indication information being used to indicate the timing advance acquisition method.

[0050] In one possible implementation, when the first delay is less than the delay threshold, the second device determines that the first acquisition method is to obtain timing advance information from the service cell of the first device; when the first delay is greater than or equal to the delay threshold, the second device determines that the second acquisition method is to obtain timing advance information from the random access response of the candidate cell.

[0051] In the above embodiment, the second device can configure the TA acquisition method of the first device, and indicate the TA acquisition method to the first device through the first indication information; for example, the specific acquisition method includes acquiring from the serving cell (referred to as the first acquisition method), or acquiring from the random access response of the candidate cell (referred to as the second acquisition method).

[0052] In one possible implementation, the second device sends LTM configuration information, which includes at least one of the following: an identifier of the first cell, an identifier of the second cell, an identifier of the LTM configuration information, a reference signal resource configuration, a reference signal measurement configuration, a random access resource configuration, a control resource configuration, a pre-configured uplink transmission resource configuration, and a transmission configuration indication status.

[0053] In this implementation, the second device may send LTM configuration information to indicate information of candidate cells (such as the first cell or the second cell), LTM configuration, resource configuration and other information to the first device to implement LTM communication.

[0054] In a possible implementation, the period of the first reference signal is a first period, the second reference signal is a non-periodic signal, or the period of the second reference signal is a second period, and the second period is greater than the first period.

[0055] In this implementation, the first reference signal is defined as a periodic signal, and the period is relatively short (usually at the millisecond (ms) level, with typical values ​​of 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms); the second reference signal is defined as a non-periodic signal or a periodic signal, and when the second reference signal is a periodic signal, the period is relatively long (usually at the second (s) level, with typical values ​​of 1s, 2s, 4s, 8s, 16s, 32s, or 64s, etc.), that is, the second period is greater than the first period, so that these two different types of reference signals can be distinguished.

[0056] In a possible implementation manner, the first reference signal and the second reference signal are reference signals of different types.

[0057] In this embodiment, it is defined that the first reference signal and the second reference signal can be different types of reference signals. For example, assuming that the first reference signal is an existing SSB synchronization signal, the second reference signal is a switching-dedicated SSB signal, or the second reference signal is another type of reference signal (such as TRS, CSI-RS, etc.), the two different types of reference signals can be distinguished.

[0058] In a possible implementation manner, the first reference signal and the second reference signal satisfy a quasi co-location (QCL) relationship.

[0059] In this embodiment, it is defined that the first reference signal and the second reference signal can satisfy the QCL relationship. For example, the properties of the second reference signal (such as the large-scale characteristics of the channel and the spatial receiver parameters, etc., the channel characteristics include Doppler frequency shift, Doppler spread, average delay, delay spread) can be inferred from the first reference signal. The first reference signal and the second reference signal can be reference signals of the same type or different types, so that the two different types of reference signals can be distinguished.

[0060] In one possible implementation, the first reference signal and the second reference signal differ in at least one of their time domain positions, frequency domain positions, or polarization modes. For example, the first reference signal and the second reference signal may have different time domain positions, but may have the same or different frequency domain positions or polarization modes; or, the first reference signal and the second reference signal may have different frequency domain positions, but may have the same or different time domain positions or polarization modes; or, the first reference signal and the second reference signal may have different polarization modes, but may have the same or different time domain positions or frequency domain positions.

[0061] In this implementation, two different types of reference signals can be distinguished through different designs of time domain positions, frequency domain positions, or polarization modes.

[0062] In a possible implementation, the first reference signal corresponds to a predefined time domain position, and the time domain position of the second reference signal is variable.

[0063] In this embodiment, the difference between the time domain positions corresponding to the first reference signal and the second reference signal is defined. For example, the resource pattern of the first reference signal (i.e., the predefined time domain position) and the resource pattern of the second reference signal are different, so that two different types of reference signals can be distinguished.

[0064] In a possible implementation, one second reference signal is associated with one transmission configuration indication state; or one second reference signal is associated with one first reference signal, and one first reference signal is associated with one transmission configuration indication state.

[0065] In this embodiment, the second reference signal needs to be associated with a transmission configuration indicator state (TCI state) to implement LTM communication. For example, the second reference signal can be directly associated with the TCI state, or the second reference signal can be associated with the first reference signal, which is pre-configured with the corresponding TCI state, thereby achieving the association between the second reference signal and the TCI state.

[0066] In one possible implementation, the first reference signal and the second reference signal are SSB synchronization signals, the first reference signal is mapped to a first type of time domain position, and the second reference signal is mapped to a second type of time domain position. The first type of time domain position satisfies a first periodicity, and the second type of time domain position is aperiodic or satisfies a second periodicity, where the second periodicity is greater than the first periodicity.

[0067] In one possible implementation, the first type of time domain position and the second type of time domain position multiplex the same SSB index.

[0068] In the above implementation, the first reference signal and the second reference signal may be reference signals of the same type, or may be a single reference signal. However, the same type, or the same reference signal, is mapped to different types of time domain positions, and thus may be considered two different types of reference signals. For example, the different types of time domain positions may be time domain positions of the first type and time domain positions of the second type, and the two types of time domain positions may have different periods.

[0069] In a third aspect, the present application provides a communication device. The communication device may be a terminal, or a component of a terminal (such as a processor, a chip, or a chip system, etc.), or a device that can be used in conjunction with a terminal. In one possible implementation, the communication device has the function of implementing the first aspect above. For example, the communication device includes a module or unit or means corresponding to the operation involved in the first aspect above. The module or unit or means can be implemented by software, or by hardware, or by a combination of software and hardware.

[0070] In one possible implementation, the communication device includes a communication unit and a processing unit. The communication unit is configured to receive a first condition and a second condition. The processing unit is configured to switch to the first cell when the first condition is met and to switch to the second cell when the second condition is met.

[0071] In this embodiment, the communication device can receive the first condition and the second condition to determine the conditions that need to be met when subsequently performing a handover. For example, the first device can subsequently trigger a handover based on the first condition and / or the second condition without requiring additional signaling instructions, thereby reducing signaling overhead. Furthermore, when the first device triggers a handover based on the conditions, it can switch to different cells based on different conditions, implementing LTM handover, thereby reducing mobility interruption delay.

[0072] Optionally, other possible implementations in the third aspect can refer to the corresponding descriptions of other possible implementations in the first aspect, and will not be repeated here.

[0073] In a fourth aspect, the present application provides a communication device. The communication device may be a network device, or a component of a network device (such as a processor, a chip, or a chip system, etc.), or a device that can be used in conjunction with a network device. In one possible implementation, the communication device has the function of implementing the second aspect above. For example, the communication device includes a module or unit or means corresponding to the operation involved in the second aspect above. The module or unit or means can be implemented specifically through software, or through hardware, or through a combination of software and hardware.

[0074] In one possible implementation, the communication device includes a communication unit and a processing unit. The processing unit is configured to determine a first condition and a second condition. The communication unit is configured to transmit the first condition and the second condition; the first condition is configured to trigger the first device to switch to the first cell; and the second condition is configured to trigger the first device to switch to the second cell.

[0075] In this embodiment, the communication device can send the first condition and the second condition, thereby indicating to the first device the conditions that need to be met when performing the switch; for example, the first device subsequently triggers the switch based on the first condition and / or the second condition, and the second device does not need to send the switching signaling to the first device again, which can reduce signaling overhead.

[0076] Optionally, other possible implementations of the fourth aspect can refer to the corresponding descriptions of other possible implementations of the second aspect, and will not be repeated here.

[0077] In a fifth aspect, the present application provides a communication device comprising a memory and one or more processors. The memory is used to store part or all of the necessary computer programs or instructions for implementing the functions involved in at least one of the first and second aspects above. The one or more processors can execute the computer programs or instructions. When the computer programs or instructions are executed, the communication device implements at least one of the following: the method in the first aspect and any possible implementation of the first aspect, and the method in the second aspect and any possible implementation of the second aspect.

[0078] In one possible design, the communication device may further include an interface circuit, wherein the processor is configured to communicate with other devices or components through the interface circuit.

[0079] In one possible design, the communication device may further include a memory.

[0080] In one possible design, the communication device may be a terminal, or a communication module in a terminal, or a chip in the terminal responsible for communication functions such as a modem chip or a SoC or SIP chip including a modem module.

[0081] In a sixth aspect, the present application provides a communication device comprising: a processor and an interface circuit, the interface circuit being used to receive signals from other communication devices and transmit them to the processor or to send signals from the processor to other communication devices, the processor being used to implement at least one of the following through logic circuits or execution code instructions: the method in the first aspect and any possible implementation of the first aspect, the method in the second aspect and any possible implementation of the second aspect.

[0082] In the seventh aspect, the present application provides a communication system, which includes at least one device or equipment among the third to sixth aspects above, so that the at least one device or equipment above performs at least one of the following: the method in the first aspect and any possible implementation of the first aspect, the method in the second aspect and any possible implementation of the second aspect.

[0083] In an eighth aspect, the present application provides a computer-readable storage medium storing instructions, which, when executed on a computer, causes the computer to execute at least one of the following: the method in the first aspect and any possible implementation of the first aspect, the method in the second aspect and any possible implementation of the second aspect.

[0084] In a ninth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, cause the computer to execute at least one of the following: the method of the first aspect and any possible implementation of the first aspect, the method of the second aspect and any possible implementation of the second aspect.

[0085] In a tenth aspect, the present application provides a chip comprising a processor (or a logic circuit). Optionally, the chip may further comprise a communication interface (or interface) for implementing at least one of the following: the method in the first aspect and any possible implementation of the first aspect, the method in the second aspect and any possible implementation of the second aspect. In one possible implementation, if the chip is the smallest processing unit in the entire machine, the chip may be a processor, or may comprise a processor and a memory, or may comprise a processor, a memory, and a transceiver, for implementing at least one of the following: the method in the first aspect and any possible implementation of the first aspect, the method in the second aspect and any possible implementation of the second aspect.

[0086] In an eleventh aspect, the present application provides a chip system. The chip system includes a processor and an interface. Optionally, the chip system may also include a memory for implementing at least one of the following: the method in the first aspect and any possible implementation of the first aspect, and the method in the second aspect and any possible implementation of the second aspect. The chip system may be composed of a chip or may include a chip and other discrete components. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] FIG1 is a schematic diagram of a network architecture provided by this application;

[0088] FIG2 is a schematic diagram of a satellite communication system;

[0089] FIG3 is a schematic diagram of a group handover;

[0090] FIG4 is a schematic diagram of a process of LTM mobility management;

[0091] FIG5 is a flow chart of a communication method provided by the present application;

[0092] FIG6 is a schematic diagram of a first reference signal and a second reference signal provided by the present application;

[0093] FIG7 is a schematic diagram of another first reference signal and a second reference signal provided by the present application;

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

[0095] FIG9 is a diagram showing the mapping relationship between two types of reference signals and RO resources provided in this application;

[0096] FIG10 is a diagram showing the mapping relationship between two types of reference signals and CORESET resources provided in this application;

[0097] FIG11 is a diagram showing the mapping relationship between two types of reference signals and CG resources provided in this application;

[0098] FIG12 is a flow chart of another communication method provided by the present application;

[0099] FIG13 is a schematic diagram of a communication device provided by the present application;

[0100] FIG14 is a schematic diagram of another communication device provided in this application. DETAILED DESCRIPTION

[0101] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0102] For ease of understanding, the following is a detailed introduction to the definitions of relevant terms involved in this application:

[0103] 1. Network architecture:

[0104] For example, the communication method provided by the present application can be applied to the network architecture shown in Figure 1. The network architecture shown in Figure 1 includes terminals (terminals 201-205 as shown in Figure 1), access network equipment (satellites 101-103 and / or ground base stations as shown in Figure 1, etc.), and core network equipment. It can be understood that Figure 1 is only an example and only shows some equipment (for example, it can also include more terminals and / or access network equipment, and the form of access network equipment may not be limited to satellites, etc.). The present application does not limit the network architecture to which the communication method is applied. Optionally, the satellite uses multiple beams to cover the service area (as shown in the beams in Figure 1), and different beams can communicate through one or more of time division, frequency division and space division. The satellite communicates wirelessly with the terminal equipment through broadcast communication signals and navigation signals, and the satellite can communicate wirelessly with the ground station equipment. The satellite mentioned in the embodiments of the present application may be a satellite base station, and may also include an orbital receiver or repeater for relaying information (such as a network controlled repeater (NCR)), or a network side device carried on a satellite (such as an integrated access and backhaul device (IAB)).

[0105] Among them, the communication method provided in the present application can be applied to NTN systems such as satellite communication systems, high altitude platform station (HAPS) communications, and drones, for example, integrated communication and navigation (IcaN) systems, global navigation satellite systems (GNSS) and ultra-dense low-orbit satellite communication systems. Satellite communication systems can be integrated with traditional mobile communication systems. For example, the mobile communication system can be a fourth-generation (4G) communication system (for example, a long-term evolution (LTE) system), a world-wide interoperability for microwave access (WiMAX) communication system, a fifth-generation (5G) communication system (for example, a new radio (NR) system), and future mobile communication systems (such as NTN or terrestrial networks (TN) converged communication systems). Optionally, the satellite communication system includes a transparent satellite architecture and a non-transparent satellite architecture. Transparent transmission, also known as bent-pipe transmission, involves signals undergoing only frequency conversion and amplification on the satellite, making the satellite transparent to the signal. Non-transparent transmission, also known as regenerative (on-board access / processing) transmission, involves the satellite performing some or all of the base station functions. For example, satellites 101 and 102 in Figure 1 represent non-transparent transmission satellite architectures, while satellite 103 represents a transparent transmission satellite architecture.

[0106] Among them, the access network device is a device with wireless transceiver functions, which is used to communicate with the terminal device. For example, the access network device is a radio access network (RAN) node that connects the terminal device to the wireless network, which can be a ground node, a non-ground node or a TN / NTN fusion node. The access network device in this application may include but is not limited to: evolved node B (eNB), baseband unit (BBU), access point (AP) in wireless fidelity (WIFI) system, wireless relay node, wireless backhaul node, transmission point (TP) or transmission reception point (TRP), etc. The network device can also be a gNB or TRP or TP in a 5G system, or one or a group of (including multiple antenna panels) antenna panels of a base station in a 5G system, or a network controlled repeater (NCR), or an integrated access and backhaul (IAB) node. In addition, the network device may also be a network node constituting a gNB or TP, such as a BBU or a distributed unit (DU). Alternatively, the network device may be a device or satellite that performs network-side functions in a device-to-device (D2D) communication system, a machine-to-machine (M2M) communication system, an Internet of Things (IoT), an Internet of Vehicles (IoV) communication system, or other communication systems.

[0107] The core network equipment is, for example, the equipment in the core network (CN) of the existing mobile communication architecture (such as the access architecture of the 5G network) or the equipment in the core network of the future mobile communication architecture. As a bearer network, the core network provides an interface to the data network, provides communication connection, authentication, management, policy control and data service bearing for user equipment. Among them, CN may further include: access and mobility management function (AMF), session management function (SMF), authentication server function (AUSF), policy control node (PCF), user plane function (UPF) and other network elements. The functions of various network elements can refer to the description in the existing protocol standards, and this application is not limited thereto.

[0108] A terminal is a device with wireless transceiver capabilities that can send signals to a base station or receive signals from a base station. The terminals mentioned in this application include various handheld devices, vehicle-mounted devices, wearable devices, computing devices, or other processing devices connected to a wireless modem with wireless communication capabilities, and specifically refer to user equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device. The terminal device may also be a satellite phone, a cellular phone, a smart phone, a wireless data card, a wireless modem, a machine type communication device, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device or a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a terminal device in a 5G network or a future communication network, etc.

[0109] Base stations and terminals can be fixed or mobile. They can be deployed on land, indoors or outdoors, handheld or vehicle-mounted; on water; or on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of base stations and terminals.

[0110] In this application, the functions of the base station can also be performed by a module in the base station (such as a chip), or by a control subsystem that includes the base station function. The control subsystem that includes the base station function here can be the control center in the above-mentioned application scenarios such as smart grid, industrial control, smart transportation, and smart city. The functions of the terminal can also be performed by a module in the terminal (such as a chip or modem), or by a device that includes the terminal function.

[0111] In this application, a base station sends downlink signals or downlink information to a terminal, and the downlink information is carried on a downlink channel; the terminal sends uplink signals or uplink information to the base station, and the uplink information is carried on an uplink channel. In order to communicate with the base station, the terminal needs to establish a wireless connection in the cell controlled by the base station. The cell with which the terminal has established a wireless connection is called the serving cell of the terminal. When the terminal communicates with the serving cell, it will also be interfered with by signals from neighboring cells.

[0112] 2. Non-terrestrial networks (NTN):

[0113] NTN, which includes nodes such as satellite networks, high-altitude platforms, and drones, boasts significant advantages, including global coverage, long-distance transmission, flexible networking, easy deployment, and unrestricted geographic presence. It has been widely adopted in a variety of fields, including maritime communications, positioning and navigation, disaster relief, scientific experiments, video broadcasting, and Earth observation. The integration of terrestrial 5G networks and satellite networks, leveraging their strengths and complementing their weaknesses, will form a seamless, integrated global communications network covering land, sea, air, space, and ground, meeting the diverse service needs of users.

[0114] As an important component of the NTN, the next-generation satellite network generally shows an ultra-dense and heterogeneous trend: First, the scale of the satellite network has grown from 66 satellites in the Iridium constellation to 720 satellites in the OneWeb constellation, and will eventually extend to the Starlink ultra-dense LEO satellite constellation of more than 12,000; second, the satellite network shows heterogeneous characteristics, developing from traditional single-layer communication networks to multi-layer communication networks. The functions of communication satellite networks are also becoming more complex and diversified, gradually becoming compatible with and supporting functions such as navigation enhancement, earth observation, and multi-dimensional information on-orbit processing.

[0115] Taking satellite communications as an example, satellite communication systems can generally be divided into staring (earth-fixed or quasi-earth-fixed) and non-staring (earth-moving) satellite communication systems based on the operating mode of the payload (e.g., beam). For example, Figure 2 is a schematic diagram of a satellite communication system, where (a) in Figure 2 is a non-staring satellite communication system, and (b) in Figure 2 is a staring satellite communication system. In a non-staring system, the satellite beam coverage moves with the satellite over a period of time (e.g., time T1, T2, and T3). In a staring system, the satellite dynamically adjusts the beam pointing direction over a period of time (e.g., time T1, T2, and T3) so that the beam covers approximately the same area on the ground.

[0116] Optionally, in a satellite communication system, the movement of the satellite may cause group handover (e.g., overall handover of connected UEs) or group reselection (e.g., overall reselection of idle UEs) for users within a certain geographical area (usually referred to as a beam). For example, FIG3 is a schematic diagram of a group handover. Within the beam within Zone-2, there is a UE cluster, such as UE-G1 in FIG3 (UE-G1 contains multiple UEs). During a first time period (Time T1), UE-G1 is served by one or more beams of satellite 102. During a second time period (Time T2), the movement of satellite 102 causes the beam to be unable to be served (e.g., the minimum service elevation angle requirement of the satellite is not met), and one or more beams of satellite 101 take over the service of UE-G1. Therefore, a group handover occurs for UE-G1. In addition, due to the high speed of the satellite (approximately 7.5 kilometers per second (km / s)), the frequency of group handovers is approximately every few seconds to tens of seconds. Therefore, in a beam-hopping satellite network, group handovers triggered primarily by network mobility become the norm.

[0117] 3. LTM mobility management method:

[0118] LTM can also be called bottom-layer handover. For example, Figure 4 is a schematic diagram of a LTM mobility management process, which is implemented by the interaction between the base station and the terminal, including the following steps:

[0119] Step 1: The terminal sends the L3 measurement result based on the SSB signal to the base station; correspondingly, the base station receives the L3 measurement result, decides to perform LTM mobility management, and configures the candidate cell set corresponding to LTM (including one or more cells).

[0120] Step 2: The base station sends RRC reconfiguration information to the terminal, where the RRC reconfiguration information includes configuration information of the candidate cell set; correspondingly, the terminal receives the RRC reconfiguration information.

[0121] Step 3: The terminal records the RRC reconfiguration information and sends an RRC reconfiguration completion message to the base station; correspondingly, the base station receives the RRC reconfiguration completion message.

[0122] Steps 4a and 4b: The terminal completes uplink and downlink synchronization with the candidate cell in advance, where the candidate cell is one or more cells in the candidate cell set. Optionally, if the UE triggers random access (physical downlink control channel (PDCCH)-ordered random access channel (RACH, PDCCH-ordered RACH)) by the serving cell, after the target cell sends a preamble, the UE does not obtain the timing advance (TA) from the random access response (RAR) of the target cell. The TA-related information is transferred from the target cell to the serving cell and indicated by the medium access control element (MAC-CE) of the serving cell.

[0123] Step 5: The terminal performs L1 measurement related to the candidate cell (for example, L1 measurement based on SSB), determines the L1 measurement result, and sends the L1 measurement result to the base station; correspondingly, the base station receives the L1 measurement result.

[0124] Step 6: The base station sends indication information to the terminal (such as through a medium access control-control element (MAC-CE) indication), where the indication information is used to instruct the terminal to switch to a target cell, where the target cell is at least one cell in the candidate cell set; correspondingly, the terminal receives the indication information.

[0125] Step 7: The terminal switches to the target cell and completes the access process to the target cell.

[0126] Step 8: The LTM measurement and handover process is completed between the terminal and the base station.

[0127] The above-mentioned LTM mobility management method can effectively reduce mobile interruption delay when applied to NTN network scenarios. However, LTM mobility measurement based on short-period SSB synchronization signal blocks is difficult to match the long-period (seconds to minutes) and regional progressive dynamic measurement requirements in NTN network scenarios. To address the above problems, the present application provides a communication method that can reduce mobile interruption time, improve the effectiveness of LTM measurement, and help reduce interference between two different reference signals.

[0128] The aforementioned LTM mobility management method can effectively reduce mobility interruption latency when applied to NTN network scenarios. However, the terminal needs to periodically report L1 measurement results, and LTM handover is still performed after being instructed by the serving cell, resulting in high signaling overhead. To address the above issues, the present application provides a communication method that can reduce signaling overhead and simultaneously lower mobility interruption latency.

[0129] For example, Figure 5 is a flow chart of a communication method provided by this application. The method is implemented by interaction between a first device and a second device, for example, the first device is a terminal and the second device is an access network device (such as a base station, satellite, etc.), and the method includes the following steps:

[0130] S101, the second device sends a first condition and a second condition; correspondingly, the first device receives the first condition and the second condition.

[0131] The first condition and the second condition are switching triggering conditions, which are used by the first device to trigger switching based on the first condition and / or the second condition, without the second device sending additional instructions to instruct the first device to switch.

[0132] In one possible implementation, the first condition is that the distance between the first device and the first reference location is greater than a first threshold and / or the distance between the first device and the second reference location is less than a second threshold, and the L1 signal quality of the first reference signal is greater than a first signal quality threshold. The first reference location, the second reference location, the first threshold, the second threshold, and the first signal quality threshold are predefined parameters. The first reference location is any location in a serving cell on the network side, for example, the center point of the serving cell, or another designated location in the serving cell. The first threshold is a distance threshold. For example, assuming the first threshold is 1000 meters, the threshold value for the distance between the terminal and the first reference location is 1000 meters. The second reference location is any location in a candidate cell on the network side, for example, the center point of a candidate cell, or another designated location in a candidate cell. A candidate cell refers to a cell that can provide service to the first device after the first or second device moves, for example, the first device can switch from the serving cell to the candidate cell to continue communication. The second threshold is a distance threshold, and the specific example is similar to the first threshold. The first signal quality threshold is a signal quality threshold value. For example, when the L1 signal quality of the first reference signal is represented by parameters such as reference signal received power (RSRP), reference signal received quality (RSRQ), and signal interference noise ratio (SINR), the corresponding first signal quality threshold can be parameters such as RSRP threshold, RSRQ threshold, and SINR threshold.

[0133] In one possible implementation, the first condition includes the following situations:

[0134] Case 1: The distance between the location of the first device and the first reference location is greater than the first threshold, and the L1 signal quality of the first reference signal is greater than the first signal quality threshold. For example, the first condition is that the distance between the location of the terminal and the serving cell is greater than the first threshold and the L1 signal quality of the first reference signal is greater than the first signal quality threshold, indicating that the location of the terminal is too far from the serving cell and the serving cell cannot provide good service to the terminal; and the L1 signal quality of the first reference signal is greater than the first signal quality threshold, indicating that the first device measures the L1 signal quality of the first reference signal of the candidate cell (such as the first cell) to be greater than the first signal quality threshold, then the first cell can be used as the target cell to which the first device switches from the current serving cell.

[0135] Case 2: The distance between the location of the first device and the second reference location is less than the second threshold, and the L1 signal quality of the first reference signal is greater than the first signal quality threshold. For example, the first condition is that the distance between the location of the terminal and the candidate cell (such as the first cell) is less than the second threshold, and the L1 signal quality of the first reference signal is greater than the first signal quality threshold, indicating that the location of the terminal is close to the first cell and the first cell can provide service to the terminal; and the L1 signal quality of the first reference signal is greater than the first signal quality threshold, indicating that the L1 signal quality of the first reference signal of the first cell measured by the first device is greater than the first signal quality threshold, then the first cell can be used as the target cell to which the first device switches from the current serving cell.

[0136] Case 3: The distance between the position of the first device and the reference position is greater than the first threshold and the distance between the position of the first device and the second reference position is less than the second threshold, and the L1 signal quality of the first reference signal is greater than the first signal quality threshold. For example, Case 3 can be regarded as a combination of Case 1 and Case 2. If the distance between the position of the terminal and the serving cell is greater than the first threshold and the distance between the position of the terminal and the candidate cell (such as the first cell) is less than the second threshold, it means that the serving cell cannot provide good service to the terminal after the terminal moves and the terminal moves closer to the first cell, and the first cell can provide service to the terminal; and the L1 signal quality of the first reference signal is greater than the first signal quality threshold, then the first cell can be used as the target cell to which the first device switches from the current serving cell.

[0137] In one possible implementation, the second condition is that the local clock of the first device is in a first time period and the L1 signal quality of the second reference signal is greater than a second signal quality threshold; the first time period and the second signal quality threshold are predefined parameters. For example, the first time period is a specified time period and can be expressed as [UTC t1 ,UTC t1 +t offset ], where UTC corresponds to Coordinated Universal Time, UTC t1 Indicates the start time of the specified time period (i.e. the first time period) in the Universal Time Coordinated Time, UTC t1 +t offset Indicates the end time of the first time period. The local clock of the first device can be expressed as UTC t0 , if UTC t0 ∈[UTC t1 ,UTC t1 +t offset], it means that the local clock of the first device is located in a predefined first time period. The definition of the second signal quality threshold is similar to that of the first signal quality threshold. For example, when the L1 signal quality of the second reference signal is represented by parameters such as RSRP, RSRQ, and SINR, the corresponding second signal quality threshold can be parameters such as RSRP threshold, RSRQ threshold, and SINR threshold. For example, the second condition is that the local clock of the terminal is located in the first time period, and the first device measures that the L1 signal quality of the second reference signal of the candidate cell (such as the second cell) is greater than the second signal quality threshold, then the second cell can be used as the target cell to which the first device switches from the current serving cell.

[0138] In one possible implementation, the first reference signal and the second reference signal are two different types of reference signals. Implementations of the first reference signal and the second reference signal may include, but are not limited to, the following situations:

[0139] Case 1: The first reference signal is an SSB synchronization signal, and the second reference signal is a handover-specific SSB signal (called HO (handover) SSB). That is, the first reference signal and the second reference signal are reference signals of different types.

[0140] The first reference signal is a periodic signal, and the period of the first reference signal is a first period. For example, a typical period of the first period is a millisecond period such as 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms.

[0141] The second reference signal can be a non-periodic signal or a periodic signal. When the second reference signal is a periodic signal, the period of the second reference signal is the second period. For example, a typical period of the second period is a period of seconds such as 1 second, 2 seconds, 4 seconds, 8 seconds, 16 seconds, 32 seconds, 64 seconds, 128 seconds, 256 seconds, 512 seconds, or 1024 seconds. The second period is greater than the first period.

[0142] Optionally, in case one, at least one of the time domain position, frequency domain position, or polarization mode of the first reference signal and the second reference signal is different. For example, the time domain position (such as the occupied frame, subframe, time slot, symbol, etc.) of the first reference signal and the second reference signal is different, such as the first reference signal and the second reference signal can be time-division multiplexed. For another example, the frequency domain position of the first reference signal and the second reference signal is different, such as the first reference signal and the second reference signal can be frequency-division multiplexed, and the second reference signal does not have to be at a pre-defined synchronization raster frequency point position. For another example, the first reference signal and the second reference signal use different polarization modes (such as linear polarization, left-hand circular polarization, right-hand circular polarization, elliptical polarization, etc.). The above three examples can be arbitrarily combined in pairs or all three can be satisfied at the same time, indicating that at least one of the time domain position, frequency domain position, or polarization mode of the first reference signal and the second reference signal is different.

[0143] Optionally, the first reference signal corresponds to a predefined time domain position, and the time domain position of the second reference signal is variable. For example, the first reference signal corresponds to a predefined time domain position, indicating that the first reference signal has a predefined resource pattern. For another example, the second reference signal has a variable time domain position, indicating that the resource pattern of the second reference signal is variable, supporting dynamic scheduling. For example, Table 1 shows several possible examples of predefined resource patterns for the first reference signal, assuming that Table 1 describes the first reference signal as an SSB.

[0144] Table 1: Several possible examples of predefined resource patterns of the first reference signal.

[0145] Among them, Case A indicates that the subcarrier spacing of SSB is 15KHz, and the time domain position of the first symbol of SSB satisfies {2,8}+14×n, where n is the time slot, and the maximum number of SSBs is limited. The meanings of other Cases are similar and will not be repeated here. Based on Table 1, the first device can determine the resource pattern of the first reference signal. The resource pattern of the second reference signal is variable, indicating that the resource pattern of the second reference signal may not be limited to the Case in Table 1, but may be more flexible (for example, the first symbol position may be variable, etc.), which is not limited in this application.

[0146] For example, Figure 6 is a schematic diagram of a first reference signal and a second reference signal provided by this application. The first reference signal is shown as a solid-line box in Figure 6, and the second reference signal is shown as a dashed-line box in Figure 6. Assume that the second reference signal in Figure 6 is a periodic signal. It can be seen that the second period is greater than the first period, and the resource pattern of the first reference signal (four solid-line boxes) and the resource pattern of the second reference signal (two dashed-line boxes) are different.

[0147] Optionally, the first reference signal and the second reference signal satisfy a quasi-co-location relationship. For example, the first reference signal and the second reference signal satisfy a quasi-co-location relationship, which means that the properties of the second reference signal can be inferred from the first reference signal.

[0148] Case 2: The first reference signal and the second reference signal are SSB synchronization signals. However, the first reference signal is mapped to a first type of time domain position (called Type-1 Occasion), and the second reference signal is mapped to a second type of time domain position (called Type-2 Occasion). In other words, the first reference signal and the second reference signal are the same type of reference signal, but are mapped to different types of time domain positions.

[0149] The time domain position of the first type satisfies the first period. For example, the Occasion mapped by the first reference signal is periodic, and a typical period of the first period is a millisecond-level period such as 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms.

[0150] The second type of time domain position is non-periodic or satisfies the second period. For example, when the second type of time domain position satisfies the second period, the Occasion mapped by the second reference signal is periodic, and a typical period of the second period is a period of seconds such as 1s, 2s, 4s, 8s, 16s, 32s, 64s, 128s, 256s, 512s, and 1024s, and the second period is greater than the first period.

[0151] Optionally, in scenario 2, at least one of the time domain position and the frequency domain position of the first reference signal and the second reference signal differs. For example, the time domain positions of the first reference signal and the second reference signal differ, such as when the first reference signal and the second reference signal can be time-division multiplexed. Another example is that the frequency domain positions of the first reference signal and the second reference signal differ, such as when the first reference signal and the second reference signal can be frequency-division multiplexed. Either or both of the above two examples may be met, indicating that at least one of the time domain position and the frequency domain position of the first reference signal and the second reference signal differs.

[0152] Optionally, the first reference signal corresponds to a predefined time domain position, and the time domain position of the second reference signal is variable. For a specific example, reference may be made to Table 1 described in Case 1. For example, based on Table 1, the first device may determine a resource pattern for the first reference signal. The resource pattern of the second reference signal is variable, indicating that the resource pattern of the second reference signal may not be limited to the case in Table 1, but may be more flexible (for example, the first symbol position may be variable, etc.), which is not limited in this application.

[0153] For example, Figure 7 is a schematic diagram of another first reference signal and a second reference signal provided by the present application. In Figure 7, taking the first reference signal and the second reference signal as an example, the SSB shown in the dotted box is mapped to the second type of time domain position, and the SSB shown in the solid box is mapped to the first type of time domain position.

[0154] Optionally, the first reference signal and the second reference signal satisfy a quasi co-location relationship. For example, in case 2, the first reference signal and the second reference signal may be mapped to the same beam in different time slots, thereby satisfying a quasi co-location relationship.

[0155] Optionally, the first type of time domain position and the second type of time domain position multiplex the same SSB index. For example, assuming that the first reference signal and the second reference signal are the same SSB, and the same SSB is mapped to different types of Occasions, the first type of time domain position and the second type of time domain position multiplex the same SSB index (the same SSB index indicates the same SSB). Optionally, the TCI state of the terminal remains unchanged during subsequent switching; for example, different types of Occasions multiplex the same SSB index, and the TCI state of the terminal remains unchanged during LTM switching.

[0156] Case 3: The first reference signal is an SSB synchronization signal, the second reference signal is another type of reference signal (such as TRS, CSI-RS, etc.), and the second reference signal and the SSB synchronization signal have a quasi-co-location relationship.

[0157] The first reference signal is a periodic signal, and the period of the first reference signal is a first period. For example, a typical period of the first period is a millisecond period such as 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms.

[0158] The second reference signal can be a non-periodic signal or a periodic signal. When the second reference signal is a periodic signal, the period of the second reference signal is the second period. For example, a typical period of the second period is a period of seconds such as 1 second, 2 seconds, 4 seconds, 8 seconds, 16 seconds, 32 seconds, 64 seconds, 128 seconds, 256 seconds, 512 seconds, or 1024 seconds. The second period is greater than the first period.

[0159] Optionally, in case three, at least one of the time domain position, frequency domain position, or polarization mode of the first reference signal and the second reference signal is different. For example, the time domain positions of the first reference signal and the second reference signal are different, such as the first reference signal and the second reference signal can be time-division multiplexed. For another example, the frequency domain positions of the first reference signal and the second reference signal are different, such as the first reference signal and the second reference signal can be frequency-division multiplexed. For another example, the first reference signal and the second reference signal use different polarization modes (such as linear polarization, left-hand circular polarization, right-hand circular polarization, elliptical polarization, etc.). The above three examples can be arbitrarily combined in pairs or all three can be satisfied at the same time, indicating that at least one of the time domain position, frequency domain position, or polarization mode of the first reference signal and the second reference signal is different.

[0160] Optionally, the first reference signal corresponds to a predefined time domain position, and the time domain position of the second reference signal is variable. For specific examples, please refer to Table 1 and Figure 6 described in Case 1. For example, based on Table 1, the first device can determine the resource pattern of the first reference signal. The resource pattern of the second reference signal is variable, indicating that the resource pattern of the second reference signal may not be limited to the case in Table 1, but may be more flexible (for example, the first symbol position may be variable, etc.), which is not limited in this application.

[0161] Optionally, S101 also includes the following process:

[0162] The second device transmits the first reference signal and the second reference signal; correspondingly, the first device receives the first reference signal and the second reference signal. For example, the second device may first transmit the first reference signal and the second reference signal, and then transmit the first condition and the second condition. In other words, the reference signal and the handover trigger condition may be transmitted via different messages. For another example, the second device may transmit the first reference signal and the second reference signal, as well as the first condition and the second condition. In other words, the reference signal and the handover trigger condition may be transmitted via the same message.

[0163] S102a: When the first condition is met, the first device switches to the first cell.

[0164] In one possible implementation, when the first condition is met, that is, when the distance between the position of the first device and the first reference position is greater than the first threshold and / or the distance between the position of the first device and the second reference position is less than the second threshold, and the L1 signal quality of the first reference signal of the first cell measured by the first device is greater than the first signal quality threshold, the first device performs LTM switching. For example, when the first condition is met, it is usually a cell switch (Handover or Cell Switch) triggered by the terminal's own movement, and there is a short switching cycle. The first device performs L1 measurement of the first reference signal and / or reports the L1 measurement results, and performs LTM switching based on the L1 measurement. Optionally, the first device continuously monitors the first cell and determines whether the first condition is met; when the first condition is met, it directly switches to the first cell.

[0165] Optionally, the first device performs L1 measurement of the first reference signal. Please refer to the corresponding description in Figure 4. For example, the terminal performs L1 measurement related to the candidate cell (for example, L1 measurement based on SSB) to determine the L1 measurement result of the first reference signal.

[0166] Optionally, the first device sends the first measurement result of the first reference signal to the second device. For example, the first device may refer to the existing SSB measurement result reporting process to send the first measurement result of the first reference signal (ie, L1 measurement result) to the second device.

[0167] S102b: When the second condition is met, the first device switches to the second cell.

[0168] In one possible implementation, when the second condition is met, that is, when the local clock of the first device is in the first time period, and the first device measures that the L1 signal quality of the second reference signal of the second cell is greater than the second signal quality threshold, the first device performs LTM switching. For example, when the second condition is met, it is usually a cell switch (Handover or Cell Switch) triggered by network-side mobility (such as satellite mobility), which has long-cycle and predictable characteristics, then the first device performs L1 measurement of the second reference signal and / or reports the L1 measurement result, and performs LTM switching based on the L1 measurement. Optionally, the first device continuously monitors the second cell and determines whether the second condition is met; when the second condition is met, it directly switches to the second cell. Optionally, the first device performs L1 measurement of the second reference signal, which is similar to the first device performing L1 measurement of the first reference signal, for example, performing L1 measurement based on HO-SSB to determine the L1 measurement result of the second reference signal.

[0169] Optionally, S102a and S102b can be regarded as two possible parallel implementation methods. It is only necessary to judge the trigger condition to determine which specific step to execute. For example, if S102a is executed, S102b may not be executed, and if S102b is executed, S102a may not be executed.

[0170] In one possible implementation, the first reference signal and the second reference signal are associated with a TCI state, thereby enabling fast communication during LTM switching. Specifically, the first reference signal and the TCI state may be associated with an identifier of the first reference signal (e.g., an SSB index) and the TCI state. Optionally, the first reference signal and the TCI state may be associated in a one-to-one relationship, e.g., one first reference signal and one TCI state, or in a one-to-many relationship, e.g., one TCI state and multiple first reference signals.

[0171] The specific manners of associating the second reference signal with the TCI state include the following two:

[0172] Method 1: The second reference signal is associated with the TCI state. Specifically, the identifier of the second reference signal (such as the HO-SSB index) can be associated with the TCI state. For example, Table 2 shows a relationship table of the second reference signal associated with the TCI state. Table 2 uses the HO-SSB index and TCI state as an example.

[0173] Table 2: A relationship table of the second reference signal and the TCI state.

[0174] The second reference signal is associated with the TCI state, which can be a one-to-one association relationship, for example, one second reference signal is associated with one TCI state (such as HO-SSB index A1 is associated with TCI state C1 as shown in Table 2); or a one-to-many association relationship, for example, one TCI state is associated with multiple second reference signals (such as HO-SSB index A2 and HO-SSB index A3 are both associated with TCI state C2 as shown in Table 2).

[0175] Optionally, in method 1, after the new TCI state takes effect, the second reference signal is not configured as the reference signal associated with the TCI state, and the TCI state information can be carried by the LTM-Candidate-TCI-State-r18 information element or a newly defined information element.

[0176] Method 2: The second reference signal is associated with the first reference signal, and the first reference signal is associated with the TCI state, thereby associating the second reference signal with the TCI state. Method 2 can specifically associate the identifier of the second reference signal (e.g., HO-SSB index) with the identifier of the first reference signal (e.g., SSB index), and the SSB index with the TCI state. For example, Table 3 shows another relationship table for associating the second reference signal with the TCI state. Table 3 uses the HO-SSB index, SSB index, and TCI state as examples.

[0177] Table 3: Another relationship table of the second reference signal and the TCI state.

[0178] The second reference signal is associated with the first reference signal, which can be a one-to-one association, for example, one second reference signal is associated with one second reference signal (such as HO-SSB index A1 is associated with SSB index B1 as shown in Table 3); or a one-to-many association, for example, one first reference signal is associated with multiple second reference signals (such as HO-SSB index A2 and HO-SSB index A3 are both associated with SSB index B2 as shown in Table 3). For example, assuming that the strongest reference signal received by the terminal is HO-SSB index A4, the terminal can obtain the strongest reference signal-associated first reference signal SSB index B3 based on Table 3, and use the TCI state C3 corresponding to the reference signal as its own TCI state for LTM communication.

[0179] In one possible implementation, the first device needs to have valid TA information when performing LTM switching. For example, if the terminal side does not have valid TA information, the terminal side needs to obtain TA through the RACH process. The specific methods for obtaining TA may include the following:

[0180] Implementation method 1: Initiate handover access based on different random access resources.

[0181] For example, when the first condition is met, the first device performs handover access based on the first random access resource associated with the first reference signal to obtain first timing advance information. For another example, when the second condition is met, the first device performs handover access based on the second random access resource associated with the second reference signal to obtain second timing advance information. It is understandable that there is an association between the reference signal and the random access resource. When the terminal side initiates the RACH process, it can specifically initiate handover access based on the random access resource associated with the reference signal, thereby accessing the network and obtaining the TA.

[0182] Implementation method 2: The candidate cell performs PDCCH-ordered RACH; the terminal side performs detection based on different control resources and switches access based on the demodulated PDCCH-ordered RACH resources.

[0183] For example, when a first condition is met, the first device detects a first control resource associated with a first reference signal and determines a first physical downlink control channel associated with the first control resource; the first device demodulates the first physical downlink control channel and performs handover access based on the demodulated resources of the first physical downlink control channel to obtain first timing advance information. For another example, when a second condition is met, the first device detects a second control resource associated with a second reference signal and determines a second physical downlink control channel associated with the second control resource; the first device demodulates the second physical downlink control channel and performs handover access based on the demodulated resources of the second physical downlink control channel to obtain second timing advance information. It is understood that reference signals and control resources are associated with each other. During the handover execution phase, for different types of handovers (e.g., when the first or second conditions are met), the second device configures different control resources. The first cell or the second cell performs a PDCCH-ordered RACH. The first device demodulates the received PDCCH and performs handover access based on the demodulated PDCCH-ordered RACH resources, thereby accessing the network and obtaining a TA.

[0184] Optionally, when the first device has timing advance information, the first device communicates through the preconfigured uplink transmission resources. For example, when there is valid TA information on the terminal side, the terminal side can adopt RACH-less switching (which can be called RACH-free switching) and communicate on the preconfigured uplink transmission resources. For example, when the first condition is met, the first device communicates through the first preconfigured uplink transmission resource associated with the first reference signal; when the second condition is met, the first device communicates through the second preconfigured uplink transmission resource associated with the second reference signal. It can be understood that there is an association between the reference signal and the preconfigured uplink transmission resource. During the switching execution phase, for different types of switching (such as meeting the first condition or the second condition), the second device configures different uplink transmission resources; the first device can adopt RACH-less switching to perform LTM communication on the preconfigured uplink transmission resource.

[0185] In this embodiment, the second device can send the first condition and the second condition to the first device, thereby indicating to the first device the conditions that need to be met when performing the switch; for example, the first device receives the first condition and the second condition, and can trigger the switch based on the first condition and / or the second condition, which can effectively reduce the mobile interruption delay; and there is no need for the second device to send switching signaling to the first device, which can reduce signaling overhead.

[0186] The following describes the specific implementation of the communication method provided in this application in different communication processes.

[0187] For example, Figure 8 is a flow chart of another communication method provided by the present application, which is implemented by interaction between a first device and a second device, for example, the first device is a terminal and the second device is an access network device. The method flow includes some steps in the LTM process (such as some steps in Figure 4), and combines the content of the embodiment of Figure 5. Assuming that the first device is in a connected state, the method includes the following steps:

[0188] S201: A first device sends an L3 measurement result and / or a location measurement report based on an SSB signal; correspondingly, a second device receives the L3 measurement result and / or the location measurement report, decides to perform LTM mobility management, and configures a candidate cell set corresponding to LTM (e.g., including a first cell and a second cell). Optionally, the specific content of the L3 measurement result and / or the location measurement report may refer to the corresponding description in the standard protocol and is not limited in this application.

[0189] S202, the second device sends LTM configuration information and LTM execution conditions; correspondingly, the first device receives the LTM configuration information.

[0190] In one possible implementation, the LTM configuration information includes at least one of the following: an identifier of the first cell, an identifier of the second cell, an identifier of the LTM configuration information, a reference signal resource configuration, a reference signal measurement configuration, a random access resource configuration, a control resource configuration, a pre-configured uplink transmission resource configuration, and a transmission configuration indication status.

[0191] The first cell identifier is used to indicate the first cell, and may be, for example, the ID of the first cell or other identifiers used to indicate the first cell. The second cell identifier is used to indicate the second cell, and may be, for example, the ID of the second cell or other identifiers used to indicate the second cell. The first cell identifier and the second cell identifier are different, so that different cells can be distinguished.

[0192] Among them, the identifier of the LTM configuration information is used to indicate the LTM configuration information, for example, it can be the ID of the LTM configuration information, which is used to distinguish the LTM configuration information for different LTM communications; for example, for different first reference signals and second reference signals, the second device may configure the first LTM configuration information and the second LTM configuration information, wherein the first LTM configuration information corresponds to the identifier of the first LTM configuration information, and the second LTM configuration information corresponds to the identifier of the second LTM configuration information.

[0193] The reference signal resource configuration includes related configurations of reference signal resources, such as resource configurations of a first reference signal (such as an SSB) and resource configurations of a second reference signal (such as HO-SSB). For example, the resource configuration of the first reference signal includes one or more first resource identifiers (RIs) and resources associated with each first RI (such as time domain resources and frequency domain resources of an SSB), and the resource configuration of the second reference signal includes one or more second RIs and resources associated with each second RI (such as time domain resources and frequency domain resources of an HO-SSB).

[0194] Among them, the reference signal measurement configuration includes relevant configurations of reference signal measurement, such as a first measurement configuration of a first reference signal and a second measurement configuration of a second reference signal. In a possible implementation, the first measurement configuration includes at least one of the measurement period of the first reference signal, the first measurement bias or the first measurement duration. The measurement period of the first reference signal is an SSB-based measurement timing configuration (SMTC) period, which indicates the repetition period of the measurement action. The first measurement bias is the starting subframe of the measurement action within the measurement period of the first reference signal. The first measurement duration is the SMTC duration, which indicates the duration that the measurement action should last after the measurement action starts. For example, if the first reference signal is SSB, the measurement period of the first reference signal can reuse the existing SMTC1 and SMTC4list configurations corresponding to the SSB, where SMTC1 contains two sub-symbols periodicityAndOffset and duration. Among them, the symbol periodicityAndOffset represents the SMTC period and SMTC bias, and duration represents the SMTC duration. Optionally, the measurement period of the first reference signal and the period of the first reference signal are usually different. The period of the first reference signal usually refers to the period for the second device to send the first reference signal, and the measurement period of the first reference signal usually refers to the repetition period of the measurement action. For example, the SMTC period can be 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms. The value of the SMTC offset is between 0 and the SMTC period minus 1ms with a granularity of 1ms. The granularity of the SMTC duration is also 1ms, and the length can be 1ms, 2ms, 3ms, 4ms, or 5ms. For example, when the SMTC period is 5ms, the value of the SMTC offset can be 0ms, 1ms, 2ms, 3ms, or 4ms, and the value of the SMTC duration can be 1ms, 2ms, 3ms, 4ms, or 5ms. SMTC4list can be configured with different offsets for SMTC1 to compensate for different satellite-to-terminal (propagation) delays in satellite scenarios. In another possible implementation, the second measurement configuration includes at least one of a measurement period of a second reference signal, a second measurement offset, or a second measurement duration. The measurement period of the second reference signal may be a measurement timing configuration period based on the HO-SSB, or a measurement timing configuration period based on other reference signals, collectively referred to as the SSB-MTC2 period, indicating a repetition period of the measurement action. The second measurement offset is the starting subframe of the measurement action within the measurement period of the second reference signal. The second measurement duration is the SMTC duration, which indicates how long the measurement action should last after the measurement action starts.For example, for the second reference signal, the second device will add an SSB-MTC2 configuration and at least one SMTC4list_new configuration; the SSB-MTC2 period is greater than SMTC1, for example, the typical value of SSB-MTC2 can be 1s, 5s, 10s, 20s, etc.; the duration value refers to SMTC1. Optionally, when the first reference signal and the second reference signal are time-division multiplexed, the selection of the second measurement bias in SMTC4list_new needs to avoid the first measurement bias in SMTC1. For example, when the SSB-MTC2 period is 1s and the value of the first measurement bias is 1ms, the value of the second measurement bias can be 1s or other values ​​that are different from the value of the first measurement bias, thereby avoiding interference and conflict problems between the two types of reference signals. Optionally, when the first reference signal and the second reference signal use different polarization modes, the values ​​of the first measurement bias and the second measurement bias can be the same or different, which is not limited here. Optionally, the measurement period of the second reference signal is greater than the measurement period of the first reference signal. For example, the measurement period of the second reference signal may be a period in seconds, such as 1s, 5s, 10s, or 20s, while the measurement period of the first reference signal may be a period in milliseconds, such as 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms. Optionally, the measurement period of the second reference signal and the period of the first reference signal are generally different. The period of the second reference signal generally refers to the period at which the second device sends the second reference signal, while the measurement period of the second reference signal generally refers to the repetition period of the measurement action.

[0195] The random access resource configuration includes the configuration related to the random access resource, such as a first access channel occasion (RO) and the resources of the first RO, and a second RO and the resources of the second RO. Optionally, the first reference signal is associated with the first random access resource, and the second reference signal is associated with the second random access resource. Therefore, the first random access resource and the second random access resource are different and have different time-frequency domain characteristics. For example, Figure 9 is a mapping relationship diagram of two types of reference signals and RO resources provided by this application. The dashed box without slash shading represents the second reference signal, and the dashed box with slash shading represents the second RO associated with the second reference signal; the solid box without slash shading represents the first reference signal, and the solid box with slash shading represents the first RO associated with the first reference signal. It can be seen that the time domain characteristics of the first RO associated with the first reference signal are similar to those of the first reference signal, for example, a periodic resource; the time domain characteristics of the second RO associated with the second reference signal are similar to those of the second reference signal, for example, a periodic or non-periodic resource, and when the second RO is a periodic resource, the period of the second RO is greater than the period of the first RO. Optionally, the frequency domain characteristics of the first RO associated with the first reference signal are similar to the first reference signal, and the frequency domain characteristics of the second RO associated with the second reference signal are similar to the second reference signal, which are not repeated here.

[0196] Among them, the control resource configuration includes the configuration of the control resource set (CORESET), and the CORESET is used to detect the PDCCH on the terminal side to obtain scheduling information. For example, the control resource configuration includes a first control resource (such as a first CORESET resource) and a second control resource (such as a second CORESET resource), the first control resource is associated with a first reference signal, and the second control resource is associated with a second reference signal. For example, Figure 10 is a mapping relationship diagram of two types of reference signals and CORESET resources provided in this application. Among them, the dotted box without checkered shading represents the second reference signal, and the dotted box with checkered shading represents the second CORESET resource associated with the second reference signal; the solid box without checkered shading represents the first reference signal, and the solid box with checkered shading represents the first CORESET resource associated with the first reference signal. It can be seen that the time domain characteristics of the first CORESET resource associated with the first reference signal are similar to those of the first reference signal, for example, a periodic resource; the time domain characteristics of the second CORESET resource associated with the second reference signal are similar to those of the second reference signal, for example, a periodic or aperiodic resource, and when the second CORESET resource is a periodic resource, the period of the second CORESET resource is greater than the period of the first CORESET resource. Optionally, the frequency domain characteristics of the first CORESET resource associated with the first reference signal are similar to those of the first reference signal, and the frequency domain characteristics of the second CORESET resource associated with the second reference signal are similar to those of the second reference signal, which will not be repeated here.

[0197] Among them, the pre-configured uplink transmission resource configuration includes the configuration of pre-configured grant (CG) resources, and the CG resources are used for uplink transmission on the terminal side. For example, the pre-configured uplink transmission resource configuration includes a first pre-configured uplink transmission resource and a second pre-configured uplink transmission resource, the first pre-configured uplink transmission resource is associated with a first reference signal, and the second pre-configured uplink transmission resource is associated with a second reference signal. For example, Figure 11 is a mapping relationship diagram of two types of reference signals and CG resources provided in this application. Among them, the dotted box without vertical line shading represents the second reference signal, and the dotted box with vertical line shading represents the second CG resource associated with the second reference signal; the solid box without vertical line shading represents the first reference signal, and the solid box with vertical line shading represents the first CG resource associated with the first reference signal. It can be seen that the time domain characteristics of the first CG resource associated with the first reference signal are similar to those of the first reference signal, for example, a periodic resource; the time domain characteristics of the second CG resource associated with the second reference signal are similar to those of the second reference signal, for example, a periodic or non-periodic resource, and when the second CG resource is a periodic resource, the period of the second CG resource is greater than the period of the first CG resource. Optionally, the frequency domain characteristics of the first CG resource associated with the first reference signal are similar to those of the first reference signal, and the frequency domain characteristics of the second CG resource associated with the second reference signal are similar to those of the second reference signal, which will not be repeated here.

[0198] Among them, the description of the transmission configuration indication state can refer to the TCI state and specific implementation method described above, which will not be repeated here.

[0199] In a possible implementation, the execution condition of the LTM includes a first condition and a second condition. The definitions of the first condition and the second condition and the description of the specific implementation can refer to the corresponding description in S101 and will not be repeated here.

[0200] In one possible implementation, the second device sends the LTM configuration information and the execution conditions of the LTM, which may be carried in one message, for example, the second device sends an RRC reconfiguration message, and the RRC reconfiguration message includes the LTM configuration information and the first condition and the second condition; or it may be carried in different messages, for example, the second device sends a first RRC message and a second RRC message, the first RRC message includes the LTM configuration information, and the second RRC message includes the first condition and the second condition. Optionally, the RRC reconfiguration message may indicate the LTM configuration information and the first condition and the second condition, for example, the RRC reconfiguration message does not directly carry the LTM configuration information and the first condition and the second condition, but carries the first indication information of the LTM configuration information and the second indication information of the first condition and the second condition; correspondingly, the first device receives the first indication information and the second indication information, and determines the LTM configuration information and the first condition and the second condition based on the relationship between the pre-configured indication information and the LTM configuration information and the LTM execution conditions. Optionally, the first RRC message and the second RRC message may also indicate the LTM configuration information and the first condition and the second condition. For example, the first RRC message and the second RRC message do not directly carry the LTM configuration information and the first condition and the second condition, but carry the first indication information of the LTM configuration information and the second indication information of the first condition and the second condition. The operation of the corresponding first device is also similar and will not be repeated here.

[0201] In a possible implementation, the second device may further send a first reference signal and a second reference signal. The definitions and specific implementations of the first reference signal and the second reference signal may be described in detail in S101 and will not be repeated here.

[0202] S203, the first device records the LTM configuration information and the execution conditions of the LTM, and sends a response message; correspondingly, the second device receives the response message.

[0203] S204a: The first device completes downlink synchronization with the candidate cell.

[0204] S204b: The first device completes uplink synchronization with the candidate cell.

[0205] In a possible implementation, the first device may perform uplink synchronization in the same manner as the UE completes uplink synchronization with the candidate cell in the existing LTM process. For the specific process, reference may be made to the corresponding description in the standard protocol and will not be repeated here.

[0206] In one possible implementation, when the candidate cell is a satellite cell, the first device can dynamically configure the TA acquisition method based on the path transmission delay of the satellite cell, thereby completing uplink synchronization with the candidate cell based on different TA acquisition methods. For example, the first device can complete uplink synchronization with the candidate cell through interaction between the first device and the second device:

[0207] (1) The first device sends an L1 measurement report to the second device. For example, the L1 measurement report includes an identifier of the candidate cell and / or a type of the candidate cell. For example, if the candidate cells include a first cell and a second cell, the identifier of the candidate cell includes an identifier of the first cell and an identifier of the second cell. The type of the candidate cell may refer to the type of track where the candidate cell is located. For example, the type of the candidate cell may be an ascending cell or a descending cell. For example, an ascending cell indicates that the cell moves from south to north, and a descending cell indicates that the cell moves from north to south.

[0208] (2) The second device determines a first delay based on the identifier of the candidate cell and / or the type of the candidate cell in the L1 measurement report. The first delay represents a path transmission delay from the serving cell to the candidate cell, for example, the first delay is a path transmission delay from the serving cell to the first cell and / or a path transmission delay from the serving cell to the second cell.

[0209] (3) The second device determines a timing advance acquisition method based on the first delay. This application assumes that there are at least two TA acquisition methods, including a first acquisition method and a second acquisition method. For example, when the first delay is less than the delay threshold, the second device configures the first acquisition method to obtain TA from the service cell of the first device; when the first delay is greater than or equal to the delay threshold, the second device configures the second acquisition method to obtain TA from the candidate cell RAR. Optionally, if the second device determines to adopt the second acquisition method, the second device also needs to configure a first gap (GAP), and the service cell within the GAP does not schedule UEs.

[0210] (4) The second device sends first indication information to the first device, where the first indication information is used to indicate a timing advance acquisition method. For example, the first indication information is used to indicate the first acquisition method and / or the second acquisition method.

[0211] (5) The first device completes uplink synchronization with the candidate cell based on the timing advance acquisition method.

[0212] Optionally, the execution order of S204a and S204b is not limited in this application. For example, S204a can be executed first and then S204b, or S204b can be executed first and then S204a, or S204a and S204b can be executed at the same time. This application does not limit this.

[0213] S205: The first apparatus performs L1 measurement related to the candidate cell (e.g., L1 measurement based on the SSB), determines an L1 measurement result, and sends the L1 measurement result to the second apparatus; in response, the second apparatus receives the L1 measurement result. The L1 measurement result includes the L1 signal quality of the first reference signal and the L1 signal quality of the second reference signal.

[0214] S206a: When the first condition is met, the first device switches to the first cell.

[0215] S206b: When the second condition is met, the first device switches to the second cell.

[0216] For example, the first device continuously monitors the candidate cell and determines whether the first condition or the second condition is met; when the first condition is met, the device switches to the first cell that meets the first condition; when the second condition is met, the device switches to the second cell that meets the second condition. The specific implementation of S206a and S206b can refer to the corresponding description of S102a and S102b and will not be repeated here.

[0217] S207a: When the first device has no timing advance information, the first device obtains the timing advance information through an access process.

[0218] For example, if there is no valid TA information on the terminal side, the terminal side needs to obtain TA through the RACH process. The specific method of obtaining TA can refer to the embodiment of Figure 5 and the corresponding description of random access resources and control resources in S202. For example, one implementation method of obtaining TA is to initiate switching access based on different RO resources. For example, when the first condition is met, the first device switches access based on the first RO associated with the first reference signal to obtain TA information; or, when the second condition is met, the first device switches access based on the second RO associated with the second reference signal to obtain TA information. The second implementation method is that the candidate cell performs PDCCH-ordered RACH; the terminal side performs detection based on different CORESET resources, and switches access based on the demodulated PDCCH-ordered RACH resources. For example, when the first condition is met, the first device detects the first CORESET resource associated with the first reference signal to obtain the first PDCCH, demodulates the first PDCCH, and switches access based on the demodulated first PDCCH resource to obtain TA information; or, when the second condition is met, the first device detects the second CORESET resource associated with the second reference signal to obtain the second PDCCH, demodulates the second PDCCH, and switches access based on the demodulated second PDCCH resource to obtain TA information.

[0219] S207b: When the first device has timing advance information, the first device communicates through pre-configured uplink transmission resources.

[0220] For example, when valid TA information exists on the terminal side, the terminal side can adopt RACH-less switching and communicate on the pre-configured CG resources. For specific examples, please refer to the embodiment of Figure 5 and the description of the pre-configured uplink transmission resources in S202. For example, when the first condition is met, the first device communicates through the first CG resource associated with the first reference signal; when the second condition is met, the first device communicates through the second CG resource associated with the second reference signal.

[0221] Optionally, S207a and S207b can be regarded as two possible parallel implementation methods. It is only necessary to determine whether there is valid TA information in the first device to determine which specific step to execute. For example, if S207a is executed, S207b may not be executed, and if S207b is executed, S207a may not be executed.

[0222] S208: The LTM switching process is completed between the first device and the second device.

[0223] For example, the first device switches from the current serving cell to the first cell and successfully accesses the first cell, thereby completing the LTM switching process from the current serving cell to the first cell.

[0224] This embodiment, based on the existing LTM process and incorporating LTM execution conditions (e.g., the first condition or the second condition), allows the first device to autonomously trigger LTM handover based on the first and / or second conditions during the LTM process, effectively reducing mobility interruption latency. Furthermore, the second device no longer needs to send handover signaling to the first device, reducing signaling overhead. Optionally, the LTM process also includes additional methods for acquiring TA information and a new method for dynamically configuring TA acquisition based on the satellite cell's path transmission delay, facilitating the implementation and completion of the LTM process.

[0225] For example, Figure 12 is a flow chart of another communication method provided by the present application, which is implemented by interaction between a terminal, a first base station (such as the source base station accessed by the terminal), a second base station (such as the target base station for terminal switching), and a core network device (such as AMF, UPF, etc.). The method flow includes some steps in the conditional handover (CHO) process and combines the contents of the embodiments of Figures 5 and 8, including the following steps:

[0226] S301: A core network device configures mobility management information of a first base station. For example, the mobility management information of the first base station includes access restrictions of a terminal, roaming information, and the like.

[0227] S302: The first base station sends L3 measurement configuration information to the terminal. For example, the L3 measurement configuration information includes measurement frequency, SMTC configuration, measurement reporting trigger conditions (such as periodic, aperiodic, event-triggered, etc.), measurement objects (such as location, signal quality), etc.

[0228] S303: The terminal sends an L3 measurement report and / or location information to the first base station. For example, the location information includes GNSS location information, beam position ID, etc. The L3 measurement report includes a measurement report related to signal quality (such as RSRP, RSRQ, SINR, etc. of the reference signal).

[0229] S304: The first base station determines to perform conditional LTM switching (C-LTM) based on the L3 measurement report.

[0230] S305: The first base station sends a handover request message to the second base station. The handover request message may be, for example, an HO request message.

[0231] S306: The second base station performs admission control and reserves resources required for handover. For example, the second base station reserves a cell radio network temporary identifier (C-RNTI), preamble, RO resources, time-frequency resources, etc. required for handover.

[0232] S307: The second base station sends a handover response message to the first base station. For example, the second base station feeds back a handover confirmation (HO acknowledge, HO ACK) message to the first base station.

[0233] S308: The first base station sends LTM configuration information and LTM execution conditions to the terminal.

[0234] In one possible implementation, the LTM configuration information includes at least one of the following: an identifier of the first cell, an identifier of the second cell, an identifier of the LTM configuration information, a reference signal resource configuration, a reference signal measurement configuration, a random access resource configuration, a control resource configuration, a preconfigured uplink transmission resource configuration, and a transmission configuration indication status. For a description of the LTM configuration information, and an implementation of the conditions for the first base station to send the LTM configuration information to the terminal and execute LTM, refer to the corresponding description in S202 and are not repeated here.

[0235] In a possible implementation, the execution condition of the LTM includes a first condition and a second condition. The definitions of the first condition and the second condition and the description of the specific implementation can refer to the corresponding description in S101 and will not be repeated here.

[0236] In a possible implementation, the second device may further send a first reference signal and a second reference signal. The definitions and specific implementations of the first reference signal and the second reference signal may be described in detail in S101 and will not be repeated here.

[0237] S309: The terminal records the LTM configuration information and the execution condition of the LTM, and sends a response message to the first base station.

[0238] S310a: The terminal completes downlink synchronization with the candidate cell.

[0239] S310b: The terminal completes uplink synchronization with the candidate cell.

[0240] The specific implementation of S310a and S310b can refer to the corresponding description in S204a and S204b, which will not be repeated here.

[0241] S311: The terminal performs L1 measurement related to the candidate cell, determines an L1 measurement result, and sends the L1 measurement result to the first base station. The L1 measurement result includes the L1 signal quality of the first reference signal and the L1 signal quality of the second reference signal.

[0242] S312a: When the first condition is met, the terminal switches to the first cell.

[0243] S312b: When the second condition is met, the terminal switches to the second cell.

[0244] For example, the terminal continuously monitors the candidate cell and determines whether the first condition or the second condition is met; when the first condition is met, the terminal switches to the first cell that meets the first condition; when the second condition is met, the terminal switches to the second cell that meets the second condition. The specific implementation of S312a and S312b can be found in the corresponding description of S102a and S102b and will not be repeated here.

[0245] S313a: When the terminal has no timing advance information, the terminal obtains the timing advance information through an access process.

[0246] S313b: When the terminal has timing advance information, the terminal communicates through the pre-configured uplink transmission resources.

[0247] The specific implementation of S313a and S313b can refer to the embodiment of FIG5 and the corresponding descriptions in S207a and S207b, which will not be repeated here.

[0248] S314: The LTM handover process is completed between the terminal and the first base station and the second base station.

[0249] For example, the terminal switches from the serving cell of the first base station to the first cell of the second base station and successfully accesses the first cell, thereby completing the LTM switching process from the current serving cell to the first cell.

[0250] S315: The second base station sends a handover success message to the first base station. For example, the handover success message is a HO success message, which is used to indicate that the terminal has successfully handed over to the first cell of the second base station.

[0251] S316: The first base station sends a path switch request message to the core network device. For example, when the terminal successfully switches to the first cell of the second base station, the path for high-layer data transmission also needs to change. In this case, the first base station needs to send a path switch request to the core network device to request switching of the high-layer data transmission path.

[0252] S317 , the core network device executes a path switching decision, and the data is transmitted from the core network device to the second base station via the new path.

[0253] S318: The core network device sends a path switch acknowledgement message to the second base station. For example, the core network device sends a path switch request ACK message to the second base station, indicating that the core network device has confirmed the path switch. Optionally, the path switch acknowledgement message also includes path indication information, which is used to indicate the new path for data transmission.

[0254] S319: The second base station sends a context release request message to the first base station, where the context release request message is used to request to release the context information of the terminal.

[0255] This embodiment, based on the existing CHO process and incorporating LTM execution conditions (e.g., the first condition or the second condition), enables the first device to autonomously trigger LTM handover based on the first and / or second conditions during the CHO process, effectively reducing mobility interruption latency. Furthermore, the second device no longer needs to send handover signaling to the first device, reducing signaling overhead. Optionally, the CHO process also includes additional methods for acquiring TA information and a new method for dynamically configuring TA acquisition based on the satellite cell's path transmission delay, facilitating the implementation and completion of the CHO and LTM processes.

[0256] It is understood that in order to implement the functions of the above-mentioned device embodiments, the base station and the terminal include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily appreciate that, in conjunction with the various exemplary units and method steps described in the embodiments disclosed herein, 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 hardware or in a computer software-driven hardware manner depends on the specific application scenario and design constraints of the technical solution.

[0257] Figures 13 and 14 are schematic diagrams of possible communication devices provided by the present application. These communication devices can be used to implement the functions of the first device (such as a base station) or the second device (such as a terminal) in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments. In the embodiments of the present application, the communication device can be a terminal as shown in Figure 1, or a satellite as shown in Figure 1, or a module (such as a chip) applied to a terminal or satellite.

[0258] As shown in Figure 13, communication device 1300 includes a processing unit 1310 and a transceiver unit 1320. Communication device 1300 is used to implement the functions of a terminal or base station in the method embodiments shown in Figures 5 to 12 above. Optionally, transceiver unit 1320 includes a transmitting unit and a receiving unit, and transceiver unit 1320 can also be referred to as a communication unit.

[0259] When the communication device 1300 is used to implement the terminal functions in the method embodiments shown in Figures 5, 8, and 12, the transceiver unit 1320 is configured to receive the first condition and the second condition. The processing unit 1310 is configured to switch to the first cell when the first condition is met and to switch to the second cell when the second condition is met.

[0260] In one possible implementation, the processing unit 1310 is configured to, when a first condition is met, switch to the first cell, including:

[0261] When the distance between the position of the first device and the reference position is greater than the first threshold and / or the distance between the position of the first device and the second reference position is less than the second threshold, and the L1 signal quality of the first reference signal of the first cell measured by the first device is greater than the first signal quality threshold, switching to the first cell is performed.

[0262] In one possible implementation, the processing unit 1310 is configured to switch to the second cell when the second condition is met, including:

[0263] When the local clock of the first device is in the first time period and the first device measures that the L1 signal quality of the second reference signal of the second cell is greater than the second signal quality threshold, the first device switches to the second cell.

[0264] In a possible implementation, the processing unit 1310 is further configured to:

[0265] When the first condition and the second condition are met, the first reference signal or the second reference signal is measured in time-sharing manner according to a preconfigured measurement gap.

[0266] In a possible implementation, the processing unit 1310 is further configured to:

[0267] When the first device has no timing advance information, the timing advance information is acquired through an access process.

[0268] In one possible implementation, the processing unit 1310 is configured to, when the first apparatus has no timing advance information, obtain the timing advance information through an access procedure, including:

[0269] When the first condition is met, performing handover access based on the first random access resource associated with the first reference signal to obtain first timing advance information;

[0270] When the second condition is met, switching access is performed based on the second random access resource associated with the second reference signal to obtain second timing advance information.

[0271] In one possible implementation, the processing unit 1310 is configured to, when the first apparatus has no timing advance information, obtain the timing advance information through an access procedure, including:

[0272] When the first condition is met, detecting a first control resource associated with the first reference signal, and determining a first physical downlink control channel associated with the first control resource;

[0273] The first physical downlink control channel is demodulated, and switching access is performed based on resources of the demodulated first physical downlink control channel to obtain first timing advance information.

[0274] In one possible implementation, the processing unit 1310 is configured to, when the first apparatus has no timing advance information, obtain the timing advance information through an access procedure, including:

[0275] When the second condition is met, detecting the second control resource associated with the second reference signal, and determining the second physical downlink control channel associated with the second control resource;

[0276] The second physical downlink control channel is demodulated, and switching access is performed based on resources of the demodulated second physical downlink control channel to obtain second timing advance information.

[0277] In a possible implementation, the processing unit 1310 is further configured to:

[0278] When the first device has timing advance information, communication is performed through pre-configured uplink transmission resources.

[0279] In one possible implementation, the processing unit 1310 is configured to communicate using preconfigured uplink transmission resources when the first apparatus has timing advance information, including:

[0280] When a first condition is met, communicating through a first pre-configured uplink transmission resource associated with a first reference signal;

[0281] When the second condition is met, communication is performed through the second pre-configured uplink transmission resources associated with the second reference signal.

[0282] In one possible implementation, the transceiver unit 1320 is further configured to:

[0283] sending an L1 measurement report, the L1 measurement report including an identifier of a candidate cell and / or a type of the candidate cell, the candidate cells including a first cell and a second cell; receiving first indication information, the first indication information being used to indicate a timing advance acquisition mode; the timing advance acquisition mode being determined by the second apparatus based on the first delay, the first delay being determined by the second apparatus based on the identifier of the candidate cell or the type of the candidate cell in the L1 measurement report;

[0284] The processing unit 1310 is further configured to:

[0285] Based on the timing advance acquisition method, uplink synchronization with the candidate cell is completed.

[0286] In one possible implementation, the transceiver unit 1320 is further configured to:

[0287] Receive LTM configuration information, where the LTM configuration information includes at least one of the following: an identifier of the first cell, an identifier of the second cell, an identifier of the LTM configuration information, a reference signal resource configuration, a reference signal measurement configuration, a random access resource configuration, a control resource configuration, a pre-configured uplink transmission resource configuration, and a transmission configuration indication status.

[0288] As can be seen, when the communication device 1300 is used to implement the terminal functions in the method embodiments shown in Figures 5, 8, and 12, the communication device 1300 can receive the first condition and the second condition to determine the conditions that need to be met when performing a subsequent handover. For example, the first device can subsequently trigger a handover based on the first condition and / or the second condition without requiring additional signaling instructions, thereby reducing signaling overhead. Furthermore, the terminal can automatically switch to different cells based on different conditions, implementing LTM-based conditional handover, thereby reducing mobile interruption delay.

[0289] When the communication device 1300 is used to implement the function of the base station in the method embodiments shown in Figures 5, 8 and 12: the processing unit 1310 is used to determine the first condition and the second condition, and the transceiver unit 1320 is used to send the first condition and the second condition; wherein the first condition is used to trigger the first device to switch to the first cell; and the second condition is used to trigger the first device to switch to the second cell.

[0290] In a possible implementation, the transceiver unit 1320 is further configured to receive an L1 measurement report, where the L1 measurement report includes an identifier of a candidate cell and / or a type of the candidate cell; the candidate cell includes a first cell and a second cell;

[0291] The processing unit 1310 is further configured to determine a first delay based on an identifier of the candidate cell or a type of the candidate cell in the L1 measurement report; and determine a timing advance acquisition method based on the first delay;

[0292] The transceiver unit 1320 is further configured to send first indication information, where the first indication information is used to indicate a timing advance acquisition method.

[0293] In one possible implementation, the processing unit 1310 is configured to determine, based on the first delay, a timing advance acquisition mode, including:

[0294] When the first delay is less than the delay threshold, determining that the first acquisition method is to acquire the timing advance information from the serving cell of the first device;

[0295] When the first delay is greater than or equal to the delay threshold, determining the second acquisition method is to acquire the timing advance information from a random access response of the candidate cell.

[0296] In one possible implementation, the transceiver unit 1320 is further configured to:

[0297] Send LTM configuration information, where the LTM configuration information includes at least one of the following: an identifier of the first cell, an identifier of the second cell, an identifier of the LTM configuration information, a reference signal resource configuration, a reference signal measurement configuration, a random access resource configuration, a control resource configuration, a pre-configured uplink transmission resource configuration, and a transmission configuration indication status.

[0298] It can be seen that when the communication device 1300 is used to implement the functions of the base station in the method embodiments shown in Figures 5, 8 and 12, the communication device 1300 can send the first condition and the second condition, thereby indicating to the first device the conditions that need to be met when performing the switch; for example, the first device subsequently triggers the switch based on the first condition and / or the second condition, and the second device does not need to send the switching signaling to the first device again, which can reduce signaling overhead.

[0299] For a more detailed description of the processing unit 1310 and the transceiver unit 1320 , reference may be made to the relevant descriptions in the method embodiments shown in FIG. 5 to FIG. 12 .

[0300] As shown in Figure 14, communication device 1400 includes a processor 1410 and an interface circuit 1420. Processor 1410 and interface circuit 1420 are coupled to each other. It is understood that interface circuit 1420 can be a transceiver or an input / output interface. Optionally, communication device 1400 may also include a memory 1430 for storing instructions executed by processor 1410, or storing input data required by processor 1410 to execute instructions, or storing data generated after processor 1410 executes instructions. Sometimes, interface circuit 1420 can also be understood as part of processor 1410, in which case communication device 1400 includes processor 1410. Optionally, a transceiver includes a transmitter and a receiver.

[0301] When the communication device 1400 is used to implement the method embodiments shown in Figures 5 to 12, the processor 1410 is used to implement the functions of the above-mentioned processing unit 1310, and the interface circuit 1420 is used to implement the functions of the above-mentioned transceiver unit 1320.

[0302] When the above-mentioned communication device is a chip applied to a terminal, the terminal chip implements the functions of the terminal in the above-mentioned method embodiment. When the terminal chip receives information from the base station, it can be understood that the information is first received by other modules in the terminal (such as a radio frequency module or antenna) and then sent to the terminal chip by these modules. When the terminal chip sends information to the base station, it can be understood that the information is first sent to other modules in the terminal (such as a radio frequency module or antenna) and then sent to the base station by these modules.

[0303] When the above-mentioned communication device is a chip applied to a base station, the base station chip implements the functions of the base station in the above-mentioned method embodiment. When the base station chip receives information from the terminal, it can be understood that the information is first received by other modules in the base station (such as a radio frequency module or antenna) and then sent to the base station chip by these modules. When the base station chip sends information to the terminal, it can be understood that the information is sent to other modules in the base station (such as a radio frequency module or antenna) and then sent to the terminal by these modules.

[0304] In this application, when entity A sends information to entity B, it can be done directly from A to B or indirectly through another entity. Similarly, when entity B receives information from entity A, it can be done directly from entity B or indirectly through another entity. Entities A and B herein can be RAN nodes or terminals, or modules within a RAN node or terminal. The sending and receiving of information can be information exchange between a RAN node and a terminal, for example, between a base station and a terminal; the sending and receiving of information can also be information exchange between two RAN nodes, for example, between a CU and a DU; the sending and receiving of information can also be information exchange between different modules within a device, for example, between a terminal chip and other modules in the terminal, or between a base station chip and other modules within the base station.

[0305] In other words, sending and receiving can be performed between devices, for example, between a network device and a terminal device, or can be performed within a device, for example, sending or receiving between components, modules, chips, software modules or hardware modules within the device through a bus, wiring or interface.

[0306] It is understandable that information may be processed between the source and destination of information transmission, such as coding, modulation, etc., but the destination can understand the valid information from the source. Similar expressions in this application can be understood similarly and will not be repeated.

[0307] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0308] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in a base station or a terminal. The processor and storage medium can also exist in a base station or a terminal as discrete components.

[0309] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0310] In the various embodiments of the present application, unless otherwise specified or there is any logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0311] In this application, "at least one" means one or more, and "more" means 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 mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship; in the formula of this application, the character " / " indicates that the previous and next associated objects are in a "division" relationship. "Including at least one of A, B and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0312] In this application, words such as "first" and "second" can be used to distinguish technical features with the same or similar functions. The words such as "first" and "second" do not limit the quantity and execution order, and the words such as "first" and "second" do not necessarily limit them to be different. In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" should not be interpreted as being more preferred or more advantageous than other embodiments or design. The use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way for easy understanding.

[0313] In the embodiments of the present application, "indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. The information indicated by a certain information (such as the indication information described below) is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, wherein there is an association between the other information and the information to be indicated; it is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance, for example, the indication of specific information can be achieved with the help of the arrangement order of each information agreed in advance (such as predefined by the protocol), thereby reducing the indication overhead to a certain extent. The present application does not limit the specific method of indication. It is understandable that, for the sender of the indication information, the indication information can be used to indicate the information to be indicated, and for the receiver of the indication information, the indication information can be used to determine the information to be indicated.

[0314] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

Claims

1. A communication method, characterized in that: The method comprises: receiving a first condition and a second condition; When the first condition is met, switching to the first cell; When the second condition is met, switch to the second cell.

2. The method according to claim 1, characterized in that The first condition is that a distance between the first device and the first reference location is greater than a first threshold and / or a distance between the first device and the second reference location is less than a second threshold, and a layer 1 L1 signal quality of the first reference signal is greater than a first signal quality threshold; The first reference position, the second reference position, the first threshold, the second threshold and the first signal quality threshold are predefined parameters.

3. The method according to claim 2, characterized in that The switching to the first cell when the first condition is met includes: When the distance between the position of the first device and the reference position is greater than the first threshold and / or the distance between the position of the first device and the second reference position is less than the second threshold, and the first device measures that the L1 signal quality of the first reference signal of the first cell is greater than the first signal quality threshold, switch to the first cell.

4. The method according to claim 1, wherein The second condition is that the local clock of the first device is in the first time period and the L1 signal quality of the second reference signal is greater than the second signal quality threshold; The first time period and the second signal quality threshold are predefined parameters.

5. The method according to claim 4, characterized in that The switching to the second cell when the second condition is met includes: When the local clock of the first device is in the first time period and the first device measures that the L1 signal quality of the second reference signal of the second cell is greater than a second signal quality threshold, switching to the second cell is performed.

6. The method according to claim 1, characterized in that The method further comprises: When the first device has no timing advance information, the timing advance information is acquired through an access process.

7. The method according to claim 6, characterized in that When the first device has no timing advance information, acquiring the timing advance information through an access process includes: When the first condition is met, performing handover access based on the first random access resource associated with the first reference signal to obtain first timing advance information; When the second condition is met, switching access is performed based on the second random access resource associated with the second reference signal to obtain second timing advance information.

8. The method according to claim 6, characterized in that When the first device has no timing advance information, acquiring the timing advance information through an access process includes: When the first condition is met, detecting a first control resource associated with the first reference signal, and determining a first physical downlink control channel associated with the first control resource; Demodulating the first physical downlink control channel, and performing handover access based on resources of the demodulated first physical downlink control channel to obtain first timing advance information; or, When the second condition is met, detecting a second control resource associated with the second reference signal, and determining a second physical downlink control channel associated with the second control resource; The second physical downlink control channel is demodulated, and switching access is performed based on resources of the demodulated second physical downlink control channel to obtain second timing advance information.

9. The method according to claim 1, characterized in that The method further comprises: When the first device has timing advance information, communication is performed through pre-configured uplink transmission resources.

10. The method according to claim 9, characterized in that The step of communicating by using pre-configured uplink transmission resources when the first device has timing advance information includes: When a first condition is met, communicating through a first pre-configured uplink transmission resource associated with a first reference signal; When the second condition is met, communication is performed through the second pre-configured uplink transmission resources associated with the second reference signal.

11. The method according to claim 1, wherein After receiving the first condition and the second condition, the method further includes: Sending an L1 measurement report, where the L1 measurement report includes an identifier of a candidate cell and / or a type of the candidate cell; the candidate cells include the first cell and the second cell; receiving first indication information, where the first indication information is used to indicate a timing advance acquisition mode; the timing advance acquisition mode is determined by the second apparatus based on a first delay, where the first delay is determined by the second apparatus based on an identifier of a candidate cell or a type of the candidate cell in the L1 measurement report; Based on the timing advance acquisition method, uplink synchronization with the candidate cell is completed.

12. The method according to claim 11, characterized in that The timing advance acquisition method includes a first acquisition method and a second acquisition method; The first acquisition method is to obtain the timing advance information from the serving cell of the first device; The second acquisition method is to acquire the timing advance information from a random access response of the candidate cell.

13. The method according to any one of claims 1 to 12, characterized in that The method further comprises: Receive layer 1 / layer 2 mobility LTM configuration information, where the LTM configuration information includes at least one of the following: an identifier of the first cell, an identifier of the second cell, an identifier of the LTM configuration information, a reference signal resource configuration, a reference signal measurement configuration, a random access resource configuration, a control resource configuration, a pre-configured uplink transmission resource configuration, and a transmission configuration indication status.

14. The method according to any one of claims 1 to 12, characterized in that The period of the first reference signal is a first period, the second reference signal is a non-periodic signal or the period of the second reference signal is a second period, and the second period is greater than the first period.

15. The method according to any one of claims 1 to 12, characterized in that The first reference signal and the second reference signal are reference signals of different types.

16. The method according to any one of claims 1 to 12, characterized in that The first reference signal and the second reference signal are synchronization signal block (SSB) synchronization signals, the first reference signal is mapped to a first type of time domain position, and the second reference signal is mapped to a second type of time domain position; The time domain positions of the first type satisfy a first period; The second type of time domain positions is non-periodic or satisfies a second period.

17. A communication method, characterized in that: The method comprises: Determine the first condition and the second condition; sending the first condition and the second condition; The first condition is used to trigger the first device to switch to the first cell; The second condition is used to trigger the first device to switch to the second cell.

18. The method according to claim 17, characterized in that The first condition is that the distance between the first device and the first reference location is greater than a first threshold and / or the distance between the first device and the second reference location is less than a second threshold, and the L1 signal quality of the first reference signal is greater than a first signal quality threshold; The first reference position, the second reference position, the first threshold, the second threshold and the first signal quality threshold are predefined parameters.

19. The method according to claim 17, wherein The second condition is that the local clock of the first device is in a first time period and the L1 signal quality of the second reference signal is greater than a second signal quality threshold; The first time period and the second signal quality threshold are predefined parameters.

20. The method according to claim 17, wherein The method further comprises: receiving an L1 measurement report, where the L1 measurement report includes an identifier of a candidate cell and / or a type of the candidate cell; the candidate cells include the first cell and the second cell; Determining a first delay based on an identifier of the candidate cell or a type of the candidate cell in the L1 measurement report; Determining a timing advance acquisition method based on the first time delay; First indication information is sent, where the first indication information is used to indicate the timing advance acquisition method.

21. The method according to claim 20, characterized in that The determining, based on the first time delay, a timing advance acquisition method includes: When the first delay is less than the delay threshold, determining that the first acquisition method is to acquire timing advance information from a serving cell of the first device; When the first delay is greater than or equal to a delay threshold, determining a second acquisition method is to acquire timing advance information from a random access response of the candidate cell.

22. The method according to any one of claims 17 to 21, characterized in that The method further comprises: Send LTM configuration information, where the LTM configuration information includes at least one of the following: an identifier of the first cell, an identifier of the second cell, an identifier of the LTM configuration information, a reference signal resource configuration, a reference signal measurement configuration, a random access resource configuration, a control resource configuration, a pre-configured uplink transmission resource configuration, and a transmission configuration indication status.

23. The method according to any one of claims 17 to 21, characterized in that The period of the first reference signal is a first period, the second reference signal is a non-periodic signal or the period of the second reference signal is a second period, and the second period is greater than the first period.

24. The method according to any one of claims 17 to 21, characterized in that The first reference signal and the second reference signal are reference signals of different types.

25. The method according to any one of claims 17 to 21, characterized in that The first reference signal and the second reference signal are synchronization signal block (SSB) synchronization signals, the first reference signal is mapped to a first type of time domain position, and the second reference signal is mapped to a second type of time domain position; The time domain positions of the first type satisfy a first period; The second type of time domain positions is non-periodic or satisfies a second period.

26. A communication device, characterized in that: The method comprises a communication unit and a processing unit, wherein the communication unit and the processing unit are configured to execute the method according to any one of claims 1 to 16 or claims 17 to 25.

27. A communication device, characterized in that: The method comprises a processor and an interface circuit, wherein the interface circuit is used to receive signals from other communication devices and transmit them to the processor or send signals from the processor to other communication devices, and the processor is used to implement the method according to any one of claims 1 to 16 or claims 17 to 25 through a logic circuit or executing code instructions.

28. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program or instruction. When the computer program or instruction is executed by the communication device, the method according to any one of claims 1 to 16 or claims 17 to 25 is implemented.

29. A computer program product, characterized in that The method comprises instructions which, when executed on a computer, cause the computer to perform the method according to any one of claims 1 to 16 or claims 17 to 25.

30. A chip or a chip system, characterized in that: The chip or chip system comprises a processor configured to execute a computer program so that the chip or chip system implements the method according to any one of claims 1 to 16 or claims 17 to 25.

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