Communication method and communication device

Abstract

The present application provides a communication method and a communication device, which can be applied to a random access channel-less handover scenario. In the method, a source access network device can send indication information of at least one beam measured by a terminal device to at least one candidate access network device when receiving a handover request acknowledgement message. The resource utilization rate can be improved while improving the flexibility of resource scheduling by an access network device.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on August 11, 2023, with application number 202311017816.0 and invention name “Communication Method and Communication Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of communications, and in particular to communication methods and communication devices. Background Art

[0003] The random access channel less (RACH-LESS) process is an access process introduced in the R14 version of Long Term Evolution (LTE). When a terminal device receives a radio resource control (RRC) reconfiguration message from a source access network device, if the RRC reconfiguration message includes the uplink resources pre-allocated by the target access network device to the terminal device, the terminal device can directly use the pre-allocated uplink resources to send an RRC reconfiguration complete message to the target access network device to confirm the completion of the handover. If the RRC reconfiguration message does not include the uplink resources pre-allocated by the target access network device to the terminal device, the terminal device monitors the physical downlink control channel (PDCCH) of the target access network device, obtains the uplink resources dynamically allocated by the target access network device from the PDCCH, and then uses the dynamically allocated uplink resources indicated by the PDCCH to send an RRC reconfiguration complete message to the target access network device to confirm the completion of the handover. Since the target access network device is accessed through RACH-LESS during handover, the target access network device does not need to allocate RACH resources to the terminal device, and the terminal device does not perform a random access procedure. Therefore, RACH-LESS is not only beneficial for saving random access channel (RACH) resources, but also for shortening the delay for the terminal device to access the target access network device after handover.

[0004] The new radio (NR) system also introduces the RACH-LESS process. The NR system reuses the process of configuring uplink resources for terminal devices in the LTE system. Unlike the LTE system, the NR system has the concept of beams. In the uplink resource allocation of RACH-LESS, one way is that at least one candidate access network device pre-allocates uplink resources for the terminal device on all beams, and another way is that the candidate access network device sends PDCCH to the terminal device on each beam to ensure that the terminal device can obtain dynamically allocated uplink resources through the PDCCH sent by a certain beam. However, the behavior of the candidate access network device blindly sending PDCCH causes a waste of uplink resources.

[0005] Therefore, in the scenario of using the RACH-LESS process, how access network equipment can flexibly schedule resources for terminal devices to improve resource utilization is a hot topic of discussion.

[0006] Summary of the Invention

[0007] In a first aspect, the present application provides a communication method that can be executed by a source access network device or by a component of the source access network device (e.g., a processor, chip, or chip system). Taking the source access network device as an example, the source access network device sends a handover request message to at least one candidate access network device; the source access network device receives a handover request confirmation message from the at least one candidate access network device; and the source access network device sends indication information of at least one beam measured by a terminal device to the at least one candidate access network device.

[0008] Optionally, the indication information of at least one beam is used by at least one candidate access network device to determine the beam for sending the physical downlink control channel PDCCH to the terminal device.

[0009] In the present application, after receiving a handover request confirmation message, the source access network device can send indication information of at least one beam measured by the terminal device to at least one candidate access network device. This is conducive to reporting the latest beam measurement results to at least one candidate access network device, and further facilitates the candidate access network device to determine, based on the indication information of at least one beam, whether to send the PDCCH to the beam that is more suitable for the terminal device, rather than sending the PDCCH to each beam in the candidate cell of the candidate access network device. Therefore, while improving the flexibility of the access network device in scheduling resources, it is possible to reduce resource waste caused by the resource scheduling process and improve resource utilization.

[0010] In a possible implementation manner, each beam in the at least one beam satisfies any one of the following preset conditions:

[0011] The beam is the beam with the best signal quality among the beams measured by the terminal device; or,

[0012] The signal quality of the beam is greater than or equal to the reference threshold; or,

[0013] The signal quality of the beam is greater than or equal to the signal quality of the reference beam, and the beam is different from the reference beam.

[0014] In this embodiment, it is proposed that the beam indicated by the indication information of at least one beam sent by the source access network device to the candidate access network device satisfies the aforementioned preset conditions. In other words, the beam sent by the source access network device to the candidate access network device is a beam with good signal quality, which facilitates the candidate access network device to transmit and downlink the PDCCH on an appropriate beam based on the beam indication information. Therefore, when the beam of the candidate cell measured by the terminal device changes, the beam to which the PDCCH is transmitted can be accurately determined, thereby improving the base station's transmission accuracy, allowing the terminal device to decode the PDCCH in advance to obtain uplink resources, reducing handover delay and improving handover efficiency.

[0015] In a possible implementation, the method further includes: the source access network device sends measurement configuration information to the terminal device, the measurement configuration information is used to instruct the terminal device to report indication information of a beam that meets preset conditions; the source access network device receives indication information of at least one beam from the terminal device.

[0016] Optionally, the measurement configuration information includes indication information of a reference beam and / or a reference threshold.

[0017] Optionally, the measurement configuration information also includes an upper limit on the number of beams to be reported.

[0018] In one possible implementation, the indication information of at least one beam includes an index of each beam in the at least one beam. Exemplarily, when the indication information of at least one beam includes only the beam index, the access network device can determine the cell to which the beam belongs by other means. For example, the access network device determines the cell identifier using the measurement identifier corresponding to the reported beam index, and thereby determines the cell to which the beam reported by the terminal device belongs.

[0019] Optionally, the indication information of at least one beam also includes a cell identifier corresponding to each beam in the at least one beam. The cell identifier corresponding to the beam is used to indicate the cell's beam measured by the terminal device, or the cell of the candidate access network device to which the beam belongs. This facilitates the candidate access network device to determine the cell's beam based on the cell identifier in the beam indication information, thereby improving the efficiency of the candidate access network device in scheduling resources for the terminal device.

[0020] Optionally, the indication information of at least one beam also includes signal quality information of each beam in the at least one beam. The signal quality information of the beam is used to indicate the quality of the signal quality of the beam. Exemplarily, the signal quality information of the beam can be any one of reference signal received power (RSRP), reference signal received quality (RSRQ), or signal to interference plus noise ratio (SINR). This is beneficial for the candidate access network device to select a beam with better signal quality based on the signal quality information to send PDCCH, thereby improving the efficiency of the candidate access network device in scheduling resources for the terminal device.

[0021] In a possible implementation manner, the measurement configuration information is measurement configuration information of an RRC layer; or, the measurement configuration information is measurement configuration information of a physical layer.

[0022] In a possible implementation, the method further includes: the source access network device sends a radio resource control RRC reconfiguration message to the terminal device, the RRC reconfiguration message includes first indication information and indication information of a cell of at least one candidate access network device, and the first indication information is used to instruct the terminal device to adopt random access-free RACH-LESS switching.

[0023] In a possible implementation, the switching request message includes indication information of at least one first beam measured by the terminal device.

[0024] Optionally, the beam indicated by the indication information of at least one beam is different from the beam indicated by the indication information of at least one first beam.

[0025] It can be understood that the source access network device first sends indication information of at least one beam (called indication information of the second beam set) to the candidate access network device. When the beam in the same cell changes, the source access network device then sends indication information of at least one first beam (called indication information of the first beam set) to the candidate access network device. Compared with the indication information of the first beam set, the indication information of the second beam set is the indication information of the updated beam or refers to the indication information of the new beam after the beam information of the neighboring cell measured by the terminal has changed. This is beneficial for the candidate access network device to determine which beam is more suitable for sending PDCCH to the terminal device based on the indication information of at least one updated beam, rather than determining the beam for sending PDCCH to the terminal device based on the indication information of at least one first beam that may be outdated or invalid. Therefore, it is beneficial to improve the flexibility and accuracy of candidate access network devices in scheduling resources and improve the efficiency of scheduling uplink resources for terminal devices.

[0026] In a possible implementation, the reference beam is a beam determined by the source access network device based on indication information of at least one first beam.

[0027] In this embodiment, it is proposed that the reference beam may be determined by the source access network device based on the indication information of at least one first beam (i.e., the indication information of the first beam set). This facilitates the terminal device to report a beam with better quality than the reference beam when the source access network device has configured a reference beam for the terminal device, thereby enabling the terminal device to report a beam with better quality than the first beam set. This facilitates the candidate access network device to determine which beam is more suitable for sending the PDCCH to the terminal device based on the indication information of at least one updated beam, rather than determining the beam for sending the PDCCH to the terminal device based on the indication information of at least one first beam that may be outdated or invalid.

[0028] In a second aspect, the present application provides a communication method, which can be executed by a terminal device or by a component of the terminal device (e.g., a processor, a chip, or a chip system). Taking the terminal device as an example, the terminal device sends indication information of at least one beam to a source access network device, and the indication information of at least one beam is used by at least one candidate access network device to determine the beam for sending a PDCCH to the terminal device, where the candidate access network device is the access network device configured by the source access network device in an RRC reconfiguration message of the terminal device.

[0029] In the present application, the terminal device can send indication information of at least one beam to the source access network device, so that the source access network device can send indication information of at least one beam measured by the terminal device to at least one candidate access network device after receiving the handover request confirmation message. This is conducive to reporting the latest beam measurement result measured by the terminal device to at least one candidate access network device, and further facilitates the candidate access network device to determine the beam that is more suitable for the terminal device to send PDCCH based on the indication information of at least one beam, rather than sending PDCCH to each beam in the candidate cell of the candidate access network device. Therefore, it is possible to reduce the resource waste caused by the resource scheduling process while improving the flexibility of the access network device in scheduling resources.

[0030] In a possible implementation manner, each beam in the at least one beam satisfies any one of the following preset conditions:

[0031] The beam is the beam with the best signal quality among the beams measured by the terminal device; or,

[0032] The signal quality of the beam is greater than or equal to the reference threshold; or,

[0033] The signal quality of the beam is greater than or equal to the signal quality of the reference beam, and the beam is different from the reference beam.

[0034] In a possible implementation, the method further includes: the terminal device receiving measurement configuration information from the source access network device, where the measurement configuration information is used to instruct the terminal device to report indication information of a beam that meets a preset condition.

[0035] Optionally, the measurement configuration information includes indication information of a reference beam and / or a reference threshold.

[0036] Optionally, the measurement configuration information also includes an upper limit on the number of beams to be reported.

[0037] In a possible implementation manner, the indication information of the at least one beam includes an index of each beam in the at least one beam.

[0038] Optionally, the indication information of at least one beam also includes a cell identifier corresponding to each beam in the at least one beam, and / or signal quality information of each beam in the at least one beam.

[0039] In a possible implementation manner, the measurement configuration information is measurement configuration information of an RRC layer; or, the measurement configuration information is measurement configuration information of a physical layer.

[0040] In a possible implementation, the method further includes: the terminal device receives an RRC reconfiguration message from the source access network device, the RRC reconfiguration message includes first indication information and cell information of at least one candidate access network device, and the first indication information is used to instruct the terminal device to adopt RACH-LESS switching.

[0041] In one possible implementation, the method further includes:

[0042] The terminal device triggers switching to the target cell of the target access network device, where the target access network device is one of the at least one candidate access network devices; the terminal device monitors the PDCCH through a beam belonging to the target cell in at least one beam, and the PDCCH is used to indicate the uplink resources allocated to the terminal device.

[0043] In a possible implementation, before the terminal device sends indication information of at least one beam to the source access network device, the method further includes: the terminal device sends indication information of at least one first beam to the source access network device.

[0044] In a possible implementation manner, the beam indicated by the indication information of at least one beam is different from the beam indicated by the indication information of at least one first beam.

[0045] It should be noted that there are many other specific implementation methods of the embodiments of the present application. Please refer to the specific implementation methods and beneficial effects of the first aspect for details, which will not be repeated here.

[0046] In a third aspect, the present application provides a communication method, which can be executed by a candidate access network device or by a component of the candidate access network device (e.g., a processor, a chip, or a chip system). Taking the candidate access network device as an example, the candidate access network device receives a handover request message from a source access network device; the candidate access network device sends a handover request confirmation message to the source access network device; the candidate access network device receives indication information of at least one beam measured by a terminal device from the source access network device; and the candidate access network device sends a PDCCH to the terminal device based on the indication information of the at least one beam.

[0047] Optionally, the terminal device is a terminal device that adopts RACH-LESS switching.

[0048] In the present application, a candidate access network device can receive indication information of at least one beam sent by a source access network device after sending a handover request confirmation message. Since the indication information of the at least one beam can reflect the latest beam measurement results, it can be understood as the optimal beam for the terminal device. Then, based on the indication information of the at least one beam, the candidate access network device determines to send the PDCCH using a beam that is more suitable for the terminal device, rather than sending the PDCCH using every beam in the candidate cell of the candidate access network device. Therefore, it is possible to reduce the resource waste caused by the resource scheduling process while improving the flexibility of the access network device in scheduling resources.

[0049] In a possible implementation, the candidate access network device sends a PDCCH to the terminal device based on indication information of at least one beam, including: the candidate access network device sends the PDCCH through the beam of the cell belonging to the candidate access network device in the indication information of at least one beam, and the PDCCH is used to indicate the uplink resources allocated to the terminal device.

[0050] In a possible implementation manner, the indication information of the at least one beam includes an index of each beam in the at least one beam.

[0051] Optionally, the indication information of at least one beam also includes a cell identifier corresponding to each beam in the at least one beam, and / or signal quality information of each beam in the at least one beam.

[0052] In a possible implementation, the switching request message includes indication information of at least one first beam measured by the terminal device.

[0053] In a possible implementation manner, the beam indicated by the indication information of at least one beam is different from the beam indicated by the indication information of at least one first beam.

[0054] It should be noted that there are many other specific implementation methods of the embodiments of the present application. Please refer to the specific implementation methods and beneficial effects of the first aspect for details, which will not be repeated here.

[0055] In a fourth aspect, the present application provides a communication method, which can be executed by a terminal device or by a component of the terminal device (for example, a processor, a chip, or a chip system). Taking the terminal device as an example, the terminal device receives first indication information and resource configuration information, the first indication information is used to instruct the terminal device to adopt RACH-LESS switching without random access, and the resource configuration information is used to indicate the pre-allocated uplink resources of the third beam set in the candidate cell and to indicate to monitor PDCCH on the beam in the fourth beam set in the candidate cell, the third beam set includes at least one beam, and the fourth beam set includes at least one beam; the terminal device determines the target beam and / or the uplink resource corresponding to the target beam from the at least one measured beam based on the resource configuration information.

[0056] It can be understood that the resource configuration information is used to configure the pre-allocated uplink resources corresponding to a portion of the beams in the candidate cell, and to instruct another portion of the beams in the candidate cell to dynamically allocate uplink resources by sending PDCCH instructions. It can also be understood that the resource configuration information is used to instruct the terminal device which beams in the candidate cell use pre-allocated uplink resources and which beams in the candidate cell monitor the PDCCH to obtain dynamically allocated uplink resources.

[0057] In the present application, since the terminal device is able to receive the first indication information and the resource configuration information, the resource configuration information configures multiple uplink authorization modes for the terminal device in a candidate cell, that is, in a candidate cell, a third beam set for using pre-allocated uplink resources is configured, and a fourth beam set for dynamically allocating uplink resources by sending a PDCCH is indicated. Therefore, it is beneficial to improve the flexibility of the terminal device in using uplink resources. In addition, compared with the traditional technology in which the candidate access network device configures pre-allocated uplink resources for each beam in the candidate cell, the solution of this embodiment reduces the number of configured pre-allocated uplink resources, which is beneficial to reducing resource waste.

[0058] In one possible implementation, the resource configuration information includes one or more of the following: indication information of the third beam set, information about pre-allocated uplink resources corresponding to each beam in the third beam set, a mapping relationship between beams in the third beam set and pre-allocated uplink resources, and indication information of the fourth beam set. The indication information of the third beam set includes an index of each beam in the third beam set, and the indication information of the fourth beam set includes an index of each beam in the fourth beam set. The information about pre-allocated uplink resources corresponding to each beam in the third beam set includes time-frequency domain location information of the pre-allocated uplink resources corresponding to each beam.

[0059] It should be noted that the mapping relationship between the beams in the third beam set and the pre-allocated uplink resources can be explicitly carried in the resource configuration information or implicitly carried in the resource configuration information. For example, the mapping relationship between the beams in the third beam set and the pre-allocated uplink resources corresponding to each beam in the third beam set can be implicitly indicated by the indication information of the third beam and the information of the pre-allocated uplink resources corresponding to each beam in the third beam set.

[0060] In one possible implementation, the terminal device determines a target beam and / or an uplink resource corresponding to the target beam from at least one measured beam based on resource configuration information, including: if at least one beam of the candidate cell measured by the terminal device belongs to a third beam set, the terminal device determines a beam as the target beam in at least one beam, and determines the pre-allocated uplink resource corresponding to the target beam as the uplink resource corresponding to the target beam.

[0061] In one possible implementation, the terminal device determines a target beam and / or an uplink resource corresponding to the target beam from at least one measured beam based on resource configuration information, including: if at least one beam of the candidate cell measured by the terminal device belongs to the fourth beam set, the terminal device determines a beam as the target beam in at least one beam, and monitors PDCCH in the target beam, and the dynamically allocated uplink resources indicated by the PDCCH are the uplink resources corresponding to the target beam.

[0062] In one possible implementation, the terminal device determines a target beam and / or an uplink resource corresponding to the target beam from at least one measured beam based on resource configuration information, including: if the terminal device measures that there is at least one beam in the candidate cell that belongs to the third beam set, and the terminal device measures that there is at least one beam in the candidate cell that belongs to the fourth beam set, then the terminal device determines a beam from the third beam set as the target beam, and determines the pre-allocated uplink resource corresponding to the target beam as the uplink resource corresponding to the target beam.

[0063] In a possible implementation, the resource configuration information also includes information on random access RACH resources; the terminal device determines the target beam and / or the uplink resource corresponding to the target beam from at least one measured beam based on the resource configuration information, including: if at least one beam of the candidate cell measured by the terminal device does not belong to the third beam set and does not belong to the fourth beam set, then the terminal device determines a beam as the target beam in at least one beam, and triggers the random access process through the RACH resource.

[0064] In a possible embodiment, the resource configuration information also includes second indication information, and the second indication information is used to instruct the terminal device to give priority to using the pre-allocated uplink resources; the terminal device determines the target beam and / or the uplink resources corresponding to the target beam from at least one measured beam based on the resource configuration information, including: if the terminal device measures that there is at least one beam in the candidate cell that belongs to the third beam set, and there is at least one beam in the candidate cell that belongs to the fourth beam set, then the terminal device determines a beam from at least one beam belonging to the third beam set as the target beam, and determines the pre-allocated uplink resources corresponding to the target beam as the uplink resources corresponding to the target beam.

[0065] In a possible embodiment, the resource configuration information also includes third indication information, and the third indication information is used to instruct the terminal device to obtain dynamically allocated uplink resources by monitoring PDCCH in priority; the terminal device determines the target beam and / or the uplink resources corresponding to the target beam from at least one measured beam based on the resource configuration information, including: if the terminal device measures that there is at least one beam in the candidate cell that belongs to the third beam set, and there is at least one beam in the candidate cell that belongs to the fourth beam set, then the terminal device determines a beam from at least one beam belonging to the fourth beam set as the target beam, and monitors PDCCH in the target beam, and the dynamically allocated uplink resources indicated by the PDCCH are the uplink resources corresponding to the target beam.

[0066] In a possible implementation, the resource configuration information also includes a first threshold corresponding to the pre-allocated uplink resources; the terminal device determines a beam as a target beam in at least one beam, including: the terminal device determines a beam in at least one beam whose signal quality is greater than or equal to the first threshold as a target beam.

[0067] In a possible implementation, the resource configuration information also includes a second threshold corresponding to the dynamically allocated uplink resources indicated by the PDCCH; the terminal device determines a beam as a target beam in at least one beam, including: the terminal device determines a beam in at least one beam whose signal quality is greater than or equal to the second threshold as a target beam.

[0068] In a possible implementation, the resource configuration information also includes a third threshold corresponding to each beam in the third beam set; the terminal device determines a beam as a target beam in at least one beam, including: the terminal device determines a beam in at least one beam whose signal quality is greater than or equal to the third threshold corresponding to the beam as the target beam.

[0069] In a possible implementation, the resource configuration information also includes a fourth threshold corresponding to each beam in the fourth beam set; the terminal device determines a beam as a target beam in at least one beam, including: the terminal device determines a beam in at least one beam whose signal quality is greater than or equal to the fourth threshold corresponding to the beam as the target beam.

[0070] In a possible implementation, the resource configuration information further includes information about random access RACH resources.

[0071] The terminal device determines the target beam and / or the uplink resources corresponding to the target beam from at least one measured beam based on the resource configuration information, including: the terminal device determines the beam with the best signal quality among at least one beam of the measured candidate cell as the target beam; if the target beam belongs to the third beam set, the terminal device determines the pre-allocated uplink resources corresponding to the target beam as the uplink resources corresponding to the target beam; if the target beam belongs to the fourth beam set, the terminal device monitors the PDCCH in the target beam, and the dynamically allocated uplink resources indicated by the PDCCH are the uplink resources corresponding to the target beam; if the target beam does not belong to the third beam set and does not belong to the fourth beam set, the terminal device triggers the random access process in the target beam through the RACH resource.

[0072] In a fifth aspect, the present application provides a communication method, which can be executed by a candidate access network device or by a component of the candidate access network device (for example, a processor, a chip, or a chip system). Taking the candidate access network device as an example, the candidate access network device sends first indication information and resource configuration information, the first indication information is used to instruct the terminal device to adopt random access-free RACH-LESS switching, and the resource configuration information is used to indicate the pre-allocated uplink resources of the third beam set in the candidate cell and to indicate to monitor the PDCCH on the beam in the fourth beam set in the candidate cell, the third beam set includes at least one beam, and the fourth beam set includes at least one beam.

[0073] In this application, a candidate access network device can configure multiple uplink authorization methods for a terminal device in a candidate cell. That is, in a candidate cell, a third beam set that uses pre-allocated uplink resources is configured, and a fourth beam set that dynamically allocates uplink resources by issuing a PDCCH is also indicated. This helps improve the flexibility of the candidate access network device in configuring uplink resources. In addition, compared to the traditional technology in which the candidate access network device configures pre-allocated uplink resources for each beam in the candidate cell, the solution of this embodiment reduces the number of configured pre-allocated uplink resources, which helps reduce resource waste.

[0074] In a possible implementation, the resource configuration information includes indication information of the third beam set, information of pre-allocated uplink resources corresponding to each beam in the third beam set, and indication information of the fourth beam set.

[0075] In a possible implementation, the resource configuration information further includes information about random access RACH resources.

[0076] In a possible implementation manner, the resource configuration information further includes a first threshold corresponding to pre-allocated uplink resources and / or a second threshold corresponding to dynamically allocated uplink resources indicated by the PDCCH.

[0077] In a possible implementation manner, the resource configuration information further includes a third threshold corresponding to each beam in the third beam set, and / or a fourth threshold corresponding to each beam in the fourth beam set.

[0078] In a possible implementation, the resource configuration information further includes second indication information, where the second indication information is used to instruct the terminal device to give priority to using the pre-allocated uplink resources.

[0079] In a possible implementation, the resource configuration information further includes third indication information, where the third indication information is used to instruct the terminal device to obtain dynamically allocated uplink resources by preferentially monitoring the PDCCH.

[0080] In a possible embodiment, before the candidate access network device sends the first message, the method also includes: a beam-level measurement result measured by a terminal device of the candidate access network device, the beam-level measurement result including indication information of at least one beam; the candidate access network device determines the indication information of the third beam set and / or the fourth beam indication information based on the beam-level measurement result.

[0081] It should be noted that there are many other specific implementation methods of the embodiments of the present application. Please refer to the specific implementation methods and beneficial effects of the first aspect for details, which will not be repeated here.

[0082] In a sixth aspect, an embodiment of the present application provides a communication device, which may be a terminal device in the aforementioned embodiment, or a chip within the terminal device. The communication device may include a processing module and a transceiver module. When the communication device is a terminal device, the processing module may be a processor, and the transceiver module may be a transceiver; the terminal device may further include a storage module, which may be a memory; the storage module is used to store instructions, and the processing module executes the instructions stored in the storage module to cause the terminal device to perform the method in the second aspect or any of the embodiments of the second aspect; or, to perform the method in the fourth aspect or any of the embodiments of the fourth aspect. When the communication device is a chip within the terminal device, the processing module may be a processor, and the transceiver module may be an input / output interface, pin, or circuit, etc.; the processing module executes the instructions stored in the storage module to cause the terminal device to perform the method in the second aspect or any of the embodiments of the second aspect; or, to perform the method in the fourth aspect or any of the embodiments of the fourth aspect. The storage module may be a storage module within the chip (e.g., a register, cache, etc.), or a storage module within the terminal device located outside the chip (e.g., a read-only memory, random access memory, etc.).

[0083] In the seventh aspect, an embodiment of the present application provides a communication device, which may be the access network device in the aforementioned embodiment, or a chip in the access network device. The access network device may be a source access network device or a candidate access network device. The communication device may include a processing module and a transceiver module. When the communication device is an access network device, the processing module may be a processor, and the transceiver module may be a transceiver; the access network device may also include a storage module, which may be a memory; the storage module is used to store instructions, and the processing module executes the instructions stored in the storage module, so that the source access network device executes the method in the first aspect or any one of the embodiments of the first aspect; or, so that the candidate access network device executes the method in the third aspect or any one of the embodiments of the third aspect; or, so that the candidate access network device executes the method in the fifth aspect or any one of the embodiments of the fifth aspect. When the communication device is a chip within an access network device, the processing module may be a processor, and the transceiver module may be an input / output interface, a pin, or a circuit, etc.; the processing module executes instructions stored in the storage module to cause the source access network device to perform the method of the first aspect or any one of the embodiments of the first aspect; or to cause the candidate access network device to perform the method of the third aspect or any one of the embodiments of the third aspect; or to cause the candidate access network device to perform the method of the fifth aspect or any one of the embodiments of the fifth aspect. The storage module may be a storage module within the chip (e.g., a register, a cache, etc.), or a storage module within the access network device located outside the chip (e.g., a read-only memory, a random access memory, etc.).

[0084] In an eighth aspect, the present application provides a communication device, which may be an integrated circuit chip. The integrated circuit chip includes a processor. The processor is coupled to a memory, which is configured to store programs or instructions. When the program or instructions are executed by the processor, the communication device performs the method described in any of the embodiments of the aforementioned aspects.

[0085] In a ninth aspect, an embodiment of the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute a method as described in any one of the aforementioned aspects.

[0086] In a tenth aspect, an embodiment of the present application provides a computer-readable storage medium comprising instructions, which, when executed on a computer, enable the computer to execute a method as described in any one of the embodiments in the foregoing aspects.

[0087] In the eleventh aspect, an embodiment of the present application provides a communication system, which includes a source access network device that executes the aforementioned first aspect and any one of the implementations of the first aspect, a terminal device that executes the aforementioned second aspect and any one of the implementations of the second aspect, and a candidate access network device that executes the aforementioned third aspect and any one of the implementations of the third aspect.

[0088] In the twelfth aspect, an embodiment of the present application provides a communication system, which includes a terminal device that executes the aforementioned fourth aspect and any one of the implementation methods of the fourth aspect, and a candidate access network device that executes the aforementioned fifth aspect and any one of the implementation methods of the fifth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] FIG1 is an example diagram of the system architecture of the communication method provided in this application;

[0090] FIG2 is a flow chart of the communication method provided by the present application;

[0091] FIG3 is another flow chart of the communication method provided by the present application;

[0092] FIG4 is another flow chart of the communication method provided by the present application;

[0093] FIG5 is another flow chart of the communication method provided by the present application;

[0094] FIG6 is a schematic diagram of an embodiment of a communication device in the present application;

[0095] FIG7 is a schematic diagram of another embodiment of a communication device in the present application;

[0096] FIG8 is a schematic diagram of another embodiment of a communication device in the present application. DETAILED DESCRIPTION

[0097] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0098] In the various embodiments of the present application, unless otherwise specified or there is a 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.

[0099] The terms "first," "second," "third," "fourth," and the like (if any) in the specification and claims of this application and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or sequential sequence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions, e.g., a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or apparatus.

[0100] It should be understood that the term "and / or" in this document simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0101] The following is a brief introduction to the professional terms involved in this application:

[0102] Beam: This refers to a directional electromagnetic wave. A beam can be represented by a spatial filter, spatial parameters, a precoding matrix, a precoding matrix index, a precoding parameter, or a port. A transmit beam can also be called a spatial transmit filter, and a receive beam can also be called a spatial receive filter. In practical applications, the beam can also be referred to by other names. In the embodiments of this application, the term "beam" is used as an example.

[0103] Pre-allocated uplink resources: refers to the uplink resources or uplink authorization pre-allocated by the access network device for the terminal device. Pre-allocated uplink resources refer to pre-allocated uplink authorization (pre-allocated uplink grant), or configured uplink authorization (configured uplink grant, CG) resources, also known as pre-allocated uplink scheduling resources. It should be understood that with the development of communication technology, pre-allocated resources can also be referred to by other names. Its essence is the resources allocated in advance by the access network device to the terminal device before the terminal device accesses. The embodiments of the present application are mainly introduced using the term "CG resources" as an example.

[0104] Dynamically allocated uplink resources: refers to the uplink resources or uplink authorization indicated by the access network device to the terminal device through the PDCCH, which can also be understood as a dynamically allocated uplink authorization (dynamic uplink grant, DG). The terminal device decodes the PDCCH to obtain downlink control information (downlink control information, DCI), and the uplink resources are indicated in the DCI. Compared with the pre-allocated uplink resources, the essence of the dynamically allocated uplink resources is that the access network device indicates the time-frequency domain position of the uplink resources to the terminal device. This allocation method is dynamic and relatively flexible. It is simply described as dynamically allocated uplink resources in this article. It should be understood that with the development of communication technology, the dynamic allocation of uplink resources can adopt other terms. In the embodiments of this application, the term "DG resources" is mainly used as an example to introduce.

[0105] For ease of understanding, the following first introduces the system architecture and application scenarios of the communication method proposed in this application:

[0106] The communication method proposed in this application can be applied to the long-term evolution (LTE) system, the 5G NR (5G New Radio) system, the sixth generation mobile communication technology (6G) system, and subsequent evolution systems, and this application does not limit this. As shown in Figure 1, the communication system includes at least a terminal device and an access network device.

[0107] Among them, the terminal device includes a device that provides voice and / or data connectivity to the user. For example, it may include a handheld device with wireless connection function or a processing device connected to a wireless modem. The terminal device can communicate with the core network (for example, 4G core network (evolved packet core, EPC) or 5G core network (5th generation core, 5GC)) via the radio access network (RAN), and can exchange voice and / or data with the RAN. The terminal device may also be referred to as a terminal (Terminal), user equipment (UE), wireless terminal device, mobile terminal (MT) device, subscriber unit (subscriber unit), subscriber station (subscriber station), mobile station (MS), mobile station (mobile), remote station (remote station), access point (AP), remote terminal device (remote terminal), access terminal device (access terminal), user terminal device (user terminal), user agent (user agent), or user equipment (user device), etc. In addition, the terminal device can be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) device, an augmented reality (AR) device, an extended reality (XR) business terminal, a cloud gaming (CG) business terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, 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, etc. It should be understood that the embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal device. The terminal device in the present application can be any of the above-mentioned devices or chips, and is not specifically limited here. Whether as a device or as a chip, the terminal device can be manufactured, sold or used as an independent product. In this embodiment and subsequent embodiments, the terminal device is used as an example for introduction.

[0108] An access network device can be any device with wireless transceiver capabilities and can be responsible for air interface-related functions, such as radio link maintenance, radio resource management, and some mobility management functions. Furthermore, the access network device can be equipped with a baseband unit (BBU) that performs baseband signal processing. For example, the access network device can be the radio access network (RAN) currently providing services to a terminal device. Currently, some common examples of access network equipment include: Node B (NB), evolved Node B (eNB or eNodeB), next generation Node B (gNB) in 5G new radio (NR) systems, nodes in 6G systems (e.g., xNodeB), transmission reception point (TRP), radio network controller (RNC), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved NodeB or home node (HNB)), etc. In addition, in network structures such as cloud radio access network (CloudRAN) or open radio access network (ORAN), access network equipment can be a device including a centralized unit (CU) (also called a control unit) and / or a distributed unit (DU). Among them, the RAN equipment including the CU and DU splits the protocol layer of the gNB in ​​the NR system. The functions of some protocol layers are centrally controlled by the CU, and the functions of some or all of the remaining protocol layers are distributed in the DU, which is centrally controlled by the CU. Furthermore, as shown in Figure 1, the CU can also be divided into the control plane (CU-CP) and the user plane (CU-UP). Among them, the CU-CP is responsible for the control plane functions, mainly including radio resource control (RRC) and the packet data convergence protocol (PDCP) (PDCP-C) corresponding to the control plane. PDCP-C is mainly responsible for encryption and decryption of control plane data, integrity protection, and data transmission.The CU-UP is responsible for user plane functions, primarily including the Service Data Adaptation Protocol (SDAP) and the corresponding PDCP (i.e., PDCP-U) for the user plane. SDAP is primarily responsible for processing core network data and mapping flows to bearers. PDCP-U is primarily responsible for data plane encryption and decryption, integrity protection, header compression, sequence number maintenance, and data transmission. The CU-CP and CU-UP are connected via the E1 interface. The CU-CP represents the gNB and connects to the core network via the NG interface. Furthermore, the CU-CP connects to the DU via the F1 interface control plane (i.e., F1-C). The CU-UP connects to the DU via the F1 interface user plane (i.e., F1-U). Alternatively, the PDCP-C is also located within the CU-UP. It should be understood that the access network device in the embodiments of this application may be any of the aforementioned devices or chips within such devices, and the specifics are not limited here. Whether as a device or a chip, the access network device can be manufactured, sold, or used as a standalone product. In this and subsequent embodiments, the access network device is used as an example.

[0109] It should be noted that in the handover process, the access network device providing services to the terminal device before the handover is referred to as the source access network device, and the access network device providing services to the terminal device after the handover is referred to as the target access network device. Furthermore, the access network devices that may provide services to the terminal device before and after the handover are referred to as candidate access network devices. The target access network device can be one of at least one candidate access network device.

[0110] Optionally, the communication method proposed in the present application can be applied to non-terrestrial networks (NTN) architecture or terrestrial networks (TN) architecture. Exemplarily, the aforementioned NTN architecture can be a non-terrestrial communication network (NTN-based NG-RAN architectures) based on the NG-RAN architecture defined in the 3GPP protocol. At this time, some or all of the functions of the aforementioned access network device can be implemented through non-terrestrial communication network equipment (for example, at least one of a satellite, a tethered unmanned aerial system (TUA), a lighter than air UAS (LTA), a heavier than air UAS (HTA), and a high altitude platform station (HAPS)); or, the access network device provides services to the terminal device through the non-terrestrial communication network device.

[0111] The communication method provided in the present application is mainly used in scenarios where RACH-LESS switching is adopted, that is, the terminal device does not perform a random access process when switching, but obtains uplink resources for sending uplink data to the target access network device through other means, and sends initial uplink data (such as a switching completion message) to the target base station. In order for the terminal device to quickly obtain uplink resources when the switching is triggered, the uplink resources (for example, CG resources) pre-allocated by the candidate access network device to the terminal device are generally included in the RRC reconfiguration message (for example, a switching command) sent by the source access network device to the terminal device, or the dynamic uplink resources (for example, DG resources) indicated by the PDCCH sent by the candidate access network device to the terminal device are used as uplink resources.

[0112] If the candidate access network device indicates DG resources to the terminal device through PDCCH, the candidate access network device sends PDCCH on each beam that the terminal device may use to ensure that the terminal device monitors PDCCH on the beam where the terminal device is located and obtains DG resources. For example, the candidate access network device may not know the beam where the terminal device is located, and the candidate access network device sends PDCCH on each beam in the candidate cell that the terminal device may access. However, the terminal device can generally obtain uplink resources by using the PDCCH sent in a certain beam. Therefore, the resources sent by the candidate access network device through PDCCH on other beams are wasted.

[0113] If the candidate access network device pre-allocates uplink resources for the terminal device, the candidate access network device may not know the beam where the terminal device is located. The candidate access network device configures CG resources for each beam in the candidate cell that the terminal device may access. However, when triggering a handover, the terminal device may only use the CG resources corresponding to a certain beam. Therefore, the CG resources configured by the candidate access network device on other beams are wasted.

[0114] To this end, the present application provides a communication method and communication device for improving the flexibility of access network device resource scheduling and reducing resource waste caused by the resource scheduling process in scenarios using RACH-LESS switching. For scenarios in which a target access network device allocates dynamic uplink resources to a terminal device, please refer to the relevant descriptions in the embodiments corresponding to Figures 2 and 3. For scenarios in which a candidate access network device configures pre-allocated uplink resources for a terminal device, please refer to the relevant descriptions in the embodiments corresponding to Figures 4 and 5.

[0115] FIG2 is a flowchart of an embodiment of the communication method provided by the present application. In this embodiment, the candidate access network device indicates the DG resources to the terminal device via the PDCCH. The terminal device, the source access network device, and the candidate access network device will perform the following steps:

[0116] Step 201: A source access network device sends a handover request message to at least one candidate access network device; correspondingly, at least one candidate access network device receives the handover request message from the source access network device.

[0117] Step 202: At least one candidate access network device sends a handover request acknowledgement message to the source access network device; accordingly, the source access network device receives the handover request acknowledgement message from the at least one candidate access network device.

[0118] In this embodiment, after making a handover decision, the source access network device may send a handover request message to the candidate access network device corresponding to the candidate cell determined for the terminal device. The candidate access network device performs access control. If the candidate access network device agrees to provide services to the terminal device in the subsequent process, the candidate access network device feeds back a handover request confirmation message to the source access network device. The handover request confirmation message includes a transparent container, which includes parameters such as the new cell radio network temporary identifier (C-RNTI) and the security-related algorithm of the candidate access network device.

[0119] In traditional handover, there is only one candidate access network device, which is the target access network device. In conditional handover, there can be one or more candidate access network devices, and the terminal device decides which candidate access network device to handover to. The candidate access network device that the terminal device decides to handover to is the target access network device.

[0120] In step 203, the terminal device sends indication information of at least one beam to the source access network device; correspondingly, the source access network device receives indication information of at least one beam from the terminal device.

[0121] The terminal device is a terminal device that adopts RACH-LESS switching. For example, the source access network device instructs the terminal device to adopt RACH-LESS switching through an RRC reconfiguration message (eg, a switching command).

[0122] Among them, the indication information of at least one beam is used to indicate at least one beam measured by the terminal device. Optionally, the beam indicated by the indication information of at least one beam is a newer beam measured by the terminal device that can reflect the location of the terminal device, so that after the terminal device reports the indication information of the at least one beam to the network side, the candidate access network device on the network side can more accurately determine one or more beams for sending PDCCH, without the need to send PDCCH in all beams in the candidate cell of the candidate access network device. Therefore, the indication information of at least one beam is used by at least one candidate access network device to determine the beam for sending PDCCH to the terminal device.

[0123] Optionally, the indication information of the at least one beam sent by the terminal device may be indication information of a beam in a candidate cell of the candidate access network device, or may be indication information of beams in multiple candidate cells of the candidate access network device. For example, the terminal device measures at least one beam in a candidate cell of the candidate access network device, and then sends the indication information of the at least one measured beam to the source access network device.

[0124] Optionally, the indication information of the aforementioned at least one beam includes the index of each beam in the at least one beam. Exemplarily, when the indication information of at least one beam only includes the index of the beam, the access network device can determine to which cell the beam belongs by other means. For example, the access network device determines the cell identifier by the measurement identifier corresponding to the index of the reported beam, and then determines to which cell the beam reported by the terminal device belongs. It should be noted that in some scenarios, the index of the beam is also called the beam number of the beam, the number of the beam, the identity (ID) of the beam, etc. This application only introduces the term "beam index".

[0125] Optionally, the indication information of at least one beam also includes a cell identifier corresponding to each beam in the at least one beam, wherein the cell identifier corresponding to the beam is used to indicate which cell's beam is measured by the terminal device, or which cell of which candidate access network device the beam belongs to.

[0126] Optionally, the indication information of at least one beam also includes an uplink signal resource number, a downlink signal resource number, an absolute index of the beam, a relative index of the beam, a logical index of the beam, an index of the antenna port corresponding to the beam, an antenna port group index corresponding to the beam, an index of the downlink signal corresponding to the beam, a time index of the downlink synchronization signal block corresponding to the beam, beam pair link (BPL) information, a transmit parameter (Tx parameter) corresponding to the beam, a receive parameter (Rx parameter) corresponding to the beam, a transmit weight corresponding to the beam, a weight matrix corresponding to the beam, a weight vector corresponding to the beam, a receive weight corresponding to the beam, an index of the transmit weight corresponding to the beam, an index of the weight matrix corresponding to the beam, an index of the weight vector corresponding to the beam, an index of the receive weight corresponding to the beam, a receive codebook corresponding to the beam, a transmit codebook corresponding to the beam, an index of the receive codebook corresponding to the beam, and an index of the transmit codebook corresponding to the beam.

[0127] In one example, the indication information of at least one beam includes a correspondence between a cell identifier and at least one beam, which can also be understood as including a cell identifier and an index of the beam under the cell.

[0128] For example, taking the beam indicated by the indication information of at least one beam as a beam of a cell as an example, the terminal device measures two beams, beam 1 and beam 2, in cell 1. The indication information of at least one beam reported by the terminal device includes the identifier of cell 1, the index of beam 1 and the index of beam 2, that is, {identifier of cell 1: index of beam 1, index of beam 2}, indicating that beam 1 and beam 2 are beams belonging to cell 1.

[0129] For example, taking the case where the beam indicated by the indication information of at least one beam includes beams of multiple cells, if the terminal device measures beams 1 and beam 2 in cell 1, and beams 3 and beam 4 in cell 2, the indication information of at least one beam reported by the terminal device includes the identifier of cell 1, the index of beam 1 in cell 1, and the index of beam 2; as well as the identifier of cell 2, the index of beam 3 in cell 2, and the index of beam 4. For example, the indication information of at least one beam in this example can be expressed in the following form:

[0130] {Cell 1 identifier: beam 1 index, beam 2 index;

[0131] Identifier of cell 2: index of beam 3, index of beam 4}.

[0132] In another example, the indication information of at least one beam includes a correspondence between each beam in the at least one beam and a cell identifier.

[0133] For example, taking the case where the beam indicated by the indication information of at least one beam is a beam of a cell, and the terminal device measures two beams, beam 1 and beam 2, in cell 1, the indication information of at least one beam reported by the terminal device includes the index of beam 1, the cell identifier corresponding to the index of beam 1, the index of beam 2, and the cell identifier corresponding to the index of beam 2. For example, the indication information of at least one beam can be expressed as {index of beam 1 - identifier of cell 1; index of beam 2 - identifier of cell 1}.

[0134] For example, taking the case where the beam indicated by the indication information of at least one beam includes beams of multiple cells, if the terminal device measures beam 1 and beam 2 in cell 1, and measures beam 3 in cell 2, then the indication information of at least one beam reported by the terminal device includes the index of beam 1, the cell identifier corresponding to the index of beam 1, the index of beam 2, the cell identifier corresponding to the index of beam 2, the index of beam 3, and the cell identifier corresponding to the index of beam 3. For example, the indication information of at least one beam in this example can be expressed in the following form:

[0135] {Beam 1 index - Cell 1 identifier;

[0136] Beam 2 index - Cell 1 ID;

[0137] Index of beam 3 - identifier of cell 2}.

[0138] Optionally, the aforementioned cell identifier may be a physical cell identifier (PCI), a global cell identifier (CGI), or a logical cell identifier, which is not limited here.

[0139] Optionally, the indication information of at least one beam also includes signal quality information of each beam in the at least one beam. The signal quality information of the beam is used to indicate the quality of the signal of the beam. Exemplarily, the signal quality information of the beam can be reference signal received power (RSRP), reference signal received quality (RSRQ), or signal to interference plus noise ratio (SINR), which is not limited here.

[0140] Exemplarily, the at least one beam may be a beam with better signal quality of the candidate cell measured by the terminal device; or, the at least one beam may be a beam suitable for receiving PDCCH from the candidate cell measured by the terminal device; or, the at least one beam may be a beam that is easy to monitor PDCCH from the candidate cell measured by the terminal device; or, the at least one beam may be a beam that meets the residence conditions of the terminal device.

[0141] In a possible implementation manner, each beam of at least one beam of a candidate cell reported by the terminal device satisfies any one of the following preset conditions:

[0142] In an exemplary preset condition, the beam reported by the terminal device is the beam with the best signal quality among the beams measured by the terminal device. Exemplarily, the terminal device compares the signal qualities of multiple beams measured in a certain neighboring area, and reports the beam with the best signal quality measured in the neighboring area to the source access network device in the form of beam indication information. The beam with the best signal quality can be the beam with the largest RSRQ value, the beam with the largest RSRP value, the beam with the largest SINR value, or the beam with the best comprehensive signal quality, which is not limited here. It can be understood that after the terminal device has reported the best beam of a candidate cell to the source access network device, when the best beam of the candidate cell measured by the terminal device changes, the terminal device reports the latest best beam to the source access network device in the form of beam indication information.

[0143] For example, the terminal device compares the signal qualities of multiple beams measured in a certain neighboring area, and reports the first few beams ranked from high to low in signal quality measured in the neighboring area to the source access network device in the form of beam indication information. The signal quality can be an RSRQ value, an RSRP value, an SINR value, or a comprehensive assessment of signal quality, which is not limited here. The specific number of beams reported can be determined by the terminal device, or the access network device can instruct the terminal device to report the number of beams.

[0144] In another exemplary preset condition, the signal quality of the beam reported by the terminal device is greater than or equal to a reference threshold. The reference threshold can be determined by the terminal device itself or configured by the source access network device. The reference threshold can be one or more of an RSRP value, an RSRQ value, and a SINR value. Exemplarily, the terminal device reports beams whose measured signal quality is greater than or equal to the reference threshold to the source access network device in the form of beam indication information.

[0145] In another exemplary preset condition, the signal quality of the beam reported by the terminal device is greater than or equal to the signal quality of the reference beam. The beam reported by the terminal device is different from the reference beam. Exemplarily, the reference beam can be a beam reported by the terminal device to the source access network device at a certain moment in history (for example, a beam sent by the terminal device to the source access network device for the source access network device to perform a switching decision), or it can be a beam determined by the source access network device, which is not limited here. The beam reported by the terminal device is different from the reference beam in that the index of the beam is different. For example, the indexes of the beam reported by the terminal device are index 1 and index 2, while the index of the reference beam is index 3. Exemplarily, the terminal device reports the beam whose measured signal quality is greater than or equal to the signal quality of the reference beam to the source access network device in the form of beam indication information.

[0146] In another exemplary preset condition, the signal quality of the beam reported by the terminal device is greater than or equal to the reference threshold, and the beam reported by the terminal device is different from the reference beam. Exemplarily, the reference beam can be a beam reported by the terminal device to the source access network device at a certain moment in history (for example, a beam sent by the terminal device to the source access network device for the source access network device to perform a switching decision), or it can be a beam determined by the source access network device, which is not limited here. Exemplarily, the terminal device measures a signal quality greater than or equal to the reference threshold, and the beam that does not belong to the reference beam is reported to the source access network device in the form of beam indication information.

[0147] It can be understood that the reference beam can be a reference beam of a neighboring cell sent by the access network device, and the terminal measures the beam of the neighboring cell and compares it with the reference beam.

[0148] It should be noted that the terminal device may report the beam indication information periodically or based on an event, such as based on a preset condition.

[0149] It should be noted that the indication information of at least one beam sent by the terminal device to the source access network device can be determined based on the physical layer measurement result (i.e., the layer 1 measurement result), or based on the measurement result after filtering the physical layer measurement result (i.e., the measurement result after layer 1 filtering), or based on the measurement result after filtering reported to the RRC layer after the physical layer measurement (i.e., the measurement result after layer 3 filtering). There is no limitation here.

[0150] It should be noted that when the terminal device measures and makes a signal quality judgment, if the measured beam is continuously greater than a certain threshold within a continuous period, the beam is considered to meet the threshold condition.

[0151] It should also be noted that in this step, the indication information of at least one beam sent by the terminal device to the source access network device can be reported by the terminal device based on the measurement configuration in the traditional technology, or can be reported based on the measurement configuration newly issued by the source access network device. The following are introduced respectively:

[0152] In a possible implementation, before the source access network device sends a handover request message to the candidate access network device, the source access network device sends measurement configuration information to the terminal device (for example, measurement configuration 1 in the embodiment corresponding to Figure 3), and the measurement configuration information is used to instruct the terminal device to report the measurement result of the beam. The source access network device makes a handover decision based on the measurement result of the beam reported by the terminal device this time. In the present application, after the terminal device reports the measurement result of the beam used by the source access network device to perform the handover decision, the terminal device can also measure the beam of the neighboring area and report the measured beam measurement result to the source access network device again, and the measurement result includes beam indication information. For example, the terminal device can continuously or periodically report the measurement result of the beam. For example, the terminal device can continuously or periodically report the measurement result of the beam before triggering the handover.

[0153] Optionally, the beam most recently reported by the terminal device is a different beam than the beam that has been reported. Optionally, the beam most recently reported by the terminal device is a beam that meets the aforementioned preset conditions. The terminal device can report the indication information of one beam through one message, or can report the indication information of multiple beams through one message. The terminal device can report the indication information of one or more beams of a cell, and the terminal device can also report the indication information of one or more beams corresponding to multiple cells.

[0154] In another possible implementation, the source access network device sends newly defined measurement configuration information (e.g., measurement configuration 2 in the embodiment corresponding to FIG3 ) to the terminal device. The measurement configuration information is used to instruct the terminal device to report indication information of beams that meet preset conditions. The terminal device measures the beams of the neighboring cell based on the received newly defined measurement configuration information, and reports at least one measured beam that meets the preset conditions to the source access network device in the form of beam indication information.

[0155] Optionally, the measurement configuration information includes indication information and / or a reference threshold of the reference beam. The indication information of the reference beam includes the index of the reference beam. Optionally, the indication information of the reference beam also includes the cell identifier of the cell where the reference beam is located. Optionally, the indication information of the reference beam also includes signal quality information of the reference beam. Optionally, the indication information of the reference beam also includes a quality type based on the reference beam (such as RSRP, RSRQ, and SINR, etc.). The reference beam can be determined by the source access network device based on the measurement report reported historically by the terminal device, or it can be selected autonomously by the source access network device, which is not limited here. The reference threshold refers to the threshold of the signal quality of the beam.

[0156] Optionally, the measurement configuration information also includes an upper limit on the number of reported beams, that is, the maximum number of beams of a certain neighboring cell that meets the conditions reported by the terminal device. For example, the upper limit on the number of reported beams is a, and the number of beams of a certain neighboring cell that meets the preset conditions measured by the terminal device is b, where a and b are both positive integers. If b is less than a, the terminal device can report indication information of b beams through one message; if b is greater than a, the terminal device can report indication information of a maximum of a beams through one message.

[0157] Optionally, the measurement configuration information may also include parameters such as measurement interval, number of reports, evaluation duration, cycle duration, reference signal type, etc., which are not limited in this application.

[0158] It should be noted that the reference threshold may be a threshold based on RSRP, a threshold based on RSRQ, or a threshold based on SINR.

[0159] Optionally, the measurement configuration information also includes a cell identifier of at least one candidate cell to indicate that the terminal device needs to measure the cell indicated by the cell identifier. When the measurement configuration information does not include a cell identifier, the terminal device defaults to measuring at least one neighboring cell, which may include one or more candidate cells.

[0160] Optionally, the measurement configuration information is the measurement configuration information of the RRC layer (i.e., layer 3 measurement configuration information); or, the measurement configuration information is the measurement configuration information of the physical layer (i.e., layer 1 measurement configuration information). The measurement configuration of the RRC layer refers to reporting the measurement results through the RRC layer. The measurement configuration of the physical layer is to report the measurement results through the physical layer (for example, the physical uplink control channel (PUCCH) or the physical uplink shared channel (PUSCH)). The physical layer measurement configuration can be sent down through RRC layer signaling or through physical layer measurement configuration. For example, if the source access network device sends down the measurement configuration information of the physical layer (i.e., layer 1 measurement configuration information), the terminal device performs physical layer measurement, and the indication information of at least one beam sent by the terminal device to the source access network device may be the physical layer measurement result (i.e., layer 1 measurement result) or the measurement result after the physical layer measurement result is filtered (i.e., layer 1 filtered measurement result); if the source access network device sends down the measurement configuration information of the RRC layer (i.e., layer 3 measurement configuration information), the terminal device performs RRC layer measurement, and the indication information of at least one beam sent by the terminal device to the source access network device is the measurement result after the physical layer measurement is reported to the RRC layer for filtering (i.e., layer 3 filtered measurement result).

[0161] Step 203 is an optional step.

[0162] In step 204, the source access network device sends indication information of at least one beam to at least one candidate access network device; correspondingly, the at least one candidate access network device receives indication information of at least one beam from the source access network device.

[0163] It should be noted that the beam indicated by the indication information of at least one beam reported by the terminal device to the source access network device in step 203 may be different from the beam indicated by the indication information of at least one beam sent by the source access network device to at least one candidate access network device in step 204.

[0164] The indication information of at least one beam received by the source access network device from the terminal device may include multiple beams of the same cell, multiple beams of different cells of the same access network device, or beams of multiple cells belonging to different access network devices. The source access network device may send the indication information of at least one beam to the candidate access network device through any of the following implementations.

[0165] In one possible implementation, the source access network device sends beam indication information for a cell of the candidate access network device to the candidate access network device. The candidate access network device receives beam indication information for its own cell. For example, if cell a belongs to candidate access network device A, the source access network device sends beam indication information for cell a to access network device A.

[0166] Illustratively, the indication information of at least one beam indicates three beams, namely beam 1, beam 2, and beam 3, where beam 1 and beam 2 belong to cell 1 of candidate access network device 1, and beam 3 belongs to cell 2 of candidate access network device 2. The source access network device sends the indication information of beam 1 and beam 2 of cell 1 to candidate access network device 1, and sends the indication information of beam 3 of cell 2 to candidate access network device 2.

[0167] In another possible implementation, the source access network device may transparently transmit the indication information of at least one beam to at least one candidate access network device, that is, each candidate access network device receives the indication information of the aforementioned at least one beam, that is, the content of the indication information of the at least one beam received by each candidate access network device is the same. The candidate access network device determines that the beam indicated by the indication information of at least one beam belongs to the beam of the candidate access network device based on the beam index in the indication information of at least one beam and / or the cell identifier corresponding to the beam. Optionally, the indication information of the beam includes the cell identifier corresponding to the beam and the index of the beam.

[0168] Exemplarily, the indication information of at least one beam indicates three beams, namely beam 1, beam 2 and beam 3, wherein beam 1 and beam 2 belong to cell 1 of candidate access network device 1, and beam 3 belongs to cell 2 of candidate access network device 2. The indication information of at least one beam sent by the source access network device to the candidate access network device 1 includes the indication information of the beam of cell 1 (for example, the identifier of cell 1, the index of beam 1 and the index of beam 2) and the indication information of the beam of cell 2 (for example, the identifier of cell 2 and the index of beam 3), and the indication information of at least one beam sent by the source access network device to the candidate access network device 2 includes the indication information of the beam of cell 1 (for example, the identifier of cell 1, the index of beam 1 and the index of beam 2) and the indication information of the beam of cell 2 (for example, the identifier of cell 2 and the index of beam 3).

[0169] It should be noted that the source access network device can newly define a message for sending indication information of at least one beam to at least one candidate access network device, or it can reuse the message in the traditional technology to send an indication signal of at least one beam to at least one candidate access network device. This application is not limited.

[0170] It should be noted that when an interface exists between the source access network device and the candidate access network device, messages containing beam indication information can be transmitted directly. When no interface exists between the source access network device and the candidate access network device, messages containing beam indication information can be transmitted through the core network. That is, the source access network device sends the message to the core network, which then passes it to the candidate access network device. When the source access network device and the candidate access network device are connected to different core networks, the message can be transparently transmitted between the core networks.

[0171] Optionally, the source access network device may further include one or more of the following in the message sending the indication information of at least one beam:

[0172] Information such as the identifier assigned by the source access network device to the terminal device and the identifier assigned by the candidate access network device to the terminal device.

[0173] It should also be noted that the source access network device can send beam indication information multiple times. For example, when the beam indication information of a neighboring cell reported by the terminal device changes, the source access network device can report the updated beam indication information of the neighboring cell to the candidate access network device. For another example, the source access network device can send beam indication information multiple times for the same candidate cell to update the beam information to the candidate cell.

[0174] Step 205: The candidate access network device sends a PDCCH to the terminal device based on the indication information of at least one beam; accordingly, the terminal device receives the PDCCH from the candidate access network device.

[0175] For example, the candidate access network device sends a PDCCH indicating uplink resources to the terminal device based on the indication information of at least one beam; accordingly, the terminal device monitors the PDCCH from the candidate access network device to obtain uplink resources.

[0176] Step 205 is an optional step.

[0177] Optionally, the candidate access network device transmits a PDCCH through a beam of a cell belonging to the candidate access network device in indication information of at least one beam, and downlink control information (DCI) carried in the PDCCH indicates an uplink resource allocated to the terminal device. For example, the uplink resource is a physical uplink shared channel (PUSCH), and the PDCCH indicates the time-frequency domain position of the PUSCH.

[0178] Exemplarily, the indication information of at least one beam indicates three beams, namely beam 1, beam 2, and beam 3, where beam 1 and beam 2 belong to cell 1 of candidate access network device 1, and beam 3 belongs to cell 2 of candidate access network device 2. Candidate access network device 1 sends a PDCCH on beam 1 and beam 2 of cell 1, where the DCI in the PDCCH indicates the time-frequency domain position of the uplink resource.

[0179] It should be noted that when a terminal device determines a target cell for RACH-LESS handover, it selects at least one beam of the target cell and monitors the PDCCH on that beam. The target cell is a cell of one of at least one candidate access network devices. The candidate access network device where the target cell resides is also referred to as the target access network device. The one beam of the target cell selected by the terminal device is a beam that meets the conditions measured by the terminal device. For example, the beam with the best signal quality in the target cell measured by the terminal device.

[0180] It should be noted that the handover in this application can be a handover through an Xn interface or a handover through an NG interface, and this application does not limit the handover type. The handover in this application can be any of traditional handover, conditional handover (CHO), layer 1 or layer 2 triggered mobility (L1 / L2-Triggered Mobility, LTM) handover, or subsequently introduced handover, and is not limited here.

[0181] In the present application, the source access network device is able to send indication information of at least one beam to at least one candidate access network device after receiving a handover request confirmation message. In conventional technology, the source access network device may only carry the measurement results reported by the terminal device in the handover request, and the measurement results may include cell-based measurement results or beam-based measurement results. In the present application, the source access network device has the ability to send indication information of at least one beam to the candidate access network device after sending a handover request message to the candidate access network device. This is beneficial for the candidate cell of the candidate access network device to determine the beam for sending the PDCCH based on the indication information of at least one beam, rather than sending the PDCCH on each beam in the candidate cell of the candidate access network device. Therefore, when the beam of the candidate cell measured by the terminal device changes, the beam for sending the PDCCH can also be accurately determined, thereby improving the sending accuracy of the base station, so that the terminal device can decode the PDCCH in advance to obtain uplink resources, reduce the handover delay, and improve the handover efficiency.

[0182] Furthermore, in one possible implementation, the handover request message in step 201 includes indication information of at least one first beam measured by the terminal device. For example, before making a handover decision, the source access network device can receive beam measurement results reported by the terminal device, i.e., indication information of at least one first beam. The source access network device then sends the beam measurement results reported by the terminal device to at least one candidate access network device via a handover request message.

[0183] Optionally, the beam indicated by the indication information of at least one beam is different from the beam indicated by the indication information of at least one first beam. For ease of description, the indication information of at least one first beam sent by the source access network device to at least one candidate access network device via the handover request message in step 201 is referred to as indication information of a first beam set, where the first beam set includes at least one first beam; and the indication information of at least one beam sent by the source access network device to at least one candidate access network device in step 204 is referred to as indication information of a second beam set, where the second beam set includes at least one beam.

[0184] Optionally, when the beam in the same cell changes, the source access network device sends indication information of the second beam set, that is, the beam belonging to a certain cell in the second beam set has changed compared to the beam of the cell in the first beam set.

[0185] In one example, the beam indicated by the indication information of at least one beam is completely different from the beam indicated by the indication information of at least one first beam. That is, the beam indicated by the indication information of the first beam set is completely different from the beam indicated by the indication information of the second beam set. For example, the indication information of the first beam set indicates beam 1 and beam 2 in cell 1, and the indication information of the second beam set indicates beam 3 and beam 4 in cell 1.

[0186] In another example, the beam indicated by the indication information of at least one beam is partially the same as the beam indicated by the indication information of at least one first beam. That is, the beam indicated by the indication information of the first beam set is not completely different from the beam indicated by the indication information of the second beam set. For example, the indication information of the first beam set indicates beam 1 and beam 2 in cell 1, and the indication information of the second beam set indicates beam 2 and beam 3 in cell 1.

[0187] It can be understood that, compared to the indication information of the first beam set, the indication information of the second beam set is the indication information of the updated beam, or refers to the indication information of the new beam after the beam information of the neighboring cell measured by the terminal has changed. This is conducive to the candidate access network device determining which beam is more suitable for sending the PDCCH to the terminal device based on the indication information of at least one updated beam, rather than determining the beam for sending the PDCCH for the terminal device based on the indication information of at least one first beam that may be outdated or invalid. Therefore, it is conducive to improving the flexibility and accuracy of the candidate access network device in scheduling resources and improving the efficiency of scheduling uplink resources for terminal devices.

[0188] In addition, it should be noted that the "handover" involved in this application may be conditional handover (CHO), which is a handover method proposed by the new radio (NR) system, referring to cell handover based on conditional triggering, which is used to improve the robustness of the terminal device when performing cell handover. In this case, the aforementioned handover request message is a conditional handover request (CHO request) message; the aforementioned handover request confirmation message is a conditional handover request acknowledgement (CHO request ACK) message; the source access network device configures conditional handover for the terminal device by carrying the conditional configuration of the conditional handover CHO in the RRC reconfiguration message; at least one candidate access network device is a candidate access network device for configuring conditional handover; the target access network device triggered by the terminal device is a candidate access network device that meets the conditional handover event measured by the terminal device.

[0189] Since there is a period of time between the terminal device obtaining the conditional configuration of the conditional handover CHO from the RRC reconfiguration message and the terminal device measuring the target cell of the target access network device that meets the handover event, the best beam measured by the terminal device in the neighboring cell during this period may no longer be the beam reported by the terminal device to the source access network device before the source access network device executes the handover decision, or the candidate access network device has not received the measurement result of the beam reported by the terminal device before the source access network device executes the handover decision. Therefore, the source access network device reports the indication information of at least one beam to at least one candidate access network device, which is conducive to reporting the latest beam measurement result measured by the terminal device to at least one candidate access network device, and further conducive to the candidate access network device determining the beam that is more suitable for the terminal device to send PDCCH based on the indication information of at least one beam, rather than sending PDCCH to each beam in the candidate cell of the candidate access network device. Therefore, when the beam of the candidate cell measured by the terminal device changes, the beam of the PDCCH can be accurately determined, thereby improving the accuracy of the base station's transmission, so that the terminal device can decode the PDCCH in advance to obtain uplink resources, reduce switching delay, and improve switching efficiency.

[0190] In addition, when the NTN system introduces RACH-LESS, the cell measured by the terminal device may change due to the movement of the NTN access network equipment (for example, satellite), and thus the optimal beam measured by the terminal device may also change. In the present application, the source satellite reports the indication information of at least one beam to at least one candidate satellite, which is conducive to reporting the latest beam measurement result measured by the terminal device to at least one candidate satellite, and thus helps the candidate satellite to determine the beam that is more suitable for the terminal device based on the indication information of at least one beam to send PDCCH, rather than sending PDCCH to each beam in the candidate cell of the candidate satellite. Therefore, when the beam of the candidate cell measured by the terminal device changes, the beam for sending PDCCH can be accurately determined, thereby improving the accuracy of the base station's sending, so that the terminal device can decode the PDCCH in advance to obtain uplink resources, reduce switching delay, and improve switching efficiency.

[0191] The communication method provided by this application is further described below in conjunction with Figure 3. As shown in Figure 3, a flow chart of an embodiment of the communication method proposed by this application is provided in the scenario of using the RACH-LESS process during conditional switching. In this embodiment, the terminal device, the source access network device, and the candidate access network device will perform the following steps:

[0192] Step 301: The source access network device sends measurement configuration 1 to the terminal device; correspondingly, the terminal device receives measurement configuration 1 from the source access network device.

[0193] Among them, measurement configuration 1 is used to instruct the terminal device to measure and report the cell signal quality of the neighboring area that meets the conditions, and / or, to instruct the terminal device to measure and report the signal quality of the beam of the neighboring area that meets the conditions.

[0194] Exemplarily, measurement configuration 1 is measurement configuration such as A3, A4 or A5.

[0195] Step 302: The terminal device sends a measurement report 1 to the source access network device; correspondingly, the source access network device receives the measurement report 1 from the terminal device.

[0196] The measurement report 1 includes measurement results of one or more beams, and the measurement results include indication information of at least one first beam, hereinafter referred to as indication information of the first beam set.

[0197] Optionally, the source access network device determines the indication information of the reference beam based on the indication information of the first beam set, where the indication information of the reference beam is used to indicate one reference beam or multiple reference beams. Exemplarily, the source access network device uses the beam with better signal quality in the first beam set as the reference beam. For example, if the first beam set includes four beams, and the signal quality of the four beams is sorted from low to high as beam 1, beam 3, beam 2, and beam 4, and the source access network device needs to determine two reference beams, the source access network device can determine beam 1 and beam 3 as the reference beams.

[0198] Optionally, the indication information of the first beam set includes an index of each beam in the first beam set.

[0199] Optionally, the indication information of the first beam set further includes a cell identifier corresponding to each beam in the first beam set.

[0200] Optionally, the indication information of the first beam set further includes signal quality information of each beam in the first beam set.

[0201] It should be noted that steps 301 and 302 are optional. For example, the source access network device may not require the terminal device to measure beam or cell signal quality before making a handover decision. For example, in traditional handovers, the source access network device must make decisions based on measurement reports. However, in conditional handover scenarios, or NTN communication scenarios, the source access network device can predict the cells in the area to be covered, and therefore can make handover decisions without relying on measurement reports.

[0202] After the source access network device and the terminal device execute steps 301 and 302, the source access network device may make a handover decision based on measurement report 1. For example, the source access network device may determine whether to use conditional handover (CHO) based on measurement report 1 and radio resource management (RRM) information. In another example, the source access network device may determine at least one candidate access network device based on measurement report 1, i.e., an access network device that may provide services to the terminal device after handover.

[0203] Step 303: The source access network device sends a handover request message to at least one candidate access network device; correspondingly, the at least one candidate access network device receives the handover request message from the source access network device.

[0204] Optionally, the handover request message is a conditional handover request message. If the source access network device decides to use conditional handover, the source access network device sends a conditional handover request message to at least one candidate access network device. That is, the source access network device sends a conditional handover request message to each candidate cell of each candidate access network device. The conditional handover request message is used by the candidate cell of the candidate access network to prepare resources for the terminal device.

[0205] Optionally, the switching request message includes measurement report 1, and measurement report 1 includes indication information of the first beam set.

[0206] Step 304: The candidate access network device sends a handover request confirmation message to the source access network device; correspondingly, the source access network device receives the handover request confirmation message from the candidate access network device.

[0207] Optionally, the handover request confirmation message is a conditional handover request confirmation (Handover Request ACK) message. After the source access network device sends a conditional handover request (Handover Request) message to at least one candidate access network device, if the candidate cell of the candidate access network device successfully admits the terminal device, the candidate access network device sends a conditional handover request confirmation message to the source access network device.

[0208] Optionally, the conditional handover request confirmation message includes the configuration of the CHO candidate cell.

[0209] Step 305: The source access network device sends an RRC reconfiguration message to the terminal device; accordingly, the terminal device receives the RRC reconfiguration message from the source access network device.

[0210] The RRC reconfiguration message includes first indication information and a CHO configuration of a cell of at least one candidate access network device, wherein the first indication information is used to instruct the terminal device to adopt RACH-LESS handover. Optionally, the CHO configuration includes an identifier of an applicable cell for CHO, a measurement identifier corresponding to the CHO, a measurement object (MO) corresponding to the CHO determined by the terminal device through the measurement identifier, and events that the applicable cell for CHO needs to meet.

[0211] Optionally, the RRC reconfiguration message does not include uplink resources pre-allocated by the candidate access network device.

[0212] It should be noted that, in traditional handover, the RRC reconfiguration message is used to trigger the terminal device to perform handover; in conditional handover, the RRC reconfiguration message contains information such as the CHO configuration and the CHO triggering condition. Therefore, in some scenarios, the RRC reconfiguration message is also called a handover command. For example, a reconfiguration message containing the reconfigurationWithSync information element is called a handover command.

[0213] Step 306: The source access network device sends measurement configuration 2 to the terminal device; correspondingly, the terminal device receives measurement configuration 2 from the source access network device.

[0214] Measurement configuration 2 is newly defined measurement configuration information by the source access network device, and can also be understood as a preset condition issued by the source access network device to the terminal device. Measurement configuration 2 is used to instruct the terminal device to report indication information for a beam that meets the preset condition. Exemplarily, the beam that meets the preset condition can be the beam with the best signal quality among the beams measured by the terminal device, or a beam with a signal quality greater than or equal to a reference threshold, or a beam with a signal quality greater than or equal to the signal quality of a reference beam.

[0215] Optionally, measurement configuration 2 includes indication information and / or a reference threshold of a reference beam. The indication information of the reference beam includes an index of the reference beam. Optionally, the indication information of the reference beam also includes a cell identifier of a cell where the reference beam is located. Optionally, the indication information of the reference beam also includes signal quality information of the reference beam. The reference beam can be determined by the source access network device based on a beam historically reported by the terminal device (for example, the reference beam is determined by the source access network device based on the first beam set in step 302), or it can be independently selected by the source access network device, which is not limited here. The reference threshold refers to the threshold of the signal quality of the beam.

[0216] Optionally, the measurement configuration information further includes a cell identifier of at least one candidate cell.

[0217] Optionally, measurement configuration 2 also includes parameters such as the upper limit of the number of reported beams, the measurement interval, the number of reports, and the evaluation duration, which are not limited in this application. Optionally, measurement configuration 2 is the measurement configuration information of the RRC layer (i.e., layer 3 measurement configuration information); or, the measurement configuration information is the measurement configuration information of the physical layer (i.e., layer 1 measurement configuration information).

[0218] Specifically, please refer to the introduction of the newly defined measurement configuration information of the source access network device in step 203 above, which will not be described in detail here.

[0219] It should be noted that step 306 is optional. If the source access network device executes step 306, that is, the source access network device issues measurement configuration 2 to the terminal device, then measurement report 2 reported by the terminal device to the source access network device in step 307 is the measurement result obtained by the terminal device based on measurement configuration 2. If the source access network device does not execute step 306, that is, the source access network device does not issue measurement configuration 2 to the terminal device, then measurement report 2 reported by the terminal device to the source access network device in step 307 is the measurement result obtained by the terminal device based on measurement configuration 1. The following description only uses the example of a terminal device performing measurements based on measurement configuration 2.

[0220] Step 307: The terminal device sends a measurement report 2 to the source access network device; correspondingly, the source access network device receives the measurement report 2 from the terminal device.

[0221] Step 307 is an optional step.

[0222] Among them, measurement report 2 includes information of at least one beam, which is hereinafter referred to as the information of at least one beam as the indication information of the second beam set. It can be understood that the beam indicated by the indication information of the second beam set is the beam that meets the preset conditions measured by the terminal device. After the terminal device reports the indication information of the second beam set to the network side, the candidate access network device on the network side can more accurately determine one or more beams for sending PDCCH for scheduling uplink resources, without the need to send PDCCH to all beams in the candidate cell of the candidate access network device. Therefore, the indication information of the second beam set is used by at least one candidate access network device to determine the beam to send PDCCH to the terminal device.

[0223] Optionally, the beams included in the second beam set are different from the beams included in the first beam set. In one example, the beams included in the second beam set are not exactly the same as the beams included in the first beam set. For example, the first beam set includes beam 1 and beam 2 in cell 1, and the second beam set includes beam 2 and beam 3 in cell 1. In another example, the beams included in the second beam set are completely different from the beams included in the first beam set. For example, the first beam set includes beam 1 and beam 2 in cell 1, and the second beam set includes beam 3 and beam 4 in cell 1. Since the second beam set is an indication information of an updated beam compared to the first beam set, it is beneficial for the candidate access network device to determine a beam that is more suitable for the terminal device to send PDCCH based on the indication information of the updated second beam set, rather than determining the beam for sending PDCCH for the terminal device based on the indication information of the first beam set that may be outdated or invalid.

[0224] Optionally, the indication information of the second beam set includes an index of each beam in the second beam set. Optionally, the indication information of the second beam set also includes a cell identifier corresponding to each beam in the second beam set. Optionally, the indication information of the second beam set also includes signal quality information for each beam in the second beam set. For an explanation of the indication information of the second beam set, please refer to the description of the indication information of at least one beam in step 203 above and will not be repeated here.

[0225] The terminal device performs measurements based on measurement configuration 2. The specific measurement process of the terminal device varies depending on the content of measurement configuration 2. The following examples are given:

[0226] In one embodiment, measurement configuration 2 does not include indication information and a reference threshold of a reference beam. If measurement configuration 2 includes the cell identifier of a candidate cell that the terminal device needs to measure, the terminal device reports the beam with the best signal quality among the beams of the candidate cell measured. For example, the terminal device reports the beam with the best signal quality among the multiple beams currently measured. Optionally, if the terminal device continues measuring, and the beam with the best signal quality measured by the terminal device changes during subsequent measurements, the terminal device may report the beam with the best signal quality currently measured again. Optionally, the terminal device may periodically report the best measured beam. That is, the terminal device in this example may execute step 307 multiple times, i.e., report measurement report 2 multiple times, and each measurement report 2 reported includes indication information of the beam with the best signal quality measured when the terminal device sends measurement report 2. For example, at time T1, the terminal device measures that the signal quality of beam 1 in neighboring cell A is the best, then the terminal device sends measurement report 2 carrying indication information of beam 1 in neighboring cell A to the source access network device; at time T1+ΔT, the terminal device measures that the signal quality of beam 2 in neighboring cell A is the best, then the terminal device sends measurement report 2' carrying indication information of beam 2 in neighboring cell A to the source access network device.

[0227] In another embodiment, measurement configuration 2 includes indication information of a reference beam, but does not include a reference threshold. In one example, the terminal device can report indication information of a beam. For example, when the beam with the best signal quality measured by the terminal device is different from the reference beam, the terminal device reports the beam with the best signal quality. Optionally, if the terminal device continues to measure, and the beam with the best signal quality measured by the terminal device changes in a subsequent measurement process, the terminal device can report again the beam with the best signal quality currently measured. In another example, the terminal device may also report indication information of multiple beams. For example, the terminal device reports to the source access network device all beams whose measured signal quality is better than the reference beam. Optionally, if the terminal device continues to measure, and the beam with the best signal quality measured by the terminal device in a subsequent measurement process changes, the terminal device can report again the beam whose currently measured signal quality is better than the reference beam.

[0228] In another embodiment, measurement configuration 2 includes a reference threshold but does not include indication information of a reference beam. The terminal device reports the measured beams in the cell that meet the reference threshold, that is, the terminal device reports the beams in the measured cell A whose signal quality is greater than the reference threshold, and reports the beams in the measured cell B whose signal quality is greater than the reference threshold. The beams with signal quality greater than the reference threshold may be one beam or multiple beams. Optionally, if the terminal device continues to measure, and the beam that meets the reference threshold changes compared to the beam reported last time, the terminal device reports the updated beam that meets the reference threshold to the source access network device. Optionally, the terminal device may report the updated beam to the source access network device when it measures a beam that is different from the beam reported last time; the terminal device may also report the updated multiple beams to the source access network device when it measures multiple beams that are all different from the beam reported last time. Optionally, measurement configuration 2 includes a reference threshold and a cell identifier, which means that if the beam of the cell with the cell identifier measured by the terminal device meets the reference threshold, the beam that meets the reference threshold will be reported. Optionally, the terminal can be configured to report periodically, reporting the beam that meets the reference threshold in each period. If there is no beam that meets the threshold, no report will be made.

[0229] In another embodiment, the measurement configuration 2 includes indication information of a reference threshold and a reference beam. The terminal device reports the measured beams that meet the reference threshold and are not reference beams to the source access network device. Optionally, the indication information of the reference beam indicates multiple reference beams. In one example, the terminal device measures multiple beams and the results meet the reference threshold. When the multiple measured beams are not within the range of the reference beam, the terminal device triggers reporting the indication information of the measured multiple beams to the source access network device. In another example, when the terminal device measures at least one beam that meets the reference threshold, and one or more of the measured beams are not within the range of the reference beam, the terminal device triggers reporting the indication information of the measured beams to the source access network device.

[0230] It should be noted that in the above examples, the beam with the best signal quality can be the beam with the largest RSRQ value, the beam with the largest RSRP value, the beam with the largest SINR value, or the beam with the best comprehensive signal quality evaluation, which is not limited here.

[0231] Step 308: The source access network device sends message 1 to at least one candidate access network device; correspondingly, at least one candidate access network device receives message 1 from the source access network device.

[0232] Message 1 includes indication information of at least one beam. The indication information of at least one beam in Message 1 may be the indication information of the aforementioned second beam set, or may be the indication information of a beam determined by the source access network device based on the indication information of the second beam set, or may be the indication information of a beam determined by the source access network device based on the indication information of the first beam set and the indication information of the second beam set, or may be the indication information of a beam determined by the source access network device based on other factors, without limitation herein. The following description uses the case where Message 1 includes the indication information of the second beam set as an example.

[0233] It should be noted that the aforementioned message 1 can be a newly defined message or a message in traditional technology, which is not limited here.

[0234] For example, consider a case where a source access network device sends beam indication information to three candidate access network devices. These three candidate access network devices include candidate access network device A, candidate access network device B, and candidate access network device C. Among them, candidate access network device A includes cells 1 and 2, candidate access network device B includes cell 3, and candidate access network device C includes cell 4. The source access network device needs to send beam indication information for cell 1 and beam indication information for cell 3.

[0235] In one example, the source access network device sends message 1-1 to candidate access network device 1, sends message 1-2 to candidate access network device 2, and does not send a message to candidate access network device 3, wherein message 1-1 includes indication information of the beam of cell 1, and message 1-2 includes indication information of the beam of cell 3.

[0236] In another example, the source access network device sends messages 1-3 to candidate access network device 1 and candidate access network device 2 respectively, and does not send a message to candidate access network device 3, wherein messages 1-3 include indication information of the beam of cell 1 and indication information of the beam of cell 3.

[0237] In another example, the source access network device sends messages 1-4 to candidate access network device 1, candidate access network device 2 and candidate access network device 3 respectively, where messages 1-4 include indication information of the beam of cell 1 and indication information of the beam of cell 3.

[0238] Step 309 : At least one candidate access network device sends a PDCCH to the terminal device based on message 1 .

[0239] For example, at least one candidate access network device sends a PDCCH to the terminal device based on the indication information of at least one beam in message 1.

[0240] Optionally, the candidate access network device transmits a PDCCH through a beam of a cell belonging to the candidate access network device in the indication information of at least one beam, where the PDCCH is used to indicate uplink resources allocated to the terminal device. For example, the uplink resource is a PUSCH, and the PDCCH indicates the time-frequency domain position of the PUSCH.

[0241] In step 310, the terminal device monitors the PDCCH in the target cell through the beamforming to obtain uplink resources.

[0242] The terminal device measures the MO corresponding to the CHO according to the measurement configuration. When the terminal device measures the target cell that meets the conditional switching event, the terminal device monitors the PDCCH in the beam belonging to the target cell in the second beam set, and then obtains uplink resources such as PUSCH based on the monitored PDCCH.

[0243] Step 311: The terminal device sends uplink data to the target access network device based on the uplink resources.

[0244] Step 311 is an optional step.

[0245] The target access network device is an access network device among at least one candidate access network device.

[0246] For example, the terminal device sends uplink data to the target access network device through the PUSCH indicated by the PDCCH.

[0247] In conventional technology, the source access network device can send indication information of a first beam set to at least one candidate access network device through a handover request message, so that the candidate access network device schedules uplink resources for the terminal based on the indication information of the first beam set. This does not take into account that when the terminal device triggers the handover, the best beam measured by the terminal device may have changed, that is, the first beam set may not contain the best beam currently measured by the terminal device. In this embodiment, the terminal device can report indication information of a second beam set to the source access network device. The indication information of the second beam set is used to indicate the latest (or newer) beam currently measured by the terminal device, which is a beam that can more accurately reflect the location of the terminal device. After the candidate access network device receives the indication information of the second beam set from the source access network device, the candidate access network device can more accurately determine one or more beams for sending PDCCH based on the indication information of the second beam set, without having to send PDCCH to all beams in the candidate cell of the candidate access network device. Therefore, it is beneficial to improve the flexibility of the candidate access network device in scheduling uplink resources for the terminal device, and can also reduce resource waste to a certain extent. In addition, when the beam of the candidate cell measured by the terminal device changes, the beam of the PDCCH can be accurately determined, thereby improving the accuracy of the base station's transmission, allowing the terminal device to decode the PDCCH in advance to obtain uplink resources, reducing switching delay and improving switching efficiency.

[0248] In addition, when the beams included in the second beam set are different from those included in the first beam set, the second beam set indicates updated beam information compared to the first beam set. Therefore, the candidate access network device can determine a beam that is more suitable for the terminal device to send the PDCCH based on the updated indication information of the second beam set, rather than determining a beam for sending the PDCCH for the terminal device based on the indication information of the first beam set, which may be outdated or invalid. This helps improve the accuracy of the candidate access network device in scheduling uplink resources for the terminal device and also helps reduce resource waste.

[0249] Figure 4 shows a flowchart of another embodiment of the communication method provided by this application. In this embodiment, the candidate access network device can pre-allocate uplink resources for the terminal device on some beams and instruct the terminal device to monitor the PDCCH on another portion of the beams to obtain uplink resources. Specifically, the terminal device and the candidate access network device will perform the following steps:

[0250] Step 401: The candidate access network device sends first indication information and resource configuration information; correspondingly, the terminal device receives the first indication information and resource configuration information.

[0251] For example, the candidate access network device sends the first indication information and resource configuration information to the terminal device through the source access network device; correspondingly, the terminal device receives the first indication information and resource configuration information from the candidate access network device through the source access network device.

[0252] Among them, the candidate access network device is the access network device determined by the source access network device for the terminal device that may provide services to the terminal device after switching. For example, the candidate access network device is the access network device that received a handover request message from the source access network device and replied to the source access network device with a handover request acknowledgement message. Optionally, the candidate access network device may also be the target access network device, that is, the access network device that provides services to the terminal device after switching. For example, if the terminal device switches to the candidate access network device, then the candidate access network device is the target access network device.

[0253] For example, the candidate access network device sends a switching request confirmation message to the source access network device, and the switching request confirmation message includes first indication information and resource configuration information. The source access network device transparently transmits the first indication information and resource configuration information to the terminal device through an RRC reconfiguration message.

[0254] The first indication information is used to instruct the terminal device to use RACH-LESS free random access when switching.

[0255] The resource configuration information is used to indicate the initial uplink resources used by the terminal device to send uplink data to the candidate cell when performing RACH-less switching. For example, the resource configuration information is used to indicate the pre-allocated uplink resources (e.g., CG resources) and dynamically allocated uplink resources (e.g., DG resources) that the terminal device can use to access the candidate cell.

[0256] Optionally, the resource configuration information is used to indicate the pre-allocated uplink resources of the third beam set in the candidate cell and to indicate monitoring of the PDCCH on the beam in the fourth beam set in the candidate cell to obtain dynamically allocated uplink resources. For example, the PDCCH is used to indicate the time-frequency domain position of the dynamically allocated uplink resources (for example, the time-frequency domain position of the DG resource). The third beam set includes at least one beam in the candidate cell, which is a subset of the multiple beams contained in the candidate cell; the fourth beam set includes at least one beam in the candidate cell, which is a subset of the multiple beams contained in the candidate cell. Optionally, any beam in the third beam set is different from any beam in the fourth beam set, that is, the intersection of the third beam set and the fourth beam is empty.

[0257] It can be understood that the resource configuration information is used to configure the CG resources corresponding to a part of the beams in the candidate cell, and to instruct another part of the beams in the candidate cell to indicate the DG resources by sending PDCCH. It can also be understood that the resource configuration information is used to instruct the terminal device which beams in the candidate cell use CG resources and which beams in the candidate cell monitor PDCCH to obtain DG resources.

[0258] Exemplarily, the candidate cell includes at least beam 1, beam 2, beam 3, and beam 4. If the third beam set includes beam 1 and beam 2, and the fourth beam set includes beam 3 and beam 4, then the resource configuration information indicates that CG resources are configured in beam 1 and beam 2, and instructs the terminal device to monitor PDCCH on beam 3 and beam 4 to obtain DG resources. In this example, the terminal device can obtain the CG resources that can be used in beam 1 or beam 2 based on the received resource configuration information, and can also obtain the DG resources used in beam 3 or beam 4 by monitoring PDCCH on beam 3 or beam 4.

[0259] Optionally, the resource configuration information is a cell-level configuration, and each candidate cell of the candidate access network device corresponds to one piece of resource configuration information. Optionally, different candidate cells in the candidate access network device correspond to different resource configuration information.

[0260] Furthermore, the resource configuration information includes one or more of the following: indication information of the third beam set, information on pre-allocated uplink resources corresponding to each beam in the third beam set, a mapping relationship between beams in the third beam set and pre-allocated uplink resources, and indication information of the fourth beam set. The indication information of the third beam set includes an index of each beam in the third beam set, and the indication information of the fourth beam set includes an index of each beam in the fourth beam set. The information on pre-allocated uplink resources corresponding to each beam in the third beam set includes time-frequency domain location information of the pre-allocated uplink resources corresponding to each beam. For example, if the candidate cell includes at least beam 1, beam 2, beam 3, and beam 4, and if the third beam set includes beam 1 and beam 2, and the fourth beam set includes beam 3 and beam 4, then the indication information of the third beam set in the resource configuration information is the index of beam 1 and the index of beam 2, and the indication information of the fourth beam set in the resource configuration information is the index of beam 3 and the index of beam 4. In addition, the resource configuration information also includes the time-frequency domain position information of the pre-allocated uplink resource 1 corresponding to the index of beam 1 and the time-frequency domain position information of the pre-allocated uplink resource 2 corresponding to the index of beam 2.

[0261] It should be noted that the mapping relationship between the beams in the third beam set and the pre-allocated uplink resources can be explicitly carried in the resource configuration information or implicitly carried in the resource configuration information. For example, the mapping relationship between the beams in the third beam set and the pre-allocated uplink resources corresponding to each beam in the third beam set can be implicitly indicated by the indication information of the third beam and the information of the pre-allocated uplink resources corresponding to each beam in the third beam set.

[0262] Optionally, the resource configuration information also includes RACH resource information, such as time-frequency domain location information of the RACH resource.

[0263] For example, if the candidate cell includes five beams, namely beam 1, beam 2, beam 3, beam 4 and beam 5, the resource configuration information may include pre-allocated uplink resources associated with beam 1 and beam 2 in the third beam set, and the fourth beam set includes indication information for monitoring PDCCH on beam 3 and beam 4 to obtain pre-allocated uplink resources, as well as RACH resources.

[0264] Optionally, the resource configuration information further includes at least one threshold, where the threshold is used to indicate that when the signal quality of a beam is greater than the threshold, the beam is a usable beam.

[0265] In one example, the threshold included in the resource configuration information is a threshold of resource type granularity, that is, the same threshold is used for resources of the same type, and different thresholds are used for resources of different types. For example, the threshold is the first threshold used by the terminal device for beam selection when pre-allocated uplink resources are used to send uplink data (also referred to as the first threshold corresponding to CG resources), and / or the second threshold used by the terminal device to select beam monitoring PDCCH to obtain dynamically allocated uplink resources (also referred to as the second threshold corresponding to DG resources). The values ​​of the first threshold and the second threshold may be the same or different.

[0266] In another example, the threshold included in the resource configuration information is a beam-granularity threshold, i.e., each beam is configured with a threshold, and different beams correspond to different thresholds. For example, the resource configuration information includes a third threshold corresponding to each beam in the third beam set and / or a fourth threshold corresponding to each beam in the fourth beam set.

[0267] In another example, the threshold included in the resource configuration information is a threshold at the beam set granularity. For example, the third beam set corresponds to one threshold, and the fourth beam set corresponds to another threshold. For example, the resource configuration information includes the threshold corresponding to the third beam set and / or the threshold corresponding to the fourth beam set.

[0268] In addition, the aforementioned message carrying the first indication information and resource configuration information also includes indication information, which is used to instruct the terminal device to give priority to using pre-allocated uplink resources (for example, CG resources), or the terminal device to obtain dynamically allocated uplink resources (for example, DG resources) by monitoring PDCCH. In one example, the message carrying the first indication information and resource configuration information also includes second indication information, and the second indication information is used to instruct the terminal device to give priority to using pre-allocated uplink resources. In another example, the message carrying the first indication information and resource configuration information also includes third indication information, and the third indication information is used to instruct the terminal device to obtain DG resources by monitoring PDCCH first.

[0269] It should be noted that if the source access network device determines multiple candidate access network devices for the terminal device that may provide services to the terminal device after switching, then at least one candidate access network device among the multiple candidate access network devices sends a first message to the terminal device. When multiple candidate access network devices among multiple candidate access network devices send a first message to the terminal device, the resource configuration information in the first message from different candidate access network devices configures different resources. For example, the resource configuration information in the first message from candidate access network device 1 is used to configure the resources of a candidate cell in candidate access network device 1, and the resource configuration information in the first message from candidate access network device 2 is used to configure the resources of a candidate cell in candidate access network device 2.

[0270] Step 402: The terminal device determines a target beam and / or uplink resources corresponding to the target beam from at least one measured beam based on resource configuration information.

[0271] Before triggering the handover, the terminal device can measure at least one beam of at least one neighboring cell, where the at least one neighboring cell includes a candidate cell of a candidate access network device.

[0272] In a possible implementation mode 1, if at least one beam of the candidate cell measured by the terminal device belongs to the third beam set, the terminal device determines a beam as the target beam in the at least one beam, and determines the CG resource corresponding to the target beam as the uplink resource corresponding to the target beam. For example, if at least one beam among the beams that meet the switching condition measured by the terminal device belongs to the third beam set, the terminal device determines a beam as the target beam from the at least one beam. Since the at least one beam belongs to the third beam set, the target beam determined from the at least one beam also belongs to the third beam set, and the target beam has the CG resource configured by the candidate access network device. Exemplarily, if the terminal device measures that a total of three beams, namely beam 1, beam 2 and beam 3, meet the switching condition, and the three beams all belong to the third beam set of the candidate cell, the terminal device selects a beam from the three beams as the target beam, and determines the CG resource corresponding to the target beam as the uplink resource corresponding to the target beam.

[0273] Optionally, the terminal device may determine the beam with the best signal quality among the at least one beam as the target beam, or may randomly determine a beam from the at least one beam as the target beam, or may determine a beam from the at least one beam as the target beam based on other information.

[0274] In one example, the resource configuration information also includes a first threshold corresponding to the CG resource. The terminal device determines that a beam among the at least one beam whose signal quality is greater than or equal to the first threshold is a target beam. Exemplarily, if the terminal device measures that three beams, namely beam 1, beam 2 and beam 3, meet the switching conditions, and the three beams all belong to the third beam set of the candidate cell. If the signal quality of beam 1 is greater than the first threshold, the signal quality of beam 2 is greater than the first threshold, and the signal quality of beam 3 is less than the first threshold, the terminal device determines one beam from beam 1 and beam 2 as the target beam.

[0275] In another example, the resource configuration information also includes a third threshold corresponding to each beam in the third beam set. The terminal device determines that the beam whose signal quality in at least one beam is greater than or equal to the third threshold corresponding to the beam is the target beam. Exemplarily, if the terminal device measures that three beams, namely beam 1, beam 2 and beam 3, meet the switching condition, and the three beams all belong to the third beam set of the candidate cell. Among them, beam 1 corresponds to the third threshold 1, beam 2 corresponds to the third threshold 2, and beam 3 corresponds to the third threshold 3. If the signal quality of beam 1 is greater than the third threshold 1, the signal quality of beam 2 is less than the third threshold 2, and the signal quality of beam 3 is less than the third threshold 3, the terminal device determines that beam 1 is the target beam.

[0276] In another possible implementation mode 2, if at least one beam of the candidate cell measured by the terminal device belongs to the fourth beam set, the terminal device determines a beam in the at least one beam as the target beam, and monitors PDCCH in the target beam, and the DG resource indicated by the PDCCH is the uplink resource corresponding to the target beam. For example, if at least one beam in the beams that meet the switching conditions measured by the terminal device belongs to the fourth beam set, the terminal device determines a beam from the at least one beam as the target beam. Since the at least one beam belongs to the fourth beam set, the target beam determined from the at least one beam also belongs to the fourth beam set, and the candidate access network device will send PDCCH to the target beam to indicate the dynamic uplink authorization resources (i.e., DG resources) available to the terminal device. For example, if the terminal device measures that three beams, namely beam 1, beam 2 and beam 3, meet the switching conditions, and the three beams all belong to the fourth beam set of the candidate cell, the terminal device selects one beam from the three beams as the target beam, and monitors the PDCCH through the target beam to obtain the DG resources corresponding to the target beam.

[0277] Optionally, the terminal device may determine the beam with the best signal quality among the at least one beam as the target beam, or may randomly determine a beam from the at least one beam as the target beam, or may determine a beam from the at least one beam as the target beam based on other information.

[0278] In one example, the resource configuration information also includes a second threshold corresponding to the DG resource indicated by the PDCCH. The terminal device determines that a beam with a signal quality greater than or equal to the second threshold among at least one beam is a target beam. Exemplarily, if the terminal device measures that three beams, namely beam 1, beam 2 and beam 3, meet the switching conditions, and the three beams all belong to the fourth beam set of the candidate cell. If the signal quality of beam 1 is greater than the second threshold, the signal quality of beam 2 is greater than the second threshold, and the signal quality of beam 3 is less than the second threshold, the terminal device determines one beam from beam 1 and beam 2 as the target beam.

[0279] In another example, the resource configuration information also includes a fourth threshold corresponding to each beam in the fourth beam set. The terminal device determines that the beam whose signal quality in at least one beam is greater than or equal to the fourth threshold corresponding to the beam is the target beam. Exemplarily, if the terminal device measures that three beams, namely beam 1, beam 2 and beam 3, meet the switching conditions, and the three beams all belong to the fourth beam set of the candidate cell. Among them, beam 1 corresponds to the fourth threshold 1, beam 2 corresponds to the fourth threshold 2, and beam 3 corresponds to the fourth threshold 3. If the signal quality of beam 1 is greater than the fourth threshold 1, the signal quality of beam 2 is less than the fourth threshold 2, and the signal quality of beam 3 is less than the fourth threshold 3, the terminal device determines that beam 1 is the target beam.

[0280] In another possible implementation mode 3, if the terminal device measures that at least one beam in the candidate cell belongs to the third beam set, and the terminal device measures that at least one beam in the candidate cell belongs to the fourth beam set, the terminal device determines a beam from the third beam set as the target beam, and determines the CG resource corresponding to the target beam as the uplink resource corresponding to the target beam. That is, when the terminal device measures that some of the beams that meet the switching conditions belong to the third beam set and another part of the beams belong to the fourth beam set, the terminal device preferentially determines the target beam from the beams in the third beam set.

[0281] For example, if the terminal device measures that a total of four beams, namely beam 1, beam 2, beam 3 and beam 4, meet the switching conditions, where beam 1 and beam 2 belong to the third beam set and beam 3 and beam 4 belong to the fourth beam set, the terminal device determines a beam from beam 1 and beam 2 as the target beam.

[0282] Specifically, the manner in which the terminal device determines the target beam from at least one beam in the third beam set can be referred to the relevant introduction in the above implementation mode 1 and will not be repeated here.

[0283] In another possible implementation manner 4, if at least one beam of the candidate cell measured by the terminal device does not belong to the third beam set and does not belong to the fourth beam set, the terminal device determines a beam from the at least one beam as a target beam and triggers a random access procedure using RACH resources. Optionally, the terminal device triggers a random access procedure on a beam configured with RACH resources from the at least one beam, so as to obtain uplink scheduling information sent by the candidate access network device through the random access procedure.

[0284] In another possible implementation manner 5, the first message further includes second indication information, where the second indication information is used to instruct the terminal device to preferentially use CG resources. If the terminal device measures that at least one beam in the candidate cell belongs to the third beam set, and at least one beam in the candidate cell belongs to the fourth beam set, the terminal device determines a beam as a target beam from at least one beam belonging to the third beam set based on the second indication information, and determines the CG resource corresponding to the target beam as the uplink resource corresponding to the target beam.

[0285] For example, if the terminal device measures that a total of four beams, namely beam 1, beam 2, beam 3 and beam 4, meet the switching conditions, where beam 1 and beam 2 belong to the third beam set, and beam 3 and beam 4 belong to the fourth beam set, and since the first message received by the terminal device carries indication information (i.e., the second indication information) to give priority to the use of CG resources, the terminal device determines a beam as the target beam from beam 1 and beam 2 belonging to the third beam set based on the second indication information.

[0286] In another possible implementation manner 6, the first message further includes third indication information, where the third indication information is used to instruct the terminal device to preferentially obtain DG resources by monitoring the PDCCH. If the terminal device detects that at least one beam in the candidate cell belongs to the third beam set, and at least one beam in the candidate cell belongs to the fourth beam set, the terminal device determines a beam from the at least one beam belonging to the fourth beam set as a target beam, and monitors the PDCCH on the target beam, where the DG resources indicated by the PDCCH are the uplink resources corresponding to the target beam.

[0287] For example, if the terminal device measures that a total of four beams, namely beam 1, beam 2, beam 3 and beam 4, meet the switching conditions, where beam 1 and beam 2 belong to the third beam set, and beam 3 and beam 4 belong to the fourth beam set, and since the first message received by the terminal device carries indication information (i.e., the third indication information) to give priority to the use of DG resources, the terminal device determines a beam as the target beam from beam 3 and beam 4 belonging to the fourth beam set based on the third indication information.

[0288] In another possible implementation manner 7, the terminal device determines the beam with the best signal quality among at least one beam of the candidate cell as the target beam. The beam with the best signal quality may be the beam with the largest RSRQ value, the beam with the largest RSRP value, the beam with the largest SINR value, or the beam with the best signal quality based on a comprehensive evaluation, which is not limited here.

[0289] If the target beam belongs to the third beam set, the terminal device determines that the CG resource corresponding to the target beam is the uplink resource corresponding to the target beam; if the target beam belongs to the fourth beam set, the terminal device monitors PDCCH in the target beam, and the DG resource indicated by PDCCH is the uplink resource corresponding to the target beam; if the target beam does not belong to the third beam set and does not belong to the fourth beam set, the terminal device triggers the random access process in the target beam through the RACH resource.

[0290] Exemplarily, if the candidate cell includes five beams, namely beam 1, beam 2, beam 3, beam 4 and beam 5, and if the third beam set includes beam 1 and beam 2, and the fourth beam set includes beam 3 and beam 4, the terminal device may also configure RACH resources for beam 5. If the terminal device measures that the beam that meets the switching conditions and has the best signal quality is a beam belonging to the third beam set, taking beam 1 as an example where the beam with the best signal quality is the beam, the terminal device determines beam 1 as the target beam, and the CG resources corresponding to beam 1 are the uplink resources corresponding to the target beam. If the terminal device measures that the beam that meets the switching conditions and has the best signal quality is a beam belonging to the fourth beam set, taking beam 3 as an example where the beam with the best signal quality is the beam, the terminal device determines beam 3 as the target beam, and the DG resources obtained by the terminal device by monitoring PDCCH in beam 3 are the uplink resources corresponding to the target beam. If the terminal device measures that the beam that meets the switching conditions and has the best signal quality belongs neither to the third beam set nor to the fourth beam set, taking beam 5 as an example, the beam with the best signal quality, the terminal device determines beam 5 as the target beam, and the terminal device triggers the random access process on the RACH resource corresponding to beam 5.

[0291] In this embodiment, the candidate access network device can configure multiple uplink authorization methods for the terminal device in a candidate cell. That is, in a candidate cell, a third beam set using CG resources is configured, and a fourth beam set indicating DG resources by sending PDCCH is indicated. Therefore, it is conducive to improving the flexibility of the candidate access network device in configuring uplink resources. In addition, compared with the traditional technology in which the candidate access network device configures CG resources for each beam in the candidate cell, the solution of this embodiment reduces the number of configured CG resources, which is conducive to reducing resource waste.

[0292] The communication method provided by this application is further described below in conjunction with Figure 5. As shown in Figure 5, a flow chart of an embodiment of the communication method proposed by this application in the RACH-LESS handover scenario. In this embodiment, the terminal device, the source access network device, and the candidate access network device will perform the following steps:

[0293] Step 501: The source access network device sends measurement configuration 1 to the terminal device; correspondingly, the terminal device receives measurement configuration 1 from the source access network device.

[0294] Step 502: The terminal device sends a measurement report 1 to the source access network device; correspondingly, the source access network device receives the measurement report 1 from the terminal device.

[0295] Step 503: The source access network device sends a handover request message to at least one candidate access network device; correspondingly, the at least one candidate access network device receives the handover request message from the source access network device.

[0296] Optionally, the handover request message includes a beam-level measurement result measured by the terminal device, where the beam-level measurement result includes indication information of at least one beam. For example, the beam-level measurement result is the indication information of at least one beam carried in the measurement report 1 in step 502.

[0297] Optionally, the indication information of the at least one beam includes an index of each beam in the at least one beam.

[0298] Optionally, the indication information of at least one beam also includes a cell identifier corresponding to each beam in the at least one beam.

[0299] Optionally, the indication information of at least one beam further includes signal quality information of each beam in the at least one beam.

[0300] Steps 501 to 503 are similar to steps 301 to 303 above. Please refer to the relevant introduction in steps 301 to 303 above for details, which will not be repeated here.

[0301] Step 504: The candidate access network device sends a handover request confirmation message to the source access network device; correspondingly, the source access network device receives the handover request confirmation message from the candidate access network device.

[0302] The handover request confirmation message includes the first indication information and resource configuration information. For the introduction of the first indication information and resource configuration information, please refer to the above step 401, which will not be described in detail here.

[0303] Optionally, the candidate access network device determines the indication information of the third beam set and / or the indication information of the fourth beam set based on the beam-level measurement result measured by the terminal device, where the beam-level measurement result includes indication information of at least one beam. Exemplarily, the candidate access network device determines that the beam with better signal quality in the beam-level measurement result is used to constitute the third beam set, and the beam with the second best signal quality in the beam-level measurement result is used to constitute the fourth beam set. For example, the candidate access network device sorts the beams in the beam-level measurement result from high to low according to signal quality, selects the first one or more beams with better signal quality to determine the third beam set; then, selects the first one or more beams with better quality from the remaining multiple beams to determine the fourth beam set.

[0304] Optionally, the handover request confirmation message is a conditional handover request confirmation (Handover Request ACK) message. After the source access network device sends a conditional handover request (Handover Request) message to at least one candidate access network device, if the candidate cell of the candidate access network device successfully admits the terminal device, the candidate access network device sends a conditional handover request confirmation message to the source access network device.

[0305] Step 505: The source access network device sends an RRC reconfiguration message to the terminal device; correspondingly, the terminal device receives the RRC reconfiguration message from the source access network device.

[0306] The RRC reconfiguration message includes first indication information and resource configuration information of one or more candidate cells.

[0307] The RRC reconfiguration information is used to instruct the terminal device to perform switching, or the terminal device evaluates candidate cells and determines a target cell for switching.

[0308] The resource configuration information is used to indicate the pre-allocated uplink resources of the third beam set in the candidate cell and to indicate monitoring of the PDCCH on the beams in the fourth beam set in the candidate cell to obtain dynamically allocated uplink resources. For example, the PDCCH is used to indicate the time-frequency domain location of the dynamically allocated uplink resources (e.g., the time-frequency domain location of the DG resources).

[0309] Optionally, the resource configuration information includes RACH resources, or the RRC reconfiguration message includes RACH resources. Optionally, the RACH resources may be contention-based RACH resources.

[0310] Step 506: The terminal device sends uplink data in a target beam determined based on the resource configuration information.

[0311] The cell in which the terminal device performs a handover is called the target cell, which is one of the candidate cells. In a traditional handover, the RRC reconfiguration message contains only one candidate cell, which is the target cell. In a CHO handover, the terminal device selects one or more candidate cells as the target cell.

[0312] In which, during the switching process, the terminal device determines the target beam and / or the uplink resources corresponding to the target beam from at least one measured beam based on the resource configuration information of the target cell.

[0313] The uplink data may be a handover completion message (ie, RRC reconfiguration completion).

[0314] Among them, the terminal device can use the latest unfiltered physical layer measurement results for beam selection, or use the filtered physical layer measurement results for beam selection, or use the L3 filtered measurement results for beam selection, which is not limited in this application.

[0315] Optionally, the terminal device measures the target cell before triggering the handover or during the handover process to obtain measurement results of one or more beams of the target cell.

[0316] Optionally, when the terminal device switches, a target beam is determined to send uplink data based on the latest measurement results of the target cell saved by the terminal device and resource configuration.

[0317] In a possible implementation mode 1, if at least one beam of the target cell measured by the terminal device belongs to the third beam set, the terminal device determines one beam in the at least one beam as the target beam, and sends uplink data on the CG resource corresponding to the target beam. Exemplarily, if at least one beam of the target cell measured by the terminal device is configured with a CG resource, the terminal device uses the CG resource on one of the at least one beam to send uplink data.

[0318] In one example, the resource configuration information includes a first threshold corresponding to the CG resource, and the terminal device determines that a beam with a signal quality greater than or equal to the first threshold in the at least one beam is a target beam. Exemplarily, if at least one beam of the target cell measured by the terminal device is configured with CG resources, and there is at least one beam with a signal quality greater than or equal to the first threshold, the terminal device considers that the at least one beam is an available beam, and the terminal device selects one of the available beams as the target beam, and uses the CG resource corresponding to the target beam to send uplink data. Optionally, the terminal device selects one of the beams with the best signal quality as the target beam, and uses the CG resource corresponding to the target beam to send uplink data. If at least one beam of the target cell measured by the terminal device that is configured with CG resources is less than or equal to the first threshold, the terminal device can arbitrarily select a beam or select the beam with the best signal quality, and trigger the random access process through the RACH resource. For example, the terminal device selects a beam from at least one beam to perform a random access process, so as to obtain the uplink scheduling information sent by the candidate access network device through the random access process. Optionally, the terminal device may select the beam with the best signal quality to perform the RACH process.

[0319] In another example, the resource configuration information also includes a third threshold corresponding to each beam in the third beam set. The terminal device determines that the beam whose signal quality in at least one beam is greater than or equal to the third threshold corresponding to the beam is the target beam. Exemplarily, if at least one beam of the target cell measured by the terminal device is configured with CG resources, and there is at least one beam whose signal quality is greater than or equal to the third threshold corresponding to the beam, the terminal device considers that the at least one beam is an available beam, and the terminal device selects one of the available beams as the target beam, and uses the CG resource corresponding to the target beam to send uplink data.

[0320] In another example, the resource configuration information includes a first threshold and a fifth threshold corresponding to CG resources. Among the one or more beams measured by the terminal device, if there is a beam greater than or equal to the first threshold, the terminal device can select the CG resource corresponding to any beam from among them to send uplink data; if there is a beam less than or equal to the first threshold and greater than or equal to the fifth threshold, the terminal device selects the beam with the strongest signal quality and selects the corresponding CG resource to send uplink data; if the signal quality of the beam is less than or equal to the fifth threshold, the terminal device performs the RACH process.

[0321] In another possible implementation mode 2, if at least one beam of the target cell measured by the terminal device belongs to the fourth beam set, the terminal device determines a beam in the at least one beam to monitor the PDCCH, and sends uplink data on the DG resource indicated by the PDCCH. For example, if at least one beam among the beams that meet the switching conditions measured by the terminal device belongs to the fourth beam set, the terminal device determines a beam from the at least one beam as the target beam. Exemplarily, if at least one beam of the target cell measured by the terminal device is a beam that is instructed to monitor the PDCCH, the terminal monitors the PDCCH on one of the at least one beam to obtain the DG resource, and then uses the DG resource to send uplink data.

[0322] Optionally, the terminal device may determine to monitor PDCCH on the beam with the best signal quality among the at least one beam, or may randomly determine a beam from the at least one beam to monitor PDCCH, or may determine a beam from the at least one beam as a target beam to monitor PDCCH based on other information.

[0323] In one example, the resource configuration information also includes a second threshold corresponding to the DG resource indicated by the PDCCH. The terminal device determines that a beam in at least one beam whose signal quality is greater than or equal to the second threshold is a target beam. Exemplarily, if at least one beam of the target cell measured by the terminal device belongs to the fourth beam set (that is, at least one beam is a beam indicating that uplink resources are obtained by monitoring PDCCH), and there is at least one beam whose signal quality is greater than or equal to the second threshold, the terminal device considers that the at least one beam is an available beam, and the terminal device selects one of the available beams as the target beam to monitor PDCCH, and uses the DG resources obtained by monitoring PDCCH to send uplink data.

[0324] In another example, the resource configuration information also includes a fourth threshold corresponding to each beam in the fourth beam set. The terminal device determines that the beam whose signal quality in at least one beam is greater than or equal to the fourth threshold corresponding to the beam is the target beam. Exemplarily, if at least one beam of the target cell measured by the terminal device belongs to the fourth beam set (that is, at least one beam is a beam indicating that uplink resources are obtained by monitoring PDCCH), and there is at least one beam whose signal quality is greater than or equal to the fourth threshold corresponding to the beam, the terminal device considers that the at least one beam is an available beam, and the terminal device selects one of the available beams to monitor PDCCH, and uses the DG resources obtained by monitoring PDCCH to send uplink data.

[0325] In another example, the resource configuration information includes a second threshold and a sixth threshold corresponding to the DG resource. Among the one or more beams measured by the terminal device, if there is a beam greater than or equal to the second threshold, the terminal device can select any beam from them to monitor the PDCCH to obtain the DG resource and send uplink data on the DG resource; if there is a beam less than or equal to the second threshold and greater than or equal to the sixth threshold, the terminal device selects the beam with the strongest signal quality to monitor the PDCCH and use the DG resource indicated by the PDCCH to send uplink data; if the signal quality of the beam is less than or equal to the sixth threshold, the terminal device performs the RACH process.

[0326] In another possible implementation method 3, if the terminal device measures that there is at least one beam in the target cell that belongs to the third beam set, and the terminal device measures that there is at least one beam in the target cell that belongs to the fourth beam set, the terminal device determines a beam from the third beam set as the target beam, and determines the CG resource corresponding to the target beam as the uplink resource corresponding to the target beam. That is to say, when the terminal device measures that at least one beam is configured with CG resources, and measures that at least one beam is instructed to monitor PDCCH, the terminal device preferentially uses the beam with pre-allocated CG resources to send uplink data.

[0327] Exemplarily, if a first threshold based on CG and a second threshold based on DG are configured, if the target cell measured by the terminal device has at least one beam greater than or equal to the first threshold belonging to the third beam set, and there is at least one beam greater than or equal to the second threshold belonging to the fourth beam set, the terminal device determines a beam from the third beam set as the target beam, and determines the CG resource corresponding to the target beam as the uplink resource corresponding to the target beam.

[0328] Specifically, the manner in which the terminal device determines the target beam from at least one beam in the third beam set can be referred to the relevant introduction in the above implementation mode 1 and will not be repeated here.

[0329] In another possible implementation method 4, if the target cell beam measured by the terminal device does not belong to the third beam set and does not belong to the fourth beam set, the terminal device determines a beam from the target cell as the target beam and triggers a random access procedure using RACH resources. Optionally, the terminal device selects a beam from the target cell beam to perform the random access procedure, thereby obtaining uplink scheduling information sent by the candidate access network device through the random access procedure. Optionally, the terminal device may select the beam with the best signal quality to perform the RACH procedure.

[0330] In another possible implementation manner 5, the first message further includes second indication information, where the second indication information is used to instruct the terminal device to preferentially use CG resources. If the terminal device measures that the target cell has at least one beam belonging to the third beam set, and the target cell has at least one beam belonging to the fourth beam set, the terminal device determines a beam from the at least one beam belonging to the third beam set as the target beam based on the second indication information, and determines the CG resource corresponding to the target beam as the uplink resource corresponding to the target beam.

[0331] In another possible implementation mode 6, the first message further includes third indication information, and the third indication information is used to instruct the terminal device to obtain DG resources by monitoring PDCCH in priority. If the terminal device measures that the target cell has at least one beam belonging to the third beam set, and the target cell has at least one beam belonging to the fourth beam set, the terminal device determines a beam from at least one beam belonging to the fourth beam set as the target beam, and monitors PDCCH in the target beam, and the DG resources indicated by the PDCCH are the uplink resources corresponding to the target beam. For examples of implementation modes 4, 5, and 6, please refer to the relevant introduction in step 402 above, which will not be repeated here.

[0332] It should be noted that the second indication information and the third indication information can be different values ​​of the same indication information. For example, if "priority resources" is: {CG, DG}, when "priority resources" = {CG} is issued, it means that CG resources are given priority; when "priority resources" = {DG} is issued, it means that DG resources are given priority.

[0333] In another possible implementation manner 7, the terminal device determines the beam with the best signal quality among at least one beam of the target cell as the target beam. The beam with the best signal quality may be the beam with the largest RSRQ value, the beam with the largest RSRP value, the beam with the largest SINR value, or the beam with the best signal quality based on a comprehensive evaluation, which is not limited here.

[0334] If the target beam belongs to the third beam set, the terminal device determines that the CG resource corresponding to the target beam is the uplink resource corresponding to the target beam; if the target beam belongs to the fourth beam set, the terminal device monitors PDCCH in the target beam, and the DG resource indicated by PDCCH is the uplink resource corresponding to the target beam; if the target beam does not belong to the third beam set and does not belong to the fourth beam set, the terminal device triggers the random access process in the target beam through the RACH resource.

[0335] In another possible implementation manner 8, if the beam of the target cell configured with CG resources measured by the terminal device does not meet the threshold, and the beam indicating monitoring of PDCCH is not measured; or the beam measured by the terminal device is instructed to monitor PDCCH, but does not meet the threshold, and the terminal device does not measure the beam configured with CG resources; or the beam configured with CG is measured to not meet the CG threshold and the beam configured with DG is measured to not meet the DG threshold, then the terminal device selects a beam to perform the RACH process. Among them, the terminal device can select any beam for RACH, or select the beam with the best beam quality for RACH.

[0336] It can be understood that when the terminal device selects a beam to send the initial uplink resource, it can determine the beam currently used to send the uplink resource according to the above embodiment. For example, when the terminal device fails to successfully select beam 1 to send the initial uplink resource according to the above embodiment, the terminal device needs to resend the initial uplink resource, then the terminal device reselects the beam to send the uplink resource according to the currently measured beam in the manner of the above embodiment. The selected beam can be the same as or different from the beam used to send the last resource. Alternatively, before the terminal device switching is completed or unsuccessful, each time the terminal device sends uplink data to the target access network device, it needs to re-judge and select whether to use CG, DG, or RACH resources for transmission in accordance with the manner in the above embodiment.

[0337] In this embodiment, the candidate access network device can configure multiple uplink authorization methods for the terminal device in a target cell, that is, in a target cell, a third beam set using CG resources is configured, and a fourth beam set indicating DG resources by sending PDCCH is indicated. Therefore, it is conducive to improving the flexibility of the candidate access network device in configuring uplink resources. In addition, compared with the traditional technology in which the candidate access network device configures CG resources for each beam in the target cell, the solution of this embodiment reduces the number of configured CG resources, which is conducive to reducing resource waste.

[0338] Corresponding to the scheme given in the above method embodiment, the embodiment of the present application also provides a corresponding communication device (also referred to as a communication device) and a communication system, which includes a module or unit for executing each part of the above embodiment. The module or unit can be software, hardware, or a combination of software and hardware. The following is only a brief description of the communication device and system. For the details of the implementation of the scheme, please refer to the description of the above method embodiment, which will not be repeated below.

[0339] Figure 6 is a schematic diagram of the structure of a communication device 60 provided in this application. It should be understood that the terminal device in the method embodiments corresponding to Figures 2, 3, 4 or 5 can be based on the structure of the communication device 60 shown in Figure 6 in this embodiment.

[0340] The communication device 60 includes at least one processor 601, at least one memory 602, and at least one transceiver 603. The processor 601, memory 602, and transceiver 603 are connected. Optionally, the communication device 60 may further include an input device 605, an output device 606, and one or more antennas 604. The antenna 604 is connected to the transceiver 603, and the input device 605 and output device 606 are connected to the processor 601.

[0341] In this embodiment, the memory 602 is mainly used to store software programs and data. The memory 602 can be independent and connected to the processor 601. Optionally, the memory 602 can be integrated with the processor 601, for example, integrated into one or more chips. Among them, the memory 602 can store program codes for executing the technical solutions of the embodiments of the present application, and the execution is controlled by the processor 601. The various types of computer program codes executed can also be regarded as drivers for the processor 601. It should be understood that Figure 6 in this embodiment only shows one memory and one processor, but in actual applications, the communication device 60 can have multiple processors or multiple memories, which is not specifically limited here. In addition, the memory 602 can also be referred to as a storage medium or a storage device. The memory 602 can be a storage element on the same chip as the processor (i.e., an on-chip storage element), or an independent storage element, which is not limited in this embodiment of the present application.

[0342] In this embodiment, the transceiver 603 can be used to support the reception or transmission of radio frequency signals between the communication device 60 and the access network device, and the transceiver 603 can be connected to the antenna 604. The transceiver 603 includes a transmitter Tx and a receiver Rx. Specifically, one or more antennas 604 can receive radio frequency signals. The receiver Rx of the transceiver 603 is used to receive the radio frequency signals from the antenna 604, convert the radio frequency signals into digital baseband signals or digital intermediate frequency signals, and provide the digital baseband signals or digital intermediate frequency signals to the processor 601 so that the processor 601 can further process the digital baseband signals or digital intermediate frequency signals, such as demodulation and decoding. In addition, the transmitter Tx in the transceiver 603 is also used to receive modulated digital baseband signals or digital intermediate frequency signals from the processor 601, convert the modulated digital baseband signals or digital intermediate frequency signals into radio frequency signals, and transmit the radio frequency signals through one or more antennas 604. Specifically, the receiver Rx can selectively perform one or more stages of down-mixing and analog-to-digital conversion on the RF signal to obtain a digital baseband signal or a digital intermediate frequency signal. The order of the down-mixing and analog-to-digital conversion processes is adjustable. The transmitter Tx can selectively perform one or more stages of up-mixing and digital-to-analog conversion on the modulated digital baseband signal or digital intermediate frequency signal to obtain a RF signal. The order of the up-mixing and digital-to-analog conversion processes is adjustable. The digital baseband signal and the digital intermediate frequency signal may be collectively referred to as digital signals.

[0343] It should be understood that the aforementioned transceiver 603 may also be referred to as a transceiver unit, a transceiver, a transceiver device, etc. Optionally, a device in the transceiver unit that implements a receiving function may be referred to as a receiving unit, and a device in the transceiver unit that implements a transmitting function may be referred to as a transmitting unit. That is, the transceiver unit includes a receiving unit and a transmitting unit. The receiving unit may also be referred to as a receiver, an input port, a receiving circuit, etc., and the transmitting unit may be referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

[0344] Processor 601 can be a baseband processor or a central processing unit (CPU). The baseband processor and CPU can be integrated or separate. Processor 601 can be used to implement various functions for the terminal device, such as processing communication protocols and communication data, controlling the entire terminal device, executing software programs, and processing software program data; assisting in completing computing tasks, such as graphics, image processing, or audio processing; or processor 601 can be used to implement one or more of the above functions.

[0345] In addition, the output device 606 communicates with the processor 601 and can display information in a variety of ways, which are not specifically limited herein.

[0346] In one design, a communication device 60 is configured to execute the method of the terminal device in the embodiment corresponding to FIG2 or FIG3 . A transceiver 603 in the communication device 60 is configured to send indication information of at least one beam to a source access network device, where the indication information of at least one beam is used by at least one candidate access network device to determine a beam for transmitting a PDCCH to the terminal device, where the candidate access network device is an access network device configured by the source access network device in an RRC reconfiguration message of the terminal device.

[0347] In a possible implementation manner, each beam in the at least one beam satisfies any one of the following preset conditions:

[0348] The beam is the beam with the best signal quality among the beams measured by the terminal device; or,

[0349] The signal quality of the beam is greater than or equal to the reference threshold; or,

[0350] The signal quality of the beam is greater than or equal to the signal quality of the reference beam, and the beam is different from the reference beam.

[0351] In a possible implementation, the transceiver 603 is further configured to receive measurement configuration information from a source access network device, where the measurement configuration information is used to instruct the terminal device to report indication information of a beam that meets a preset condition.

[0352] Optionally, the measurement configuration information includes indication information of a reference beam and / or a reference threshold.

[0353] Optionally, the measurement configuration information also includes an upper limit on the number of beams to be reported.

[0354] Optionally, the measurement configuration information is measurement configuration information of an RRC layer; or, the measurement configuration information is measurement configuration information of a physical layer.

[0355] In a possible implementation manner, the indication information of the at least one beam includes an index of each beam in the at least one beam.

[0356] Optionally, the indication information of at least one beam also includes a cell identifier corresponding to each beam in the at least one beam, and / or signal quality information of each beam in the at least one beam.

[0357] In a possible implementation, the transceiver 603 is further configured to receive an RRC reconfiguration message from a source access network device, the RRC reconfiguration message including first indication information and cell information of at least one candidate access network device, the first indication information being used to instruct the terminal device to adopt RACH-LESS switching.

[0358] In one possible embodiment, the processor 601 is used to trigger switching to a target cell of a target access network device, where the target access network device is one of at least one candidate access network device; the processor 601 controls the transceiver 603 to monitor the PDCCH through a beam belonging to the target cell in at least one beam, where the PDCCH is used to indicate the uplink resources allocated to the terminal device.

[0359] In a possible implementation, the transceiver 603 is further configured to send indication information of at least one first beam to the source access network device.

[0360] Optionally, the beam indicated by the indication information of at least one beam is different from the beam indicated by the indication information of at least one first beam.

[0361] In another design, the communication device 60 is configured to execute the method of the terminal device in the embodiment corresponding to FIG4 or FIG5 . The transceiver 603 is configured to receive first indication information and resource configuration information, wherein the first indication information is used to instruct the terminal device to adopt random access-free RACH-LESS switching, and the resource configuration information is used to indicate the pre-allocated uplink resources of a third beam set in the candidate cell and to indicate monitoring of the PDCCH on a beam in a fourth beam set in the candidate cell, where the third beam set includes at least one beam and the fourth beam set includes at least one beam. The processor 601 is configured to determine a target beam and / or uplink resources corresponding to the target beam from the at least one measured beam based on the resource configuration information.

[0362] In a possible implementation, the resource configuration information includes indication information of the third beam set, information of pre-allocated uplink resources corresponding to each beam in the third beam set, and indication information of the fourth beam set.

[0363] In one possible implementation, the processor 601 is specifically used to determine a beam as a target beam in at least one beam when it is determined that at least one beam of the measured candidate cell belongs to a third beam set, and to determine the pre-allocated uplink resources corresponding to the target beam as the uplink resources corresponding to the target beam.

[0364] In one possible implementation, the processor 601 is specifically used to determine a beam as a target beam in at least one beam when at least one beam of a candidate cell measured by the terminal device belongs to a fourth beam set, and to monitor PDCCH in the target beam, and the dynamically allocated uplink resources indicated by the PDCCH are the uplink resources corresponding to the target beam.

[0365] In one possible implementation, the processor 601 is specifically used to determine a beam from the third beam set as a target beam when the terminal device measures that there is at least one beam in the candidate cell belonging to the third beam set, and measures that there is at least one beam in the candidate cell belonging to the fourth beam set, and determine the pre-allocated uplink resources corresponding to the target beam as the uplink resources corresponding to the target beam.

[0366] In a possible implementation, the resource configuration information further includes information about random access RACH resources.

[0367] The processor 601 is specifically configured to, when at least one beam of a candidate cell measured by the terminal device does not belong to the third beam set and does not belong to the fourth beam set, determine a beam as a target beam in at least one beam, and trigger a random access procedure through RACH resources.

[0368] In a possible implementation, the resource configuration information further includes second indication information, where the second indication information is used to instruct the terminal device to give priority to using the pre-allocated uplink resources.

[0369] The processor 601 is specifically used to determine a beam as a target beam from at least one beam belonging to the third beam set when the terminal device detects that there is at least one beam in the candidate cell belonging to the third beam set, and that there is at least one beam in the candidate cell belonging to the fourth beam set, and to determine the pre-allocated uplink resources corresponding to the target beam as the uplink resources corresponding to the target beam.

[0370] In a possible implementation, the resource configuration information further includes third indication information, where the third indication information is used to instruct the terminal device to obtain dynamically allocated uplink resources by preferentially monitoring the PDCCH.

[0371] Processor 601 is specifically used to determine a beam as a target beam from at least one beam belonging to the fourth beam set when the terminal device detects that there is at least one beam in the candidate cell belonging to the third beam set, and that there is at least one beam in the candidate cell belonging to the fourth beam set, and to monitor PDCCH in the target beam, and the dynamically allocated uplink resources indicated by the PDCCH are the uplink resources corresponding to the target beam.

[0372] In a possible implementation manner, the resource configuration information further includes a first threshold corresponding to the pre-allocated uplink resources.

[0373] The processor 601 is specifically configured to determine a beam, among the at least one beam, whose signal quality is greater than or equal to a first threshold, as a target beam.

[0374] In a possible implementation manner, the resource configuration information further includes a second threshold corresponding to the dynamically allocated uplink resources indicated by the PDCCH.

[0375] The processor 601 is specifically configured to determine a beam, among the at least one beam, whose signal quality is greater than or equal to a second threshold, as a target beam.

[0376] In a possible implementation manner, the resource configuration information further includes a third threshold corresponding to each beam in the third beam set.

[0377] The processor 601 is specifically configured to determine, among at least one beam, a beam whose signal quality is greater than or equal to a third threshold corresponding to the beam as a target beam.

[0378] In a possible implementation manner, the resource configuration information further includes a fourth threshold corresponding to each beam in the fourth beam set.

[0379] The processor 601 is specifically configured to determine, among at least one beam, a beam whose signal quality is greater than or equal to a fourth threshold corresponding to the beam as a target beam.

[0380] In a possible implementation, the resource configuration information further includes information about random access RACH resources.

[0381] The processor 601 is specifically configured to determine a beam with the best signal quality among at least one beam of the candidate cell as a target beam;

[0382] If the target beam belongs to the third beam set, determining the pre-allocated uplink resources corresponding to the target beam as the uplink resources corresponding to the target beam;

[0383] If the target beam belongs to the fourth beam set, the PDCCH is monitored in the target beam, and the dynamically allocated uplink resources indicated by the PDCCH are the uplink resources corresponding to the target beam;

[0384] If the target beam does not belong to the third beam set and does not belong to the fourth beam set, the random access process is triggered in the target beam through the RACH resource.

[0385] It should be noted that the specific implementation and beneficial effects of this embodiment can be referred to the method of the terminal device in the above embodiment, and will not be repeated here.

[0386] FIG7 is a schematic diagram of the structure of another communication device 70 provided in this embodiment. It should be understood that the access network device (e.g., source access network device, candidate access network device, or target access network device) in the method embodiments corresponding to FIG2 , FIG3 , FIG4 , or FIG5 can be based on the structure of the communication device 70 shown in FIG7 in this embodiment.

[0387] The communication device 70 includes at least one processor 701, at least one memory 702, at least one transceiver 703, at least one network interface 705, and one or more antennas 704. The processor 701, memory 702, transceiver 703, and network interface 705 are connected via a connection device, and the antenna 704 is connected to the transceiver 703. The aforementioned connection device may include various interfaces, transmission lines, or buses, etc., and this embodiment does not limit this.

[0388] Among them, the memory 702 is mainly used to store software programs and data. The memory 702 can be independent and connected to the processor 701. Optionally, the memory 702 can be integrated with the processor 701, for example, integrated into one or more chips. Among them, the memory 702 can store program codes for executing the technical solutions of the embodiments of the present application, and is controlled and executed by the processor 701. The various types of computer program codes executed can also be regarded as drivers for the processor 701. It should be understood that Figure 7 in this embodiment only shows one memory and one processor, but in actual applications, the communication device 70 can have multiple processors or multiple memories, which are not specifically limited here. In addition, the memory 702 can also be referred to as a storage medium or a storage device, etc. The memory 702 can be a storage element on the same chip as the processor (i.e., an on-chip storage element), or an independent storage element, which is not limited in the embodiments of the present application.

[0389] In this embodiment, the transceiver 703 can be used to support the reception or transmission of radio frequency signals between the communication device 70 and the terminal device, and the transceiver 703 can be connected to the antenna 704. The transceiver 703 includes a transmitter Tx and a receiver Rx. Specifically, one or more antennas 704 can receive radio frequency signals. The receiver Rx of the transceiver 703 is used to receive the radio frequency signals from the antenna 704, convert the radio frequency signals into digital baseband signals or digital intermediate frequency signals, and provide the digital baseband signals or digital intermediate frequency signals to the processor 701 so that the processor 701 can further process the digital baseband signals or digital intermediate frequency signals, such as demodulation and decoding. In addition, the transmitter Tx in the transceiver 703 is also used to receive modulated digital baseband signals or digital intermediate frequency signals from the processor 701, convert the modulated digital baseband signals or digital intermediate frequency signals into radio frequency signals, and transmit the radio frequency signals through one or more antennas 704. Specifically, the receiver Rx can selectively perform one or more stages of down-mixing and analog-to-digital conversion on the RF signal to obtain a digital baseband signal or a digital intermediate frequency signal. The order of the down-mixing and analog-to-digital conversion processes is adjustable. The transmitter Tx can selectively perform one or more stages of up-mixing and digital-to-analog conversion on the modulated digital baseband signal or digital intermediate frequency signal to obtain a RF signal. The order of the up-mixing and digital-to-analog conversion processes is adjustable. The digital baseband signal and the digital intermediate frequency signal may be collectively referred to as digital signals.

[0390] It should be understood that the aforementioned transceiver 703 may also be referred to as a transceiver unit, a transceiver, a transceiver device, etc. Optionally, a device in the transceiver unit that implements a receiving function may be referred to as a receiving unit, and a device in the transceiver unit that implements a transmitting function may be referred to as a transmitting unit. That is, the transceiver unit includes a receiving unit and a transmitting unit. The receiving unit may also be referred to as a receiver, an input port, a receiving circuit, etc., and the transmitting unit may be referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

[0391] Furthermore, the aforementioned processor 701 is primarily used to process communication protocols and communication data, control the entire network device, execute software programs, and process software program data, for example, to support the communication device 70 in performing the actions described in the aforementioned embodiments. The communication device 70 may include a baseband processor and a central processing unit. The baseband processor is primarily used to process communication protocols and communication data, while the central processing unit is primarily used to control the entire communication device 70, execute software programs, and process software program data. As shown in FIG7 , the processor 701 may integrate the functions of a baseband processor and a central processing unit. Those skilled in the art will appreciate that the baseband processor and the central processing unit may also be independent processors interconnected via a bus or other technology. Those skilled in the art will appreciate that the communication device 70 may include multiple baseband processors to accommodate different network standards, multiple central processing units to enhance its processing capabilities, and that the various components of the communication device 70 may be connected via various buses. The baseband processor may also be referred to as a baseband processing circuit or a baseband processing chip. The central processing unit may also be referred to as a central processing circuit or a central processing chip. The function of processing the communication protocol and communication data may be built into the processor, or may be stored in the memory in the form of a software program, and the processor executes the software program to implement the baseband processing function.

[0392] In addition, the aforementioned network interface 705 is used to connect the communication device 70 to other communication devices via a communication link. Specifically, the network interface 705 may include a network interface between the communication device 70 and a core network element, such as an S1 interface; the network interface 705 may also include a network interface between the communication device 70 and other network devices (such as other access network devices or core network elements), such as an X2 or Xn interface.

[0393] In one design, the communication device 70 is configured to perform the method of the source access network device in the embodiment corresponding to FIG. 2 or FIG. The transceiver 703 is configured to: send a handover request message to at least one candidate access network device; receive a handover request confirmation message from at least one candidate access network device; and send an indication of at least one beam measured by the terminal device to the at least one candidate access network device.

[0394] Among them, the indication information of at least one beam is used by at least one candidate access network device to determine the beam for sending the physical downlink control channel PDCCH to the terminal device.

[0395] In a possible implementation manner, each beam in the at least one beam satisfies any one of the following preset conditions:

[0396] The beam is the beam with the best signal quality among the beams measured by the terminal device; or,

[0397] The signal quality of the beam is greater than or equal to the reference threshold; or,

[0398] The signal quality of the beam is greater than or equal to the signal quality of the reference beam, and the beam is different from the reference beam.

[0399] In a possible embodiment, the transceiver 703 is also used to send measurement configuration information to the terminal device, where the measurement configuration information is used to instruct the terminal device to report indication information of a beam that meets preset conditions; and to receive indication information of at least one beam from the terminal device.

[0400] Optionally, the measurement configuration information includes indication information of a reference beam and / or a reference threshold.

[0401] Optionally, the measurement configuration information also includes an upper limit on the number of beams to be reported.

[0402] Optionally, the measurement configuration information is measurement configuration information of an RRC layer; or, the measurement configuration information is measurement configuration information of a physical layer.

[0403] In a possible implementation manner, the indication information of the at least one beam includes an index of each beam in the at least one beam.

[0404] In a possible implementation, the indication information of the at least one beam further includes a cell identifier corresponding to each beam in the at least one beam, and / or signal quality information of each beam in the at least one beam.

[0405] In a possible implementation, the transceiver 703 is also used to send a radio resource control RRC reconfiguration message to the terminal device, the RRC reconfiguration message including first indication information and indication information of a cell of at least one candidate access network device, the first indication information being used to instruct the terminal device to adopt random access-free RACH-LESS switching.

[0406] In a possible implementation, the switching request message includes indication information of at least one first beam measured by the terminal device.

[0407] In a possible implementation manner, the beam indicated by the indication information of at least one beam is different from the beam indicated by the indication information of at least one first beam.

[0408] In a possible implementation, the reference beam is a beam determined by the source access network device based on indication information of at least one first beam.

[0409] In another design, the communication device 70 is configured to execute the method for a candidate access network device in the embodiment corresponding to FIG. 2 or FIG. The transceiver 703 is configured to: receive a handover request message from a source access network device; send a handover request confirmation message to the source access network device; and receive, from the source access network device, indication information of at least one beam measured by a terminal device. The processor 701 is configured to send a PDCCH to the terminal device based on the indication information of the at least one beam.

[0410] In a possible implementation manner, the terminal device is a terminal device that adopts RACH-LESS switching.

[0411] In a possible implementation, the processor 701 is specifically configured to send a PDCCH through a beam of a cell belonging to a candidate access network device in indication information of at least one beam, where the PDCCH is used to indicate uplink resources allocated to the terminal device.

[0412] In a possible implementation manner, the indication information of the at least one beam includes an index of each beam in the at least one beam.

[0413] Optionally, the indication information of at least one beam also includes a cell identifier corresponding to each beam in the at least one beam, and / or signal quality information of each beam in the at least one beam.

[0414] In a possible implementation, the switching request message includes indication information of at least one first beam measured by the terminal device.

[0415] In a possible implementation manner, the beam indicated by the indication information of at least one beam is different from the beam indicated by the indication information of at least one first beam.

[0416] In another design, a communication device 70 is configured to execute the method for a candidate access network device in the embodiment corresponding to FIG. 4 or 5 . A transceiver 703 in the communication device 70 is configured to send first indication information and resource configuration information, wherein the first indication information is configured to instruct the terminal device to employ RACH-LESS handover, and the resource configuration information is configured to indicate pre-allocated uplink resources of a third beam set in the candidate cell and to indicate monitoring of a PDCCH on a beam in a fourth beam set in the candidate cell, where the third beam set includes at least one beam and the fourth beam set includes at least one beam.

[0417] In a possible implementation, the resource configuration information includes indication information of the third beam set, information of pre-allocated uplink resources corresponding to each beam in the third beam set, and indication information of the fourth beam set.

[0418] In a possible implementation, the resource configuration information further includes information about random access RACH resources.

[0419] In a possible implementation manner, the resource configuration information further includes a first threshold corresponding to pre-allocated uplink resources and / or a second threshold corresponding to dynamically allocated uplink resources indicated by the PDCCH.

[0420] In a possible implementation manner, the resource configuration information further includes a third threshold corresponding to each beam in the third beam set, and / or a fourth threshold corresponding to each beam in the fourth beam set.

[0421] In a possible implementation, the resource configuration information further includes second indication information, where the second indication information is used to instruct the terminal device to give priority to using the pre-allocated uplink resources.

[0422] In a possible implementation, the resource configuration information further includes third indication information, where the third indication information is used to instruct the terminal device to obtain dynamically allocated uplink resources by preferentially monitoring the PDCCH.

[0423] In a possible embodiment, the transceiver 703 is also used to receive beam-level measurement results measured by the terminal device, where the beam-level measurement results include indication information of at least one beam; the processor 701 is also used to determine indication information of the third beam set and / or indication information of the fourth beam set based on the beam-level measurement results.

[0424] In another design, a communication device 70 is configured to perform the method of the source access network device in the embodiment corresponding to FIG. 4 or 5 . A transceiver 703 in the communication device 70 is configured to send a handover request message to at least one candidate access network device. The handover request message includes a beam-level measurement result measured by the terminal device, and the beam-level measurement result includes indication information of at least one beam.

[0425] Optionally, the indication information of the at least one beam includes an index of each beam in the at least one beam.

[0426] Optionally, the indication information of at least one beam also includes a cell identifier corresponding to each beam in the at least one beam.

[0427] Optionally, the indication information of at least one beam further includes signal quality information of each beam in the at least one beam.

[0428] In one possible implementation, the transceiver 703 is configured to receive a handover request confirmation message from a candidate access network device. The handover request confirmation message includes first indication information and resource configuration information, wherein the first indication information is used to instruct the terminal device to adopt RACH-LESS handover, and the resource configuration information is used to indicate pre-allocated uplink resources of a third beam set in the candidate cell and to indicate monitoring of the PDCCH on a beam in a fourth beam set in the candidate cell, where the third beam set includes at least one beam and the fourth beam set includes at least one beam.

[0429] In a possible implementation, the transceiver 703 is configured to send an RRC reconfiguration message to the terminal device, where the RRC reconfiguration message includes first indication information and resource configuration information.

[0430] It should be noted that the specific implementation and beneficial effects of this embodiment can be referred to the method of accessing the network device in the above embodiment, which will not be repeated here.

[0431] As shown in FIG8 , the present application further provides a communication device 80. The communication device 80 may be a terminal device or an access network device, or a component of the terminal device or access network device (e.g., an integrated circuit, a chip, etc.). The access network device may be a source access network device, a candidate access network device, or a target access network device. The communication device 80 may also be another communication module for implementing the method in the method embodiment of the present application.

[0432] The communication device 80 may include a processing module 801 (or processing unit). Optionally, it may also include an interface module 802 (or transceiver unit or transceiver module) and a storage module 803 (or storage unit). The interface module 802 is used to implement communication with other devices. The interface module 802 may be, for example, a transceiver module or an input / output module.

[0433] In one possible design, one or more modules shown in FIG8 may be implemented by one or more processors, or by one or more processors and memory, or by one or more processors and a transceiver, or by one or more processors, memory, and a transceiver, although this is not limited in the present embodiment. The processor, memory, and transceiver may be provided separately or integrated.

[0434] The communication device 80 has the functions of implementing the terminal device described in the embodiment of the present application. For example, the communication device 80 includes a module or unit or means (means) corresponding to the terminal device performing the steps involved in the terminal device described in the embodiment of the present application. The functions or units or means (means) can be implemented by software, or by hardware, or by hardware executing the corresponding software implementation, or by a combination of software and hardware. For details, please refer to the corresponding description in the aforementioned corresponding method embodiment. Please refer to the communication device 60 in the corresponding embodiment of Figure 6 above.

[0435] Alternatively, the communication device 80 has the function of implementing the access network device described in the embodiment of the present application. For example, the communication device 80 includes a module or unit or means (means) corresponding to the access network device performing the steps involved in the access network device described in the embodiment of the present application. The function or unit or means (means) can be implemented by software, or by hardware, or by hardware executing the corresponding software implementation, or by a combination of software and hardware. For details, please refer to the corresponding description in the aforementioned corresponding method embodiment. For details, please refer to the communication device 70 in the corresponding embodiment of Figure 7 above.

[0436] In addition, the present application provides a computer program product comprising one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function according to the embodiment of the present application is generated in whole or in part. For example, the method related to the access network device (source access network device or candidate access network device) in Figures 2, 3, 4, or 5 is implemented. For another example, the method related to the terminal device in Figures 2, 3, 4, or 5 is implemented. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be stored by a computer or a data storage device such as a server or data center that includes one or more available media. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0437] In addition, the present application also provides a computer-readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement a method related to the access network device as shown in Figures 2, 3, 4 or 5 above.

[0438] In addition, the present application also provides a computer-readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement a method related to the terminal device as shown in Figures 2, 3, 4 or 5 above.

[0439] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0440] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A communication method, characterized in that: include: The source access network device sends a switching request message to at least one candidate access network device; The source access network device receives a handover request confirmation message from the at least one candidate access network device; The source access network device sends indication information of at least one beam measured by the terminal device to the at least one candidate access network device.

2. The method according to claim 1, characterized in that The indication information of the at least one beam is used by the at least one candidate access network device to determine the beam for sending the physical downlink control channel PDCCH to the terminal device.

3. The method according to claim 1 or 2, characterized in that: Each beam in the at least one beam satisfies any one of the following preset conditions: The beam is a beam with the best signal quality among the beams measured by the terminal device; or, The signal quality of the beam is greater than or equal to a reference threshold; or, The signal quality of the beam is greater than or equal to the signal quality of a reference beam, and the beam is different from the reference beam.

4. The method according to claim 3, characterized in that: The method further comprises: The source access network device sends measurement configuration information to the terminal device, where the measurement configuration information is used to instruct the terminal device to report indication information of the beam that meets the preset condition; The source access network device receives indication information of the at least one beam from the terminal device.

5. The method according to claim 4, characterized in that The measurement configuration information includes indication information of the reference beam and / or the reference threshold.

6. The method according to claim 5, characterized in that The measurement configuration information also includes an upper limit on the number of beams reported.

7. The method according to any one of claims 1 to 6, characterized in that: The indication information of the at least one beam includes an index of each beam in the at least one beam.

8. The method according to claim 7, characterized in that The indication information of the at least one beam further includes a cell identifier corresponding to each beam in the at least one beam, and / or signal quality information of each beam in the at least one beam.

9. The method according to any one of claims 1 to 8, characterized in that The measurement configuration information is measurement configuration information of a radio resource control (RRC) layer; or, the measurement configuration information is measurement configuration information of a physical layer.

10. The method according to any one of claims 1 to 9, characterized in that The method further comprises: The source access network device sends an RRC reconfiguration message to the terminal device, where the RRC reconfiguration message includes first indication information and indication information of a cell of the at least one candidate access network device, where the first indication information is used to instruct the terminal device to adopt random access-free RACH-LESS switching.

11. The method according to any one of claims 1 to 10, characterized in that The switching request message includes indication information of at least one first beam measured by the terminal device.

12. The method according to claim 11, characterized in that The beam indicated by the indication information of the at least one beam is different from the beam indicated by the indication information of the at least one first beam.

13. The method according to claim 11 or 12, characterized in that: The reference beam is a beam determined by the source access network device based on the indication information of the at least one first beam.

14. A communication method, characterized in that: include: The terminal device sends indication information of at least one beam to the source access network device, and the indication information of at least one beam is used by at least one candidate access network device to determine the beam for sending PDCCH to the terminal device. The candidate access network device is the access network device configured by the source access network device in the RRC reconfiguration message of the terminal device.

15. The method according to claim 14, characterized in that Each beam in the at least one beam satisfies any one of the following preset conditions: The beam is a beam with the best signal quality among the beams measured by the terminal device; or, The signal quality of the beam is greater than or equal to a reference threshold; or, The signal quality of the beam is greater than or equal to the signal quality of a reference beam, and the beam is different from the reference beam.

16. The method according to claim 15, characterized in that The method further comprises: The terminal device receives measurement configuration information from the source access network device, where the measurement configuration information is used to instruct the terminal device to report indication information of a beam that meets the preset condition.

17. The method according to claim 16, characterized in that The measurement configuration information includes indication information of the reference beam and / or the reference threshold.

18. The method according to claim 17, characterized in that The measurement configuration information also includes an upper limit on the number of beams reported.

19. The method according to any one of claims 14 to 18, characterized in that The indication information of the at least one beam includes an index of each beam in the at least one beam.

20. The method according to claim 19, characterized in that The indication information of the at least one beam further includes a cell identifier corresponding to each beam in the at least one beam, and / or signal quality information of each beam in the at least one beam.

21. The method according to any one of claims 14 to 20, characterized in that The measurement configuration information is measurement configuration information of an RRC layer; or, the measurement configuration information is measurement configuration information of a physical layer.

22. The method according to any one of claims 14 to 21, characterized in that The method further comprises: The terminal device receives an RRC reconfiguration message from the source access network device, where the RRC reconfiguration message includes first indication information and cell information of the at least one candidate access network device, where the first indication information is used to instruct the terminal device to adopt RACH-LESS switching.

23. The method according to claim 22, characterized in that The method further comprises: The terminal device triggers switching to a target cell of a target access network device, where the target access network device is one of the at least one candidate access network devices; The terminal device monitors the PDCCH through a beam belonging to the target cell among the at least one beam, and the PDCCH is used to indicate uplink resources allocated to the terminal device.

24. The method according to any one of claims 14 to 23, characterized in that Before the terminal device sends indication information of at least one beam to the source access network device, the method further includes: The terminal device sends indication information of at least one first beam to the source access network device.

25. The method according to claim 24, characterized in that The beam indicated by the indication information of the at least one beam is different from the beam indicated by the indication information of the at least one first beam.

26. A communication method, characterized in that: include: The candidate access network device receives a handover request message from the source access network device; The candidate access network device sends a handover request confirmation message to the source access network device; The candidate access network device receives, from the source access network device, indication information of at least one beam measured by the terminal device; The candidate access network device sends the PDCCH to the terminal device based on the indication information of the at least one beam.

27. A communication method, characterized in that: include: The terminal device receives first indication information and resource configuration information, where the first indication information is used to indicate that the terminal device adopts random access-free RACH-LESS switching, and the resource configuration information is used to indicate the pre-allocated uplink resources of the third beam set in the candidate cell and to indicate to monitor the PDCCH on the beam in the fourth beam set in the candidate cell to obtain uplink resources, where the third beam set includes at least one beam, and the fourth beam set includes at least one beam; The terminal device determines a target beam and / or an uplink resource corresponding to the target beam from at least one measured beam based on the resource configuration information.

28. The method according to claim 27, characterized in that The resource configuration information includes indication information of the third beam set, information of pre-allocated uplink resources corresponding to each beam in the third beam set, and indication information of the fourth beam set.

29. The method according to claim 28, characterized in that The terminal device determines a target beam and / or an uplink resource corresponding to the target beam from at least one measured beam based on the resource configuration information, including: If at least one beam of the candidate cell measured by the terminal device belongs to the third beam set, the terminal device determines a beam among the at least one beam as a target beam, and determines the pre-allocated uplink resources corresponding to the target beam as the uplink resources corresponding to the target beam.

30. The method according to claim 28, characterized in that The terminal device determines a target beam and / or an uplink resource corresponding to the target beam from at least one measured beam based on the resource configuration information, including: If at least one beam of the candidate cell measured by the terminal device belongs to the fourth beam set, the terminal device determines a beam among the at least one beam as a target beam, and monitors PDCCH in the target beam, and the dynamically allocated uplink resources indicated by the PDCCH are the uplink resources corresponding to the target beam.

31. The method according to claim 28, characterized in that The terminal device determines a target beam and / or an uplink resource corresponding to the target beam from at least one measured beam based on the resource configuration information, including: If the terminal device measures that there is at least one beam of the candidate cell that belongs to the third beam set, and the terminal device measures that there is at least one beam of the candidate cell that belongs to the fourth beam set, the terminal device determines a beam from the third beam set as the target beam, and determines that the pre-allocated uplink resources corresponding to the target beam are the uplink resources corresponding to the target beam.

32. The method according to claim 31, characterized in that The resource configuration information also includes information on random access RACH resources; The terminal device determines a target beam and / or an uplink resource corresponding to the target beam from at least one measured beam based on the resource configuration information, including: If at least one beam of the candidate cell measured by the terminal device does not belong to the third beam set and does not belong to the fourth beam set, the terminal device determines a beam as a target beam among the at least one beam, and triggers a random access process through the RACH resource.

33. The method according to claim 28, characterized in that The resource configuration information further includes second indication information, where the second indication information is used to instruct the terminal device to preferentially use the pre-allocated uplink resources; The terminal device determines a target beam and / or an uplink resource corresponding to the target beam from at least one measured beam based on the resource configuration information, including: If the terminal device detects that there is at least one beam in the candidate cell that belongs to the third beam set, and there is at least one beam in the candidate cell that belongs to the fourth beam set, the terminal device determines a beam from at least one beam belonging to the third beam set as a target beam, and determines the pre-allocated uplink resources corresponding to the target beam as the uplink resources corresponding to the target beam.

34. The method according to claim 28, characterized in that The resource configuration information further includes third indication information, where the third indication information is used to instruct the terminal device to obtain dynamically allocated uplink resources by monitoring the PDCCH in priority; The terminal device determines a target beam and / or an uplink resource corresponding to the target beam from at least one measured beam based on the resource configuration information, including: If the terminal device detects that at least one beam of the candidate cell belongs to the third beam set, and at least one beam of the candidate cell belongs to the fourth beam set, the terminal device determines a beam as a target beam from at least one beam belonging to the fourth beam set, and monitors PDCCH on the target beam, and the dynamically allocated uplink resources indicated by the PDCCH are the uplink resources corresponding to the target beam.

35. The method according to claim 29, 31 or 33, characterized in that The resource configuration information also includes a first threshold corresponding to the pre-allocated uplink resource; The terminal device determines a beam as a target beam in the at least one beam, including: The terminal device determines a beam among the at least one beam whose signal quality is greater than or equal to the first threshold as the target beam.

36. The method according to claim 30 or 34, characterized in that The resource configuration information also includes a second threshold corresponding to the dynamically allocated uplink resources indicated by the PDCCH; The terminal device determines a beam as a target beam in the at least one beam, including: The terminal device determines a beam among the at least one beam whose signal quality is greater than or equal to the second threshold as the target beam.

37. The method according to claim 29, 31 or 33, characterized in that The resource configuration information also includes a third threshold corresponding to each beam in the third beam set; The terminal device determines a beam as a target beam in the at least one beam, including: The terminal device determines a beam among the at least one beam whose signal quality is greater than or equal to a third threshold corresponding to the beam as the target beam.

38. The method according to claim 30 or 34, characterized in that The resource configuration information also includes a fourth threshold corresponding to each beam in the fourth beam set; The terminal device determines a beam as a target beam in the at least one beam, including: The terminal device determines a beam among the at least one beam whose signal quality is greater than or equal to a fourth threshold corresponding to the beam as the target beam.

39. The method according to claim 28, characterized in that The resource configuration information also includes information on random access RACH resources; The terminal device determines a target beam and / or an uplink resource corresponding to the target beam from at least one measured beam based on the resource configuration information, including: The terminal device determines a beam with the best signal quality among at least one beam of the candidate cell as a target beam; If the target beam belongs to the third beam set, the terminal device determines that the pre-allocated uplink resource corresponding to the target beam is the uplink resource corresponding to the target beam; If the target beam belongs to the fourth beam set, the terminal device monitors the PDCCH in the target beam, and the dynamically allocated uplink resources indicated by the PDCCH are the uplink resources corresponding to the target beam; If the target beam does not belong to the third beam set and does not belong to the fourth beam set, the terminal device triggers a random access procedure in the target beam through the RACH resource.

40. A communication method, characterized in that: include: The candidate access network device sends first indication information and resource configuration information, wherein the first indication information is used to instruct the terminal device to adopt random access-free RACH-LESS switching, and the resource configuration information is used to indicate the pre-allocated uplink resources of the third beam set in the candidate cell and to indicate to monitor PDCCH on the beam in the fourth beam set in the candidate cell, the third beam set includes at least one beam, and the fourth beam set includes at least one beam.

41. A communication device, characterized in that: including a processor and a memory; wherein the memory stores a computer program; The processor calls the computer program to enable the communication device to execute the method of the source access network device according to any one of claims 1 to 13.

42. A communication device, characterized in that: including a processor and a memory; wherein the memory stores a computer program; The processor calls the computer program to cause the communication device to execute the method of the terminal device as described in any one of claims 14 to 25; or, execute the method of the terminal device as described in any one of claims 27 to 39.

43. A communication device, characterized in that: including a processor and a memory; wherein the memory stores a computer program; The processor calls the computer program to cause the communication device to execute the method of the candidate access network device according to claim 26 or 40.

44. A computer-readable storage medium, characterized in that Instructions are stored, and when the instructions are executed on a computer, the computer executes the method as claimed in any one of claims 1 to 13; or, executes the method as claimed in any one of claims 14 to 25; or, executes the method as claimed in any one of claims 27 to 39; or, executes the method as claimed in claim 26 or 40.

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