Cell handover method and apparatus, device, and readable storage medium

Abstract

The present application is applied to the field of communications, and provides a cell handover method and apparatus, a device, and a readable storage medium. The method comprises: evaluating a handover condition and determining a target cell from among candidate cells, the target cell meeting the handover condition; obtaining first information, the first information comprising at least one of a first scheduling resource and dedicated preamble configuration information, wherein the first scheduling resource is used to send a cell handover result to the target cell, and the cell handover result is used to indicate that a terminal device completes a cell handover using the first scheduling resource; and the dedicated preamble configuration information is used to initiate random access to the target cell to complete a cell handover, and the cell handover refers to handover from a source cell to the target cell. By means of different first information, cell handover with different handover modes is implemented to meet different scenario requirements.

Description

Cell switching method, device, apparatus and readable storage medium

[0001] The present application claims priority from the Chinese patent application No. 202410741237.9 filed on June 7, 2024, and entitled "Cell switching method, device, apparatus and readable storage medium", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of communication, in particular to a cell switching method, device, apparatus and readable storage medium. BACKGROUND

[0003] In a communication system, cell switching refers to that when a terminal moves from a source cell to a target cell, and adjusts from data communication with the source cell to data communication with the target cell.

[0004] In the related art, two switching mechanisms are introduced for cell switching, which are conditional handover (CHO) mechanism and layer 1 / layer 2 triggered mobility (LTM) switching mechanism. In the CHO mechanism, the terminal evaluates candidate cells according to the configuration conditions and corresponding switching conditions of the candidate cells sent by the source cell, and when there is a target cell in the candidate cells that meets the switching condition, the terminal disconnects the connection with the source cell and switches to the target cell. In the LTM mechanism, after the terminal receives the configuration information of the candidate cells, the terminal performs downlink synchronization and uplink synchronization on the candidate cells, and when receiving the switching command sent by the source cell, the terminal switches from the source cell to the target cell. In R19, the CHO mechanism and the LTM mechanism are combined to obtain a conditional LTM mechanism.

[0005] However, how the terminal performs cell switching in the conditional LTM mechanism is a technical problem to be solved. SUMMARY

[0006] The present application provides a cell switching method, device, apparatus and readable storage medium, which can improve the cell switching efficiency.

[0007] In a first aspect, a method for cell switching is provided. The method is applied to a terminal device connected to a source cell. The method comprises: evaluating a switching condition, determining a target cell from candidate cells, the target cell satisfying the switching condition; obtaining first information, the first information comprising at least one of: a first scheduling resource; dedicated preamble configuration information; wherein the first scheduling resource is used for sending a cell switching result to the target cell, the cell switching result being used for indicating that the terminal device completes the cell switching by using the first scheduling resource; the dedicated preamble configuration information being used for initiating random access to the target cell to complete the cell switching, the cell switching being switching from the source cell to the target cell.

[0008] In the technical solution of the present application, in the process of the LTM mechanism of the execution condition, the terminal device evaluates the switching condition, determines the target cell satisfying the switching condition from the candidate cells, and obtains the first information allocated by the candidate cells. When the first information is the first scheduling resource, the cell switching without random access is completed by using the first scheduling resource. When the first information is the dedicated preamble configuration information, the random access to the target cell is initiated by using the dedicated preamble configuration information to complete the cell switching. On the one hand, the cell switching mode initiated by the terminal device can actively perform the cell switching when a better cell compared to the source cell is found, thereby reducing the time length of waiting for the switching instruction issued by the network device, and improving the efficiency of the cell switching. On the other hand, the cell switching in different switching modes by different first information meets different scene requirements, reduces the switching delay of the terminal device in the process of the cell switching, and reduces the signaling overhead of the terminal device in the process of the cell switching.

[0009] Illustratively, when the first information is the first scheduling resource, the terminal device implements the cell switching without random access by using the first scheduling resource, that is, directly completes the switching from the source cell to the target cell by using the first scheduling resource.

[0010] When the first information is implemented as the first scheduling resource, the first scheduling resource refers to the uplink (UL) channel resource used by the terminal device for sending the cell switching result to the target cell. The cell switching result is used for indicating to the target cell that the terminal device has completed the access to the cell. Optionally, the cell switching result comprises at least one of the uplink signaling or the uplink data packet.

[0011] Optionally, the first scheduling resource is the scheduling resource allocated by the target cell to the terminal device; or the first scheduling resource is the scheduling resource allocated by the candidate cell other than the target cell to the terminal device.

[0012] Illustratively, when the first information is dedicated preamble configuration information, after the terminal device receives the dedicated preamble configuration information, the terminal device initiates a random access request to the target cell to perform a random access process, and after the random access process is completed, the terminal device is switched from the source cell to the target cell.

[0013] In some implementations of the first aspect, the first information indicates a first scheduling resource; and before the first information is obtained, the method further includes: receiving first indication information, the first indication information indicating a time at which the candidate cell allocates the first scheduling resource to the terminal device.

[0014] Since the cell switching is initiated by the terminal device, the network device cannot determine how to allocate the scheduling resource to the terminal device, and therefore, by sending the first indication information to the terminal device, the network device informs the terminal device of the time at which the scheduling resource is allocated, so that the network device does not need to continuously allocate the scheduling resource to the terminal device, but only needs to allocate the scheduling resource at the specified time, thereby saving signaling resource overhead.

[0015] In some implementations of the first aspect, the first indication information is carried in a first medium access control control element (MAC CE) signaling.

[0016] In some implementations of the first aspect, the first indication information is sent in at least one of the following manners: by the target cell; by the target cell to the source cell and then by the source cell; or by the source cell.

[0017] In some implementations of the first aspect, the first indication information includes at least one of the following: a scheduling start time of the first scheduling resource; a scheduling stop time of the first scheduling resource; a scheduling period of the first scheduling resource; a number of periods of the first scheduling resource; a duration of a single scheduling period of the first scheduling resource; an identifier of the candidate cell; and an identifier of candidate cell configuration information.

[0018] By setting various time parameters corresponding to the time at which the first scheduling resource is allocated in the first indication information, the probability of the terminal device obtaining the first scheduling resource can be improved.

[0019] In some implementations of the first aspect, the first information includes the first scheduling resource; and before the first information is obtained, the method further includes: receiving discontinuous reception (DRX) configuration information; and obtaining the first information includes: detecting a physical downlink control channel (PDCCH) in a DRX manner to obtain the first scheduling resource.

[0020] With reference to the first aspect, in some implementations of the first aspect, the PDCCH is detected by using the DRX configuration information in the DRX active state period to obtain the first scheduling resource.

[0021] With reference to the first aspect, in some implementations of the first aspect, the PDCCH is detected by using the DRX configuration information in the DRX active state period to obtain the first scheduling resource.

[0022] With reference to the first aspect, in some implementations of the first aspect, the dedicated preamble configuration information includes at least one of: dedicated preamble configuration information associated with the first beam, the first beam being configured by the target cell; and dedicated preamble configuration information associated with the second beam, the second beam being configured by the source cell.

[0023] The dedicated preamble is configured in various ways to ensure that the dedicated preamble is successfully configured, improve the feasibility of cell switching, and improve the efficiency of cell switching.

[0024] With reference to the first aspect, in some implementations of the first aspect, after obtaining the first information, the method further includes: in a case where the third beam meets an association condition, sending the dedicated preamble to the target cell through the third beam, the third beam being a beam corresponding to activated transmission configuration indicator (TCI) information of the target cell, the source cell being configured to activate the TCI information of the target cell; the association condition being at least one of: the third beam belonging to the first beam; and the third beam belonging to the second beam.

[0025] When the third beam corresponding to the dedicated preamble has been activated, the dedicated preamble is directly sent through the third beam, which simplifies the preamble sending process and improves the signaling transmission efficiency.

[0026] With reference to the first aspect, in some implementations of the first aspect, after obtaining the first information, the method further includes: in a case where the third beam does not meet the association condition, determining whether any one of the first beam and the second beam meets a beam quality condition.

[0027] With reference to the first aspect, in some implementations of the first aspect, after obtaining the first information, the method further includes: in a case where the first beam meets the beam quality condition, performing a contention free random access (CFRA) to complete the cell switching by using a dedicated preamble sent by the first beam; or in a case where the second beam meets the beam quality condition, performing the CFRA to complete the cell switching by using a dedicated preamble sent by the second beam.

[0028] When the CFRA is performed to complete the cell switching in a case where the first beam / second beam meets the beam quality condition, the completion degree of the cell switching can be ensured, and the cell switching efficiency is improved.

[0029] With reference to the first aspect, in some implementations of the first aspect, after obtaining the first information, the method further includes: in a case where the first beam does not meet the beam quality condition, performing a contention based random access (CBRA) to complete the cell switching; or in a case where the second beam does not meet the beam quality condition, performing the CBRA to complete the cell switching.

[0030] In a case where the third beam does not meet the beam quality condition, the CBRA-based manner is used to complete the cell switching, and multiple different feasible schemes are provided for the cell switching manner, so that the cell switching is smoothly performed, and the cell switching efficiency is improved.

[0031] With reference to the first aspect, in some implementations of the first aspect, the first information refers to a first scheduling resource, and before obtaining the first information, the method further includes: in a case where the target cell meets the switching condition, sending a first preamble to the target cell, the first preamble being used to request the target cell to allocate the first scheduling resource.

[0032] By using the manner that the terminal device actively requests the network device to send the first scheduling resource, the network device can allocate the first scheduling resource to the terminal device at an accurate timing, and resource waste is avoided.

[0033] With reference to the first aspect, in some implementations of the first aspect, before evaluating the switching condition and determining the target cell from the candidate cells, the method further includes: obtaining a first timing advance (TA) value; and wherein the first TA value is obtained in at least one of the following manners: the first TA value is carried in a random access response (RAR); the first TA value is carried in a second MAC CE signaling; or the first TA value is measured by the terminal device.

[0034] In some implementations of the first aspect, the first TA value is carried in the second MAC CE signaling; and before the first information is acquired, the method further includes: sending a second preamble, the second preamble being used to request acquisition of the first TA value corresponding to the candidate cell; and receiving the second MAC CE signaling, the second MAC CE signaling including at least one of a candidate cell identifier or a TA timer; and starting the TA timer based on the second MAC CE signaling, the TA timer being used to determine a validity state of the first TA value, the validity state being used to determine a switching mode of the terminal device performing cell switching.

[0035] The second MAC CE signaling is sent to the terminal device, which is used to determine the validity state of the first TA value by the terminal device. When the target cell meets the switching condition, the terminal device can immediately determine the validity state of the first TA value, and cell switching is performed when the first TA value is in the validity state, thereby improving the efficiency of cell switching.

[0036] In some implementations of the first aspect, the first TA value is measured by the terminal device; and the first indication information is received by: sending third indication information, the third indication information being used to instruct the terminal device to measure the first TA value; and receiving the first indication information when the third indication information is received by the target cell.

[0037] In some implementations of the first aspect, the first TA value is measured by the terminal device; and the first indication information is received by: receiving the first indication information when fourth indication information is sent from the source cell to the target cell, the fourth indication information being used to instruct the terminal device to measure the first TA value corresponding to the target cell.

[0038] After the terminal device measures the first TA value, the third indication information is sent to the target cell, or the fourth indication information is sent from the source cell to the target cell before the first indication information is sent to the terminal device, which can ensure that the terminal device has successfully acquired the first TA value when the first scheduling resource is allocated to the terminal device, thereby reducing the probability of cell switching failure caused by blind configuration of the scheduling resource by the target cell, and improving the efficiency of cell switching.

[0039] In some implementations of the first aspect, the first information refers to the first scheduling resource, and the first scheduling resource includes a grant resource; and after the first information is acquired, the method further includes: sending a third preamble to the target cell, the third preamble being used to instruct activation of the grant resource corresponding to the target cell; and sending a cell switching result to the target cell using the grant resource when the grant resource is activated.

[0040] The third preamble is sent to the terminal device to activate the grant resource, which ensures that the grant resource can be applied to cell switching, thereby improving the efficiency of cell switching.

[0041] In a second aspect, a method for cell switching is provided, and applied to a network device. The method comprises: sending first information, the first information comprising at least one of: first scheduling resources; dedicated preamble configuration information; wherein the first scheduling resources are used for receiving a cell switching result, the cell switching result being used for indicating that, in a case where a terminal device evaluates a switching condition and determines a target cell from candidate cells, the terminal device completes cell switching by using the first scheduling resources, and the target cell meets the switching condition; and the dedicated preamble configuration information is used for receiving a random access for completing cell switching sent by the terminal device, the cell switching being switching from a source cell to a target cell.

[0042] It should be understood that the technical effects of the technical solutions of the second aspect can be referred to the related description of the first aspect, and will not be repeated.

[0043] In combination with the second aspect, in some implementations of the second aspect, the first information comprises the first scheduling resources; and before the sending of the first information, the method further comprises: sending first indication information, the first indication information being used for indicating a time when the target cell allocates the first scheduling resources to the terminal device.

[0044] In combination with the second aspect, in some implementations of the second aspect, the first indication information is carried in a first MAC CE signaling.

[0045] In combination with the second aspect, in some implementations of the second aspect, the sending mode of the first indication information comprises at least one of: being sent by the target cell; being sent by the target cell to the source cell and then being sent by the source cell; and being sent by the source cell.

[0046] In combination with the second aspect, in some implementations of the second aspect, the sending of the first scheduling resources comprises: sending DRX configuration information; and allocating the first scheduling resources in a PDCCH in a DRX manner.

[0047] In combination with the second aspect, in some implementations of the second aspect, the first indication information comprises at least one of: a scheduling start time of the first scheduling resources; a scheduling stop time of the first scheduling resources; a scheduling period of the first scheduling resources; a number of periods of the first scheduling resources; a duration of a single scheduling period of the first scheduling resources; a candidate cell identifier; and an identifier of candidate cell configuration information.

[0048] In combination with the second aspect, in some implementations of the second aspect, the first information comprises the first scheduling resources; and before the sending of the first information, the method further comprises: sending DRX configuration information; and the sending of the first information comprises: allocating the first scheduling resources in a PDCCH in a DRX manner.

[0049] With reference to the second aspect, in some implementations of the second aspect, the DRX configuration information is used for the target cell to allocate the first scheduling resource to the terminal device through PDCCH in a DRX active state period.

[0050] With reference to the second aspect, in some implementations of the second aspect, the dedicated preamble configuration information comprises at least one of: dedicated preamble configuration information associated with the first beam, the first beam being configured by the target cell; dedicated preamble configuration information associated with the second beam, the second beam being configured by the source cell.

[0051] With reference to the second aspect, in some implementations of the second aspect, after the first information is sent, the method further comprises: receiving a dedicated preamble through a third beam in a case where the third beam meets an association condition, the third beam being a beam corresponding to activated TCI information of the target cell, the source cell being configured to activate the TCI information of the target cell; the association condition being at least one of: the third beam belonging to the first beam; the third beam belonging to the second beam.

[0052] With reference to the second aspect, in some implementations of the second aspect, after the first information is sent, the method further comprises:

[0053] In a case where the first beam meets a beam quality condition, establishing a radio resource control (RRC) connection with the terminal device based on CFRA using the dedicated preamble sent by the third beam; or in a case where the second beam meets the beam quality condition, establishing the RRC connection with the terminal device based on CFRA using the dedicated preamble sent by the third beam.

[0054] With reference to the second aspect, in some implementations of the second aspect, after the first information is sent, the method further comprises:

[0055] In a case where the first beam does not meet the beam quality condition, establishing the RRC connection with the terminal device based on CBRA; or in a case where the second beam does not meet the beam quality condition, establishing the RRC connection with the terminal device based on CBRA.

[0056] With reference to the second aspect, in some implementations of the second aspect, the first information refers to the first scheduling resource; before the first information is sent, the method further comprises: in a case where the terminal device evaluates that the target cell meets a handover condition, receiving a first preamble, the first preamble being used to allocate the first scheduling resource to the terminal device.

[0057] With reference to the second aspect, in some implementations of the second aspect, before the first information is sent, the method further comprises: sending a second MAC CE signaling, the second MAC CE signaling carrying the first TA value; or sending a RAR, the RAR carrying the first TA value.

[0058] In some implementations of the second aspect, the first TA value is carried in the second MAC CE signaling; and the sending of the second MAC CE signaling includes: receiving a second preamble, the second preamble being used to request the first TA value corresponding to the target cell; and sending the second MAC CE signaling, the second MAC CE signaling including at least one of the first TA value, an identification number of the target cell, or a TA timer used to determine a validity state of the first TA value, the validity state being used to determine a switching mode of the terminal device performing the cell switching.

[0059] In some implementations of the second aspect, the terminal device measures the first TA value; and before the sending of the first indication information, the method further includes: receiving third indication information, the third indication information being used to instruct the terminal device to measure the first TA value corresponding to the target cell.

[0060] In some implementations of the second aspect, the terminal device measures the first TA value; and before the sending of the first indication information, the method further includes: generating fourth indication information, the fourth indication information being used to instruct the terminal device to measure the first TA value corresponding to the target cell.

[0061] In some implementations of the second aspect, the first information is a first scheduling resource, and the first scheduling resource includes a grant resource; and after the sending of the first information, the method further includes: receiving a third preamble, the third preamble being used to instruct to activate the grant resource corresponding to the target cell, the grant resource being used to receive the cell switching result in the activated case.

[0062] In some implementations of the second aspect, after the sending of the first information, the method further includes: obtaining fifth indication information, the fifth indication information being used to instruct other candidate cells except the target cell to stop sending the first information.

[0063] In some implementations of the second aspect, the fifth indication information includes a scheduling termination moment of a second scheduling resource, and the other candidate cells are used to stop allocating the second scheduling resource when the scheduling termination moment is reached.

[0064] When the target cell implements the cell switching, the other candidate cells can stop allocating the scheduling resource to the terminal device according to the scheduling termination moment, or stop allocating the scheduling resource to the terminal device according to the sixth indication information, which can reduce the signaling overhead of the other candidate cells and reduce the waste of communication resources.

[0065] A third aspect provides a device for cell switching, the device including a unit composed of software and / or hardware and used to execute any one of the methods in the first aspect or the second aspect.

[0066] In a fourth aspect, an electronic device is provided, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, any method of the first aspect or the second aspect can be implemented.

[0067] Optionally, when the electronic device is used to implement any method of the first aspect, the electronic device can be a terminal device, and when the electronic device is used to implement any method of the second aspect, the electronic device can be a network device.

[0068] In a fifth aspect, a chip is provided, which includes a processor, and the processor is used to read and execute a computer program stored in a memory, and when the computer program is executed by the processor, any method of the first aspect or the second aspect can be implemented.

[0069] Optionally, the chip further includes the memory, and the memory is electrically connected with the processor.

[0070] Optionally, the chip can further include a communication interface.

[0071] In a sixth aspect, a computer readable storage medium is provided, which stores a computer program, and when the computer program is executed by a processor, any method of the first aspect or the second aspect can be implemented.

[0072] In a seventh aspect, a computer program product is provided, which includes a computer program, and when the computer program is executed by a processor, any method of the first aspect or the second aspect can be implemented. BRIEF DESCRIPTION OF DRAWINGS

[0073] FIG. 1 is an interaction diagram of a conditional handover method according to an embodiment of the present application.

[0074] FIG. 2 is an interaction diagram of an LTM handover method according to an embodiment of the present application.

[0075] FIG. 3 is an interaction diagram of a conditional LTM handover method according to an embodiment of the present application.

[0076] FIG. 4 is a schematic diagram of a network scenario according to an embodiment of the present application.

[0077] FIG. 5 is a schematic flowchart of a cell handover method according to an embodiment of the present application.

[0078] FIG. 6 is a schematic flowchart of another cell handover method according to an embodiment of the present application.

[0079] FIG. 7 is a schematic diagram of content of a first indication information according to an embodiment of the present application.

[0080] FIG. 8 is a schematic diagram of contents of another first indication information according to an embodiment of the present application.

[0081] FIG. 9 is a schematic diagram of an indication information indication manner according to an embodiment of the present application.

[0082] FIG. 10 is a schematic flowchart of another cell switching method according to an embodiment of the present application.

[0083] FIG. 11 is a schematic flowchart of another cell switching method according to an embodiment of the present application.

[0084] FIG. 12 is a schematic diagram of a timing indication method according to an embodiment of the present application.

[0085] FIG. 13 is a schematic diagram of contents of a MAC CE signaling according to an embodiment of the present application.

[0086] FIG. 14 is a schematic diagram of another timing indication method according to an embodiment of the present application.

[0087] FIG. 15 is a schematic diagram of another timing indication method according to an embodiment of the present application.

[0088] FIG. 16 is a flowchart of a scheduling resource allocation manner according to an embodiment of the present application.

[0089] FIG. 17 is a flowchart of a cell switching method according to an embodiment of the present application.

[0090] FIG. 18 is a flowchart of another cell switching method according to an embodiment of the present application.

[0091] FIG. 19 is a schematic diagram of a cell switching apparatus according to an embodiment of the present application.

[0092] FIG. 20 is a schematic diagram of a hardware structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0093] First, related terms in the embodiments of the present application are introduced.

[0094] Cell: A cell refers to a smallest management unit in a mobile communication network, and can also be understood as a wireless signal coverage unit formed by a base station and its coverage area. The base station can also be referred to as a network device, the coverage range of each network device can be divided into at least one cell, and each cell can correspond to at least one frequency point.

[0095] In the embodiments of the present application, different cells can correspond to the same network device or different network devices, for example: the first cell and the second cell are two different cells, the first cell and the second cell can belong to the same network device, that is, the network device can manage the first cell and the second cell at the same time, or the first cell belongs to the first network device and the second cell belongs to the second network device, that is, the first cell and the second cell are managed by different network devices respectively.

[0096] Cell switching: cell switching refers to, in a wireless communication system, when a terminal device moves from one cell to another cell or approaches, in order to maintain the communication continuity of the terminal device, switching needs to be performed.

[0097] In the embodiments of the present application, the source cell represents the cell that provides services for the terminal device before switching, and the target cell represents the cell that provides services for the terminal device after switching. The related information of the target cell (such as the physical cell identifier of the target cell, frequency information, random access resource information required for switching to the target cell, etc.) can be indicated by a switching message, for example: by a no-RRC reconfiguration message, the switching message is sent by the network device to which the source cell belongs (that is, the source network device) to the terminal device, or the switching message is sent by the network device of the target cell (that is, the target network device) to the source network device, and then forwarded by the source network device to the terminal device.

[0098] Optionally, the cell switching includes any one of intra-site switching or inter-site switching. The intra-site switching can refer to that the source cell and the target cell belong to the same network device, wherein the source cell and the target cell can be the same cell or different cells, in this case, the target cell corresponds to a TA value of 0 for the terminal device. The inter-site switching refers to that the source cell and the target cell belong to different network devices. The present application does not limit this.

[0099] It should be understood that the source cell corresponds to the source network device or the source base station, and the target cell corresponds to the target network device or the target base station.

[0100] Random access: random access refers to the process that the terminal device starts to try to access the network device to send a random access preamble index, and then a connection is established between the terminal device and the network device. The random access process can be applied to scenarios such as cell switching and RRC re-establishment.

[0101] Optionally, the random access can be divided into contention-based random access (CBRA) and non-contention-based random access (CFRA).

[0102] Transmission configuration indicator (TCI) state: refers to the quasi co location (QCL) relationship between two reference signals. Each TCI state can include the index of the serving cell (source cell), the bandwidth part (band width part, BWP) identifier (ID) and the reference signal resource identifier, which can include at least one of the following: non-zero power (NZP), channel state information-reference signal (CSI-RS) resource identifier (resource id), NZP CSI-RS reference signal resource set identifier (resource set id) or synchronization signal and physical broadcast channel block (SSB-PBCH) index. TCI can be used to indicate the QCL information of PDCCH or PDSCH, which can be used to indicate the QCL relationship between the demodulation reference signal (DMRS) of PDCCH or PDSCH and the reference signal, and then the terminal device can use the same or similar spatial parameters (for example: receiving beam) to receive PDCCH or PDSCH. In TCI, the reference signal index can be used to indicate the QCL relationship between the DMRS of PDCCH / PDSCH and the reference signal.

[0103] Next, the communication technology in the embodiments of the present application is introduced.

[0104] ·Contention-based random access (CBRA)

[0105] The resource used by CFRA is CFRA resource, which is dedicated random access channel (RACH) resource. The process of CBRA can include the following steps S1 to S4.

[0106] Step S1, random access preamble transmission as message 1 (Msg1).

[0107] The terminal device randomly selects a preamble from the shared preamble pool, and sends the preamble index to the corresponding beam of the network device through the physical random access channel (PRACH).

[0108] Step S2, the random access response (RAR) as message2 (Msg2).

[0109] When the network device receives the preamble index, the network device applies for a temporary cell-radio network temporary identifier (C-RNTI) and uplink and downlink scheduling resources. Then, the network device sends the random access response (RAR) through the physical downlink shared channel (PDSCH). The RAR contains the responding TA value, uplink grant (UL grant) information, etc.

[0110] A PDSCH can carry the RAR for multiple terminal devices.

[0111] Step S3, the RRC connection request (RRC connection request) as message3 (Msg3).

[0112] The terminal device sends the message3 to the network device on the specified uplink resource, which contains the identification number corresponding to the terminal device and the necessary information required for establishing the RRC connection.

[0113] Step S4, the RRC establishment message (RRC connection setup) as message4 (Msg4).

[0114] When the network device receives the message / data sent by the terminal device on the allocated UL grant resource, if there is no conflict (or no contention), the network device sends the terminal device a contention resolution message, for example, the network device sends the terminal device an RRC establishment message. After that, the terminal device can communicate with the network device.

[0115] • Non-contention random access (CFRA)

[0116] The resources used by the CFRA can include a preamble index and a time-frequency resource. In a new radio (NR) network, the CFRA resource can be a CFRA resource associated with a certain beam of a cell. If the network device configures a CFRA resource for the terminal device, the terminal device can initiate a CFRA procedure using the CFRA resource. If the CFRA fails or the network device does not configure a CFRA resource, the terminal device can initiate a CBRA to the network device. The CBRA resource can be understood as a common resource, and the terminal device can use the CBRA resource to perform a CBRA procedure in a competitive manner.

[0117] The CFRA procedure can include the following steps S10 to S20.

[0118] Step S10, the preamble transmission as Msg1.

[0119] The terminal device sends a random access preamble index (or random access preamble sequence) to the network device through the PRACH. In the non-competitive random access procedure, the random access preamble index is allocated to the terminal device by the network device in advance. That is, the random access preamble index is dedicated to the terminal device.

[0120] Step S20, the random access response (RAR) as Msg2.

[0121] The network device sends a random access response to the terminal device. The random access response can include a responding TA value, an UL grant, etc.

[0122] Conditional handover (CHO)

[0123] CHO is a new handover procedure introduced in R16 protocol: allows the terminal device to (itself) decide to perform cell handover when certain conditions are met, while in the traditional cell handover process, the network device is usually responsible for deciding whether the handover should be performed.

[0124] For illustration, please refer to FIG. 1, which shows a conditional handover method interaction diagram provided by an example embodiment of the present application, as shown in FIG. 1, a terminal device in a current communication system, a source cell currently establishing a communication connection with the terminal device, and a candidate cell, wherein the candidate cell further includes a target cell and a potential cell. The conditional handover method can include the following steps.

[0125] Step 110, measurement reporting.

[0126] The terminal device reports measurement results to the source cell. The measurement results can include at least one of Layer 1 (L1) measurement results, Layer 2 (L2) measurement results, or Layer 3 (L3) measurement results.

[0127] Step 120, conditional handover decision.

[0128] After the source cell receives the measurement results reported by the terminal device, the source cell makes a CHO decision based on the measurement results to obtain a decision result, wherein the decision result includes two results of performing CHO or not performing CHO.

[0129] Step 130, preparation of conditional handover.

[0130] If the decision result of the source cell is to perform CHO, the network device sends a handover request to the target cell and the potential cell (collectively referred to as candidate cells) respectively, to request configuration information corresponding to the target cell and configuration information corresponding to the potential cell. The target cell and the potential cell respectively send a handover request response, wherein the handover request response sent by the target cell includes configuration information corresponding to the target cell and a handover condition (also referred to as an execution condition), and the handover request response sent by the potential cell includes configuration information corresponding to the potential cell and a handover condition.

[0131] The source cell can receive a handover request response corresponding to each of up to eight candidate cells (including the target cell or the potential cell).

[0132] The candidate cell configures one or two trigger conditions. The trigger conditions include event A3 or event A5.

[0133] For example, event A3 can mean that if the quality of a neighboring cell is higher than the quality of the source cell, cell handover can be triggered; and event A5 can mean that if the quality of the source cell is less than an absolute threshold and the quality of a neighboring cell is higher than an absolute threshold, cell handover can be triggered.

[0134] Step 140, RRC reconfiguration message.

[0135] The source cell sends the configuration information of the candidate cells (including the target cell and the potential cell) and the handover conditions to the terminal device through an RRC reconfiguration message.

[0136] After receiving the RRC reconfiguration message, the terminal device saves the RRC reconfiguration message and performs corresponding configuration.

[0137] Step 150, RRC reconfiguration completion.

[0138] After the terminal device completes the corresponding configuration according to the RRC reconfiguration message, the terminal device sends a feedback message of RRC reconfiguration completion to the source cell.

[0139] The RRC reconfiguration message can configure a plurality of candidate cells and corresponding handover conditions.

[0140] Step 160, CHO evaluation.

[0141] After the terminal receives the RRC reconfiguration message sent by the source cell, the CHO evaluation or detection is performed, and when at least one candidate cell satisfies the corresponding handover condition, the candidate cell can be determined as the target cell.

[0142] Step 170, disconnecting the connection with the source cell.

[0143] After the terminal device disconnects the connection with the source cell, the target cell is connected, and the cell handover is completed.

[0144] Step 180, CHO completion.

[0145] After the cell handover is completed, the terminal device can release the configuration information corresponding to the conditional handover.

[0146] Layer 1 / layer 2 triggered mobility (L1 / L2 triggered mobility, LTM) handover

[0147] In the LTM handover process, the source cell can pre-configure the candidate cell.

[0148] For illustration, refer to FIG. 2, which shows an LTM handover method interaction diagram provided by an example embodiment of the present application. In the communication system shown in FIG. 2, the terminal device, the source cell, and the candidate cell are included, wherein the candidate cell includes the target cell and the potential cell. As shown in FIG. 2, the method includes the following steps.

[0149] Step 210, measurement reporting.

[0150] The terminal device reports the measurement result to the source cell according to the configured candidate cell. The measurement result includes at least one of the layer 1 measurement result, the layer 2 measurement result, or the layer 3 measurement result.

[0151] Step 220, LTM handover preparation.

[0152] After the source cell receives the measurement result, it determines to perform LTM handover according to the support capability of the terminal device for LTM handover. The source cell sends a handover request to the target cell and the potential cell respectively, for requesting configuration information corresponding to the target cell and configuration information corresponding to the potential cell. The source cell receives a handover request response sent by the target cell and the potential cell respectively, wherein the handover request response sent by the target cell includes the configuration information corresponding to the target cell and a handover condition (which can also be referred to as an execution condition), and the handover request response sent by the potential cell includes the configuration information corresponding to the potential cell and the handover condition.

[0153] Step 230, RRC reconfiguration message.

[0154] The source cell sends the configuration information of the candidate cells (including the target cell and the potential cell) and the handover condition to the terminal device through the RRC reconfiguration message.

[0155] After the terminal device receives the RRC reconfiguration message, it saves the RRC reconfiguration message and performs corresponding configuration.

[0156] Step 240, RRC reconfiguration completion.

[0157] After the terminal device completes the corresponding configuration according to the RRC reconfiguration message, it sends a feedback message of RRC reconfiguration completion to the source cell.

[0158] The RRC reconfiguration message can configure a plurality of candidate cells and corresponding handover conditions.

[0159] Step 250, downlink synchronization for the candidate cells.

[0160] After receiving the configuration information of the candidate cells, the terminal device can perform downlink synchronization for each candidate cell respectively.

[0161] Step 260, uplink synchronization for the candidate cells.

[0162] After receiving the configuration information of the candidate cells, the terminal device can perform uplink synchronization for each candidate cell respectively.

[0163] During the execution of the uplink synchronization with the candidate cells, when the source cell indicates in the RRC reconfiguration information that the terminal device measures the uplink TA value by itself, the terminal device measures the TA value of the source cell and determines the TA value of the candidate cell according to the reception time difference between the source cell and the candidate cell; in another way, the source cell triggers a CFRA-based random access through a PDCCH order, for obtaining the TA value of the candidate cell, the terminal device initiates the CFRA to obtain the TA value from the candidate cell, and the network device manages the validity state of the TA value.

[0164] Step 270, measurement reporting.

[0165] The terminal device performs layer 3 measurement on the source cell and the candidate cell, and reports the layer 3 measurement result to the source cell.

[0166] Step 280, LTM handover command.

[0167] The source cell determines the target cell from the candidate cell according to the layer 3 measurement result, and sends an LTM handover command to the terminal device. The LTM handover command can be carried in a MAC CE signaling. The MAC CE can at least include the following information: TA value, TCI state identity (ID), CFRA resource information, and candidate cell configuration information identity.

[0168] Step 290, disconnecting the connection with the source cell.

[0169] After receiving the LTM handover command sent by the source cell, the terminal device can disconnect the connection with the source cell.

[0170] Step 2100, performing a random access procedure.

[0171] The terminal device performs a random access procedure, connects to the target cell, and performs data transmission through the target cell.

[0172] Step 2110, completing LTM handover.

[0173] When the terminal device receives the MAC CE signaling, if the TA value is carried in the MAC CE signaling, or when the terminal device measures the TA value by itself, the terminal device will initiate a RACH-less handover to the target cell, that is, the terminal device only needs to send an uplink signaling or the first uplink data packet to the target cell, to indicate to the target cell that the terminal device has accessed the target cell.

[0174] Conditional LTM (C-LTM)

[0175] In R19, the CHO mechanism is combined with the LTM handover mechanism to obtain conditional LTM, that is, the terminal device evaluates the handover condition by itself, determines the target cell that meets the handover condition from the candidate cell, and sends a random access channel (RACH) to the target cell, to send a random access request to the target cell, to establish a wireless connection with the target cell.

[0176] For illustration, refer to FIG. 3, which shows an interaction diagram of a conditional LTM switching method according to an example embodiment of the present application. In the communication system shown in FIG. 3, there are a terminal device, a source cell, and candidate cells, wherein the candidate cells include a target cell and potential cells. As shown in FIG. 3, the method includes the following steps.

[0177] Step 310: Measurement reporting.

[0178] The terminal device reports the measurement results to the source cell according to the configured candidate cells. The measurement results include at least one of layer 1 measurement results, layer 3 measurement results, or layer 3 measurement results.

[0179] Step 320: LTM switching preparation.

[0180] After receiving the measurement results, the source cell determines to perform LTM switching according to the support capability of the terminal device for LTM switching. The source cell sends a switching request to the target cell and the potential cells respectively, for requesting the configuration information corresponding to the target cell and the configuration information corresponding to the potential cells. The source cell receives the switching request responses sent by the target cell and the potential cells respectively, wherein the switching request response sent by the target cell includes the configuration information corresponding to the target cell and switching conditions (also referred to as execution conditions), and the switching request response sent by the potential cells includes the configuration information corresponding to the potential cells and switching conditions.

[0181] Step 330: RRC reconfiguration message.

[0182] The source cell sends the configuration information of the candidate cells (including the target cell and the potential cells) and the switching conditions to the terminal device through an RRC reconfiguration message.

[0183] After receiving the RRC reconfiguration message, the terminal device saves the RRC reconfiguration message and performs corresponding configuration.

[0184] Step 340: RRC reconfiguration completion.

[0185] After completing the corresponding configuration according to the RRC reconfiguration message, the terminal device sends a feedback message of RRC reconfiguration completion to the source cell.

[0186] The RRC reconfiguration message can configure multiple candidate cells and corresponding switching conditions.

[0187] Step 350: Downlink synchronization for the candidate cells.

[0188] After receiving the configuration information of the candidate cells, the terminal device can perform downlink synchronization for each candidate cell respectively.

[0189] Step 360: Uplink synchronization for the candidate cells.

[0190] After receiving the configuration information of the candidate cell, the terminal device can perform uplink synchronization for each candidate cell respectively.

[0191] In the process of performing uplink synchronization with the candidate cell, when the source cell indicates in the RRC reconfiguration information that the terminal device measures the uplink TA value by itself, the terminal device measures the TA value of the source cell and determines the TA value of the candidate cell according to the time difference in receiving the source cell and the candidate cell; in another way, the source cell triggers the random access based on CFRA through PDCCH command to obtain the TA value of the candidate cell, the terminal device initiates CFRA to obtain the TA value of the candidate cell, and the network device manages the validity of the TA value.

[0192] Step 370, CHO evaluation.

[0193] After the terminal device completes the uplink synchronization with the candidate cell, the CHO evaluation or detection is performed, and when at least one candidate cell meets the corresponding handover condition, the candidate cell can be determined as the target cell.

[0194] Step 380, disconnecting the connection with the source cell.

[0195] After the terminal device evaluates the handover condition and determines the target cell, the connection with the source cell can be disconnected.

[0196] Step 390, performing the random access procedure.

[0197] The terminal device performs the random access procedure, connects to the target cell, and performs data transmission through the target cell.

[0198] Step 3100, completing the conditional LTM handover.

[0199] When the terminal device completes the handover from the source cell to the target cell, the conditional LTM handover is completed.

[0200] It should also be understood that the network device of the source cell and the network device of the target cell can be the same device, or in other words, the source cell and the target cell can be co-located. The network device of the source cell and the network device of the target cell can be different devices, or in other words, the source cell and the target cell can not be co-located.

[0201] It should also be understood that the handover message and the above-mentioned RRC message indicating handover are described from different angles. The handover message is described from the functional angle, aiming to express that the message is used to instruct the terminal device to perform handover. The RRC message is described from the message type angle, aiming to express that the message is high-layer signaling. The RRC reconfiguration message is an enumeration of the RRC message. In other words, the handover message is issued to the terminal device through high-layer signaling.

[0202] The scheme of the embodiments of the present application is introduced below in combination with the drawings. The cell switching method provided by the present application can be applied to various wireless communication systems.

[0203] FIG. 4 is a schematic diagram of a network scenario to which an embodiment of the present application is applicable. As shown in FIG. 4, the wireless communication system in this scenario includes at least one network device 410 and at least one user equipment (UE) 420. The wireless communication system can be a long term evolution (LTE) network or a fifth generation (5G) network or any other wireless communication system capable of carrying cell switching services.

[0204] In the embodiments of the present application, the network device 410 can include an access network (AN) device, a radio access network (RAN) device, an access network device such as a base station (e.g., an access point), which can refer to a device in an access network that communicates with wireless terminal devices through one or more cells over the air interface. For example, the base station can be an evolved Node B (eNB or e-NodeB), or it can include a next generation Node B (gNB) or a next generation evolved Node B (ng-eNB) in a 5G system, an en-gNB (enhanced next generation Node B, gNB), an enhanced next generation base station, or a centralized unit (CU) and a distributed unit (DU) in a cloud radio access network (Cloud RAN) system, and the like, which are not listed one by one.

[0205] The user equipment 420 can also be referred to as a terminal device, which can be a mobile phone, a smart watch, a tablet computer, a notebook computer, an XR terminal, a vehicle-mounted terminal, and the like. The XR terminal can also include a virtual reality (VR) terminal, an augmented reality (AR) terminal, and a mixed reality (MR) terminal.

[0206] Currently, two switching mechanisms are introduced for cell switching mode, which are CHO mechanism and layer 1 / layer 2 triggered mobility switching mechanism. In the CHO mechanism, the terminal evaluates the candidate cells according to the configuration conditions and corresponding switching conditions of the candidate cells sent by the source cell, and when there is a target cell in the candidate cells that meets the switching condition, the terminal disconnects the connection with the source cell and switches to the target cell. In the LTM mechanism, after the terminal receives the configuration information of the candidate cells, the terminal performs downlink synchronization and uplink synchronization on the candidate cells, and when receiving the switching command sent by the source cell, the terminal switches from the source cell to the target cell. In R19, the CHO mechanism and the LTM mechanism are combined to obtain the conditional LTM mechanism. In the conditional LTM, after the uplink synchronization is completed according to steps 210 to 260 in FIG. 2, the terminal device evaluates the candidate cells, and when there is a target cell that meets the switching condition, how the terminal device performs cell switching is a technical problem to be solved.

[0207] In the technical solution of the present application, in the process of executing the conditional LTM mechanism, the terminal device evaluates the switching condition, determines the target cell that meets the switching condition from the candidate cells, and obtains the first information allocated by the candidate cell. When the first information is a first scheduling resource, the cell switching without random access is completed by using the first scheduling resource. When the first information is dedicated preamble configuration information, the random access is initiated to the target cell by using the dedicated preamble configuration information to complete the cell switching. On the one hand, the cell switching mode initiated by the terminal device can actively perform cell switching when a better cell than the source cell is found, which reduces the time length of waiting for the switching instruction issued by the network device, thereby improving the efficiency of cell switching. On the other hand, the cell switching of different switching modes is realized by different first information to meet different scene requirements, reduce the switching delay of the terminal device in the cell switching process, and reduce the signaling overhead of the terminal device in the cell switching process.

[0208] Next, the cell switching method provided by the embodiment of the present application will be described in detail. For illustration, please refer to FIG. 5, which shows a schematic flowchart of the method of cell switching provided by an exemplary embodiment of the present application. As shown in FIG. 5, the method includes the following steps.

[0209] Step 510, the terminal device evaluates the switching condition and determines the target cell from the candidate cells.

[0210] The target cell meets the switching condition.

[0211] The target cell is a candidate cell that meets the handover condition among the candidate cells. That is, there are potential cells among the candidate cells in addition to the target cell. The target cell is also a cell in the potential cells before it is determined as the target cell by the terminal device.

[0212] In this embodiment, the network device can be implemented as any one of a source network device or a target network device.

[0213] Optionally, the handover condition comprises at least one of the following:

[0214] • A3 event: the quality of the neighboring cell is higher than the quality of the source cell, and the cell handover can be triggered;

[0215] • A5 event: the quality of the source cell is less than an absolute threshold (absolute threshold 1), and the quality of the neighboring cell is higher than an absolute threshold (absolute threshold 2), and the cell handover can be triggered;

[0216] • B1 event: the quality of the inter-system neighboring cell is higher than a certain threshold, and the cell handover can be triggered, wherein the base station corresponding to the inter-system neighboring cell and the base station corresponding to the source cell belong to different base stations;

[0217] • B2 event: the signal quality of the source cell is lower than a certain threshold (absolute threshold 3), and the signal quality of the inter-system neighboring cell is higher than another threshold (absolute threshold 4), and the cell handover can be triggered.

[0218] Optionally, the evaluation manner of the terminal device comprises at least one of the following manners:

[0219] Firstly, whether each candidate cell meets the handover condition is evaluated, and if the candidate cell meets the handover condition, the candidate cell is determined as the target cell;

[0220] Secondly, whether a plurality of candidate cells meet the handover condition is evaluated in sequence, and when the ith candidate cell meets the handover condition, the ith candidate cell is determined as the target cell and the evaluation is stopped, wherein i is a positive integer.

[0221] It is worth noting that the above evaluation manners are only illustrative examples, and the embodiments of the present application are not limited thereto.

[0222] In step 520, the network device sends the first information to the terminal device.

[0223] The first information includes at least one of the following: a first scheduling resource; dedicated preamble configuration information; the first scheduling resource is used to send a cell switching result to the target cell, and the cell switching result is used to indicate that the terminal device completes cell switching by using the first scheduling resource; the dedicated preamble configuration information is used to initiate random access to the target cell to complete cell switching, and the cell switching refers to switching from the source cell to the target cell.

[0224] The terminal device is connected to the source cell, and the first scheduling resource is a scheduling resource allocated by the candidate cell to the terminal device.

[0225] Optionally, the first scheduling resource includes at least one of a dynamic resource or an authorized resource.

[0226] Optionally, the first information includes different contents corresponding to different cell switching processes.

[0227] Optionally, the first scheduling resource is used to implement cell switching without random access, that is, the terminal device only needs to use the first scheduling resource to send a cell switching result to the target cell to complete switching from the source cell to the target cell.

[0228] In some embodiments, after the terminal device obtains the first TA value of the candidate cell, the terminal device obtains the first scheduling resource sent by the candidate cell to the terminal device.

[0229] Optionally, the first scheduling resource is allocated to the PDCCH before the terminal device evaluates that the target cell meets the switching condition; or the first scheduling resource is allocated to the PDCCH when the terminal device evaluates that the target cell meets the switching condition; or the first scheduling resource is allocated to the PDCCH at a specified time after the terminal device evaluates that the target cell meets the switching condition, which is not limited in the embodiment.

[0230] Optionally, the network device allocates the first scheduling resource to the terminal device through the PDCCH at a specified time; or after the terminal device sends a specified preamble (referred to as the first preamble in the application) to the network device, the network device allocates the first scheduling resource to the terminal device through the PDCCH.

[0231] Optionally, the first scheduling resource is a scheduling resource that can be used by only one terminal device, or the first scheduling resource includes scheduling resources that can be used by multiple terminal devices (for example, resource 1 that can be used by a first terminal device and resource 2 that can be used by a second terminal device), and the first terminal device selects and uses resource 1 from the first scheduling resource after obtaining the first scheduling resource.

[0232] Optionally, the resource 1 and the resource 2 can be shared, that is, the first terminal device can use the resource 1 or the resource 2; or the terminal device using the resource 1 and the resource 2 is fixed, that is, the first terminal device can only use the resource 1, and the second terminal device can only use the resource 2, which is not limited in the embodiments of the present application.

[0233] Optionally, the target cell is obtained by the terminal device according to the handover condition; or the target cell is obtained by the source cell according to the handover condition, which is not limited.

[0234] In a possible case, the first scheduling resource is allocated to the terminal device in the form of downlink control information (DCI), for example, the resource position of the first scheduling resource is indicated in the DCI, and the terminal device obtains the first scheduling resource according to the resource position indicated in the DCI after detecting the DCI.

[0235] Illustratively, the source cell is a cell currently serving the terminal device, and the candidate cell is a cell not yet connected to the terminal device.

[0236] Optionally, when the source cell and the candidate cell belong to the same network device, the first scheduling resource allocated by the candidate cell to the terminal device can be sent to the terminal device by the network device; when the source cell and the candidate cell belong to different network devices, the source cell corresponds to a source network device, and the candidate cell corresponds to a candidate network device, therefore, the first scheduling resource can be implemented by being sent from the candidate network device to the source network device, and then being sent from the source network device to the terminal device, or the first scheduling resource can be implemented by being sent from the candidate network device to the terminal device, which is not limited.

[0237] In some embodiments, the first scheduling resource is a scheduling resource sent by the network device to the terminal device through the PDCCH.

[0238] Illustratively, the terminal device sends the uplink instruction or the uplink data packet to the target cell using the first scheduling resource, to inform the target cell that the cell handover is completed, as the result of the cell handover.

[0239] Optionally, the first scheduling resource used to send the result of the cell handover to the target cell is the first scheduling resource allocated by the target cell itself, that is, the terminal device sends the result of the cell handover to the target cell using the first scheduling resource allocated by the target cell; or the first scheduling resource used to send the result of the cell handover to the target cell is the first scheduling resource allocated by the potential cell in the candidate cell, that is, the terminal device sends the result of the cell handover to the target cell using the first scheduling resource allocated by the potential cell under the authorization of the potential cell.

[0240] Optionally, the terminal device sends the cell switching result to the source cell, and the source cell forwards the cell switching result to the target cell; or the terminal device sends the cell switching result to the source cell and the target cell simultaneously; or the terminal device sends the cell switching result to the target cell only; or the terminal device sends the cell switching result to the source cell, the target cell and other candidate cells (also referred to as potential cells) except the target cell, without limitation.

[0241] When the terminal device sends the cell switching result to the source cell and the potential cell, at least one of the following implementation manners can be included:

[0242] Case 1: The source cell and the potential cell belong to the same network device (source network device), and belong to different network devices with the target cell, so the terminal device needs to obtain the second scheduling resource allocated by the source network device in addition to the first scheduling resource, and sends the cell switching result to the source cell and the potential cell through the second scheduling resource;

[0243] Case 2: The source cell and the potential cell belong to different network devices, that is, the source cell corresponds to the source network device, and the potential cell corresponds to the potential network device, so the terminal device needs to obtain the second scheduling resource allocated by the source network device and the third scheduling resource allocated by the potential network device in addition to the first scheduling resource, sends the cell switching result to the source cell through the second scheduling resource, and sends the cell switching result to the potential cell through the third scheduling resource;

[0244] Case 3: The source cell, the potential cell and the target cell belong to the same network device, so the terminal device can directly send the cell switching result to the source cell, the potential cell and the target cell through the first scheduling resource respectively.

[0245] It is worth noting that the above-mentioned manner of the cell switching result is only an illustrative example, and the embodiments of the present application are not limited thereto.

[0246] Illustratively, the dedicated preamble configuration information is used to implement the cell switching with random access (RACH-based), wherein the cell switching with random access includes performing CFRA to complete the switching from the source cell to the target cell, or performing CBRA to complete the switching from the source cell to the target cell.

[0247] In some embodiments, when the first information is implemented as the dedicated preamble configuration information, the corresponding first preamble is sent by using the dedicated preamble configuration information as the random access request corresponding to CFRA; or a random preamble is directly sent as the random access request of CBRA, without limitation.

[0248] Optionally, the cell switching mode comprises at least one of the following modes:

[0249] Firstly, when the terminal device acquires the first TA value of the candidate cell, when the target cell meeting the switching condition is evaluated, the first scheduling resource allocated by the target cell is acquired, and the cell switching result is sent to the target cell by using the first scheduling resource to complete the switching from the source cell to the target cell.

[0250] Secondly, when the terminal device acquires the first TA value of the candidate cell, when the target cell meeting the switching condition is evaluated, the first preamble is sent to the target cell to request the first scheduling resource, after the target cell receives the first preamble, the first scheduling resource is sent to the terminal device, and the terminal device sends the cell switching result to the target cell by using the first scheduling resource to complete the switching from the source cell to the target cell.

[0251] Secondly, when the terminal acquires the RRC reconfiguration information containing the configuration information of the candidate cell, the dedicated preamble configuration information corresponding to the candidate cell is pre-configured, wherein the dedicated preamble configuration information is used to configure the dedicated preamble, when the terminal device evaluates the target cell meeting the switching condition, the dedicated preamble configuration information is directly used to execute the switching from the source cell to the target cell with random access;

[0252] Thirdly, when the terminal acquires the RRC reconfiguration information containing the configuration information of the candidate cell, the dedicated preamble configuration information corresponding to the candidate cell is pre-configured, wherein the dedicated preamble configuration information is used to configure the dedicated preamble, when the terminal device evaluates the target cell meeting the switching condition, and the terminal device does not acquire the first scheduling resource sent by the target cell, the dedicated preamble configuration information is used to execute the switching from the source cell to the target cell with random access;

[0253] Fourthly, when the terminal acquires the RRC reconfiguration information containing the configuration information of the candidate cell, the dedicated preamble configuration information corresponding to the candidate cell is pre-configured, when the terminal device evaluates the target cell meeting the switching condition, and the terminal device acquires the first scheduling resource sent by the target cell, the cell switching result is sent to the target cell by using the first scheduling resource to complete the switching from the source cell to the target cell.

[0254] Fifthly, when the terminal device acquires the first TA value of the candidate cell, the fourth preamble is sent to the candidate cell to request the dedicated preamble configuration information, when the target cell meeting the switching condition is evaluated, the dedicated preamble configuration information of the target cell is used to execute the switching from the source cell to the target cell with random access.

[0255] Sixth, when the evaluation meets the switching condition of the target cell, and the terminal device does not acquire the first scheduling resource sent by the target cell, a fourth preamble is sent to the target cell, which is used to request to acquire the dedicated preamble configuration information, and the switching from the source cell to the target cell with random access is performed according to the dedicated preamble configuration information.

[0256] That is, when the first information is the dedicated preamble configuration information, the dedicated preamble configuration information can be configured in the pre-configuration information corresponding to the candidate cell; or after the terminal device acquires the first TA value of the candidate cell, the dedicated preamble configuration information is configured through the dedicated signaling.

[0257] In summary, the method provided by the embodiments of the present application, in the process of the LTM mechanism of the execution condition, the terminal device evaluates the switching condition, determines the target cell meeting the switching condition from the candidate cell, and acquires the first information allocated by the candidate cell, when the first information is the first scheduling resource, the cell switching without random access is completed by using the first scheduling resource, and when the first information is the dedicated preamble configuration information, the cell switching is initiated by using the dedicated preamble configuration information to the target cell to complete the cell switching, on the one hand, the cell switching mode initiated by the terminal device can be actively performed by the terminal device when a better cell compared with the source cell is found, which reduces the time length of waiting for the switching instruction issued by the network device, thereby improving the efficiency of the cell switching, on the other hand, the cell switching of different switching modes through different first information meets the different scene requirements, reduces the switching delay of the terminal device in the process of the cell switching, and reduces the signaling overhead of the terminal device in the process of the cell switching.

[0258] It is worth noting that the target cell, the source cell and the potential cell involved in the present application all send / receive data in the process of executing data communication by the network device respectively, so it can be understood that "xx message sent by the target cell" is equivalent to "xx message sent by the target network device corresponding to the target cell", and the network devices corresponding to the target cell, the source cell and the potential cell can be the same or different, which is not limited.

[0259] It is worth noting that the execution order between step 510 and step 520 can be to execute step 510 first and then execute step 520, or to execute step 520 first and then execute step 510, or to execute step 510 and step 520 synchronously, and the embodiments of the present application do not limit this.

[0260] Next, when the first information is the first scheduling resource, the transmission of two different scheduling resources is described in detail.

[0261] The first kind is to indicate the allocation time of the first scheduling resource by sending indication information

[0262] In an implementation, the first indication information is carried in the first MAC CE signaling. Referring to FIG. 6, which shows a schematic flowchart of cell switching according to another example embodiment of the present application, step 520 further includes step 521, and step 520 further includes step 530 after step 520:

[0263] In step 510a, the network device sends the first indication information to the terminal device.

[0264] The first information refers to the first scheduling resource, and the first indication information is used to indicate the time at which the candidate cell allocates the first scheduling resource to the terminal device.

[0265] In some embodiments, since the terminal device evaluates the target cell that meets the switching condition, the network device cannot accurately determine when the terminal device performs cell switching, and thus cannot determine when to initiate scheduling (i.e., allocate scheduling resources) to the terminal device. Therefore, by sending the first indication information to the terminal device, the terminal device is indicated the time at which the first scheduling resource is allocated, for example, the current time is time 1, and the first indication information indicates that the first scheduling resource is allocated to the terminal device at time 2, which is after time 1. By indicating the time, the terminal device can be dynamically allocated scheduling resources, which saves the signaling overhead of the network device and improves the efficiency and success rate of the terminal device in obtaining scheduling resources.

[0266] Optionally, the first indication information only includes the allocation time of the first scheduling resource, or the first indication information includes the allocation time of the first scheduling resource and the allocation time of other scheduling resources, wherein the other scheduling resources can be used by the terminal device to send other messages (which can or can not include the cell switching result), or the other scheduling resources are channel resources for other terminal devices, which are not limited.

[0267] In some embodiments, the first indication information is carried in the first MAC CE signaling.

[0268] In this embodiment, the first indication information can be sent to the terminal device by the first MAC CE signaling.

[0269] When the first indication information is sent to the terminal device by the first MAC CE signaling, the network device sends the first indication information to the terminal device after the terminal device obtains the first TA value corresponding to the candidate cell.

[0270] The first TA value is used to control a transmission time of the terminal device in a time domain, so as to ensure accurate transmission of uplink and downlink data between the terminal device and the cell.

[0271] In some embodiments, the MAC CE carrying the first indication information is identified by a logical channel identification (LCID).

[0272] The LCID is used to represent at least one of a logical channel, a control message type, or a padding field.

[0273] In this embodiment, a pre-set LCID is selected from a logical channel identifier (LCID) value table of a downlink shared channel as the LCID in the first indication message, and the table 1 can be referred to for details.

[0274] Table 1

[0275] In this embodiment, any one of the LCIDs 35-46 reserved in the table 1 is selected as the LCID in the first indication information.

[0276] In some embodiments, the first indication message includes at least one of the following:

[0277] a scheduling start time of the first scheduling resource;

[0278] The scheduling start time of the first scheduling resource represents a time at which the candidate cell starts to allocate the first scheduling resource to the terminal device, and the scheduling start time is determined according to a reference point, which can be implemented as taking a time at which the RAR is received as the reference point, or taking a specified time as the reference point.

[0279] In this embodiment, the specified slot after the reference point is taken as the scheduling start time, for example, the second slot after the reference point is determined as the scheduling start time, or the specified subframe after the reference point is taken as the scheduling start time, for example, the third subframe after the reference point is taken as the scheduling start time.

[0280] One radio frame (10 ms) is usually divided into a plurality of subframes, and each subframe contains a certain number of slots.

[0281] a scheduling end time of the first scheduling resource;

[0282] The scheduling stop moment of the first scheduling resource refers to a moment at which the candidate cell stops allocating the first scheduling resource to the terminal device. The determination manner of the moment can be the same as that of the scheduling start moment, which will not be repeated here.

[0283] • A scheduling period of the first scheduling resource;

[0284] In this embodiment, in order to reduce the excessive cost of channel resources, the candidate cell does not continuously allocate the first scheduling resource to the terminal device, but periodically allocates the first scheduling resource to the terminal device. For example, the first time slot of the first downlink subframe corresponding to the RAR is taken as a reference point, the candidate cell allocates the first scheduling resource to the terminal device from the second time slot, and stops allocating the first scheduling resource to the terminal device at the end of the sixth time slot, that is, the scheduling period is 5 time slots, and the first time slot of the second downlink subframe is taken as a reference point, and the execution process of the second period starts from the second time slot.

[0285] Therefore, by using the periodic scheduling manner, the channel resource cost of the network device can be saved, the scheduling resources can be reasonably allocated, the flexible allocation of the scheduling resources can be realized, and the resource utilization rate and the communication reliability can be improved.

[0286] • A number of periods;

[0287] The number of periods refers to the number of scheduling periods corresponding to the allocation of the first scheduling resource by the candidate cell to the terminal device.

[0288] • A duration of the scheduling in a single scheduling period;

[0289] The duration of the scheduling in a single scheduling period refers to a time period in which the candidate cell allocates the first scheduling resource to the terminal device, starting from the scheduling start moment to the scheduling stop moment.

[0290] Optionally, the time period in which the candidate cell allocates the first scheduling resource to the terminal device is the same as the time period from the scheduling start moment to the scheduling stop moment, or the time period in which the candidate cell allocates the first scheduling resource to the terminal device is shorter than the time period from the scheduling start moment to the scheduling stop moment, which is not limited.

[0291] • A target cell ID.

[0292] The cell ID of the candidate cell is used to uniquely represent the candidate cell.

[0293] • An identifier of the candidate cell configuration information.

[0294] Illustratively, in the cell handover process, the candidate cell corresponds to configuration information, and the candidate cell can configure the configuration information with a corresponding identifier, send the identifier of the configuration information to the terminal device through the first indication information, and when the terminal device receives the first indication information, obtain the configuration information corresponding to the candidate cell through the identifier of the candidate cell configuration information in the first indication information.

[0295] In this embodiment, the configuration information of the candidate cell can also be referred to as the pre-configuration information of the candidate cell.

[0296] Illustratively, please refer to FIG. 7 and FIG. 8, which show the content schematic diagram of the first indication information provided by one exemplary embodiment of the present application, wherein FIG. 7 and FIG. 8 show two kinds of first indication information containing different contents.

[0297] As shown in FIG. 7, it currently includes candidate cell identifier 710, scheduling start time 720, scheduling period 730, scheduling duration period in a single scheduling period 740, and candidate cell configuration information identifier 750.

[0298] Among them, the first indication information contains 8 bit fields 701 for use by each field, that is, the above four contents can correspond to different bit positions in order, which is not limited.

[0299] As shown in FIG. 8, it currently includes candidate cell identifier 810, scheduling start time 820, scheduling period 830, scheduling duration period in a single scheduling period 840, scheduling stop time 850, period number 860, and candidate cell configuration information identifier 870.

[0300] Similarly, the first indication information contains 8 bit fields 801 for use by each field.

[0301] It is worth noting that FIG. 7 and FIG. 8 only show two different first indication information, and in actual application process, the content contained in the first indication information can be adjusted according to needs, which is not limited by the embodiments of the present application.

[0302] In some embodiments, the sending mode of the first indication information includes at least one of the following:

[0303] Mode 1: sent by the target cell;

[0304] In this embodiment, the network device is implemented as a target network device corresponding to the target cell, and the first indication information is sent to the terminal device after being configured by the target network device.

[0305] Mode 2: sent to the source cell by the target cell, and sent by the source cell;

[0306] In the embodiment, the network device is implemented as a source network device corresponding to the source cell. When the target network device corresponding to the target cell configures the first indication information, the target network device sends the first indication information to the source network device. After the source network device receives the first indication information, the source network device forwards the first indication information to the terminal device.

[0307] Option 3: sent by the source cell.

[0308] In the embodiment, after the source network device configures the first indication information, the source network device sends the first indication information to the terminal device.

[0309] Option 4: sent by the potential cell;

[0310] In the embodiment, the network device is implemented as a target network device corresponding to the potential cell. After the first indication information is configured by the potential network device, the target network device sends the first indication information to the terminal device.

[0311] Option 5: sent by the potential cell to the source cell, and then sent by the source cell.

[0312] In the embodiment, the network device is implemented as a source network device corresponding to the source cell. When the target network device corresponding to the potential cell configures the first indication information, the target network device sends the first indication information to the source network device. After the source network device receives the first indication information, the source network device forwards the first indication information to the terminal device.

[0313] In the process of configuring the first indication information by the source network device, the source network device receives configuration information sent by a candidate network device corresponding to a candidate cell. The source network device configures the first indication information according to the received configuration information.

[0314] For illustration, refer to FIG. 9, which shows a schematic diagram of an indication information indication method according to an example embodiment of the present application. As shown in FIG. 9, the communication system includes a terminal device, a source cell, a target cell, and a potential cell (or other candidate cell).

[0315] First, step 910 is performed. In step 910, the terminal device acquires a first TA value and a second TA value corresponding to the target cell and the potential cell respectively.

[0316] Optionally, the first TA value and the second TA value are acquired in the same way or in different ways, which is not limited.

[0317] Optionally, the first TA value and the second TA value are the same or different, which is not limited.

[0318] Secondly, after the terminal device acquires the first TA value and the second TA value, taking the case that the target cell meets the handover condition as an example, any one of the following steps is executed: step 920, step 930, or step 940.

[0319] In step 920, after the target cell configures the first indication information, the target cell sends the first indication information to the source cell, and then the source cell sends the first indication information to the terminal device.

[0320] In step 930, after the source cell configures the first indication information corresponding to the target cell, the source cell sends the first indication information to the terminal device.

[0321] In step 940, after the target cell configures the first indication information, the target cell sends the first indication information to the terminal device.

[0322] In step 521, the terminal device obtains the first scheduling resource according to the first indication information.

[0323] In this embodiment, the network device sends DCI information in the PDCCH, and the DCI information indicates the resource location (including the time domain location and the frequency domain location) of the first scheduling resource. Therefore, after the terminal device detects the PDCCH to obtain the DCI information, the terminal device acquires the first scheduling resource according to the content indicated in the DCI information.

[0324] Optionally, the terminal device receives the PDCCH according to the timing indicated by the first indication information, and detects the PDCCH to obtain the first scheduling resource. Alternatively, the terminal device first receives the PDCCH, and then detects the PDCCH according to the timing indicated by the first indication information, thereby obtaining the first scheduling resource.

[0325] In some embodiments, the terminal device determines a channel detection period based on the scheduling start time and the scheduling stop time, detects the PDCCH in the channel detection period, and obtains the first scheduling resource.

[0326] In this embodiment, when the first indication information is carried in the first MAC CE signaling, the terminal device determines a channel detection period according to the scheduling start time and the scheduling stop time in the first indication information. The channel detection period refers to a time range in which the target cell sends the first scheduling resource (actually DCI information) allocated to the terminal device in the PDCCH. The terminal device performs channel detection on the PDCCH in the channel detection period. If the terminal device detects the DCI information allocated by the target cell, the terminal device regards the scheduling resource indicated by the DCI information as the first scheduling resource.

[0327] In step 530, the terminal device sends a cell handover result to the network device.

[0328] Optionally, the first scheduling resource is allocated to the PDCCH before the terminal device evaluates that the target cell meets the handover condition; or the first scheduling resource is allocated to the PDCCH when the terminal device evaluates that the target cell meets the handover condition; or the first scheduling resource is allocated to the PDCCH at a specified time after the terminal device evaluates that the target cell meets the handover condition, which is not limited in the embodiment.

[0329] Optionally, the network device allocates the first scheduling resource to the terminal device through the PDCCH at a specified time; or the network device allocates the first scheduling resource to the terminal device through the PDCCH after the terminal device sends a specified preamble (referred to as the first preamble in the application) to the network device.

[0330] Optionally, the network device allocates the first scheduling resource to the terminal device through the PDCCH at a specified time; or the network device allocates the first scheduling resource to the terminal device through the PDCCH after the terminal device sends a specified preamble (referred to as the first preamble in the application) to the network device.

[0331] In a possible implementation, the first scheduling resource is allocated to the terminal device in the form of downlink control information, for example, the resource position of the first scheduling resource is indicated in the DCI information, and the terminal device obtains the first scheduling resource according to the resource position indicated in the DCI information after detecting the DCI information.

[0332] Optionally, the source cell is a cell currently serving the terminal device, and the candidate cell is a cell not yet connected to the terminal device.

[0333] Optionally, when the source cell and the candidate cell belong to the same network device, the first scheduling resource allocated to the terminal device by the candidate cell can be sent to the terminal device by the network device; when the source cell and the candidate cell belong to different network devices, the source cell corresponds to a source network device, and the candidate cell corresponds to a candidate network device, therefore, the first scheduling resource can be implemented by being sent from the candidate network device to the source network device and then sent to the terminal device by the source network device, or the first scheduling resource can be implemented by being sent from the candidate network device to the terminal device, which is not limited.

[0334] In some embodiments, the first scheduling resource is a scheduling resource sent to the terminal device by the network device through the PDCCH.

[0335] Optionally, the terminal device sends an uplink instruction or an uplink data packet to the target cell through the first scheduling resource, to inform the target cell that the cell handover has been completed, as the cell handover result.

[0336] Optionally, the first scheduling resource used for sending the cell switching result to the target cell is a first scheduling resource allocated by the target cell, that is, the terminal device sends the cell switching result to the target cell by using the first scheduling resource allocated by the target cell; or the first scheduling resource used for sending the cell switching result to the target cell is a first scheduling resource allocated by a potential cell in the candidate cells, that is, under the authorization of the potential cell, the terminal device sends the cell switching result to the target cell by using the first scheduling resource allocated by the potential cell.

[0337] In the following, the first indication information is taken as the DRX configuration information as an example for illustration. As shown in FIG. 10, the flowchart of the cell switching method provided in an example embodiment of the present application is shown, and after step 510, step 520b is included, and step 520 further includes step 522.

[0338] In step 510b, the terminal device receives the discontinuous reception (DRX) configuration information sent by the network device.

[0339] As an example, the DRX refers to a discontinuous reception technology, which enables the terminal device to enter a sleep state when no data needs to be received, thereby saving the power of the terminal device. That is, the terminal device can periodically acquire the first scheduling resource allocated by the candidate cell in the DRX mode, and enter the sleep state when the allocation time of the first scheduling resource is not reached.

[0340] As an example, the DRX configuration information is configured by the RRX message.

[0341] Optionally, the RRC message includes at least one of an RRC reconfiguration message, an RRC connection establishment message, or an RRC connection reestablishment message, and the present application is not limited in this regard.

[0342] Optionally, the DRX configuration information configured by the RRC message is sent to the terminal device after the terminal device acquires the first TA value corresponding to the candidate cell; or the DRX configuration information configured by the RRC message is added on the basis of the RRC reconfiguration message before the terminal device starts to evaluate the candidate cell, and is sent to the terminal device by the RRC reconfiguration message.

[0343] In some embodiments, the DRX configuration information includes second indication information, and the second indication information is used to indicate that the DRX configuration information is applied to the target cell.

[0344] The DRX configuration information includes a plurality of fields, such as at least one of the following: a DRX-on duration timer, a DRX-inactivity timer, a DRX start offset, or a long DRX-cycle.

[0345] The second indication information indicates that the DRX configuration information is used to detect the first scheduling resource for candidate cell allocation in the PDCCH.

[0346] In the embodiment, the DRX configuration information configured by the RRC message further includes the second indication information in addition to the existing fields.

[0347] In some embodiments, the DRX configuration information is used by the terminal device to detect the PDCCH in the DRX active period.

[0348] The DRX configuration information is used to indicate the DRX information used by the terminal device to detect the PDCCH, that is, the terminal device detects the PDCCH in the DRX active period according to the indication of the DRX configuration information, and does not detect the PDCCH when not in the DRX active period, or the DRX information indicates the DRX information corresponding to the DG scheduling of the target cell, that is, the second DRX information includes a plurality of contents (such as a scheduling period) in the first indication information as shown above, and the target cell periodically allocates the first scheduling resource to the terminal device according to the DRX information.

[0349] In the embodiment, the periodic dynamic allocation of the first scheduling resource is referred to as dynamic grant (DG) scheduling.

[0350] In step 514, the terminal device detects the PDCCH by the DRX method to obtain the first scheduling resource.

[0351] In some embodiments, the DRX active period is determined when the terminal device evaluates the target cell that meets the handover condition, and the PDCCH is detected in the DRX active period to obtain the first scheduling resource.

[0352] In this embodiment, when the first indication information is the DRX configuration information configured by the RRC, when the terminal device evaluates that the target cell meets the switching condition, the terminal device determines the DRX active period according to the scheduling start time and the scheduling end time configured in the DRX configuration information, wherein the DRX active period refers to the time range corresponding to the first scheduling resource (actually DCI information) assigned to the terminal device by the target cell in the PDCCH, and the terminal device performs channel detection on the PDCCH in the DRX active period, and if the DCI information assigned by the target cell is detected, the scheduling resource indicated by the DCI information is used as the first scheduling resource.

[0353] Secondly, after the terminal device sends the preamble to the network device, the network device sends the first scheduling resource to the terminal device. In addition to the above-mentioned embodiment in which the target cell sends one time indication to the terminal device, the terminal device can also actively request the target cell to send the first scheduling resource.

[0354] That is, after step 510, step 520c can also be included, that is, the schematic flow chart of the cell switching method provided by one exemplary embodiment of the present application shown in FIG. 11 can be implemented as one specific embodiment corresponding to FIG. 5.

[0355] Step 520c: In the case where the terminal device evaluates that the target cell meets the switching condition, the terminal device sends a first preamble to the network device.

[0356] The first preamble is used to request the target cell to assign the first scheduling resource.

[0357] Illustratively, the terminal device starts to evaluate the conditional switching of the candidate cell, and when there is a target cell meeting the switching condition in the candidate cell, the terminal device sends a first preamble to the target network device corresponding to the target cell.

[0358] Since the terminal device has completed the downlink synchronization and uplink synchronization with each candidate cell before evaluating the conditional switching, when the target cell receives the first preamble, it knows that the terminal device currently needs to perform cell switching.

[0359] Therefore, after receiving the first preamble, the target cell assigns the first scheduling resource to the terminal device.

[0360] Illustratively, please refer to FIG. 12, which shows a flow chart of a scheduling resource allocation method provided by one exemplary embodiment of the present application. As shown in FIG. 12, in a communication system including a terminal device, a source cell, a target cell and a potential cell, the method includes the following steps.

[0361] Step 1210: The terminal device completes the switching preparation with the target cell and the potential cell.

[0362] In the handover preparation process, the terminal device first performs measurement reporting on the source cell, and then the source cell obtains pre-configuration information corresponding to the target cell and the potential cell respectively. After obtaining the pre-configuration information, the source cell sends an RRC reconfiguration message to the terminal device. After the reconfiguration is completed, the terminal device sends an RRC reconfiguration completion message to the source cell. After the reconfiguration is completed, the terminal device performs downlink synchronization and uplink synchronization with the target cell, and the terminal device performs downlink synchronization and uplink synchronization with the potential cell.

[0363] In the process of uplink synchronization between the terminal device and the target cell, the terminal device obtains a first TA value corresponding to the target cell, and in the process of uplink synchronization between the terminal device and the potential cell, the terminal device obtains a second TA value corresponding to the potential cell.

[0364] Step 1220, the terminal device performs conditional LTM handover evaluation.

[0365] After the terminal device obtains the first TA value and the second TA value, the terminal device performs conditional LTM handover evaluation on the target cell and the potential cell according to the handover condition.

[0366] Step 1230, the terminal device sends a first preamble to the target cell.

[0367] When the target cell meets the handover condition, the terminal device sends a first preamble to the target cell.

[0368] It is worth noting that if the potential cell meets the handover condition, the terminal device sends a first preamble to the potential cell as the target cell.

[0369] Step 1240, the target cell sends a first scheduling resource to the terminal device.

[0370] After the target cell receives the first preamble, the target cell sends a first scheduling resource to the terminal device.

[0371] Step 1250, the terminal device sends a cell handover result to the target cell.

[0372] After the terminal device receives the first scheduling resource, the terminal device sends an RRC reconfiguration completion message to the target cell through the first scheduling resource as a cell handover result. At this time, the terminal device completes the RACH-Less cell handover.

[0373] In this application, before obtaining the first scheduling resource, the terminal device needs to obtain a first TA value corresponding to the candidate cell. The following will explain in detail the acquisition and management method of the first TA value.

[0374] Method 1: The network device calculates the first TA value

[0375] In some embodiments, the terminal device acquires the first TA value, wherein the acquisition manner of the first TA value comprises at least one of the following: the first TA value is carried in a random access response (RAR); and the first TA value is carried in a second MAC CE signaling.

[0376] Illustratively, when the first TA value is calculated by the network device, the network device indirectly sends the first TA value to the terminal device by sending the RAR to the terminal device and carrying the first TA value in the RAR, or sending the second MAC CE signaling to the terminal device and carrying the first TA value in the second MAC CE signaling.

[0377] In some embodiments, the first TA value is carried in the second MAC CE signaling; a second preamble is sent to the network device, the second preamble is used to request to acquire the first TA value corresponding to the candidate cell; the second MAC CE signaling is received, the second MAC CE signaling comprises at least one of the following: a candidate cell identifier and a TA timer; and the TA timer is started based on the second MAC CE signaling, the TA timer is used to determine the validity state of the first TA value, and the validity state is used to determine the switching manner of the terminal device performing cell switching.

[0378] Optionally, the terminal device sends the second preamble to the source network device, the source network device forwards the second preamble to the candidate network device; or the terminal device sends the second preamble to the source network device; or the terminal device sends the second preamble to the candidate network device; or the candidate cell and the source cell correspond to the same network device, and the terminal device directly sends the second preamble to the network device.

[0379] In this embodiment, taking the candidate network device corresponding to the candidate cell as an example, when the terminal device sends the second preamble to the candidate cell, the candidate cell understands the second preamble as calculating the second preamble to obtain the first TA value and feed back to the terminal device.

[0380] In one implementation manner, after the candidate cell calculates the first TA value, the candidate cell sends the first TA value to the source cell through the second MAC CE signaling, and the source cell sends the second MAC CE signaling to the terminal device after receiving the second MAC CE signaling.

[0381] Illustratively, please refer to FIG. 13, which shows a MAC CE signaling content schematic diagram provided by one example embodiment of the present application, as shown in FIG. 13, the second MAC CE signaling comprises a candidate cell identifier 1310, a first TA value 1320, a TA timer 1330 and candidate cell configuration information identifier 1340.

[0382] The second MAC CE signaling includes 8-bit field 1301 for use by each field.

[0383] The candidate cell identifier is used to indicate that the second MAC CE signaling is the signaling corresponding to the candidate cell, and the TA timer is used to determine the validity state of the first TA value, that is, the TA timer is pre-set with a specified time range, and the first TA value is in a valid state within the specified time range, and the first TA value is in an invalid state when the specified time range is not reached or exceeded.

[0384] It is worth noting that when the first TA value is in a valid state, the terminal device performs RACH-less cell switching. If the first TA value is in an invalid state, the terminal device performs cell switching with random access, that is, a random access request needs to be sent to the target cell. The cell switching with random access includes any one of CFRA or CBRA.

[0385] It is worth noting that the above only shows one possible implementation of the signaling content included in the second MAC CE signaling, and the embodiments of the present application do not limit the specific signaling content included in the second MAC CE signaling.

[0386] Method 2: The terminal device measures the first TA value by itself

[0387] Illustratively, in addition to measuring the first TA value by the network device, the terminal device can also measure the first TA value of the candidate cell by itself. For example, the terminal device measures the TA value corresponding to the source cell, and calculates the reception time difference between the source cell and the candidate cell (the timing difference between the downlink reception timing corresponding to the source cell and the downlink reception timing corresponding to the candidate cell), and then obtains the first TA value according to the TA value corresponding to the source cell and the reception time difference.

[0388] In some embodiments, the terminal device measures the first TA value corresponding to the target cell; and sends third indication information to the network device.

[0389] In one implementation, after the terminal device measures the first TA value corresponding to the target cell by itself, the terminal device sends third indication information to the source cell, the third indication information being used to inform the source cell that the terminal device has obtained the first TA value corresponding to the target cell. After the source cell receives the third indication information, the source cell sends the third indication information to the target cell, which is used to inform the target cell that the terminal device has obtained the first TA value corresponding to the target cell. After the target cell receives the third indication information, the target cell determines the timing of allocating the first scheduling resource, generates the first indication information, and sends it to the source cell. After the source cell receives the first indication information, the source cell forwards it to the terminal device.

[0390] In this embodiment, the signaling content contained in the third indication information can be implemented as the signaling content contained in the second MAC CE signaling in the above-mentioned embodiments, which will not be described herein.

[0391] Illustratively, refer to FIG. 14, which shows a schematic diagram of a timing indication method according to an example embodiment of the present application. As shown in the communication system in FIG. 14, the communication system includes a terminal device, a source cell and a target cell.

[0392] In step 1410, a first TA value is measured.

[0393] In the process of performing step 1410, the terminal device measures a first TA value corresponding to the target cell by itself.

[0394] In step 1420, the terminal device sends third indication information to the source cell.

[0395] The third indication information is used to inform the source cell that the terminal has measured the first TA value corresponding to the target cell.

[0396] In step 1430, the source cell sends the third indication information to the target cell.

[0397] In step 1440, the target cell sends the first indication information to the source cell.

[0398] After receiving the third indication information, the target cell determines the timing of allocating the first scheduling resource, generates the first indication information and sends it to the source cell.

[0399] In step 1450, the source cell sends the first indication information to the terminal device.

[0400] After receiving the first indication information, the source cell forwards it to the terminal device.

[0401] In some embodiments, in the case where the source cell sends fourth indication information to the target cell, the terminal device receives the first indication information sent by the source cell, and the fourth indication information is used to indicate that the terminal device measures the first TA value corresponding to the target cell.

[0402] Illustratively, the source cell sends the fourth indication information to the target cell, which is used to inform the target cell that it does not need to send the first TA value, and the terminal device measures the first TA value corresponding to the target cell by itself.

[0403] Illustratively, after receiving the fourth indication information, the target cell determines the timing of allocating the first scheduling resource to the first terminal device by itself, generates the first indication information and sends it to the source cell. After receiving the first indication information, the source cell forwards it to the terminal device.

[0404] For illustration, refer to FIG. 15, which shows a schematic diagram of a timing indication method according to an example embodiment of the present application. As shown in the communication system of FIG. 15, the communication system includes a terminal device, a source cell and a target cell.

[0405] At step 1510, the source cell sends fourth indication information to the target cell.

[0406] The fourth indication information sent by the source cell to the target cell is used to inform the target cell that the target cell does not need to send the first TA value, and the terminal device measures the first TA value corresponding to the target cell by itself.

[0407] At step 1520, the target cell sends first indication information to the source cell.

[0408] After receiving the fourth indication information, the target cell determines the timing corresponding to the first scheduling resource allocated to the first terminal device by itself, generates the first indication information, and sends the first indication information to the source cell.

[0409] At step 1530, the source cell sends the first indication information to the terminal device.

[0410] After receiving the first indication information, the source cell forwards the first indication information to the terminal device.

[0411] In the following, the case where the first information is implemented as dedicated preamble configuration information is described.

[0412] In some embodiments, the terminal device sends a fourth preamble to the target cell.

[0413] For illustration, when the terminal device does not detect the first scheduling resource in the process of detecting PDCCH in multiple scheduling periods, or when the terminal device does not obtain the first scheduling resource due to the expiration of the TA timer, the terminal device sends the fourth preamble to the target cell, which is used to inform the target cell that the terminal device does not obtain the first scheduling resource, and request the target cell to send dedicated preamble configuration information to the terminal device, which is used to perform cell switching.

[0414] That is, if the terminal device does not obtain the first scheduling resource, the terminal device cannot perform RACH-Less switching at this time. Therefore, the terminal device sends the fourth preamble to the target cell, and requests the target cell to send dedicated preamble configuration information, so that the terminal device can perform CFRA cell switching or CBRA cell switching through the dedicated preamble.

[0415] In another optional case, the dedicated preamble configuration information can also be configured in the pre-configuration information corresponding to the candidate cell. Therefore, the terminal device does not need to send the fourth preamble, and can directly obtain the dedicated preamble configuration information through the pre-configuration information corresponding to the candidate cell.

[0416] In some embodiments, the dedicated preamble configuration information comprises at least one of: dedicated preamble configuration information associated with the first beam, the first beam being configured by the target cell; dedicated preamble configuration information associated with the second beam, the second beam being configured by the source cell.

[0417] In an implementation, the dedicated preamble configuration information is associated with the first beam configured blindly by the target cell, wherein the blind configuration means that the target network device corresponding to the target cell automatically identifies and configures the first beam. In the process of blind configuration, the target cell first determines and automatically identifies the candidate beam to be configured, divides the candidate beam into different groups, and according to actual needs, the beams in the same group can correspond to the same or different preamble configurations. For each beam or beam group, a dedicated preamble is configured, and the dedicated preamble is used to identify the specified beam or beam group in the random access process. That is, the association between the dedicated preamble and the specified beam is completed, and in the process of performing CFRA, the terminal device will select the dedicated preamble according to the received system broadcast information. Then, the terminal device will transmit the dedicated preamble in the uplink beam consistent with the identified downlink beam. When the target cell receives the dedicated preamble, it will identify the specified beam according to the configuration information corresponding to the dedicated preamble, so as to determine the random access request corresponding to the specified beam. The first beam can be implemented as one or more beams.

[0418] In an implementation, the dedicated preamble configuration information is associated with the second beam configured by the source cell, and the configuration process is consistent with the configuration process of the dedicated preamble by the target cell, which will not be described here. The second beam can be implemented as the first beam or multiple beams.

[0419] In an implementation, when the source cell activates the TCI information corresponding to the target cell before determining that the target cell meets the handover condition, if the third beam corresponding to the TCI information belongs to the first beam or the second beam, the dedicated preamble is sent to the target cell through the third beam.

[0420] In some embodiments, in the case that the third beam is not associated with the activated TCI information, it is determined whether the first beam or the second beam meets the beam quality condition; in the case that the first beam or the second beam meets the beam quality condition, the dedicated preamble sent by the first beam or the second beam is used to perform the non-competitive random access CFRA, and the handover from the source cell to the target cell is completed; in the case that the first beam or the second beam does not meet the beam quality condition, the handover from the source cell to the target cell is completed by performing the competitive random access CBRA.

[0421] Illustratively, if the third beam does not correspond to the activated TCI information, the terminal device further needs to further judge the first beam or the second beam, wherein a quality condition is pre-set: a threshold corresponding to the beam, if the first beam or the second beam reaches the threshold, it is considered that the first beam or the second beam meets the quality condition, a dedicated preamble is sent to the target cell through the first beam or the second beam, a non-contention random access CFRA is performed, and the cell switching from the source cell to the target cell is completed. If the first beam or the second beam does not reach the threshold, the terminal device implements the cell switching through the CBRA.

[0422] Notably, the third beam is for the dedicated preamble, the first beam and the second beam are for the dedicated preamble configuration information, and the dedicated preamble configuration information is used to configure the dedicated preamble, and then perform the cell switching with the random access (CBRA / CFRA).

[0423] Optionally, the first beam and the second beam are the same; or the first beam and the third beam are the same; or the second beam and the third beam are the same; or the first beam, the second beam and the third beam are the same, which is not limited.

[0424] In the embodiment, when the first beam or the second beam reaches the threshold, a dedicated preamble is sent to the network device through the first beam or the second beam, and when the first beam or the second beam does not reach the threshold, a random preamble is selected from a preamble pool and sent to the network device to perform the CBRA to complete the cell switching.

[0425] Illustratively, please refer to FIG. 16, which shows a flow chart of a cell switching method provided by an example embodiment of the present application, as shown in FIG. 16, in a communication system including a terminal device, a source cell, a target cell and a potential cell, the method includes the following steps.

[0426] Step 1610, configure resources.

[0427] The source cell sends an LTM switching request to the target cell and the potential cell respectively, to obtain the pre-configuration information corresponding to the target cell and the pre-configuration information corresponding to the potential cell.

[0428] For example, the target cell configures the dedicated preamble configuration information associated with the first beam in the pre-configuration information, and sends the dedicated preamble configuration information to the source cell; or the target cell blindly configures the dedicated preamble configuration information associated with the first beam, and sends the dedicated preamble configuration information to the source cell; or the target cell sends the pre-configuration information to the source cell, and the source cell configures the dedicated preamble configuration information associated with the second beam.

[0429] Step 1620, early synchronization.

[0430] The terminal device acquires a first TA value corresponding to the target cell, and acquires a second TA value corresponding to the potential cell.

[0431] Step 1630, conditional LTM handover evaluation.

[0432] The terminal device evaluates the target cell and the potential cell according to the pre-set handover condition. When the target cell (or the potential cell) meets the handover condition, the terminal device receives the first indication information sent by the target cell, and detects the PDCCH according to the timing indicated by the first indication information to obtain the first scheduling resource; or, when the target cell (or the potential cell) meets the handover condition, the terminal device sends the first preamble to the target cell, and the target cell allocates the first scheduling resource to the terminal device after receiving the first preamble.

[0433] Step 1640, sending RRC reconfiguration completion.

[0434] If the terminal device successfully acquires the first scheduling resource, the terminal device performs RACH-Less cell handover, that is, completes the cell handover by sending the RRC reconfiguration completion information to the target cell.

[0435] Step 1650, CFRA / CBRA determination.

[0436] If the terminal device does not acquire the first scheduling resource, the terminal device sends the fourth preamble to the target cell to request the target cell to send the dedicated preamble configuration information, so that the terminal device can perform CFRA cell handover.

[0437] If the third beam corresponding to the dedicated preamble does not meet the preset condition and the fourth preamble cannot be sent, the terminal device performs CBRA cell handover.

[0438] Step 1660, sending the fourth preamble.

[0439] In the process of determining that the terminal device performs CFRA cell handover, the terminal device sends the fourth preamble to the target cell.

[0440] Step 1670, stopping dynamic scheduling.

[0441] In some embodiments, the target cell is a candidate cell that meets the handover condition among multiple candidate cells.

[0442] Illustratively, in the process of evaluating whether each candidate cell meets the handover condition by the terminal device, in addition to the target cell allocating the first scheduling resource to the terminal, other candidate cells (potential cells) also allocate scheduling resources to the terminal.

[0443] When the target cell meets the handover condition and the cell handover between the terminal device and the target cell is completed, other candidate cells (potential cells) in the candidate cells need to stop scheduling to the terminal device. Therefore, the potential cells send first indication information for indicating a timing of allocating first scheduling resources to the terminal device by the other candidate cells. In some embodiments, the first indication information further includes a scheduling termination time corresponding to the other candidate cells, and the other candidate cells are configured to stop allocating second scheduling resources when the scheduling termination time arrives.

[0444] In the embodiment, the fifth indication information further includes the scheduling termination time, and the other candidate cells automatically stop allocating the first scheduling resources to the terminal device when the scheduling termination time arrives.

[0445] In some embodiments, the fifth indication information is acquired, and the fifth indication information is used for indicating that the other candidate cells stop allocating the second scheduling resources.

[0446] In the embodiment, when the terminal device and the target cell complete the cell handover, the source cell sends the fifth indication information to the other candidate cells after receiving the handover completion indication information sent by the target cell, so as to indicate that the other candidate cells stop allocating the first scheduling resources to the terminal device, or the source cell sends the fifth indication information to the other candidate cells after receiving the handover completion indication information sent by the terminal device, so as to indicate that the other candidate cells stop allocating the first scheduling resources to the terminal device.

[0447] The step 520 further includes a step 520d, and the step 530 further includes a step 531, that is, the flow chart of the cell handover method shown in FIG. 17 can be implemented as a specific embodiment corresponding to FIG. 4.

[0448] The step 520d includes sending the third preamble to the network device.

[0449] The first information refers to the first scheduling resources, and the first scheduling resources are configured with the authorized resources; and the third preamble is used for indicating the activation of the authorized resources.

[0450] Illustratively, the preconfigured information corresponding to the target cell is further configured with a configure grant (CG) resource (type-2 CG resource) configured for handover, that is, in the process of handover preparation, the configuration of the CG resource is completed at the same time as the configuration of the target cell, and a dedicated preamble resource is configured at the same time; or after the terminal device acquires the first TA value corresponding to the target cell, the target cell configures the CG resource and the dedicated preamble configuration information through a dedicated signaling. The configuration is configured by the target cell, and then the source cell sends the configuration information to the terminal.

[0451] When there is a target cell that meets the condition, if the target cell pre-configures CG resources, the terminal device sends a third preamble to the target cell to indicate that the CG resources need to be activated.

[0452] In this embodiment, the terminal device sends the third preamble to the target cell.

[0453] Step 531, in the case of authorized resource activation, the terminal device sends a cell handover result to the network device based on the authorized resource.

[0454] Illustratively, after the target cell receives the third preamble, the CG resources are activated, so that the terminal device sends an RRC reconfiguration complete message using the CG resources to complete the RACH-Less cell handover.

[0455] Illustratively, please refer to FIG. 18, which shows a flowchart of a cell handover method provided by an exemplary embodiment of the present application. As shown in FIG. 18, in a communication system, there are a terminal device, a source cell, a target cell, and a potential cell.

[0456] Step 1810, the terminal device completes handover preparation with the target cell and the potential cell.

[0457] In the handover preparation process, the terminal device first performs measurement reporting on the source cell, and then the source cell obtains pre-configuration information corresponding to the target cell and the potential cell. After obtaining the pre-configuration information, the source cell sends an RRC reconfiguration message to the terminal device. After the reconfiguration is completed, the terminal device sends an RRC reconfiguration complete message to the source cell. After the reconfiguration is completed, the terminal device performs downlink synchronization and uplink synchronization with the target cell, and performs downlink synchronization and uplink synchronization with the potential cell.

[0458] The pre-configuration information corresponding to the target cell further includes pre-configured authorized resources (type-2 CG resources) for handover, i.e., in the process of preparing for handover, the configuration of the CG resources is completed at the same time as the configuration of the target cell, and dedicated preamble resources are configured at the same time. Or, after the terminal device obtains the first TA value corresponding to the target cell, the target cell configures the CG resources and the dedicated preamble configuration information through dedicated signaling. The configuration is configured by the target cell, and then the source cell sends the configuration information to the terminal.

[0459] In the process of uplink synchronization between the terminal device and the target cell, the terminal device obtains the first TA value corresponding to the target cell, and in the process of uplink synchronization between the terminal device and the potential cell, the terminal device obtains the second TA value corresponding to the potential cell.

[0460] Step 1820, the terminal device performs conditional LTM handover evaluation.

[0461] After the terminal device acquires the first TA value and the second TA value, conditional LTM handover evaluation is performed on the target cell and the potential cell according to a handover condition.

[0462] In step 1830, the terminal device sends a third preamble to the target cell.

[0463] When there is a target cell meeting the condition, if the target cell pre-configures CG resources, the terminal device sends a third preamble to the target cell to indicate that the CG resources need to be activated.

[0464] In this embodiment, the terminal device sends a third preamble to the target cell.

[0465] It is worth noting that if the potential cell meets the handover condition, the potential cell is taken as the target cell, and the potential cell is configured with CG resources, the terminal device sends a third preamble to the potential cell.

[0466] In step 1840, the terminal device sends a cell handover result to the target cell.

[0467] When the target cell activates the CG resources, the terminal device sends an RRC reconfiguration completion message to the target cell through the CG resources as the cell handover result, and at this time, the terminal device completes the RACH-Less cell handover.

[0468] It is worth noting that the fourth preamble, the first preamble, the third preamble, the second preamble and the fifth preamble in the above embodiments can be implemented as the same preamble, but the network device understands the preambles differently when used in different scenarios; or the above preambles can be implemented as different preambles, corresponding to different requests respectively.

[0469] The above mainly introduces the method of cell handover of the embodiments of the application in combination with the drawings. It should be understood that although each step in the flowchart involved in each of the above embodiments is displayed in sequence, these steps are not necessarily executed in sequence as shown in the figure. Unless explicitly stated herein, the execution of these steps has no strict sequence limitation, and these steps can be executed in other orders. Moreover, at least part of the steps in the flowchart involved in each of the above embodiments can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed in rotation or alternation with other steps or steps or stages in other steps. The following introduces the device of cell handover of the embodiments of the application in combination with the drawings.

[0470] FIG. 19 is a schematic diagram of an apparatus for cell switching according to an embodiment of the present application. As shown in FIG. 19, the apparatus 2000 includes a transceiver 2001 and a processing unit 2002. The apparatus 2000 can be integrated in a user equipment or a network equipment.

[0471] The apparatus 2000 can be configured to perform the steps performed by the user equipment or the network equipment in any of the methods of cell switching described above. For example, the transceiver 2001 can be configured to perform step 520, and the processing unit 2002 can be configured to perform step 510. In an implementation, the apparatus 2000 can further include a storage unit configured to store data streams and the like. The storage unit can be integrated in the processing unit 2002, or can be a unit independent of the transceiver 2001 and the processing unit 2002.

[0472] FIG. 20 is a schematic diagram of a hardware structure of an electronic device according to an embodiment of the present application. As shown in FIG. 20, the electronic device 4000 includes at least one processor 4001 (only one processor is shown in FIG. 20), a memory 4002, and a computer program 4003 stored in the memory 4002 and executable on the at least one processor 4001, wherein the processor 4001 implements the steps in any of the methods described above when executing the computer program 4003.

[0473] Those skilled in the art can understand that FIG. 18 is only an example of the electronic device, and does not constitute a limitation on the electronic device. In practice, the electronic device can include more or fewer components than those shown in the figure, or combine certain components, or include different components, for example, can also include an input / output device, a network access device, and the like.

[0474] The processor 4001 can be a central processing unit (CPU), other general purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, etc. The general purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0475] The memory 4002 can be an internal storage unit of the electronic device 4000, such as a hard disk or a memory of the electronic device 4000 in some embodiments. The memory 4002 can also be an external storage device of the electronic device 4000, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, and the like equipped on the electronic device 4000 in some other embodiments. Alternatively, the memory 4002 can include both an internal storage unit and an external storage device of the electronic device 4000. The memory 4002 is configured to store an operating system, an application program, a boot loader, data, and other programs, such as program codes of the computer program, and the like. The memory 4002 can also be configured to temporarily store data that has been output or is to be output.

[0476] It should be noted that the information interaction and execution process between the above apparatuses / units are based on the same concept as the method embodiments of the present application, and the specific functions and technical effects brought by the above apparatuses / units can be referred to the method embodiments part, which will not be described herein.

[0477] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is taken as an example for illustration, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to complete all or part of the above described functions. Each functional unit and module in the embodiments can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of software functional unit. In addition, the specific names of each functional unit and module are only for easy distinction, and do not limit the protection scope of the present application. The specific working process of the units and modules in the system can refer to the corresponding process in the foregoing method embodiments, which will not be described herein.

[0478] The embodiments of the present application also provide an electronic device, which comprises at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, wherein the processor implements the steps in any of the method embodiments described above when executing the computer program.

[0479] The electronic device can be a user equipment, configured to perform the steps performed by the user equipment, such as receiving indication information and monitoring PDCCH according to the indication information; or the electronic device can be a network equipment, configured to perform the steps performed by the network equipment, such as generating and sending indication information.

[0480] The embodiment of the present application further provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to realize the steps in the above-mentioned various method embodiments.

[0481] The embodiment of the present application further provides a chip, which comprises a processor, and the processor is used to read and execute a computer program stored in a memory, and the computer program is executed by the processor to realize the steps in the above-mentioned various method embodiments.

[0482] Optionally, the chip further comprises a memory, and the memory is electrically connected with the processor.

[0483] Optionally, the chip can further comprise a communication interface.

[0484] The embodiment of the present application further provides a computer program product, which comprises a computer program, and the computer program is executed by a processor to realize the steps in the above-mentioned various method embodiments.

[0485] The integrated unit, if realized in the form of a software function unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the embodiment of the present application realizes all or part of the processes in the above-mentioned method embodiments, which can be completed by a computer program instructing related hardware. The computer program can be stored in a computer readable storage medium, and the computer program is executed by a processor to realize the steps in the above-mentioned various method embodiments. The computer program comprises computer program code, which can be in the form of source code, object code, executable file or some intermediate form. The computer readable medium at least includes any entity or device capable of carrying the computer program code to the photographing device / terminal equipment, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, electric signal and software distribution medium. For example, U disk, mobile hard disk, magnetic disk or optical disk and the like. In some jurisdictions, according to legislation and patent practice, the computer readable medium cannot be an electric carrier signal and an electric signal.

[0486] In the above-mentioned embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0487] Those skilled in the art can appreciate that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized in electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solutions. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0488] In the embodiments provided in the present application, it should be understood that the disclosed apparatus / equipment and methods can be implemented in other ways. For example, the apparatus / equipment embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, another division mode can be used. For example, a plurality of units or components can be combined or integrated into another system, or some features can be omitted or not implemented. In addition, the coupling or direct coupling or communication connection between the displayed or discussed units can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0489] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e., they can be located in one place or distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0490] It should be understood that when used in the specification and the appended claims of the present application, the term "comprising" indicates the presence of described features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or sets thereof.

[0491] It should also be understood that the term "and / or" used in the specification and the appended claims of the present application means any combination of one or more of the associated listed items and all possible combinations thereof, and includes these combinations.

[0492] As used in the specification and the appended claims of the present application, the term "if" can be interpreted as "when" or "upon" or "in response to a determination" or "in response to detecting" depending on the context. Similarly, the phrase "if it is determined" or "if [a described condition or event] is detected" can be interpreted as meaning "upon determining" or "in response to determining" or "upon detecting [a described condition or event]" or "in response to detecting [a described condition or event]" depending on the context.

[0493] In addition, in the description of the present application and the appended claims, the terms "first", "second", "third", etc. are used only to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0494] The description of "one embodiment", "some embodiments", and the like in the present application description means that the specific features, structures, or characteristics described in connection with the embodiment are included in one or more embodiments of the present application. Therefore, the statements "in one embodiment", "in some embodiments", "in other some embodiments", "in further some embodiments", and the like appearing in different places in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "include", "contain", "have" and their variants mean "include but not limited to", unless otherwise specifically emphasized.

[0495] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A cell handover method, characterized by, The method is applied to a terminal device connected with a source cell, and comprises: evaluating a handover condition, and determining a target cell from candidate cells, wherein the target cell meets the handover condition; obtaining first information, wherein the first information comprises at least one of: a first scheduling resource; dedicated preamble configuration information; wherein the first scheduling resource is used for sending a cell handover result to the target cell, and the cell handover result is used for instructing the terminal device to complete cell handover by using the first scheduling resource; and the dedicated preamble configuration information is used for initiating random access to the target cell to complete cell handover, and the cell handover refers to switching from the source cell to the target cell.

2. The method of claim 1, wherein, The first information refers to the first scheduling resource. Before the obtaining of the first information, the method further comprises: receiving first indication information, wherein the first indication information is used for indicating a time when the candidate cell allocates the first scheduling resource to the terminal device.

3. The method of claim 2, wherein: the first indication information is carried in a first medium access control (MAC) control element (CE) signaling.

4. The method of claim 3, wherein, The sending mode of the first indication information comprises at least one of: being sent by the target cell; being sent by the target cell to the source cell and then being sent by the source cell; and being sent by the source cell.

5. The method of claim 3, wherein, The first indication information comprises at least one of: a scheduling start time of the first scheduling resource; a scheduling stop time of the first scheduling resource; a scheduling period of the first scheduling resource; a number of periods of the first scheduling resource; a duration period of scheduling within a single scheduling period of the first scheduling resource; a candidate cell identifier; and an identifier of candidate cell configuration information.

6. The method of claim 1, wherein, The first information comprises the first scheduling resource. Before the obtaining of the first information, the method further comprises: receiving discontinuous reception (DRX) configuration information. The obtaining of the first information comprises: detecting a physical downlink control channel (PDCCH) in a DRX manner to obtain the first scheduling resource.

7. The method of claim 6, wherein: the PDCCH is detected in a DRX active state period by using the DRX configuration information to obtain the first scheduling resource.

8. The method of claim 7, wherein, The detecting of the PDCCH in the DRX manner to obtain the first scheduling resource comprises: in a case where the target cell meeting the handover condition is evaluated, the PDCCH of the target cell is detected in the DRX active state period by using the DRX configuration information to obtain the first scheduling resource.

9. The method of claim 1, wherein, The dedicated preamble configuration information comprises at least one of: dedicated preamble configuration information associated with a first beam, wherein the first beam is configured by the target cell; and dedicated preamble configuration information associated with a second beam, wherein the second beam is configured by the source cell.

10. The method of claim 9, wherein, After the obtaining of the first information, the method further comprises: In a case where a third beam meets the beam association condition, a dedicated preamble is sent to the target cell through the third beam, the third beam being a beam corresponding to activated transmission configuration indication (TCI) information of the target cell, and the source cell being configured to pre-activate the TCI information of the target cell; The association condition is at least one of the following: The third beam belongs to the first beam; The third beam belongs to the second beam.

11. The method of claim 10, wherein, After the first information is acquired, the method further includes: In a case where the third beam does not meet the association condition, it is determined whether any one of the first beam and the second beam meets a beam quality condition.

12. The method of claim 11, wherein, After the first information is acquired, the method further includes: In a case where the first beam meets the beam quality condition, a contention-free random access (CFRA) is performed to complete cell switching by using the dedicated preamble sent by the first beam; or In a case where the second beam meets the beam quality condition, the CFRA is performed to complete cell switching by using the dedicated preamble sent by the second beam.

13. The method of claim 11, wherein, After the first information is acquired, the method further includes: In a case where the first beam does not meet the beam quality condition, a contention-based random access (CBRA) is performed to complete cell switching; or In a case where the second beam does not meet the beam quality condition, the CBRA is performed to complete cell switching.

14. The method according to any one of claims 1 to 8, characterized in that, The first information refers to the first scheduling resource; Before the first information is acquired, the method further includes: In a case where the target cell meets the switching condition, a first preamble is sent to the target cell, the first preamble being used to request the target cell to allocate the first scheduling resource.

15. The method according to any one of claims 2 to 13, characterized in that, Before the switching condition is evaluated and the target cell is determined from the candidate cells, the method further includes: A first timing advance (TA) value is acquired; The first TA value is acquired in at least one of the following manners: The first TA value is carried in a random access response (RAR); The first TA value is carried in a second MAC CE signaling; The first TA value is measured by the terminal device.

16. The method of claim 15, wherein, The first TA value is carried in the second MAC CE signaling. Before the first information is acquired, the method further includes: A second preamble is sent, the second preamble being used to request the first TA value corresponding to the candidate cell; The second MAC CE signaling is received, the second MAC CE signaling including at least one of a candidate cell identifier or a TA timer; The TA timer is started based on the second MAC CE signaling, the TA timer being used to determine a validity state of the first TA value, and the validity state being used to determine a switching mode of cell switching performed by the terminal device.

17. The method of claim 15, wherein, The first TA value is measured by the terminal device. The first indication information is received, including: Third indication information is sent, the third indication information being used to instruct the terminal device to measure the first TA value; In a case where the target cell receives the third indication information, the first indication information is received.

18. The method of claim 15, wherein, The first TA value is measured by the terminal device; The receiving the first indication information comprises: In a case that the source cell sends fourth indication information to the target cell, the first indication information is received, and the fourth indication information is used to indicate that the terminal device measures the first TA value corresponding to the target cell.

19. The method of any one of claims 1 to 13, wherein, The first information refers to the first scheduling resource, and the first scheduling resource comprises a granted resource; After the first information is acquired, the method further comprises: The third preamble is sent to the target cell, and the third preamble is used to indicate that the granted resource corresponding to the target cell is activated. In a case that the granted resource is activated, the cell switching result is sent to the target cell by using the granted resource.

20. A cell handover method, characterized by, The method is applied to a network device, and the method comprises: The first information is sent, and the first information comprises at least one of the following: The first scheduling resource; The dedicated preamble configuration information; The first scheduling resource is used to receive a cell switching result, and the cell switching result is used to indicate that, in a case that a terminal device evaluates a switching condition and determines a target cell from candidate cells, the terminal device completes cell switching by using the first scheduling resource, and the target cell meets the switching condition; and the dedicated preamble configuration information is used to receive a random access completion cell switching sent by the terminal device, and the cell switching refers to switching from a source cell to the target cell.

21. The method of claim 20, wherein, The first information refers to the first scheduling resource; Before the first information is sent, the method further comprises: The first indication information is sent, and the first indication information is used to indicate a time when the target cell allocates the first scheduling resource to the terminal device.

22. The method of claim 21, wherein The first indication information is carried in a first MAC CE signaling.

23. The method of claim 22, wherein, The sending mode of the first indication information comprises at least one of the following: The first indication information is sent by the target cell; The first indication information is sent by the target cell to the source cell and then sent by the source cell; The first indication information is sent by the source cell.

24. The method of claim 22, wherein, The first indication information comprises at least one of the following: A scheduling start time of the first scheduling resource; A scheduling stop time of the first scheduling resource; A scheduling period of the first scheduling resource; A period number of the first scheduling resource; A duration period of scheduling in a single scheduling period of the first scheduling resource; A candidate cell identifier; An identifier of candidate cell configuration information.

25. The method of claim 20, wherein, The first information comprises the first scheduling resource; Before the first information is sent, the method further comprises: The DRX configuration information is sent. The first information is sent, comprising: The first scheduling resource is allocated in the PDCCH by using the DRX mode.

26. The method of claim 25, wherein The DRX configuration information is used for the target cell to allocate the first scheduling resource to the terminal device by using the PDCCH in a DRX active state period.

27. The method of claim 20, wherein, The dedicated preamble configuration information comprises at least one of the following: Dedicated preamble configuration information associated with a first beam, and the first beam is configured by the target cell; Dedicated preamble configuration information associated with a second beam, the second beam being configured by the source cell.

28. The method of claim 27, wherein, The method further comprises: In a case where a third beam meets an association condition, receiving the dedicated preamble through the third beam, the third beam being a beam corresponding to activated TCI information corresponding to the target cell, the source cell being configured to pre-activate the TCI information in the target cell; The association condition is at least one of the following: The third beam belongs to the first beam; The third beam belongs to the second beam.

29. The method of claim 28, wherein, The method further comprises: In a case where the first beam meets a beam quality condition, establishing a radio resource control (RRC) connection with the terminal device based on CFRA using the dedicated preamble sent by the third beam; or In a case where the second beam meets the beam quality condition, establishing an RRC connection with the terminal device based on CFRA using the dedicated preamble sent by the third beam.

30. The method of claim 28, wherein, The method further comprises: In a case where the first beam does not meet a beam quality condition, establishing an RRC connection with the terminal device based on CBRA; or In a case where the second beam does not meet the beam quality condition, establishing an RRC connection with the terminal device based on CBRA.

31. The method of any one of claims 20 to 26, wherein, The first information refers to the first scheduling resource; The method further comprises: In a case where the target cell meets the handover condition, receiving a first preamble, the first preamble being used to allocate the first scheduling resource to the terminal device.

32. The method of any one of claims 20 to 26, wherein, The method further comprises: Sending second MAC CE signaling, the second MAC CE signaling carrying a first TA value; or Sending a RAR, the RAR carrying the first TA value.

33. The method of claim 32, wherein, The second MAC CE signaling carries the first TA value. The sending of the second MAC CE signaling comprises: Receiving a second preamble, the second preamble being used to request the first TA value corresponding to the candidate cell; Based on the second preamble, sending the second MAC CE signaling, the second MAC CE signaling including at least one of a candidate cell identifier or a TA timer, the TA timer being used to determine the validity state of the first TA value, the validity state being used to determine the switching mode of the terminal device performing cell switching.

34. The method of claim 32, wherein, The terminal device measures the first TA value; The method further comprises: Receiving third indication information, the third indication information being used to instruct the terminal device to measure the first TA value corresponding to the candidate cell.

35. The method of claim 32, wherein, The terminal device measures the first TA value; The method further comprises: Generating fourth indication information, the fourth indication information being used to instruct the terminal device to measure the first TA value corresponding to the candidate cell.

36. The method of any one of claims 20 to 26, wherein, The first information refers to the first scheduling resource, the first scheduling resource including a grant resource; The method further comprises: receive a third preamble, the third preamble being used to indicate that the authorized resource corresponding to the target cell is activated, and the authorized resource being used to receive the cell switching result in the case of activation.

37. The method of any one of claims 20 to 26, wherein, The method further comprises, after the sending the first information: obtain fifth indication information, the fifth indication information being used to indicate that other candidate cells except the target cell stop sending the first information.

38. A cell handover apparatus, comprising: The method comprises: a processing unit, configured to evaluate a switching condition, and determine a target cell from candidate cells, the target cell meeting the switching condition; a transceiving unit, configured to obtain first information, the first information comprising at least one of the following: first scheduling resource; and dedicated preamble configuration information; wherein the first scheduling resource is used to send a cell switching result to the target cell, the cell switching result being used to indicate that the terminal device completes cell switching by using the first scheduling resource; and the dedicated preamble configuration information is used to initiate random access to the target cell to complete cell switching, the cell switching being switching from the source cell to the target cell.

39. A cell handover apparatus, comprising: The method comprises: a transceiving unit, configured to send first information, the first information comprising at least one of the following: first scheduling resource; and dedicated preamble configuration information; wherein the first scheduling resource is used to receive a cell switching result, the cell switching result being used to indicate that, in the case that the terminal device evaluates a switching condition and determines a target cell from candidate cells, the terminal device completes cell switching by using the first scheduling resource, and the target cell meets the switching condition; and the dedicated preamble configuration information is used to receive random access sent by the terminal device to complete cell switching, the cell switching being switching from the source cell to the target cell.

40. A user equipment comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor implements the method of any one of claims 1-19 when executing the computer program.

41. A network device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein, The processor implements the method of any one of claims 20-37 when executing the computer program.

42. A computer-readable storage medium, the computer-readable storage medium storing a computer program, characterized in that, The computer program is executed by the processor to implement the method of any one of claims 1-19, or 20-37.

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