WO2024066947A1

WO2024066947A1 - Communication method and related device

Info

Publication number: WO2024066947A1
Application number: PCT/CN2023/116926
Authority: WO
Inventors: 朱世超; 史玉龙; 朱元萍; 孙飞
Original assignee: 华为技术有限公司
Priority date: 2022-09-27
Filing date: 2023-09-05
Publication date: 2024-04-04
Also published as: CN117835337A

Abstract

Provided in the present application are a communication method and a related device, which are used for reducing overheads for triggering a cell handover process, and improving the execution speed of cell handover, so as to improve the success rate of cell handover. The method comprises: a terminal device receiving a first message, the first message comprising handover configuration information for N cells, N being a positive integer, wherein the handover configuration information is used for a cell handover process, which is triggered on the basis of a second message; and after receiving the second message, the terminal device performing cell handover on the basis of the handover configuration information.

Description

A communication method and related equipment

This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on September 27, 2022, with application number 202211183378.0, and invention name “A communication method and related equipment”, all contents of which are incorporated by reference in this application.

Technical Field

The present application relates to the field of wireless communication technology, and in particular to a communication method and related equipment.

Background technique

In a communication system, after a terminal device accesses a cell, the cell accessed by the terminal device can be switched by cell switching. Before the cell switching is performed, the cell accessed by the terminal device can be called a source cell, and after the cell switching is performed, the cell accessed by the terminal device can be called a target cell.

Currently, during the cell switching process, after the source cell detects that the signal quality between the source cell and the terminal device has deteriorated, it can send a switching message carrying the configuration information of the target cell, so that the terminal device can access the target cell based on the configuration information of the target cell after receiving the message.

However, in the above implementation, the network device needs to trigger the sending of the switching message to the terminal device only when it detects that the signal quality has deteriorated. The transmission of the switching message may be slow due to the poor signal quality, affecting the speed of cell switching or even causing cell switching failure.

Summary of the invention

The present application provides a communication method and related equipment for saving the overhead of triggering a cell switching process and improving the execution speed of the cell switching, so as to improve the success rate of the cell switching.

In a first aspect, the present application provides a communication method, which is executed by a terminal device, or the method is executed by some components in the terminal device (such as a processor, a chip or a chip system, etc.), or the method can also be implemented by a logic module or software that can realize all or part of the functions of the terminal device. In the first aspect and its possible implementation, the communication method is described as being executed by a terminal device. In this method, the terminal device receives a first message, and the first message includes switching configuration information of N cells, where N is a positive integer, wherein the switching configuration information is used for a cell switching process triggered by a second message; after receiving the second message, the terminal device performs cell switching based on the switching configuration information.

Based on the above technical solution, the terminal device receives a first message including switching configuration information of N cells, and the switching configuration information is used for a cell switching process triggered by a second message. Thereafter, after receiving the second message, the terminal device performs cell switching based on the switching configuration information. Compared with the implementation method in which the switching message that triggers the execution of cell switching carries the configuration information of the target cell, the terminal device can obtain the switching configuration information used for the cell switching process triggered by the second message in advance, and can trigger the execution of cell switching based on the switching configuration information after receiving the second message. Thus, in the case where it is determined that the terminal device needs to be scheduled to execute cell switching, the second message that triggers the execution of cell switching and is sent to the terminal device does not need to carry the switching configuration information of the target cell, which can save the overhead of the triggering process and improve the execution speed of the cell switching, so as to improve the success rate of the cell switching.

In addition, compared to the implementation method in which the terminal device triggers cell switching locally based on a measurement event of signal quality deterioration, the above-mentioned technical solution of executing cell switching by triggering the second message can support more cell switching scenarios, that is, when the signal quality between the terminal device and the source cell has not deteriorated (for example, when the integrated access and backhaul (IAB) node where the source cell is located migrates across a centralized unit (CU) and the target cell corresponding to the target CU is enabled, or, when the IAB node where the source cell is located needs to schedule the terminal device to connect to other cells in the IAB node, or when the IAB node where the source cell is located determines that the source cell is to be shut down or deactivated, etc.), the cell switching can still be triggered by the second message, so that the above-mentioned technical solution can save the overhead of the triggering process and improve the execution speed of the cell switching, and can also avoid the situation where the cell switching cannot be executed because the terminal device cannot trigger the cell switching locally when the signal quality has not deteriorated.

In a possible implementation manner of the first aspect, the second message includes first information, and the first information is carried in any one of the following items: downlink control information (download control information, The information in the short message field in the DCI; the information in the paging occasion (PO); or any broadcast information of N cells.

Based on the above technical solution, the second message can be implemented through any of the above items. In other words, the source cell or N cells can trigger the terminal device to perform cell switching through any of the above methods to improve the flexibility of the solution implementation.

It can be understood that, when the first information is carried in the short message field, the second message may be a DCI message; when the first information is carried in the information in the PO, the second message may be a message indicating a system information update by the PO; when the first information is carried in any broadcast information of N cells, the second message may be a message sent by any broadcast of the N cells.

In a possible implementation of the first aspect, the first message also includes at least one of the following: first indication information, indicating that the switching configuration information is used for a cell switching process triggered by a second message; or, second indication information, indicating that the second message is monitored on all POs.

Optionally, all POs indicated by the second indication information refer to all POs in a paging frame (PF) that can be perceived by the terminal device, or all POs indicated by the second indication information refer to any PO in the PF that can be perceived by the terminal device.

Based on the above technical solution, the first message containing the switching configuration information of N cells may also include at least one of the above-mentioned indication information, indicating that the switching configuration information is used for the cell switching process triggered by the second message by displaying the indication information, and/or instructing to monitor the second message on all POs, so that the terminal device can clarify the execution of the cell switching based on the indication information carried by the display.

In a possible implementation manner of the first aspect, the second message is a broadcast message.

Based on the above technical solution, the switching configuration information carried by the first message is used for the cell switching process triggered by the second message, that is, the second message is used to trigger the terminal device to perform the cell switching process, so that the implementation method of the second message being a message sent in a broadcast manner (i.e., a broadcast message) can trigger multiple terminal devices to perform cell switching based on the scheduling of the broadcast message to save overhead. In addition, the sending speed of the second message can be increased, so as to increase the speed at which multiple terminal devices perform cell switching based on the broadcast message trigger.

In a possible implementation manner of the first aspect, the value of N is 1.

Based on the above technical solution, when the value of N is 1, the implementation method in which the first message includes the switching configuration information of a certain cell can save the overhead of the first message while also reducing the overhead of the terminal device monitoring the signals of multiple cells during the cell switching process.

In a possible implementation of the first aspect, the handover configuration information is conditional handover (CHO) configuration information.

Optionally, when the handover configuration information included in the first message is CHO configuration information, the trigger condition corresponding to the CHO configuration information is triggered based on the second message. In addition, CHO configuration information is the name of the handover configuration information for triggering the execution of cell handover based on the trigger condition in the current standard/protocol. In future standards/protocols, CHO configuration information may also have other names, which are not limited here.

The second aspect of the present application provides a communication method, which is executed by a terminal device, or the method is executed by some components in the terminal device (such as a processor, a chip or a chip system, etc.), or the method can also be implemented by a logic module or software that can realize all or part of the terminal device functions. In the second aspect and its possible implementation, the communication method is described as being executed by a terminal device. In this method, the terminal device receives a first message, and the first message includes switching configuration information of N cells, where N is a positive integer; after determining (within a preset time) that a second message has not been received or determining that an indication message indicating that the cell switching process corresponding to the switching configuration information has been cancelled is received, the terminal device ignores or deletes the switching configuration information, and the second message is used to trigger the cell switching process corresponding to the switching configuration information.

Based on the above technical solution, when a terminal device receives a first message including a switching configuration of N cells, the terminal device ignores or deletes the switching configuration information after determining that a second message (the second message is used to trigger a cell switching process corresponding to the switching configuration information) has not been received or determining that an indication message indicating cancellation of the cell switching process corresponding to the switching configuration information has been received. Compared with the implementation method in which a cell switching is triggered when a terminal device receives a switching message carrying configuration information of a target cell, the terminal device can obtain in advance the switching configuration information for the cell switching process triggered based on the second message, and can determine to ignore or delete the switching configuration information based on the scheduling of the network device (for example, the network device does not send the second message, or the network device sends an indication message to cancel the cell switching, etc.), that is, the terminal device can determine not to perform the cell switching based on the scheduling of the network device to avoid cell switching failure.

In a possible implementation manner of the second aspect, the handover configuration information is used for a cell handover process triggered by a second message, or the handover configuration information is CHO configuration information triggered by a measurement event.

Based on the above technical solution, the configuration information of N cells carried by the first message can be implemented through the above-mentioned multiple methods to improve the flexibility of the solution implementation.

The third aspect of the present application provides a communication method, which is executed by a source CU, or the method is executed by some components in the source CU (such as a processor, a chip or a chip system, etc.), or the method can also be implemented by a logic module or software that can implement all or part of the source CU functions. In the third aspect and its possible implementation, the communication method is described as being executed by the source CU. In the method, the source CU determines a first message, and the first message includes switching configuration information of N cells, where N is a positive integer, and the switching configuration information is used for a cell switching process triggered by a second message; wherein the N cells are located in a target distributed unit (DU); the source CU sends the first message to the terminal device through an IAB node.

Based on the above technical solution, the first message sent by the source CU to the terminal device through the IAB node includes the switching configuration information of N cells, and the switching configuration information is used for the cell switching process triggered by the second message. Compared with the implementation method in which the switching message that triggers the execution of cell switching carries the configuration information of the target cell, the terminal device can obtain the switching configuration information for the cell switching process triggered by the second message in advance, and can subsequently trigger the execution of cell switching based on the switching configuration information after receiving the second message, in order to improve the success rate of cell switching.

In a possible implementation manner of the third aspect, the target DU is located in the IAB node.

Based on the above technical solution, the IAB node to which the terminal device is connected includes a source DU where the source cell is located, and the target DU where the target cell is located is located at the IAB node where the source DU is located. This enables the solution to be applied to scenarios where the terminal device performs cell switching between different DUs in the same IAB node (or scenarios where the IAB node migrates across CUs and the target cell corresponding to the target CU is enabled).

Optionally, when the target DU is located at the IAB node, the link between the terminal device and the IAB node can be a direct link (i.e., there is no other IAB node between the two), or the link between the terminal device and the IAB node can be a non-direct link (i.e., there may be other IAB nodes between the two), which is not limited here.

Optionally, the target DU may also be located at other IAB nodes.

In a possible implementation of the third aspect, the method further includes: after the source CU determines that the target DU has established an F1 connection with the target CU, the source CU sends a switching request message of the terminal to the target CU; the source CU receives a switching response message from the target CU, and the switching response message includes the switching configuration information.

Based on the above technical solution, after the source CU determines that the target DU and the target CU have established an F1 connection, the source CU determines that the cell under the target DU can be used as a potential target cell. To this end, the source CU can obtain the switching configuration information through the interaction of switching request messages and switching response messages with the target CU, so that the source CU can subsequently send a first message containing the switching configuration information to the terminal device.

In a possible implementation manner of the third aspect, the method further includes: the source CU sending the second message to the terminal device.

Based on the above technical solution, the source CU can also send the second message to the terminal device, so that the terminal device triggers the execution of cell switching based on the second message. Compared with the implementation method in which the switching message that triggers the execution of cell switching carries the configuration information of the target cell, the terminal device can obtain the switching configuration information for the cell switching process triggered by the second message in advance, and can trigger the execution of cell switching based on the switching configuration information after receiving the second message. Thus, in the case of determining that the terminal device needs to be scheduled to execute cell switching, the second message sent to the terminal device to trigger the execution of cell switching does not need to carry the switching configuration information of the target cell, which can save the overhead of the triggering process and improve the execution speed of the cell switching, so as to improve the success rate of the cell switching.

In addition, compared to the implementation method in which the terminal device triggers cell switching locally based on a measurement event of signal quality deterioration, the above-mentioned technical solution of triggering cell switching by a second message can support more cell switching scenarios, that is, when the signal quality between the terminal device and the source cell has not deteriorated (for example, when the IAB node where the source cell is located undergoes cross-CU migration and the target cell corresponding to the target CU is enabled, or, when the IAB node where the source cell is located needs to schedule the terminal device to connect to other cells in the IAB node, or when the IAB node where the source cell is located determines that the source cell is going to be shut down or deactivated, etc.), the cell switching can still be triggered by the second message, so that the above-mentioned technical solution can save the overhead of the triggering process and improve the execution speed of the cell switching, and can also avoid the situation where the cell switching cannot be executed because the terminal device cannot trigger the cell switching locally when the signal quality has not deteriorated.

In a possible implementation manner of the third aspect, when at least one of the following is met, the source CU sends the second message to the terminal device, including: the source CU determines that the target DU has established an F1 connection with the target CU; the source CU determines that the mobile terminal (mobile termination, MT) in the IAB node is about to switch to the target CU; or the source CU receives an indication from the target CU allowing the terminal device to establish an F1 connection based on the target CU. The switching configuration information performs cell switching.

Based on the above technical solution, when at least one of the above items is met, the source CU determines that the terminal device is currently capable of performing cell switching and successfully switching to the N cells under the target DU. To this end, the source CU can send a second message to the terminal device, so that the terminal device triggers the execution of cell switching based on the received second message.

In a possible implementation of the third aspect, the source CU sends the first message when any of the following items is met, including: after the source CU sends a first switching request message to the target CU, it receives a first switching response message from the target CU, and the first switching response message includes switching configuration information of N cells; after the source CU sends a second switching request message to the target CU, it receives a second switching response message from the target CU, and the second switching request message includes the identifiers of N cells and the N cells are unactivated cells; or, after the source CU receives the first configuration information from the target DU and sends the first configuration information to the target CU, it receives the switching configuration information of N cells from the target CU, and the switching configuration information of the N cells includes the first configuration information and the second configuration information.

Based on the above technical solution, when at least one of the above items is met, the source CU determines that the cell under the target DU will be used as a potential target cell. To this end, the source CU can send a first message containing switching configuration information of N cells to the terminal device, so that the switching configuration information of N cells is sent before the switching conditions are met, so that when it is subsequently determined that the terminal device needs to be scheduled to switch to the N cells and the scheduling message is sent, the signaling consumption of the scheduling message can be saved, so as to improve the success rate of cell switching.

In a possible implementation of the third aspect, the first configuration information includes radio link control (RLC) layer configuration information and/or media access control (MAC) layer configuration information, and the second configuration information includes packet data convergence protocol (PDCP) layer configuration information and/or service data adaptation protocol (SDAP) layer configuration information.

Based on the above technical solution, when an F1 connection has not been established between the target DU and the target CU, the target DU can send the first configuration information (including RLC and/or MAC layer configuration information) to the target CU through the source CU, so that the target CU determines the switching configuration information of the N cells under the target DU based on the first configuration information (including RLC and/or MAC configuration information, and PDCP and/or SDAP configuration information), and the target CU can send the switching configuration information of the N cells to the terminal device through the source CU in the form of a first message.

Optionally, the handover configuration information of the N cells sent by the target CU to the source CU may be carried in a handover response message (eg, the first handover response message or the second handover response message mentioned above), or other messages.

In a possible implementation of the third aspect, the source CU determines that the target DU and the target CU have established an F1 connection, including: the source CU determines that the target DU and the target CU have established an F1 connection based on third indication information from the target CU, and the third indication information indicates that the terminal device performs cell switching based on the switching configuration information.

Based on the above technical solution, the source CU can determine that the target DU has established an F1 connection with the target CU through the third indication information sent by the target CU, and further determine that the terminal device can successfully perform cell switching to the target DU based on the switching configuration information.

Optionally, the third indication information can also be implemented in other ways. For example, the third indication information indicates that the terminal device is allowed to perform cell switching based on the switching configuration information; for example, the third indication information indicates (allows) the source CU to send switching configuration information of N cells to the terminal device; for example, the third indication information indicates that N cells in the target DU have been activated.

In a possible implementation of the third aspect, the second message includes first information, and the first information is carried in any one of the following: a short message field in the DCI of the PDCCH encrypted by P-RNTI; information in the PO; or any broadcast information of N cells.

In a possible implementation of the third aspect, the first message also includes at least one of the following: first indication information, indicating that the switching configuration information is used for a cell switching process triggered by a second message; or, second indication information, indicating that the second message is monitored on all POs.

Based on the above technical solution, the first message including the switching configuration information of N cells may also include the above at least one indication information. The switching configuration information is indicated by displaying the indication information to be used for the cell switching process triggered by the second message, and/or, the second message is indicated to be monitored on all POs, so that the terminal device can clearly determine the execution of the cell switching based on the indication information carried by the display.

In a possible implementation manner of the third aspect, the second message is a broadcast message.

In a possible implementation manner of the third aspect, the value of N is 1.

In a possible implementation of the third aspect, the handover configuration information is conditional handover (CHO) configuration information.

In a possible implementation manner of the third aspect, the method further includes: the source CU sends indication information to the terminal device indicating that the cell switching process corresponding to the switching configuration information is cancelled.

Optionally, the source CU may also implicitly indicate cancellation of the cell switching process corresponding to the switching configuration information in other ways, for example, the source CU does not send the second message (within a preset time period).

Based on the above technical solution, the terminal device can obtain in advance the switching configuration information for the cell switching process triggered by the second message, and can determine to ignore or delete the switching configuration information based on the scheduling of the source CU (for example, the source CU does not send the second message, or the source CU sends an indication information to cancel the cell switching, etc.), that is, the terminal device can determine not to perform the cell switching based on the scheduling of the network device to avoid cell switching failure.

The fourth aspect of the present application provides a communication method, which is executed by a target CU, or the method is executed by some components in the target CU (such as a processor, a chip or a chip system, etc.), or the method can also be implemented by a logic module or software that can implement all or part of the target CU functions. In the fourth aspect and its possible implementation, the communication method is described as being executed by the target CU. In this method, after determining that an F1 connection has been established with the target DU, the target CU determines third indication information, and the third indication information indicates that the terminal device is allowed to perform cell switching based on the switching configuration information, and the target DU includes N cells, where N is a positive integer; wherein the switching configuration information is used for a cell switching process triggered by a second message; the target CU sends the third indication information to the source CU.

Based on the above technical solution, after the target CU determines that an F1 connection has been established with the target DU, the target CU can determine that the terminal device can switch to the N cells contained in the target DU based on the cell switching process. To this end, the target CU sends a third indication information to the source CU indicating that the terminal device is allowed to perform cell switching based on the switching configuration information, so that the source CU can determine that the terminal device can be triggered to perform cell switching based on the third indication information. Among them, the switching configuration information is used for the cell switching process triggered by the second message, so that the terminal device can subsequently trigger the cell switching based on the switching configuration information after receiving the second message, in order to improve the success rate of cell switching. Compared with the implementation method in which the switching message that triggers the execution of cell switching carries the configuration information of the target cell, when the source CU determines that the terminal device needs to be scheduled to perform cell switching based on the third indication information from the target CU, the second message that triggers the execution of cell switching sent to the terminal device does not need to carry the switching configuration information of the target cell, which can save the overhead of the triggering process and improve the execution speed of the cell switching, in order to improve the success rate of the cell switching.

In addition, compared to the implementation method in which the terminal device triggers cell switching locally based on a measurement event of signal quality deterioration, the above-mentioned technical solution of triggering cell switching by a second message can support more cell switching scenarios, that is, when the signal quality between the terminal device and the source cell has not deteriorated (for example, when the IAB node where the source cell is located undergoes cross-CU migration and the target cell corresponding to the target CU is enabled, or, when the IAB node where the source cell is located needs to schedule the terminal device to connect to other cells in the IAB node, or when the IAB node where the source cell is located determines that the source cell is going to be shut down or deactivated, etc.), the cell switching can still be triggered by the second message, so that the above-mentioned technical solution can obtain the gain of saving the overhead of the triggering process and improving the execution speed of the cell switching, and can also avoid the situation where the cell switching cannot be executed because the terminal device cannot trigger the cell switching locally when the signal quality has not deteriorated. situation occurs.

In a possible implementation manner of the fourth aspect, the target CU sending the third indication information to the source CU includes: after the target CU determines that the target DU has configured the context of the terminal device, the target CU sends the third indication information to the source CU.

Based on the above technical solution, after the target CU determines that the target DU has been configured with the context of the terminal device, the target CU can determine that the terminal device can access the network through the N cells contained in the target DU. To this end, the target CU can send the third indication information to the source CU, so that the source CU schedules the terminal device to perform cell switching based on the third indication information from the target CU.

In a possible implementation of the fourth aspect, before the target CU sends the third indication information to the source CU, the method also includes: the target CU receives a second switching request message from the source centralized unit CU, the second switching request message includes the identifiers of N cells and the N cells are unactivated cells; wherein the N cells are located in the target DU; the target CU sends a second switching response message to the source CU, the second switching response message includes the switching configuration information of the N cells.

Based on the above technical solution, before the target CU sends the third indication information to the source CU, the target CU and the source CU can interact through the second switching request message and the second switching response message, so that the target CU determines the corresponding switching configuration information based on the N unactivated cells, and then sends the switching configuration information to the terminal device through the source CU, so that the terminal device can subsequently execute the cell switching process corresponding to the switching configuration information based on the triggering of the second message.

In a possible implementation of the fourth aspect, before the target CU sends the third indication information to the source CU, the method also includes: after the target CU receives the first configuration information from the source centralized unit CU, sending switching configuration information of N cells to the source CU, the switching configuration information of the N cells includes the first configuration information and the second configuration information.

Optionally, the first configuration information includes RLC layer configuration information and/or MAC layer configuration information, and the second configuration information includes PDCP layer configuration information and/or SDAP layer configuration information.

Based on the above technical solution, when an F1 connection has not been established between the target DU and the target CU, the target DU can send the first configuration information (including RLC and/or MAC layer configuration information) to the target CU through the source CU, so that the target CU determines the switching configuration information of the N cells under the target DU based on the first configuration information (including RLC and/or MAC configuration information, and PDCP and/or SDAP configuration information), and the target CU can send the switching configuration information of the N cells to the terminal device through the source CU in the form of a first message, so that the terminal device can subsequently execute the cell switching process corresponding to the switching configuration information based on the triggering of the second message.

The fifth aspect of the present application provides a communication method, which is executed by a first CU, or the method is executed by some components in the first CU (such as a processor, a chip or a chip system, etc.), or the method can also be implemented by a logic module or software that can implement all or part of the functions of the first CU. In the fifth aspect and its possible implementation, the communication method is described as being executed by the first CU. In the method, the first CU determines third configuration information, and the third configuration information includes third configuration information of the first DU; wherein the first DU is located at an IAB node, and the IAB node also includes a second DU and an MT; the first CU sends the third configuration information to the IAB node.

Based on the above technical solution, when there is a communication connection between the first CU and the IAB node (for example, there is a radio resource control (RRC) connection between the first CU and the MT in the IAB node and/or there is an F1 connection between the first CU and the second DU in the IAB node), the first CU can send the third configuration information of the first DU (i.e., other DUs except the second DU) to the IAB node, so that the first DU can communicate based on the third configuration information. Among them, the MT in the IAB node does not need to receive the configuration information from the first CU again through the RRC connection, so that the first DU in the IAB node can obtain the third configuration information and communicate based on the third configuration information. Therefore, in the case that the MT in the IAB node cannot obtain the configuration information from the first CU in time (for example, the case that the MT and the first DU are connected to different CUs for communication, and the case that the MT and the first DU are switched to the same CU but the switching timing of the MT is later than the switching timing of the first DU, etc.), the first DU can be enabled to communicate based on the third configuration information to avoid the situation that the first DU cannot communicate due to the lack of the third configuration information.

In a possible implementation manner of the fifth aspect, the third configuration information is carried in an F1 application protocol (F1application protocol, F1AP) message, or the third configuration information is carried in an RRC message.

Based on the above technical solution, the first CU can send the third configuration information to the IAB node in a variety of ways. Among them, the third configuration information can be transmitted through the F1 connection between the second DU and the first CU in the IAB node, that is, the third configuration information can be carried in the F1AP message on the F1 connection. Alternatively, the third configuration information can be transmitted through the RRC connection between the MT and the first CU in the IAB node, that is, the third configuration information can be carried in the RRC message on the RRC connection.

In a possible implementation of the fifth aspect, the third configuration information includes at least one of the following: a new radio cell global identifier (NCGI), a CU identifier used to determine the NCGI, or a first key for the first DU to establish encrypted communication with other CUs for an F1 connection, or a physical cell identifier (PCI) of a cell in the first DU.

Optionally, the third configuration information sent by the first CU to the IAB node may include configuration information of the first DU and other communication nodes (such as CU or other IAB nodes or terminal devices, etc.), and the configuration information may include the above-mentioned NCGI, used to determine the CU identifier of NCGI, PCI, or other configuration information, which is not limited here.

In a possible implementation of the fifth aspect, after the first CU sends the third configuration information to the IAB node, the method also includes: the first CU receives fourth indication information, and the fourth indication information is used to indicate that the third configuration information of the first DU has taken effect, or to indicate that the first CU sends a switching command to a terminal device connected to the second DU, or to indicate that the first DU has sent a third message determined based on the third configuration information.

Based on the above technical solution, when the first DU is able to communicate based on the third configuration information, the first DU may also send indication information to the first CU so that the first CU knows clearly that the third configuration information has taken effect on the first DU. Subsequently, the first CU may schedule the first DU and/or the terminal device connected to the first DU based on the third configuration information.

In the sixth aspect of the present application, a communication method is provided, which is executed by an IAB node, or the method is executed by some components in the IAB node (such as a processor, a chip or a chip system, etc.), or the method can also be implemented by a logic module or software that can implement all or part of the functions of the IAB node. In the sixth aspect and its possible implementation, the communication method is described as being executed by an IAB node. In the method, the IAB node receives third configuration information, and the third configuration information includes the third configuration information of the first DU; the IAB node sends a third message, and the third message is obtained based on the third configuration information.

Based on the above technical solution, when there is a communication connection between the first CU and the IAB node (for example, there is an RRC connection between the first CU and the MT in the IAB node and/or there is an F1 connection between the first CU and the second DU in the IAB node), the IAB node receives the third configuration information of the first DU (i.e., other DUs except the second DU) from the first CU, so that the first DU can send a third message based on the third configuration information. Among them, the MT in the IAB node does not need to receive the configuration information from the first CU through the RRC connection again, so that the first DU in the IAB node can obtain the third configuration information and communicate based on the third configuration information. Therefore, in the case where the MT in the IAB node cannot obtain the configuration information from the first CU in time (for example, the case where the MT and the first DU are connected to different CUs for communication, and the case where the MT and the first DU are switched to the same CU but the switching timing of the MT is later than the switching timing of the first DU, etc.), the first DU can be enabled to communicate based on the third configuration information to avoid the situation where the first DU cannot communicate due to the lack of the third configuration information.

In a possible implementation manner of the sixth aspect, the third configuration information is carried in an F1AP message, or the third configuration information is carried in an RRC message.

In a possible implementation of the sixth aspect, the third configuration information includes at least one of the following: a new wireless cell global identifier NCGI, a CU identifier used to determine the NCGI, a first key for the first DU to establish encrypted communication with other CUs for an F1 connection, or a physical cell identifier PCI of a cell in the first DU.

Optionally, the third configuration information sent by the first CU to the IAB node may include configuration information of the first DU and other communication nodes (such as CU or other IAB nodes or terminal devices, etc.), and the configuration information may include the above-mentioned NCGI, which is used to determine the CU of NCGI. Identification, PCI, or other configuration information is not limited here.

In a possible implementation of the sixth aspect, the first DU sends a third message when at least one of the following items is met, including: the MT of the IAB node determines that the cell switching execution condition is met, and the target cell corresponding to the cell switching is located in the other CU; the first DU of the IAB node determines to establish an F1 connection with the other CU; or the IAB node detects that the PCI of any cell under the first DU conflicts with other PCIs.

Based on the above technical solution, when the first DU determines that at least one of the above items is satisfied, the first DU can determine that communication can be performed based on the third configuration information. To this end, the first DU can send a third message obtained based on the third configuration information.

In a possible implementation of the sixth aspect, after the first DU sends the third message, the method also includes: the first DU sends fourth indication information to the first CU, and the fourth indication information is used to indicate that the third configuration information of the first DU has taken effect, or to instruct the first CU to send a switching command to the terminal device connected to the first DU.

In a possible implementation of the sixth aspect, the third message includes a synchronization signal/physical broadcast channel PBCH block (SS/PBCH block) (which may be referred to as SS/PBCH block or SSB for short) sent by the first DU to the terminal device, or an F1 connection establishment request message sent by the first DU to other CUs.

Optionally, in addition to the above-mentioned SSB, the third message may also include other messages between the first DU and the lower-level communication node (such as a terminal device or other IAB node).

Optionally, in addition to the above-mentioned F1 connection establishment request message, the third message may also include other messages between the first DU and the upper-level communication node (such as CU or other IAB nodes), which is not limited here.

In the seventh aspect of the present application, a communication device is provided, which is a terminal device, or the device is a partial component in the terminal device (such as a processor, a chip or a chip system, etc.), or the device can also be a logic module or software that can realize all or part of the functions of the terminal device. In the seventh aspect and its possible implementation, the communication device is described as an example of execution as a terminal device. The device includes a transceiver unit and a processing unit; the transceiver unit is used to receive a first message, the first message includes switching configuration information of N cells, N is a positive integer, wherein the switching configuration information is used for a cell switching process triggered by a second message; the processing unit is used to perform cell switching based on the switching configuration information after the transceiver unit receives the second message.

In a possible implementation manner of the seventh aspect, the second message includes first information, and the first information is carried in any one of the following items:

The short message field in the downlink control information DCI of the physical downlink control channel PDCCH scrambled by the paging radio network temporary identifier P-RNTI;

The information in the pager PO; or,

Any broadcast information of N cells.

In a possible implementation manner of the seventh aspect, the first message further includes at least one of the following:

first indication information, indicating that the switching configuration information is used for a cell switching process triggered by a second message; or,

The second indication information indicates to monitor the second message on all POs.

In a possible implementation manner of the seventh aspect, the second message is a broadcast message.

In a possible implementation manner of the seventh aspect, the value of N is 1.

In a possible implementation manner of the seventh aspect, the switching configuration information is conditional switching CHO configuration information.

In the seventh aspect of the embodiment of the present application, the constituent modules of the communication device can also be used to execute the steps performed in each possible implementation method of the first aspect and achieve corresponding technical effects. For details, please refer to the first aspect and will not be repeated here.

In an eighth aspect of the present application, a communication device is provided, which is a terminal device, or the device is a partial component in the terminal device (such as a processor, a chip or a chip system, etc.), or the device can also be a logic module or software that can implement all or part of the functions of the terminal device. In the eighth aspect and its possible implementation, the communication device is described as an example of execution as a terminal device. The device includes a transceiver unit and a processing unit; the transceiver unit is used to receive a first message, and the first message includes switching configuration information of N cells, N is a positive integer; the processing unit is used to ignore or delete the switching configuration information after determining that the second message is not received (the second message is used to trigger the cell switching process corresponding to the switching configuration information) or determining that an indication message indicating the cancellation of the cell switching process corresponding to the switching configuration information is received.

In a possible implementation manner of the eighth aspect, the switching configuration information is used for a cell switching process triggered by a second message.

In a possible implementation manner of the eighth aspect, the switching configuration information is conditional switching CHO configuration information triggered by a measurement event.

In the eighth aspect of the embodiments of the present application, the constituent modules of the communication device can also be used to execute the steps performed in each possible implementation method of the second aspect and achieve corresponding technical effects. For details, please refer to the second aspect and will not be repeated here.

The ninth aspect of the present application provides a communication method, wherein the device is a source CU, or the device is a partial component in the source CU (such as a processor, a chip or a chip system, etc.), or the device can also be a logic module or software that can implement all or part of the source CU functions. In the ninth aspect and its possible implementation methods, the communication device is described as an example of execution as a source CU. The device includes a transceiver unit and a processing unit; the processing unit is used to determine a first message, the first message includes switching configuration information of N cells, N is a positive integer, and the switching configuration information is used for a cell switching process triggered based on a second message; wherein the N cells are located in the target DU; the transceiver unit is used to send the first message to the terminal device through the access backhaul integrated IAB node.

In a possible implementation manner of the ninth aspect, the target DU is located in the IAB node.

In a possible implementation of the ninth aspect, the transceiver unit is also used to send a switching request message of the terminal to the target CU after the processing unit determines that the target DU has established an F1 connection with the target centralized unit CU; the transceiver unit is also used to receive a switching response message from the target CU, and the switching response message includes the switching configuration information.

In a possible implementation manner of the ninth aspect, the transceiver unit is further used to send the second message to the terminal device.

In a possible implementation manner of the ninth aspect, when at least one of the following items is met, the transceiver unit sends the second message to the terminal device, including:

The processing unit determines that the target DU has established an F1 connection with the target CU;

The processing unit determines that the mobile terminal MT in the IAB node is to be switched to the target CU; or,

The processing unit determines that receiving an indication from the target CU allows the terminal device to perform a cell switch based on the switching configuration information.

In a possible implementation manner of the ninth aspect, when any of the following items is met, the transceiver unit sends the first message, including:

The processing unit determines that after the transceiver unit sends the first handover request message to the target CU, a first handover response message is received from the target CU, where the first handover response message includes handover configuration information of N cells;

The processing unit receives a second switching response message from the target CU after determining that the transceiver unit sends a second switching request message to the target CU, wherein the second switching request message includes identifiers of N cells and the N cells are inactivated cells; or,

The processing unit determines that after the transceiver unit receives the first configuration information from the target DU and sends the first configuration information to the target CU, it receives switching configuration information of N cells from the target CU, and the switching configuration information of the N cells includes the first configuration information and the second configuration information.

In a possible implementation of the ninth aspect, the first configuration information includes radio link control RLC layer configuration information and/or media access control MAC layer configuration information, and the second configuration information includes packet data convergence protocol PDCP layer configuration information and/or service data adaptation protocol SDAP layer configuration information.

In a possible implementation of the ninth aspect, the determination unit is specifically used to determine that the target DU has established an F1 connection with the target centralized unit CU based on third indication information from the target CU, and the third indication information indicates that the terminal device performs cell switching based on the switching configuration information.

In a possible implementation manner of the ninth aspect, the second message includes first information, and the first information is carried in any one of the following items:

The information in the pager PO; or,

Any broadcast information of N cells.

In a possible implementation manner of the ninth aspect, the first message further includes at least one of the following:

In a possible implementation manner of the ninth aspect, the second message is a broadcast message.

In a possible implementation manner of the ninth aspect, the value of N is 1.

In a possible implementation manner of the ninth aspect, the method further includes:

Send indication information indicating cancellation of the cell handover process corresponding to the handover configuration information.

In the ninth aspect of the embodiments of the present application, the constituent modules of the communication device can also be used to execute the steps performed in each possible implementation method of the third aspect and achieve corresponding technical effects. For details, please refer to the third aspect and will not be repeated here.

The tenth aspect of the present application provides a communication method, wherein the device is a target CU, or the device is a partial component in the target CU (such as a processor, a chip or a chip system, etc.), or the device can also be a logic module or software that can implement all or part of the target CU functions. In the tenth aspect and its possible implementation, the communication device is described as an example of execution as a target CU. The device includes a transceiver unit and a processing unit; the processing unit is used to determine a third indication information after determining that an F1 connection has been established with a target distributed unit DU, and the third indication information indicates that the terminal device performs a cell switch based on the switching configuration information, and the target DU includes N cells, N is a positive integer; wherein the switching configuration information is used for a cell switching process triggered based on a second message; the transceiver unit is used to send the third indication information to the source CU.

In a possible implementation manner of the tenth aspect, the transceiver unit is specifically used to send the third indication information to the source CU after the processing unit determines that the target DU has been configured with the context of the terminal device.

In a possible implementation of the tenth aspect, the transceiver unit is also used to receive a second switching request message from a source centralized unit CU, the second switching request message including the identifiers of N cells and the N cells are unactivated cells; wherein the N cells are located in the target DU; the transceiver unit is also used to send a second switching response message to the source CU, the second switching response message including the switching configuration information of the N cells.

In a possible implementation of the tenth aspect, the transceiver unit is also used to send switching configuration information of N cells to the source centralized unit CU after receiving the first configuration information from the source CU, and the switching configuration information of the N cells includes the first configuration information and the second configuration information.

In a possible implementation of the tenth aspect, the first configuration information includes radio link control RLC layer configuration information and/or media access control MAC layer configuration information, and the second configuration information includes packet data convergence protocol PDCP layer configuration information and/or service data adaptation protocol SDAP layer configuration information.

In the tenth aspect of the embodiment of the present application, the constituent modules of the communication device can also be used to execute the steps performed in each possible implementation method of the fourth aspect and achieve corresponding technical effects. For details, please refer to the fourth aspect and will not be repeated here.

In the eleventh aspect of the present application, a communication device is provided, which is a source CU, or the device is a partial component in the source CU (such as a processor, a chip or a chip system, etc.), or the device can also be a logic module or software that can implement all or part of the source CU functions. In the eleventh aspect and its possible implementation methods, the communication device is described as an example of execution as a source CU. The device includes a transceiver unit and a processing unit; the processing unit is used to determine third configuration information, and the third configuration information includes third configuration information of a first centralized unit DU; wherein the first DU is located at an access backhaul integrated IAB node, and the IAB node also includes a second DU and a mobile terminal MT; the transceiver unit is used to send the third configuration information to the IAB node.

In a possible implementation manner of the eleventh aspect, the third configuration information is carried in an F1AP message, or the third configuration information is carried in an RRC message.

In a possible implementation of the eleventh aspect, the third configuration information includes at least one of the following: a new wireless cell global identifier NCGI, used to determine the CU identifier of the NCGI, or a first key for the first DU to establish encrypted communication with other CUs for an F1 connection, or a physical cell identifier PCI of a cell in the first DU.

In a possible implementation of the eleventh aspect, the transceiver unit is also used to receive fourth indication information, which is used to indicate that the third configuration information of the first DU has taken effect, or to instruct the first CU to send a switching command to a terminal device connected to the second DU.

In the eleventh aspect of the embodiment of the present application, the constituent modules of the communication device can also be used to execute the steps performed in each possible implementation method of the fifth aspect and achieve corresponding technical effects. For details, please refer to the fifth aspect and will not be repeated here.

A twelfth aspect of the present application provides a communication method, wherein the device is an IAB node, or the device is a partial component (such as a processor, a chip or a chip system, etc.) in the IAB node, or the device can also be a logic device capable of realizing all or part of the functions of the IAB node. In the twelfth aspect and possible implementations thereof, the communication device is described as an IAB node. The device includes a transceiver unit and a processing unit; the device includes a processing unit and a transceiver unit, the transceiver unit is used to receive third configuration information, the third configuration information includes the third configuration information of the first DU; the processing unit is used to determine a third message, the third message is obtained based on the third configuration information; the transceiver unit is also used to send a third message.

In a possible implementation manner of the twelfth aspect, the third configuration information is carried in an F1AP message, or the third configuration information is carried in an RRC message.

In a possible implementation of the twelfth aspect, the third configuration information includes at least one of the following: a new wireless cell global identifier NCGI, a CU identifier used to determine the NCGI, a first key for the first DU to establish encrypted communication with other CUs for an F1 connection, or a physical cell identifier PCI of a cell in the first DU.

In a possible implementation manner of the twelfth aspect, when at least one of the following items is met, the transceiver unit sends the third message, including:

The processing unit determines that a cell switching execution condition is met, and a target cell corresponding to the cell switching is located in the other CU;

The processing unit determines to establish an F1 connection with the other CU; or,

The processing unit determines that a PCI of any cell under the first DU is detected to conflict with other PCIs.

In a possible implementation of the twelfth aspect, the transceiver unit is also used to send fourth indication information to the first CU, and the fourth indication information is used to indicate that the third configuration information of the first DU has taken effect, or to instruct the first CU to send a switching command to a terminal device connected to the first DU.

In a possible implementation manner of the twelfth aspect, the third message includes an SSB sent by the first DU to the terminal device, or an F1 connection establishment request message sent by the first DU to other CUs.

In the twelfth aspect of the embodiment of the present application, the constituent modules of the communication device can also be used to execute the steps performed in each possible implementation method of the sixth aspect and achieve corresponding technical effects. For details, please refer to the sixth aspect and will not be repeated here.

A thirteenth aspect of an embodiment of the present application provides a communication device, comprising at least one processor, wherein the at least one processor is coupled to a memory; the memory is used to store programs or instructions; wherein the at least one processor is used to execute the program or instructions so that the device implements the method described in any one of the first to sixth aspects and any possible implementation method thereof.

A fourteenth aspect of an embodiment of the present application provides a communication device, including at least one logic circuit and an input/output interface; the logic circuit is used to execute the method described in any one of the first to sixth aspects and any possible implementation method thereof.

A fifteenth aspect of an embodiment of the present application provides a computer-readable storage medium, which stores instructions. When the instructions are executed by a processor, the processor executes the method described in any one of the first to sixth aspects above and any possible implementation method thereof.

A sixteenth aspect of an embodiment of the present application provides a computer program product (or computer program), which includes a computer program code. When the computer program code is executed by a processor, the processor executes the method described in any one of the first to sixth aspects and any possible implementation method thereof.

A seventeenth aspect of an embodiment of the present application provides a chip system, which includes at least one processor for supporting a communication device to implement the functions involved in any one of the first to sixth aspects above and any possible implementation methods thereof.

In one possible design, the chip system may also include a memory for storing program instructions and data necessary for the first communication device. The chip system may be composed of a chip, or may include a chip and other discrete devices. Optionally, the chip system also includes an interface circuit, which provides program instructions and/or data for the at least one processor.

An eighteenth aspect of an embodiment of the present application provides a communication system, which includes at least two of the communication device of the fourth aspect, the communication device of the fifth aspect, and the communication device of the sixth aspect.

Alternatively, the communication system includes a source CU and a terminal device, and optionally, the communication system also includes a target CU. The terminal device is used to execute the method in the first aspect or the second aspect and any possible implementation thereof, the source CU is used to execute the method in the third aspect and any possible implementation thereof, and the target CU is used to execute the method in the fourth aspect and any possible implementation thereof.

Alternatively, the communication system includes a first CU and an IAB node, wherein the first CU is used to execute the method in the fifth aspect and any possible implementation thereof, and the IAB node is used to execute the method in the sixth aspect and any possible implementation thereof.

It should be understood that the technical effects brought about by any one of the design methods in the seventh to eighteenth aspects can be referred to in the first to sixth aspects above. The technical effects brought about by the different design methods in the surface will not be elaborated here.

It can be seen from the above technical solutions that the solution provided by this application has the following beneficial effects:

In some embodiments, a terminal device receives a first message including switching configuration information of N cells, and the switching configuration information is used for a cell switching process triggered by a second message. Thereafter, after receiving the second message, the terminal device performs cell switching based on the switching configuration information. Compared to the implementation method in which the switching message that triggers the execution of cell switching carries the configuration information of the target cell, the terminal device can obtain the switching configuration information for the cell switching process triggered by the second message in advance, and can trigger the execution of cell switching based on the switching configuration information after receiving the second message. Thus, in the case where it is determined that the terminal device needs to be scheduled to execute cell switching, the second message that triggers the execution of cell switching and is sent to the terminal device does not need to carry the switching configuration information of the target cell, which can save the overhead of the triggering process and improve the execution speed of the cell switching, so as to improve the success rate of the cell switching.

In some embodiments, when there is a communication connection between the first CU and the IAB node (for example, there is a radio resource control (RRC) connection between the first CU and the MT in the IAB node and/or there is an F1 connection between the first CU and the second DU in the IAB node), the first CU may send the third configuration information of the first DU (i.e., other DUs except the second DU) to the IAB node, so that the first DU can communicate based on the third configuration information. Among them, the MT in the IAB node does not need to receive the configuration information from the first CU again through the RRC connection, so that the first DU in the IAB node can obtain the third configuration information and communicate based on the third configuration information. Therefore, in the case where the MT in the IAB node cannot obtain the configuration information from the first CU in time (for example, the case where the MT and the first DU are connected to different CUs for communication, and the case where the MT and the first DU are switched to the same CU but the switching timing of the MT is later than the switching timing of the first DU, etc.), the first DU can be enabled to communicate based on the third configuration information to avoid the situation where the first DU cannot communicate due to the lack of the third configuration information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a schematic diagram of a communication system provided by the present application;

FIG1b is another schematic diagram of a communication system provided by the present application;

FIG2 a is a schematic diagram of IAB node migration across CUs;

FIG2 b is another schematic diagram of IAB node cross-CU migration;

FIG3 is another schematic diagram of a communication system provided by the present application;

FIG4 is a schematic diagram of a communication method provided by the present application;

FIG5 is another schematic diagram of the communication method provided by the present application;

FIG6 is another schematic diagram of the communication method provided by the present application;

FIG7 is another schematic diagram of the communication method provided by the present application;

FIG8 is another schematic diagram of the communication method provided by the present application;

FIG9 is another schematic diagram of the communication method provided by the present application;

FIG10 is another schematic diagram of the communication method provided by the present application;

FIG11 is another schematic diagram of the communication method provided by the present application;

FIG12 is a schematic diagram of a communication device provided by the present application;

FIG13 is another schematic diagram of a communication device provided by the present application;

FIG14 is another schematic diagram of a communication device provided by the present application;

FIG. 15 is another schematic diagram of the communication device provided in the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

First, some terms in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

(1) Terminal device: It can be a wireless terminal device that can receive network device scheduling and instruction information. The wireless terminal device can be a device that provides voice and/or data connectivity to users, or a handheld device with wireless connection function, or other processing devices connected to a wireless modem.

The terminal equipment can communicate with one or more core networks or the Internet via the radio access network (RAN). The terminal equipment can be a mobile terminal equipment, such as a mobile phone (or "cellular" phone, mobile phone), a computer and a data card. For example, it can be a portable, pocket-sized, handheld, computer-built-in or vehicle-mounted mobile device that exchanges voice and/or data with the radio access network. For example, personal communication service (PCS) phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDA), tablet computers (Pad), computers with wireless transceiver functions and other devices. Wireless terminal equipment can also be called system, subscriber unit, subscriber station, mobile station, mobile station (MS), remote station, access point (AP), remote terminal equipment (remote terminal), access terminal equipment (access terminal), user terminal equipment (user terminal), user agent (user agent), subscriber station (SS), customer premises equipment (CPE), terminal, user equipment (UE), mobile terminal (MT), etc.

As an example but not limitation, in the embodiments of the present application, the terminal device may also be a wearable device. Wearable devices may also be referred to as wearable smart devices or smart wearable devices, etc., which are a general term for the application of wearable technology to intelligently design and develop wearable devices for daily wear, such as glasses, gloves, watches, clothing and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also powerful functions achieved through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include full-featured, large-sized, and independent of smartphones to achieve complete or partial functions, such as smart watches or smart glasses, etc., as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various types of smart bracelets, smart helmets, smart jewelry, etc.

The terminal can also be a drone, a robot, a terminal in device-to-device (D2D) communication, a terminal in vehicle to everything (V2X), a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc.

In addition, the terminal device may also be a terminal device in a communication system that evolves after the fifth generation (5th generation, 5G) communication system (e.g., a sixth generation (6th generation, 6G) communication system, etc.) or a terminal device in a future-evolved public land mobile network (PLMN), etc. Exemplarily, the 6G network can further expand the form and function of the 5G communication terminal, and the 6G terminal includes but is not limited to a car, a cellular network terminal (with integrated satellite terminal function), a drone, and an Internet of Things (IoT) device.

(2) Network equipment: It can be equipment in a wireless network. For example, the network equipment can be a RAN node (or device) that connects a terminal device to a wireless network, which can also be called a base station. At present, some examples of RAN equipment are: base station gNB (gNodeB) in a 5G communication system, transmission reception point (TRP), evolved Node B (eNB), radio network controller (RNC), Node B (NB), home base station (e.g., home evolved Node B, or home Node B, HNB), base band unit (BBU). In addition, in a network structure, the network equipment can include a centralized unit (CU) node, a distributed unit (DU) node, or a RAN device including a CU node and a DU node.

The network device may be any other device that provides wireless communication functions for the terminal device. The embodiments of the present application do not limit the specific technology and specific device form used by the network device. For the convenience of description, the embodiments of the present application do not limit.

In the embodiment of the present application, the device for realizing the function of the network device may be a network device, or may be a device capable of supporting the network device to realize the function, such as a chip system, which may be installed in the network device. In the technical solution provided in the embodiment of the present application, the technical solution provided in the embodiment of the present application is described by taking the device for realizing the function of the network device as an example that the network device is used as the device.

(3) Configuration and pre-configuration: In this application, configuration and pre-configuration are used at the same time. Configuration refers to the network device/server sending some parameter configuration information or parameter values to the terminal through messages or signaling, so that the terminal can determine the communication parameters or resources during transmission based on these values or information. Pre-configuration is similar to configuration, and can be parameter information or parameter values pre-negotiated between the network device/server and the terminal device, or parameter information or parameter values used by the base station/network device or terminal device specified by the standard protocol, or parameter information or parameter values pre-stored in the base station/server or terminal device. This application does not limit this.

Furthermore, these values and parameters can be changed or updated.

(4) Paging: The paging sent by the network device to the terminal device has two main functions: one is paging (for example, for the terminal device in the RRC idle state (RRC_IDLE) and the RRC inactive state (RRC_INACTIVE)), and the other is system message update (for example, for the terminal device in the RRC connected state (RRC_CONNECTED)).

Generally, the content of the Paging message (paging message) is sent to the terminal device through the physical downlink service channel (PDSCH) resource location, and the PDSCH resource is indicated by the P-RNTI (where P-RNTI is a fixed value for the entire network) scrambled PDCCH. In other words, in order to obtain the Paging message, the terminal device must first wake up periodically to monitor the PDCCH channel scrambled by P-RNTI, and then parse the DCI to further obtain the time-frequency location of the PDSCH channel. The terminal device parses the content of the Paging message at the corresponding PDSCH channel location. The DCI field contains fields such as short message indicator and short message.

Optionally, for the short message field in the DCI, if the network device sends paging to the terminal device only for paging, this field is reserved (or has no effect, the terminal device will ignore this field). Short message is mainly used to indicate system information updates other than paging. After receiving the system message update indication in the short message field in the DCI, the terminal device will receive new system messages in the next modification period.

In addition, the frequency domain resources occupied by the Paging message are specified by the PDCCH scrambled by P-RNTI. In the time domain, the terminal device will try to receive the Paging message at the PO of a specific frame (called PF) within its Paging cycle, so the network device needs to send the Paging message from the air interface at this moment, so that the terminal device can receive the Paging message at this moment. PF is a radio frame, which may contain one or more POs. PO is a collection of PDCCH monitoring occasions, which may contain multiple slots (or frames, subframes, symbols, etc.), on which there may be a PDCCH scrambled by P-RNTI and indicating the Paging message. When discontinuous reception (DRX) is used, the terminal device needs to detect 1 PO in each DRX cycle (DRX cycle), that is, for each terminal device, there is 1 PO in each Paging cycle that can be used to send Paging. Among them, DRX cycle and Paging cycle are the same concept.

Optionally, the PF and PO used for paging are determined in the following manner.

The system frame number of PF (denoted as (SFN+PF_offset) mod T) is determined by:
(SFN+PF_offset) mod T = (T div N) * (UE_ID mod N);

The index of PO (denoted as i_s) is determined by:
i_s = floor(UE_ID/N) mod Ns;

The meaning of each parameter is shown in Table 1 below:

Table 1

From the above content, it can be seen that: the system message update can be indicated by the short message field in the DCI used to indicate the frequency domain position of the paging message. In addition, the PF and PO of each terminal device are related to its own UE_ID. Generally, in order to save power, the terminal device will detect PDCCH on the PF and PO related to its own UE_ID, receive DCI, and then receive the paging message. In particular, when DRX is configured, the terminal device will only receive in one PO in a DRX cycle. The network device knows the PO of each terminal device. When the network device wants to page a terminal device, it will send a Paging message in the time domain resources of its corresponding PO. If the network device wants to broadcast system message updates to all terminal devices, it will send a Paging message in the PO time domain resources of all terminal devices.

(5) Integrated access and backhaul (IAB) technology.

IAB technology can use wireless transmission solutions for both access links (Access Link) and backhaul links (Backhaul Link), which can reduce fiber optic deployment; and can meet the needs of increased network capacity, wider coverage, ultra-high reliability and ultra-low latency.

In the IAB network, the relay node, or IAB-node, can provide wireless access services for terminal devices. The service data of the terminal device is transmitted by the IAB-node to the IAB host (IAB-donor) through the wireless backhaul link. The IAB-node consists of an MT part and a DU part. When the IAB-node faces its parent node, it can act as a terminal device, that is, the role of MT; when the IAB-node faces its child node (the child node may be another IAB-node, or an ordinary terminal device), it is regarded as a network device, that is, the role of DU. The IAB-donor is an access network element with complete base station (such as gNB) functions, including CU and DU. The IAB-donor is connected to the core network that serves the terminal device (for example, connected to the 5G core network).

The IAB network will be introduced below in conjunction with the implementation examples shown in FIG. 1a and FIG. 1b .

FIG. 1a is a schematic diagram of a wireless relay scenario.

In the IAB network shown in FIG1a, the terminal devices include UE1 and UE2, and the IAB nodes include IAB Node 1 to IAB Node 5, and an IAB donor node. One or more IAB-nodes may be included in a transmission path between any UE and an IAB-donor. Each IAB-node needs to maintain a wireless backhaul link to the parent node, and also needs to maintain a wireless link with the child node. If the child node of the IAB-node is a terminal device (such as UE1 or UE2 in FIG1a), the wireless access link is between the IAB-node and the child node (ie, the UE). If the child node of the IAB-node is another IAB-node, the wireless backhaul link is between the IAB-node and the child node (ie, the other IAB-node). For example, in Figure 1a, in the path "UE1→IAB-node4→IAB-node3→IAB-node1→IAB-donor", UE1 accesses IAB-node4 through a wireless access link, IAB-node4 is connected to IAB-node3 through a wireless backhaul link, IAB-node3 is connected to IAB-node1 through a wireless backhaul link, and IAB-node1 is connected to IAB-donor through a wireless backhaul link.

As shown in FIG. 1b , it is a schematic diagram of realizing a wireless relay scenario through standalone (SA) networking.

As shown in Figure 1b, the communication nodes include the 5G core network (5G core, 5GC), the 5G access network equipment (denoted as gNodeB in the figure), the IAB-donor, and one or more IAB-nodes. In Figure 1b, the IAB-node DU (hereinafter simply referred to as IAB-DU) is logically connected to the IAB-donor CU (hereinafter simply referred to as CU) through the F1 interface. In fact, the connection between the IAB-DU and the CU is realized through the NR Uu interface between the IAB-node MT and the parent node DU of each hop, but because the IAB-DU can communicate with the CU in the end, it can be considered that the F1 interface exists logically.

Optionally, the F1 interface supports a user plane protocol (F1-user plane, F1-U) and a control plane protocol (F1-control plane, F1-C), wherein the user plane protocol includes one or more of the following protocol layers: general packet radio service tunneling protocol user plane (GTP-U), user datagram protocol (UDP), internet protocol (IP) and other protocol layers. The control plane protocol includes one or more of the following: F1 application protocol (F1AP), stream control transport protocol (SCTP), IP and other protocol layers. Through F1-C, interface management, IAB-DU management, and UE context-related configuration can be performed between the IAB-donor and the IAB-node. Through F1-U, user plane data transmission can be performed between the IAB-donor and the IAB-node, and Downlink transmission status feedback and other functions.

(6) Inter-CU migration: In the IAB network, for any IAB node between the terminal device and the IAB-donor node, inter-CU migration is supported.

Among them, in the switching scenario of cross-CU migration, the IAB node where the migration occurs can be called a boundary node, and the cross-CU migration is divided into two scenarios: partial migration and full migration, depending on whether an F1 connection needs to be established with the target CU.

The following will introduce the scenarios shown in Figures 2a and 2b respectively.

As shown in FIG. 2 a , it is an implementation example of a switching process of partial migration, where the boundary node is IAB-node2.

Before switching, the communication link between the terminal device and the source CU (denoted as CU1 in the figure) passes through IAB-node4 (including IAB-MT4 and IAB-DU4 in the figure), IAB-node2 (including IAB-MT2 and IAB-DU2 in the figure), IAB-node1 (including IAB-MT1 and IAB-DU1 in the figure) and Donor-DU1.

After the switch, the communication link between the terminal device and the source CU (denoted as CU1 in the figure) passes through IAB-node4 (including IAB-MT4 and IAB-DU4 in the figure), IAB-node2 (including IAB-MT2 and IAB-DU2 in the figure), IAB-node3 (including IAB-MT3 and IAB-DU3 in the figure) and Donor-DU1 respectively.

In the implementation example shown in Figure 2a, before partial migration, there is an RRC connection between IAB-MT2 and CU1, an F1 interface between IAB-DU2 and CU1, and IAB-node2 and IAB-donor communicate through the source path (through IAB-node1 composed of IAB-MT1 and IAB-DU1). During partial migration, IAB-MT2 undergoes cross-CU cell switching and establishes an RRC connection with CU2. However, in order to avoid introducing the re-establishment process of the F1 interface, IAB-DU2 still maintains the F1 interface with CU1 and does not establish the F1 interface with CU2. Therefore, the communication path between CU1 and IAB-DU2 becomes cross-topology: In Figure 2a, CU1 and CU2 are respectively called the terminating CU on the F1 interface (F1-terminating CU) and the non-terminating CU on the F1 interface (non-F1-terminating CU). It should be noted that data does not pass through CU2 when transmitted on this path. CU1 and Donor-DU2 communicate directly through the IP network.

As shown in FIG. 2 b , it is an implementation example of the switching process of the entire migration, and the boundary node is IAB-node3.

Before switching, the communication link between the terminal device and the source CU (denoted as CU1 in the figure) passes through IAB-DU3a and IAB-MT3 in IAB-node3 (including IAB-MT3, IAB-DU3a and IAB-DU3b in the figure), IAB-node1 (including IAB-MT1 and IAB-DU1 in the figure) and Donor-DU1.

After the switch, the communication link between the terminal device and the source CU (denoted as CU1 in the figure) passes through IAB-DU3b and IAB-MT3 in IAB-node3 (including IAB-MT3, IAB-DU3a and IAB-DU3b in the figure), IAB-node2 (including IAB-MT2 and IAB-DU2 in the figure) and Donor-DU1. The path after the switch can be called the target path.

In the scenario example of full migration shown in Figure 2b, the F1 interface between IAB-DU3 and CU1 needs to be migrated to CU2. Since the protocol does not support the simultaneous existence of F1 interfaces between one DU and two CUs, in order to implement the switching process, IAB-DU3 is expanded into two logical DUs, namely IAB-DU3a and IAB-DU3b. IAB-DU3a always maintains the F1 interface with CU1, while IAB-DU3b is used to establish a new F1 interface with CU2. DU3a and DU3b can be regarded as two DUs, each with an F1 interface. The terminal device needs to perform a switch from the cell under IAB-DU3a to the cell under IAB-DU3b. Full migration includes the following three implementation methods.

Gradual Top-down. In this implementation, the first few steps are similar to partial migration. First, according to the partial migration process, MT3 is switched to establish cross-topology F1-C and F1-U between DU3a and CU1. When CU2 helps to establish cross-topology F1-C and F1-U between DU3a and CU1, it also establishes F1-C and F1-U between DU3b and CU2. Then the terminal device is switched to DU3b, and the terminal device can communicate with CU2 directly on the target path.

Gradual Bottom-up: In this implementation, first, the cross-topology F1-C and F1-U between DU3b and CU2 are established to enable the terminal device to switch to DU3b, and the control plane and user plane data transmission between DU3b and CU2 through IAB-Node1 and Donor-DU1 are established. After the terminal device switches successfully, a switching command is sent to MT or the switching command of MT is effective, and then F1-C/F1-U is established on the target path, so that the traffic of the terminal device can be migrated to the target path.

Full Nested: This implementation is similar to Gradual Bottom-up. First, a cross-topology F1-C is established between DU3b and CU2 (only cross-topology F1-C is established to allow CU2 to switch the terminal device to DU3b when making a switching decision, but cross-topology F1-U is not established, and cross-topology data transmission is not performed), so that the terminal device can be allowed to switch to DU3b. After sending the switching command, the switching command is immediately sent to the MT or the switching command of the MT is effective, and then F1-C/F1-U is directly established on the target path so that the traffic of the terminal device can be migrated to the target path.

From the above implementation example, we can see that in partial migration, MT switches across CUs, but DU still maintains an F1 connection with the source CU; while in full migration, DU needs to establish an F1 connection with the target CU.

Optionally, in a migration scenario for IAB nodes based on load balancing, partial migration can be used. By switching MT, the F1 interface can be transmitted over a different path without changing the anchor point of the F1 interface.

Optionally, in a migration scenario caused by IAB node movement, when the IAB node moves over a large range, it is inappropriate to maintain an F1 connection with the source CU, and the anchor point of the F1 connection also needs to be changed to the target CU. Therefore, full migration may be a required feature of mobile IAB.

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

In this application, unless otherwise specified, the same or similar parts between the various embodiments can refer to each other. In the various embodiments in this application, and the various methods/designs/implementations in each embodiment, if there is no special description and logical conflict, the terms and/or descriptions between different embodiments and the various methods/designs/implementations in each embodiment are consistent and can be referenced to each other. The technical features in different embodiments and the various methods/designs/implementations in each embodiment can be combined to form new embodiments, methods, or implementations according to their inherent logical relationships. The implementation methods of this application described below do not constitute a limitation on the scope of protection of this application.

FIG3 is a schematic diagram of the architecture of a communication system 1000 used in an embodiment of the present application.

As shown in FIG3 , the communication system includes a wireless access network 100 and a core network 200. Optionally, the communication system 1000 may also include the Internet 300. The wireless access network 100 may include at least one wireless access network device (which may also be understood as a network device introduced in the foregoing text, such as 110a and 110b in FIG3 ), and may also include at least one terminal (which may also be understood as a terminal device introduced in the foregoing text, such as 120a-120j in FIG3 ). In addition, the wireless access network device may be a macro base station (such as 110a in FIG3 ), a micro base station or an indoor station (such as 110b in FIG3 ), or a relay node or a donor node, etc. It can be understood that all or part of the functions of the wireless access network device in the present application may also be implemented by software functions running on hardware, or by virtualization functions instantiated on a platform (such as a cloud platform). The embodiments of the present application do not limit the specific technology and specific device form adopted by the wireless access network device.

For the convenience of description, a base station is used as a wireless access network device, and a terminal device is recorded as a terminal as an example for description. It can be understood that when the communication system includes an IAB network, the base station can be an IAB node.

In this application, the base station and the terminal can be fixed or movable. The base station and the terminal can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted, or on the water surface, or on aircraft, balloons, and artificial satellites in the air. The embodiments of this application do not limit the application scenarios of the base station and the terminal.

The roles of the base station and the terminal may be relative. For example, the helicopter or drone 120i in FIG. 3 may be configured as a mobile base station. For the terminal 120j that accesses the wireless access network 100 through 120i, the terminal 120i is a base station. However, for the base station 110a, 120i is a terminal, that is, 110a and 120i communicate through a wireless air interface protocol. Of course, 110a and 120i may also communicate through an interface protocol between base stations. In this case, relative to 110a, 120i is also a base station. Therefore, base stations and terminals may be collectively referred to as communication devices. 110a and 110b in FIG. 3 may be referred to as communication devices with base station functions, and 120a-120j in FIG. 3 may be referred to as communication devices with terminal functions.

Communication between base stations and terminals, between base stations and base stations, and between terminals and terminals can be carried out through authorized spectrum, unauthorized spectrum, or both. Communication can be carried out through spectrum below 6 gigahertz (GHz), spectrum above 6 GHz, or spectrum below 6 GHz and spectrum above 6 GHz at the same time. The embodiments of the present application do not limit the spectrum resources used for wireless communication.

In the embodiments of the present application, the functions of the base station may also be performed by a module (such as a chip) in the base station, or by a control subsystem including the base station function. The control subsystem including the base station function here may be a control center in the application scenarios of the above-mentioned terminals such as smart grid, industrial control, smart transportation, smart city, etc. The functions of the terminal may also be performed by a module (such as a chip or a modem) in the terminal, or by a device including the terminal function.

In this application, the base station sends a downlink signal (or downlink information) to the terminal, and the downlink signal (or downlink information) is carried on a downlink channel. The terminal sends an uplink signal (or uplink information) to the base station, and the uplink signal (or uplink information) is carried on an uplink channel.

It should be understood that the present application can be applied to a long term evolution (LTE) system, a new radio (NR) system, or a communication system evolved after 5G (such as 6G, etc.). The communication system includes a network device and a terminal device.

In a communication system, after a terminal device accesses a cell, the cell accessed by the terminal device can be switched by cell switching. Before the cell switching is performed, the cell accessed by the terminal device can be called a source cell, and after the cell switching is performed, the cell accessed by the terminal device can be called a target cell. In the process of implementing the cell switching, after the source cell detects that the signal quality between the source cell and the terminal device has deteriorated, it can send a switching message carrying the configuration information of the target cell, so that the terminal device can access the target cell based on the configuration information of the target cell after receiving the message.

In a possible implementation, the network device can send CHO configuration information that needs to be triggered based on a measurement event to the terminal device before the signal quality deteriorates, so that after the terminal device determines that the signal quality has deteriorated locally based on the measurement event, the terminal device performs cell switching based on the CHO configuration information, which can speed up the switching speed of the terminal device and, to a certain extent, avoid the switching failure that may be caused by the switching preparation only after the signal quality deteriorates in the traditional switching process. However, this implementation still positions the triggering method of cell switching in the scenario of signal quality deterioration, and when the signal quality between the terminal device and the source cell has not deteriorated (for example, in the scenario shown in FIG. 2b, the IAB node where the source cell is located undergoes cross-CU migration and the newly configured cell in the IAB-DU3b corresponding to the target CU is enabled, or the IAB node where the source cell is located needs to schedule the terminal device to connect to other cells in the IAB node, or the IAB node where the source cell is located determines that the source cell is to be closed or deactivated, etc.), the CHO configuration information triggered based on the measurement event will not take effect, and still cannot achieve the effect of improving the cell switching speed to improve the cell switching success rate.

In summary, how to improve the execution speed of cell switching in order to improve the success rate of cell switching is a technical problem that needs to be solved urgently.

In order to solve the above problems, the present application provides a communication method and related devices for saving the overhead of triggering the cell switching process, improving the execution speed of the cell switching, and thereby improving the success rate of the cell switching.

Please refer to FIG. 4 , which is a schematic diagram of an implementation of the communication method provided in the present application. The method includes the following steps.

S401. The source CU determines the first message.

In this embodiment, the source CU determines a first message in step S401, where the first message includes switching configuration information of N cells, where N is a positive integer, and the switching configuration information is used for a cell switching process triggered by a second message.

S402. The source CU sends a first message to the terminal device.

In this embodiment, the source CU sends a first message to the terminal device through the IAB node in step S402, and correspondingly, the terminal device receives the first message in step S402.

In a possible implementation, the target DU is located at the IAB node. Specifically, when the IAB node to which the terminal device is connected includes the source DU where the source cell is located, and the target DU where the target cell is located is located at the IAB node where the source DU is located, the solution can be applied to the scenario where the terminal device performs cell switching between different DUs in the same IAB node (or the scenario where the IAB node undergoes cross-CU migration and the target cell corresponding to the target CU is enabled).

Optionally, the target DU may also be located at other IAB nodes.

In a possible implementation, the first message sent by the source CU in step S402 further includes at least one of the following: a first indication message Information indicating that the switching configuration information is used for the cell switching process triggered by the second message; or, second indication information indicating that the second message is monitored on all POs. Specifically, the first message containing the switching configuration information of N cells may also include at least one of the above-mentioned indication information, indicating that the switching configuration information is used for the cell switching process triggered by the second message by displaying the indication information, and/or indicating that the second message is monitored on all POs, so that the terminal device can clearly determine the execution of the cell switching based on the indication information carried by the display.

Optionally, the second message is a broadcast message. Specifically, the switching configuration information carried by the first message is used for the cell switching process triggered by the second message, that is, the second message is used to trigger the terminal device to perform the cell switching process, so that the implementation method of the second message being a message sent in a broadcast manner (i.e., a broadcast message) can trigger multiple terminal devices to perform cell switching based on the scheduling of the broadcast message to save overhead. In addition, the sending speed of the second message can be increased, in order to increase the speed at which multiple terminal devices perform cell switching based on the broadcast message trigger.

Optionally, the value of N is 1. Specifically, when the value of N is 1, the implementation method in which the first message includes the switching configuration information of a certain cell can save the overhead of the first message and also reduce the overhead of the terminal device monitoring signals of multiple cells during the cell switching process.

In a possible implementation, the handover configuration information included in the first message sent by the source CU in step S402 is conditional handover (CHO) configuration information. Optionally, when the handover configuration information included in the first message is CHO configuration information, the trigger condition corresponding to the CHO configuration information is triggered based on the second message. In addition, the CHO configuration information is the name of the handover configuration information for executing cell handover based on the trigger condition in the current standard/protocol. In future standards/protocols, the CHO configuration information may have other names, which are not limited here.

In a possible implementation, before step S401, the method further includes: after the source CU determines that the target DU has established an F1 connection with the target CU, the source CU sends a switching request message of the terminal to the target CU; the source CU receives a switching response message from the target CU, and the switching response message includes the switching configuration information. Specifically, after the source CU determines that the target DU has established an F1 connection with the target CU, the source CU determines that the cell under the target DU can be used as a potential target cell. To this end, the source CU can obtain the switching configuration information through the interaction of the switching request message and the switching response message with the target CU, so that the source CU can subsequently send a first message containing the switching configuration information to the terminal device.

Optionally, the source CU determines that the target DU has established an F1 connection with the target CU, including: the source CU determines that the target DU has established an F1 connection with the target CU based on third indication information from the target CU, and the third indication information indicates that the terminal device performs a cell switch based on the switching configuration information. Specifically, the source CU can determine that the target DU has established an F1 connection with the target CU through the third indication information sent by the target CU, and further determine that the terminal device can successfully perform a cell switch to the target DU based on the switching configuration information.

In a possible implementation, when any of the following conditions is met, the source CU sends the first message in step S402, including:

After the source CU sends a first handover request message to the target CU, the source CU receives a first handover response message from the target CU, where the first handover response message includes handover configuration information of N cells (for ease of reference in the following text, this method is referred to as method A);

After the source CU sends a second handover request message to the target CU, the source CU receives a second handover response message from the target CU, where the second handover request message includes identifiers of N cells, and the N cells are inactivated cells (for ease of reference in the following text, this method is referred to as method B); or,

After the source CU receives the first configuration information from the target DU and sends the first configuration information to the target CU, it receives the switching configuration information of N cells from the target CU, and the switching configuration information of the N cells includes the first configuration information and the second configuration information (for ease of reference below, this method is recorded as method C).

In the above-mentioned method A, when the source CU determines that the target DU has established an F1 connection with the target CU, the source CU and the target CU can interact through the first handover request message and the first handover response message, so that the source CU can obtain the handover configuration information of the N cells under the target DU. Accordingly, after the source CU obtains the configuration information of the N cells, the source CU can send a packet to the terminal device in step S402. The first message contains the configuration information of the N cells.

It can be understood that in mode A, the moment when the F1 connection between the target CU and the target DU is completed is before the moment when the source CU sends the configuration information to the terminal device in step S402, and this solution can be applied to the full nested and gradual bottom-up processes of full migration. At this time, the target DU is ready, and the N cells under the target DU can be configured as potential target cells of the terminal device in the first message.

In the above-mentioned method B, when the source CU determines that the target DU may need to switch to the target CU, the source CU may determine that the N cells under the target CU are potential target cells of the terminal device. To this end, the source CU and the target CU may interact through a first switching request message and a second switching response message to inform the target CU that the target DU may switch to the target CU. After that, the source CU may send a first message containing the configuration information of the N cells to the terminal device in step S402.

It is understandable that, in mode B, the moment when the F1 connection between the target CU and the target DU is completed is after the moment when the source CU sends the configuration information to the terminal device in step S402, and this solution can be applied to the gradual top-down process of full migration. Exemplarily, in the gradual top-down, the F1 connection between the target DU and the target CU is established almost at the end. If you want to get the gain of the configuration information of N cells configured in advance, you need to send the first message containing the configuration information of N cells in advance. At the time of sending the first message in step S402, the N cells in the target DU have not been activated, and the real switching preparation process cannot be performed at present.

In the above-mentioned method C, when the source CU determines that the target DU may need to switch to the target CU, the source CU may obtain the first configuration information from the target DU and send the first configuration information to the target CU to inform the target CU that the target DU may switch to the target CU, so that the target CU determines the configuration information of N cells based on the first configuration information and sends it to the source CU. Accordingly, after the source CU obtains the configuration information of the N cells, the source CU may send a first message containing the configuration information of the N cells to the terminal device in step S402.

Optionally, in mode C, the first configuration information includes radio link control (radio link control, RLC) layer configuration information and/or media access control (media access control, MAC) layer configuration information, and the second configuration information includes packet data convergence protocol (packet data convergence protocol, PDCP) layer configuration information and/or service data adaptation protocol (service data adaptation protocol, SDAP) layer configuration information. Specifically, when an F1 connection has not been established between the target DU and the target CU, the target DU can send the first configuration information (including RLC and/or MAC layer configuration information) to the target CU through the source CU, so that the target CU determines the switching configuration information (including RLC and/or MAC configuration information, and PDCP and/or SDAP configuration information) of the N cells under the target DU based on the first configuration information, and the target CU can send the switching configuration information of the N cells to the terminal device through the source CU in the form of a first message.

It can be understood that, similar to method B, the moment when the F1 connection between the target CU and the target DU is completed is after the moment when the source CU sends the configuration information to the terminal device in step S402. This solution can be applied to the gradual top-down process of full migration.

In the traditional switching scheme, the RRC reconfiguration message (carrying the CHO switching command) sent by the source CU to the terminal device needs to carry the RLC layer, MAC layer configuration, and PDCP layer and SDAP layer configuration after the target cell (for example, the cell group configuration (CellGroupConfig) information element in the RRC reconfiguration message carries the RLC layer and MAC layer configuration of the target cell, and the radio bearer configuration (RadioBearerConfig) information element in the RRC reconfiguration message includes the PDCP layer and SDAP layer configuration after the terminal device reaches the target cell). In other words, the terminal device needs to know the configuration of multiple protocol stacks after switching to the target cell. However, the RLC layer and MAC layer configurations need to be generated by the target DU, and the higher-layer PDCP layer and SDAP layer need to be generated by the target CU. When no F1 connection is established between the target DU and the target CU, the technical solution provided by method C is required to enable the terminal device to obtain the RLC layer, MAC layer configuration, and PDCP layer and SDAP layer configurations.

In method C, an F1 connection is established between the target DU and the source CU so that the first configuration information of the N cells in the target DU can be sent to the source CU, and then sent to the target CU via the source CU. After the second configuration information is added at the target CU, the complete configuration information of the N cells is sent to the source CU (for example, the configuration information of the N cells is carried in a radio resource control container (RRC Container)), and then the source CU sends a first message containing the configuration information of the N cells to the terminal device in step S402.

Specifically, when at least one of the above-mentioned methods A, B and C is met, the source CU determines that the cell under the target DU will be used as a potential target cell. To this end, the source CU can send a first message containing switching configuration information of N cells to the terminal device. The switching configuration information of N cells is sent before the switching conditions are met, so that when it is subsequently determined that the terminal device needs to be scheduled to switch to the N cells and the scheduling message is sent, the signaling consumption of the scheduling message can be saved, thereby improving the success rate of cell switching.

S403. The source CU sends a second message to the terminal device.

In this embodiment, the source CU sends a second message to the terminal device in step S403, and correspondingly, the terminal device receives the second message in step S403.

In a possible implementation, the second message sent by the source CU in step S403 includes the first information, which is carried in any one of the following: a short message field in the downlink control information (DCI) of the physical downlink control channel (PDCCH) scrambled by the paging radio network temporary identifier (P-RNTI); information in the paging occasion (PO); or, any broadcast information of N cells. Specifically, the second message can be implemented by any of the above items. In other words, the source cell or N cells can trigger the terminal device to perform cell switching by any of the above methods to improve the flexibility of the solution implementation.

In a possible implementation, when at least one of the following conditions is met, the source CU sends the second message to the terminal device in step S403, including: the source CU determines that the target DU has established an F1 connection with the target CU; the source CU determines that the mobile terminal (mobile termination, MT) in the IAB node is about to switch to the target CU; or the source CU receives an indication from the target CU to allow the terminal device to perform a cell switch based on the switching configuration information. Specifically, when at least one of the above conditions is met, the source CU determines that the terminal device is currently able to perform a cell switch and successfully switch to the N cells under the target DU. To this end, the source CU may send a second message to the terminal device, so that the terminal device triggers the execution of a cell switch based on the received second message.

S404. The terminal device performs cell switching.

In this embodiment, after the terminal device receives the second message in step S403, the cell switching process of step S404 is triggered, that is, the terminal device is triggered to perform cell switching based on the switching configuration information received in step S402.

Based on the technical solution shown in FIG4 , the terminal device receives a first message including switching configuration information of N cells in step S402, and the switching configuration information is used for a cell switching process triggered by a second message. Thereafter, after receiving the second message in step S403, the terminal device performs cell switching based on the switching configuration information in step S404. Compared with the implementation method in which the switching message for triggering the execution of cell switching carries the configuration information of the target cell, the terminal device can obtain the switching configuration information for the cell switching process triggered by the second message in advance, and can trigger the execution of cell switching based on the switching configuration information after receiving the second message. Thus, in the case of determining that the terminal device needs to be scheduled to execute cell switching, the second message for triggering the execution of cell switching sent to the terminal device does not need to carry the switching configuration information of the target cell, which can save the overhead of the triggering process and improve the execution speed of the cell switching, so as to improve the success rate of the cell switching.

In a possible implementation, in the implementation shown in FIG4 , the process of the source CU sending the first message in step S402 and/or the process of the source CU sending the second message in step S403 may need to rely on the indication of the target CU. The following will be described in detail based on the implementation shown in FIG5 .

Please refer to FIG5 , which is a schematic diagram of an implementation of the communication method provided in the present application. The method includes the following steps.

S501. The target CU determines third indication information.

In this embodiment, the target CU determines the third indication information in step S501, where the third indication information is used to indicate that the terminal device is allowed to The cell switching is performed according to the switching configuration information, and the target DU includes N cells, where N is a positive integer.

S502. The target CU sends third indication information to the source CU.

In this embodiment, after the target CU determines the third indication information in step S501, the target CU sends the third indication information to the source CU in step S502.

In a possible implementation, the target CU sends the third indication information to the source CU in step S502, including: after the target CU determines that the target DU has been configured with the context of the terminal device, the target CU sends the third indication information to the source CU. Specifically, after the target CU determines that the target DU has been configured with the context of the terminal device, the target CU can determine that the terminal device can access the network through the N cells included in the target DU. For this purpose, the target CU can send the third indication information to the source CU, so that the source CU schedules the terminal device to perform cell switching based on the third indication information from the target CU.

In a possible implementation, before the target CU sends the third indication information to the source CU in step S502, the method also includes: the target CU receives a second switching request message from the source centralized unit CU, the second switching request message includes the identifiers of N cells and the N cells are unactivated cells; wherein the N cells are located in the target DU; the target CU sends a second switching response message to the source CU, the second switching response message includes the switching configuration information of the N cells. Specifically, before the target CU sends the third indication information to the source CU, the target CU and the source CU can interact through the second switching request message and the second switching response message, so that after the target CU determines the corresponding switching configuration information based on the N unactivated cells, the target CU sends the switching configuration information to the terminal device through the source CU, so that the terminal device can subsequently execute the cell switching process corresponding to the switching configuration information based on the triggering of the second message.

In a possible implementation, before the target CU sends the third indication information to the source CU, the method also includes: after the target CU receives the first configuration information from the source centralized unit CU, the target CU sends the switching configuration information of N cells to the source CU, and the switching configuration information of the N cells includes the first configuration information and the second configuration information. Specifically, when an F1 connection has not yet been established between the target DU and the target CU, the target DU can send the first configuration information (including RLC and/or MAC layer configuration information) to the target CU through the source CU, so that the target CU determines the switching configuration information of the N cells under the target DU based on the first configuration information (including RLC and/or MAC configuration information, and PDCP and/or SDAP configuration information), and the target CU can send the switching configuration information of the N cells to the terminal device through the source CU in the form of a first message, so that the terminal device can subsequently perform the cell switching process corresponding to the switching configuration information based on the triggering of the second message.

It should be noted that the above implementation method can refer to the implementation process of method A to method C in the embodiment of Figure 4 above, and achieve corresponding technical effects, which will not be repeated here.

In addition, the embodiment shown in FIG5 is an optional implementation process of the embodiment shown in FIG4 , and the source CU receiving the third indication information in step S502 can be used as a trigger condition for the source CU to trigger the execution of step S504, that is, the execution order of step S502 is before step S504. Alternatively, the source CU receiving the third indication information in step S502 can be used as a trigger condition for the source CU to trigger the execution of step S505, that is, the execution order of step S502 is before step S505.

S503. The source CU determines the first message.

In this embodiment, the source CU determines a first message in step S503, where the first message includes switching configuration information of N cells, where N is a positive integer, and the switching configuration information is used for a cell switching process triggered by a second message.

S504. The source CU sends a first message to the terminal device.

In this embodiment, the source CU sends a first message to the terminal device in step S504, and correspondingly, the terminal device receives the first message in step S504.

S505. The source CU sends a second message to the terminal device.

In this embodiment, the source CU sends a second message to the terminal device in step S505, and correspondingly, the terminal device receives the second message in step S505.

S506. The terminal device performs cell switching.

In this embodiment, after the terminal device receives the second message in step S505, the cell switching process of step S506 is triggered, that is, the terminal device is triggered to perform cell switching based on the switching configuration information received in step S505.

It should be noted that the implementation process of step S503 to step S506 can refer to the implementation process of the aforementioned step S401 to step S404, and achieve corresponding technical effects, which will not be repeated here.

Based on the technical solution shown in FIG5 , after the target CU determines that an F1 connection has been established with the target DU, the target CU can determine that the terminal device can switch to the N cells contained in the target DU based on the cell switching process. To this end, the target CU sends a third indication information to the source CU indicating that the terminal device is allowed to perform cell switching based on the switching configuration information, so that the source CU can determine that the terminal device can be triggered to perform cell switching based on the third indication information. Among them, the switching configuration information is used for the cell switching process triggered by the second message, so that the terminal device can subsequently trigger the cell switching based on the switching configuration information after receiving the second message, in order to improve the success rate of cell switching. Compared with the implementation method in which the switching message that triggers the execution of cell switching carries the configuration information of the target cell, when the source CU determines that the terminal device needs to be scheduled to perform cell switching based on the third indication information from the target CU, the second message that triggers the execution of cell switching sent to the terminal device does not need to carry the switching configuration information of the target cell, which can save the overhead of the triggering process and improve the execution speed of the cell switching, in order to improve the success rate of the cell switching.

Please refer to FIG6 , which is a schematic diagram of an implementation of the communication method provided in the present application. The method includes the following steps.

S601. The source CU determines the first message.

In this embodiment, the source CU determines a first message in step S503, where the first message includes handover configuration information of N cells, where N is a positive integer.

S602. The source CU sends a first message to the terminal device.

S603. The terminal device ignores or deletes the switching configuration information.

In this embodiment, when the terminal device receives indication information indicating cancellation of the cell switching process corresponding to the switching configuration information or determines that the second message is not received, the terminal device determines to ignore or delete the switching configuration information received in step S602.

Specifically, the source CU sends an indication message to the terminal device indicating the cancellation of the cell switching process corresponding to the switching configuration information. The terminal device can obtain the switching configuration information for the cell switching process triggered by the second message in advance, and can determine to ignore or delete the switching configuration information based on the scheduling of the source CU (for example, the source CU does not send the second message, or the source CU sends an indication message to cancel the cell switching, etc.), that is, the terminal device can determine not to perform the cell switching based on the scheduling of the network device to avoid the failure of the cell switching.

It should be noted that the handover configuration information is used for the cell handover process triggered by the second message, or the handover configuration information is CHO configuration information triggered by a measurement event. Wherein, in the case where the handover configuration information is used for the cell handover process triggered by the second message, the implementation process of step S601 and step S602 can refer to the implementation process of step S401 to step S402 shown in the aforementioned FIG. 4, and achieve the corresponding technical effect, which will not be described in detail here.

Based on the technical solution shown in FIG6 , the terminal device receives a first message including the switching configuration of N cells in step S602, and the terminal device determines in step S603 that the second message (the second message is used to trigger the cell switching process corresponding to the switching configuration information) has not been received or determines that the indication information indicating the cancellation of the cell switching process corresponding to the switching configuration information has been received, and then ignores or deletes the switching configuration information. Compared with the implementation method in which the cell switching is triggered when the terminal device receives a switching message carrying the configuration information of the target cell, the terminal device can obtain the switching configuration information for the cell switching process triggered based on the second message in advance, and can determine to ignore or delete the switching configuration information based on the scheduling of the network device (for example, the network device does not send the second message, or the network device sends the indication information to cancel the cell switching, etc.), that is, the terminal device can determine not to perform the cell switching based on the scheduling of the network device to avoid the failure of the cell switching.

It can be seen from the implementation methods shown in Figures 4 to 6 above that the above technical solution can be applied to the scenario where cross-CU migration occurs at the IAB node where the source DU connected to the terminal device is located. For the source CU, there may be multiple relationships between the moment when the N cells under the target DU are activated (or the target DU has obtained the UE context configuration of the terminal device) and the moment when the terminal device obtains the switching configuration information of the N cells.

For example, the moment when the former occurs may be before the moment when the latter occurs (such as the aforementioned method A). This situation will be exemplarily described in the scenario shown in FIG. 2 b in combination with the example shown in FIG. 7 .

For another example, the time when the former occurs may be after the time when the latter occurs (such as the aforementioned method B and method C). This situation will be exemplified in the scenario shown in FIG. 2 b in combination with the examples shown in FIG. 8 and FIG. 9 .

It should be understood that in the embodiments of Figures 7 to 9 below, the terminal device is recorded as UE, the source CU is recorded as CU1, the target CU is recorded as CU2, the source DU is DU3a and the target DU is DU3b for illustration.

Please refer to FIG. 7 , which is a schematic diagram of an implementation of the communication method provided in the present application. The method includes the following steps.

1. CU2 sends an F1 connection response message to the IAB node. Correspondingly, the IAB node receives the F1 connection response message from CU2 in this step.

In step 1, the F1-C interface between DU3b and CU2 is established, and CU2 sends an F1SETUP RESPONSE message to DU3b.

2. CU2 sends third indication information to CU1. Correspondingly, CU1 receives the third indication information from CU2 in this step.

In step 2, CU2 informs CU1 that DU3b is ready to send a handover request for the UE (not limited to a CHO handover request).

3. The UE sends a measurement report to CU1. Accordingly, CU1 receives the measurement report from the UE in this step.

In step 3, CU1 receives the measurement report from the UE. This step is optional because DU3b and DU3a are logical DUs under the same physical DU, and the cells under DU3b may correspond to the cells under DU3a. In this case, the target cell of the UE can be directly specified without measurement.

Optionally, step 3 is an optional step.

4. CU1 sends a switching request message to CU2. Correspondingly, CU2 receives the switching request message from CU1 in this step.

5.CU2 admission control.

6. CU2 sends a handover response message to CU1. Correspondingly, CU1 receives a handover response message from CU2 in this step.

Steps 4 to 6 are the CHO handover preparation process of the UE between CU1 and CU2.

7. CU1 sends a first message to the UE. Correspondingly, the UE receives the first message from CU1 in this step.

In step 7, CU1 sends a first message to the UE, where the first message may be an RRC message (may be carried in a CHO handover command message). Optionally, the RRC message carries at least one of the following information:

1) Inform the UE that this CHO will be triggered by broadcast; and/or

2) If there is a corresponding relationship between the cells under DU3b and DU3a, directly specify a unique target cell for each UE under DU3b.

Here, 1) contains two layers of information. First, it informs the UE that this CHO will be triggered, which is different from the traditional CHO based on self-judgment. Second, it informs the UE that this CHO will be triggered by broadcast, not unicast. The above two layers of information may not appear at the same time, and the hierarchy needs to be reflected when writing the authority.

8.UE monitoring.

After receiving the RRC message in step 7, the UE monitors the PDCCH on all possible PFs and POs. In other words, step 7 may also optionally instruct the UE to monitor the PDCCH on all possible PFs and POs.

9. The IAB node sends a measurement report to CU1. Correspondingly, CU1 receives the measurement report from the IAB node in this step.

10. CU1 determines whether MT switching needs to be performed.

In steps 9 to 10, CU1 determines that MT3 meets the switching condition based on the measurement report of MT3.

Optionally, steps 9 to 10 are optional steps.

11. CU1 sends indication information indicating the cancellation of switching to the UE. Correspondingly, the UE receives indication information indicating the cancellation of switching from CU1 in this step.

In step 11, if MT3 still does not meet the switching conditions, it is considered that full migration may not be executed. The network can send an indication message to the UE (for example, the indication message is carried in an RRC message) to inform the UE that the CHO is cancelled and the UE deletes the configuration in the previous CHO switching command.

12. CU1 controls the IAB node to send a second message, and the first information in the second message is carried in the short message field. Correspondingly, the UE receives the second message from CU1 through the IAB node in this step.

In step 12, CU1 broadcasts DCI encrypted with P-RNTI to UE via DU3a, indicating group CHO execution in the short message field.

13. CU1 controls the IAB node to send the short message field, which is used to indicate the time domain position of PO. Correspondingly, in this step, the UE receives the short message field carried in the DCI from CU1 through the IAB node.

14. CU1 controls the IAB node to send a second message, in which the first information is carried in the PO. Correspondingly, in this step, the UE receives the second message from CU1 through the IAB node.

CU1 broadcasts DCI encrypted with P-RNTI to UE via DU3a in step 13, indicating system information update in the short message field, and then CU1 instructs group CHO execution in the updated system message in step 14.

It can be understood that the broadcast scheme enables all UEs under DU3a to receive the message, and the reserved bit of the short message field can be used to indicate the execution of group CHO, or after the UE receives the system message update through paging, the group CHO execution can be indicated in the new system message.

It should also be noted that in steps 9-10, MT3 may have reached the switching condition, but the execution order of MT3 switching and steps 12-14 is not limited here. Although according to the full nested and gradual bottom-up processes, the UE needs to be switched before MT3 switching, but the implementation scenario is not limited to the three processes of full nested/gradual bottom-up/gradual top-down. It may also appear that "DU3b and CU2 establish a cross-topology F1 interface - MT3 switching - DU3a and CU1 establish a cross-topology F1 interface, and the F1 interface between DU3b and CU2 migrates from cross-topology to same topology". At this time, MT3 may switch first and then instruct UE to perform CHO. In short, steps 11-12 may be before MT3 switching or after MT3 switching, as long as the F1 connection between DU3a and CU1 and the F1 connection between DU3b and CU2 exist.

It is understandable that in steps 12 to 14, the network side triggers CHO execution in the form of broadcast, because if CHO execution is instructed in the form of unicast at this time, CHO may have a small gain. The source of CHO gain is the advance configuration of UE, and the UE directly executes when it determines that switching is required. Considering that the UE may not be able to judge by itself, the network side uses broadcast to send the CHO execution instruction message to multiple UEs at one time to obtain more gain.

15. A cell handover is performed between the UE and the IAB node.

The UE initiates random access to the target cell under DU3b. If step 7 (2) exists, the UE directly accesses the designated target cell, otherwise the UE selects the target cell to access based on the measurement results of the cells under DU3b.

As can be seen from the embodiment shown in FIG. 7 , this embodiment provides a situation where the F1-C interface of DU3b is issued before the CHO configuration of the UE (applicable to the full nested and gradual bottom-up processes of full migration). At this time, DU3b is ready, and the cell under DU3b can be configured as a potential target cell of the UE in the CHO switching command. Among them, the network side sends a broadcast message to the UE to trigger the CHO execution, which reduces the execution time of the full migration process. In addition, this embodiment solves the problem that in the vehicle-mounted mobile IAB scenario, the UE cannot judge the CHO execution by itself because there is no relative motion between the UE and the vehicle-mounted IAB node, and enables the execution of UE CHO during the vehicle-mounted mobile IAB migration.

Please refer to FIG8 , which is a schematic diagram of an implementation of the communication method provided in the present application. The method includes the following steps.

1. CU1 sends a handover request message to CU2. Accordingly, CU2 receives the handover request message from CU1 in this step.

In step 1, CU1 sends a handover request (HO REQUEST) message about UE CHO to CU2, in which the target cell identifier under DU3b corresponds to the target cell that has not been activated. Since DU3b and DU3a belong to the same entity DU, the identifier of the cell to be activated under DU3b may be pre-configured, and IAB-node3 may inform CU1 of it (the signaling of informing CU1 of the identifier of the cell to be activated under DU3b is protected by other patents). Therefore, CU1 may carry the identifier of the target cell that has not been activated in the HO REQUEST and inform CU2 that the target cell is not activated.

2.CU2 admission control.

In step 2, CU2 performs admission control, but does not perform UE context configuration for DU3b because the F1 interface with DU3b has not been established.

3. CU2 sends a handover response message to CU1. Correspondingly, CU1 receives a handover response message from CU2 in this step.

4. CU1 sends a first message to the UE through the IAB node. Correspondingly, the UE receives the first message from CU1 in this step.

In step 4, it is substantially the same as step 7 in the embodiment shown in Fig. 7. Optionally, if the first message sent in step 4 carries the target cell identifier, the target cell corresponding to the target cell identifier is not yet activated.

5. The MT in the IAB node performs the handover.

6. The DU in the IAB node establishes an F1 connection with CU2.

In step 6, an F1 interface is established between DU3b and CU2 under the topology of CU2. After the F1 interface of DU3b is established, CU2 configures the UE context to DU3b according to the UE context obtained in step 1.

7. CU2 sends third indication information to CU1. Correspondingly, CU1 receives the third indication information from CU2 in this step.

In step 7, after CU2 completes configuring the UE context to DU3b, it sends third indication information to inform CU1 that the CHO of the UE can be executed.

8. CU1 controls the IAB node to send a second message, and the first information in the second message is carried in the short message field. Correspondingly, the UE receives the second message from CU1 through the IAB node in this step.

9. CU1 controls the IAB node to send the short message field, which is used to indicate the time domain position of the PO. Correspondingly, the UE receives the short message field carried on the DCI from CU1 through the IAB node in this step.

10. CU1 controls the IAB node to send a second message, in which the first information is carried in the PO. Correspondingly, the UE receives the second message from CU1 through the IAB node in this step.

The implementation shown in steps 8 to 10 may refer to the implementation shown in steps 12 to 14 in the implementation shown in FIG. 7 .

It should be understood that the implementation shown in FIG. 8 can also support the implementation of canceling the switching configuration shown in step 11 of the implementation shown in FIG. 7 , and the implementation process thereof can refer to the aforementioned embodiment.

11. The UE detects any broadcast message of the N cells. Accordingly, the N cells send broadcast messages in this step.

In step 11, the UE detects the signal under DU3b, and triggers CHO execution. In this embodiment, since DU3b is activated later and the UE's CHO switching command is issued earlier than the activation of DU3b, it is allowed to perform CHO switching once the UE detects the signal under DU3b.

12. A cell handover is performed between the UE and the IAB node.

The implementation shown in step 12 may refer to the implementation shown in step 15 in the implementation shown in FIG. 7 .

This embodiment shows the situation that the UE's CHO configuration is sent before the establishment of the F1-C interface of DU3b (applicable to the gradual top-down process of full migration). In the gradual top-down, the F1-C interface of DU3b is established almost at the end. If you want to get the gain of CHO, you need to send the UE's CHO switching command before the MT3 switching. At this time, the target cell under DU3b has not been activated, and the real switching preparation process cannot be carried out. Among them, the network side sends a broadcast message to the UE to trigger the CHO execution, or the UE triggers the CHO execution when it detects the signal of DU3b, which reduces the execution time of the full migration process. In addition, this embodiment solves the problem that in the vehicle-mounted mobile IAB scenario, the UE cannot judge the CHO execution by itself because there is no relative motion between the UE and the vehicle-mounted IAB node, and enables the execution of UE CHO during the migration of the vehicle-mounted mobile IAB.

Please refer to FIG9 , which is a schematic diagram of an implementation of the communication method provided in the present application. The method includes the following steps.

1. An F1 connection is established between the IAB node and CU1.

In step 1, the F1 interface is established between DU3b and CU1, but in the F1SETUP RESPONSE message sent by CU1 to DU3b.

Optionally, do not activate any cell under DU3b. At this time, the cells under DU3b do not need to be activated, because the F1 interface established between DU3b and CU1 is only for receiving the underlying configuration information of per UE from CU1, and is not really ready to accept the UE switching to DU3b. If the subsequent steps adopt step 11 in the embodiment shown in Figure 8, the N cells under DU3b should not be activated at this time.

2. CU1 requests the IAB node for first configuration information. Accordingly, the IAB node receives the request from CU1 in this step.

In step 2, CU1 configures the UE context to DU3b through F1AP and sends a UE CONTEXT SETUP REQUEST message.

3. The IAB node sends the first configuration information to CU1. Correspondingly, CU1 receives the first configuration information from the IAB node in this step.

In step 3, DU3b generates the underlying configuration information of the UE (i.e., the first configuration information) and sends it to CU1 through the UE CONTEXT SETUP RESPONSE message.

4. CU1 sends the first configuration information to CU2. Accordingly, CU2 receives the first configuration information from CU1 in this step.

In step 4, CU1 sends the lower-level configuration information of DU3b to CU2. Because CU2 is the CU with which DU3b will eventually establish the F1 interface, the higher-level configuration information (ie, the second configuration information) of the UE under DU3b needs to be generated by CU2.

5. CU2 sends the handover configuration information of N cells to CU1. Correspondingly, CU1 receives the handover configuration information of N cells from CU2 in this step.

In step 5, CU2 combines the bottom layer configuration information of DU3b received in step 4 with the high layer configuration information and sends it to RRC Container Sent to CU1.

6. CU1 sends a first message to the UE. Accordingly, the UE receives the first message from CU1 in this step.

In step 6, CU1 sends an RRC reconfiguration message (CHO handover command) to the UE, carrying the complete protocol stack configuration information of the UE in the target cell.

7. The F1 connection between DU3b and CU1 in the IAB node is released.

8. The MT in the IAB node performs the handover.

In step 8, MT3 switches to the target cell under CU2.

9. DU3b in the IAB node establishes an F1 connection with CU2.

In step 9, DU3b re-establishes the F1 interface with CU2 and activates the cell.

Thereafter, the UE, the IAB node, CU1 and CU2 execute steps 7 to 12 shown in FIG. 8 .

In the traditional handover preparation process, the source CU sends a HANDOVER REQUEST to the target CU, and then the target CU sends a UE CONTEXT SETUP REQUEST to the target DU. The target DU returns a UE CONTEXT SETUP RESPONSE (carrying the underlying configuration) to the target CU. The target CU combines the underlying configuration reported by the DU with the high-level configuration generated by itself, and returns it to the source CU through the RRC Container in the HANDOVER REQUEST ACKNOWLEDGE message. The source CU then sends an RRC reconfiguration message (handover command) to the UE, transparently transmitting the information in the RRC Container. In this embodiment, since DU3b cannot directly establish an F1 interface with CU2, it is proposed to use CU1 as a transfer station so that DU3b reports the underlying configuration to CU1, and then CU1 informs CU2. In the embodiment shown in FIG9 , it is necessary to establish an F1 interface between DU3b and CU1 before MT3 switching, so as to achieve communication between DU3b and CU2 through the F1 interface between DU3b and CU1 and the interface between CU1 and CU2 (such as the XN interface).

In this embodiment, before MT3 switching, an F1 interface is established between DU3b and CU1. Through the F1 interface between DU3b and CU1, and the interface between CU1 and CU2 (such as the XN interface), CU1 can obtain the complete protocol stack configuration of the UE under DU3b, and then send a CHO switching command to the UE. In addition, this embodiment solves the problem that the UE cannot be configured with a complete protocol stack under DU3b when DU3b has not established an F1 interface with CU2, so that UE CHO can be performed under the premise of performing the full migration of the IAB node in a gradual top-down manner.

In the IAB network, when the configuration information for the DU in the IAB node to communicate needs to be sent down, it is generally necessary to obtain it from the host node through the MT in the IAB node. However, if the MT in the IAB node fails to obtain the third configuration information in time (for example, the MT and the first DU are respectively connected to different CUs for communication, or the MT and the first DU are switched to the same CU but the switching timing of the MT is later than the switching timing of the first DU, etc.), it may cause the DU in the IAB node to fail to communicate normally. The following will use Figures 10 and 11 and related embodiments provided by this application to solve this problem.

Please refer to FIG. 10 , which is a schematic diagram of an implementation of the communication method provided in the present application. The method includes the following steps.

S1001. The first CU determines third configuration information.

In this embodiment, the first CU determines third configuration information in step S1001, where the third configuration information includes third configuration information of the first DU; wherein the first DU is located in an IAB node, and the IAB node also includes a second DU and an MT.

S1002. The first CU sends third configuration information to the IAB node.

In this embodiment, after the first CU determines the third configuration information in step S1001, the first CU sends the third configuration information to the IAB node in step S1002, and correspondingly, the IAB node receives the third configuration information in step S1002.

In a possible implementation, the third configuration information sent by the first CU in step S1002 is carried in an F1 application protocol (F1AP) message, or the third configuration information sent by the first CU in step S1002 is carried in an RRC message. Specifically, the first CU can send the third configuration information to the IAB node in a variety of ways. Among them, the third configuration information can be transmitted through the F1 connection between the second DU and the first CU in the IAB node, that is, the third configuration information can be carried in the F1AP message on the F1 connection. Alternatively, the third configuration information can be transmitted through the RRC connection between the MT and the first CU in the IAB node, that is, the third configuration information can be carried in the RRC message on the RRC connection.

In one possible implementation, the third configuration information sent by the first CU in step S1002 includes at least one of the following: a new radio cell global identifier (NCGI), a CU identifier for determining the NCGI, or a first key for the first DU to establish an encrypted communication with other CUs for an F1 connection, or a physical cell identifier of a cell in the first DU. (physical cell identifier, PCI).

Optionally, the third configuration information sent by the first CU in step S1002 may include configuration information of the first DU and other communication nodes (such as CU or other IAB nodes or terminal devices, etc.), and the configuration information may include the above-mentioned NCGI, used to determine the CU identifier of NCGI, PCI, or other configuration information, which is not limited here.

In a possible implementation, after the first CU sends the third configuration information to the IAB node in step S1002, the method further includes: the first CU receives fourth indication information, and the fourth indication information is used to indicate that the third configuration information of the first DU has taken effect, or to indicate that the first CU sends a switching command to the terminal device connected to the second DU, or to indicate that the first DU has sent a third message determined based on the third configuration information. Specifically, when the first DU is able to communicate based on the third configuration information, the first DU may also send indication information to the first CU so that the first CU knows that the third configuration information has taken effect on the first DU, and the first CU may subsequently schedule the first DU and/or the terminal device connected to the first DU based on the third configuration information.

In one possible implementation, the third message includes a synchronization signal/physical broadcast channel PBCH block (SS/PBCH block) (which may be referred to as SS/PBCH block or SSB for short) sent by the first DU to the terminal device, or an F1 connection establishment request message sent by the first DU to other CUs.

Exemplarily, the information that may be included in the third configuration information will be introduced below through some implementation examples.

In the implementation example where the third configuration information includes NCGI or the CU identifier of NCGI. NCGI is used to uniquely identify a cell globally and can be carried in the System Information Block 1 (SIB1) message broadcast by the DU and received by the UE. NCGI is composed of the gNB ID of the F1 anchor CU and the cell ID of the cell under the DU. The cell ID of DU3b is pre-configured to IAB-node3. Therefore, when the F1 anchor CU of DU3b is determined, the NCGI of the cell under DU3b after activation can be determined. In partial migration, since the IAB-DU has not replaced the F1 anchor CU, the NCGI will not change. After the introduction of full migration, the NCGI change of the cell under DU3b needs to be considered. This embodiment extends it to the CHO scenario of MT or the scenario where DU and MT migration are decoupled.

In the implementation example where the third configuration information includes PCI. The meaning of PCI is physical cell identifier, which is used to distinguish physical resources of different cells (such as SSB resources). For example, the number of PCIs available in NR is 1008, which is much smaller than the number of NR cells in the world, so PCI needs to be reused to a certain extent. In order to avoid interference between neighboring cells, the PCIs of neighboring cells need to be different. During network planning, the IAB cell was not originally adjacent to other cells, so the same PCI may have been used, but due to mobility, it became a neighboring cell. At this time, there will be a conflict. At this time, the cell under IAB needs to change the PCI. The replacement method is to start a new DU (DU3b), use the new PCI, and then switch the UE from DU3a to DU3b.

In the implementation example where the third configuration information includes the first key. When the IAB-DU communicates with the donor-CU on the F1 interface, the data on the F1 interface needs to be securely encrypted, and its security key (Kiab) is calculated and generated according to the security algorithm, which requires three input parameters: the IP address of the IAB-DU, the IP address of the donor-CU, and the Key of the donor-CU (KgNB) (the Key of the donor-CU or the security key is the first key).

Based on the technical solution shown in FIG. 10 , when there is a communication connection between the first CU and the IAB node (for example, there is a radio resource control (RRC) connection between the first CU and the MT in the IAB node and/or there is an F1 connection between the first CU and the second DU in the IAB node), the first CU can send the third configuration information of the first DU (i.e., other DUs except the second DU) to the IAB node, so that the first DU can communicate based on the third configuration information. Among them, the MT in the IAB node does not need to receive the configuration information from the first CU again through the RRC connection, so that the first DU in the IAB node can obtain the third configuration information and communicate based on the third configuration information. Therefore, in the case where the MT in the IAB node cannot obtain the configuration information from the first CU in time (for example, the case where the MT and the first DU are connected to different CUs for communication, and the case where the MT and the first DU are switched to the same CU but the switching timing of the MT is later than the switching timing of the first DU, etc.), the first DU can be enabled to communicate based on the third configuration information to avoid the situation where the first DU cannot communicate due to the lack of the third configuration information.

As an implementation example of the technical solution shown in FIG10, the implementation method shown in FIG11 is described below. In the embodiment shown in FIG11, the scenario where the MT in the IAB node is configured with CHO or the scenario where the MT in the IAB node is decoupled from the migration of the DU is considered. The core idea of this embodiment is to send the information required by the first DU under the second CU (such as PCI, NCGI, KgNB) in advance. When the IAB-DU determines the second CU or the IAB-node detects a PCI conflict, the IAB-DU determines to use the corresponding information under the second CU. For a scenario triggered based on a PCI conflict, the first CU and the second CU may be the same.

Please refer to FIG. 11 , which is a schematic diagram of an implementation of the communication method provided in the present application. The method includes the following steps.

1. The first CU sends the third configuration information to the IAB node. Correspondingly, the IAB node receives the third configuration information from the first CU in this step.

In step 1, the IAB node is informed in advance of the information (such as NCGI, KgNB, PCI) required by (at least one) first DU under multiple potential second CUs in the RRC message of the MT in the IAB node or the F1AP message of the second DU. The RRC message may be a CHO switching command of MT3. It should be noted that the PCI information usually does not need to come from another CU, as long as the PCI is a PCI that does not conflict with the neighboring area.

Among them, the specific implementation process of the third configuration information can refer to the description of the embodiment shown in the aforementioned Figure 10, and will not be repeated here.

2. The IAB node determines a trigger event, where the trigger event is used to trigger the effectiveness of the third configuration information.

In this embodiment, when the IAB node determines that the triggering event occurs, the first DU in the IAB node determines to take the third configuration information into effect, that is, the first DU in the IAB node executes step 3 and/or step 4.

Optionally, in step 2, the triggering event may include at least one of the following:

When the MT in the IAB node meets the switching condition and needs to switch to the second CU, the first DU in the IAB node determines that the CU establishing the F1 interface is the second CU, or the IAB node detects that the cell PCI of the first DU conflicts with the PCI of a nearby cell.

It should be understood that in the communication system, in order to avoid interference from neighboring cells, the PCI of neighboring cells needs to be different. During network planning, the IAB cell and other cells were not originally adjacent, so they may have used the same PCI, but due to mobility, they became neighboring cells, and there would be conflicts. At this time, the cell under IAB needs to change the PCI. The way to change is to start a new DU (such as the first DU), use the new PCI, and then switch the UE from the second DU to the first DU. Therefore, detecting a PCI conflict can also be used as a condition for the configuration under the first DU to take effect.

Optionally, the IAB node detects that the cell PCI of the first DU conflicts with the PCI of a nearby cell, which may include any of the following implementation processes, for example: the MT in the IAB node detects the PCI of the neighboring cell through neighboring cell measurement, and finds that it is the same as the cell PCI under the second DU; or the second DU in the IAB node obtains information about the PCI conflict through implementation (such as: the current PCI is available within a preconfigured geographical range, and the second DU finds that it has moved to an area where the current PCI is not available based on the positioning device).

3. The IAB node sends a third message to the terminal device. Correspondingly, the terminal device receives the third message from the IAB node in this step.

It should be understood that, in the case where the third configuration information includes configuration information for communicating with the terminal device, the IAB node may send a third message to the terminal device in step 3 based on the configuration information.

4. The IAB node sends a third message to the second CU. Accordingly, CU2 receives the third message from the IAB node in this step.

It should be understood that, in the case where the third configuration information includes configuration information for communicating with the CU, the IAB node may send a third message to the second CU in step 3 based on the configuration information.

5. The IAB node sends indication information to the first CU. Correspondingly, the first CU receives indication information from the IAB node in this step.

Step 5 is an optional step. When the IAB node determines that the third configuration information is effective, the IAB node will send an indication message to the first CU (which can be carried by the RRC message of the MT or the F1AP message of the second DU or the F1AP message of the first DU, wherein the method of using the F1AP of DU3b is only applicable to the scenario where the F1 anchor CU of DU3b and DU3a is the same, that is, the scenario where the PCI is changed above), indicating that the configuration of DU3b has taken effect, or indicating that the UE can be switched to the first DU.

In this embodiment, the third configuration information (such as NCGI, KgNB, PCI) required by the first DU is sent in advance. When the MT in the IAB node or the second DU in the IAB node determines to connect to other CUs, or when the IAB node detects a PCI conflict, the first DU of the IAB node determines to use the corresponding information under the target CU. In order to enable the scenario where the MT is switched through CHO or the migration of the DU and the MT is decoupled, this embodiment can allow the first DU to correctly obtain the required configuration information (such as NCGI, KgNB, PCI) in these two scenarios.

The present application is described above from the perspective of method, and other embodiments provided by the present application will be further described below.

Please refer to Figure 12, which is a schematic diagram of an implementation of the communication device provided in the present application. The communication device 1200 includes a processing unit 1201 and a transceiver unit 1202. The communication device 1200 can implement the functions of the communication device (including terminal equipment, source CU, target CU, first CU or IAB node, etc.) in the above method embodiment, and thus can also achieve the beneficial effects of the above method embodiment. In the embodiment of the present application, the communication device 1200 can be a terminal device (or source CU, target CU, first CU or IAB node, etc.), or it can be a terminal device An integrated circuit or component, such as a chip, inside a terminal device (or source CU, target CU, first CU or IAB node, etc.). The following embodiments are described by taking the communication device 1200 as a terminal device (or source CU, target CU, first CU or IAB node, etc.) as an example.

In one possible implementation, when the device 1200 is used to execute the method executed by the terminal device in the aforementioned embodiment, the device includes a processing unit 1201 and a transceiver unit 1202; the transceiver unit 1202 is used to receive a first message, the first message including switching configuration information of N cells, N is a positive integer, wherein the switching configuration information is used for a cell switching process triggered by a second message; the processing unit 1201 is used to perform cell switching based on the switching configuration information after the transceiver unit 1202 receives the second message.

In one possible implementation, the second message includes first information, and the first information is carried in any one of the following: a short message field in the downlink control information DCI of a physical downlink control channel PDCCH scrambled by a paging radio network temporary identifier P-RNTI; information in a paging opportunity PO; or any broadcast information of N cells.

In a possible implementation, the first message also includes at least one of the following: first indication information, indicating that the switching configuration information is used for a cell switching process triggered based on the second message; or, second indication information, indicating that the second message is monitored on all POs.

In a possible implementation manner, the second message is a broadcast message.

In a possible implementation, the value of N is 1.

In a possible implementation manner, the handover configuration information is conditional handover CHO configuration information.

In one possible implementation, when the device 1200 is used to execute the method executed by the terminal device in the aforementioned embodiment, the device includes a processing unit 1201 and a transceiver unit 1202; the transceiver unit 1202 is used to receive a first message, and the first message includes switching configuration information of N cells, N is a positive integer; the processing unit 1201 is used to ignore or delete the switching configuration information after determining that a second message is not received (the second message is used to trigger the cell switching process corresponding to the switching configuration information) or determining that an indication message indicating cancellation of the cell switching process corresponding to the switching configuration information is received.

In a possible implementation manner, the switching configuration information is used for a cell switching process triggered by a second message.

In a possible implementation manner, the handover configuration information is conditional handover CHO configuration information triggered by a measurement event.

In one possible implementation, when the device 1200 is used to execute the method executed by the source CU in the aforementioned embodiment, the device includes a processing unit 1201 and a transceiver unit 1202; the processing unit 1201 is used to determine a first message, the first message includes switching configuration information of N cells, N is a positive integer, and the switching configuration information is used for a cell switching process triggered by a second message; wherein the N cells are located in the target DU; the transceiver unit 1202 is used to send the first message to the terminal device through an access backhaul integrated IAB node.

In a possible implementation manner, the target DU is located at the IAB node.

In one possible implementation, the transceiver unit 1202 is also used to send a switching request message of the terminal to the target CU after the processing unit 1201 determines that the target DU has established an F1 connection with the target centralized unit CU; the transceiver unit 1202 is also used to receive a switching response message from the target CU, and the switching response message includes the switching configuration information.

In a possible implementation, the transceiver unit 1202 is further configured to send the second message to the terminal device.

In one possible implementation, the transceiver unit 1202 sends the second message to the terminal device when at least one of the following is met, including: the processing unit 1201 determines that the target DU has established an F1 connection with the target CU; the processing unit 1201 determines that the mobile terminal MT in the IAB node is about to switch to the target CU; or, the processing unit 1201 determines that receiving an indication from the target CU allows the terminal device to perform cell switching based on the switching configuration information.

In a possible implementation, the transceiver unit 1202 sends the first message when any of the following items is met, including: the processing unit 1201 determines that after the transceiver unit 1202 sends a first switching request message to the target CU, it receives a first switching response message from the target CU, and the first switching response message includes switching configuration information of N cells; the processing unit 1201 determines that after the transceiver unit 1202 sends a second switching request message to the target CU, it receives a second switching response message from the target CU, and the second switching request message includes the identifiers of N cells and the N cells are unactivated cells; or, the processing unit 1201 determines that after the transceiver unit 1202 receives the first configuration information from the target DU and sends the first configuration information to the target CU, it receives the switching configuration information of N cells from the target CU, and the switching configuration information of the N cells includes the first configuration information and the second configuration information.

In a possible implementation, the first configuration information includes radio link control RLC layer configuration information and/or media access control MAC layer configuration information, and the second configuration information includes packet data convergence protocol PDCP layer configuration information and/or service data adaptation protocol SDAP layer configuration information.

In a possible implementation manner, the determining unit is specifically configured to determine the target DU based on the third indication information from the target CU. An F1 connection has been established with the target centralized unit CU, and the third indication information instructs the terminal device to perform cell switching based on the switching configuration information.

In a possible implementation manner, the second message is a broadcast message.

In a possible implementation, the value of N is 1.

In a possible implementation manner, the method further includes: sending indication information indicating cancellation of the cell handover process corresponding to the handover configuration information.

In one possible implementation, when the device 1200 is used to execute the method executed by the target CU in the aforementioned embodiment, the device includes a processing unit 1201 and a transceiver unit 1202; the processing unit 1201 is used to determine third indication information after determining that an F1 connection has been established with the target distributed unit DU, and the third indication information indicates that the terminal device performs cell switching based on the switching configuration information, and the target DU includes N cells, N is a positive integer; wherein the switching configuration information is used for a cell switching process triggered by a second message; the transceiver unit 1202 is used to send the third indication information to the source CU.

In a possible implementation, the transceiver unit 1202 is specifically used to send the third indication information to the source CU after the processing unit 1201 determines that the target DU has been configured with the context of the terminal device.

In one possible implementation, the transceiver unit 1202 is also used to receive a second switching request message from a source centralized unit CU, wherein the second switching request message includes the identifiers of N cells and the N cells are unactivated cells; wherein the N cells are located in the target DU; the transceiver unit 1202 is also used to send a second switching response message to the source CU, wherein the second switching response message includes the switching configuration information of the N cells.

In a possible implementation, the transceiver unit 1202 is further used to send switching configuration information of N cells to the source centralized unit CU after receiving the first configuration information from the source CU, where the switching configuration information of the N cells includes the first configuration information and the second configuration information.

In one possible implementation, when the device 1200 is used to execute the method executed by the first CU in the aforementioned embodiment, the device includes a processing unit 1201 and a transceiver unit 1202; the processing unit 1201 is used to determine third configuration information, and the third configuration information includes third configuration information of the first centralized unit DU; wherein the first DU is located at an access and backhaul integrated IAB node, and the IAB node also includes a second DU and a mobile terminal MT; the transceiver unit 1202 is used to send the third configuration information to the IAB node.

In a possible implementation manner, the third configuration information is carried in an F1AP message, or the third configuration information is carried in an RRC message.

In one possible implementation, the third configuration information includes at least one of the following: a new wireless cell global identifier NCGI, used to determine the CU identifier of the NCGI, or a first key for the first DU to establish encrypted communication with other CUs for an F1 connection, or a physical cell identifier PCI of a cell in the first DU.

In a possible implementation, the transceiver unit 1202 is also used to receive fourth indication information, where the fourth indication information is used to indicate that the third configuration information of the first DU has taken effect, or to instruct the first CU to send a switching command to a terminal device connected to the second DU.

In one possible implementation, when the device 1200 is used to execute the method executed by the IAB node in the aforementioned embodiment, the device includes a processing unit 1201 and a transceiver unit 1202; the transceiver unit 1202 is used to receive third configuration information, and the third configuration information includes the third configuration information of the first DU; the processing unit 1201 is used to determine a third message, and the third message is obtained based on the third configuration information; the transceiver unit 1202 is also used to send a third message.

In a possible implementation manner, the third configuration information includes at least one of the following: a new wireless cell global identifier NCGI, which is used to identify The CU identifier of the specified NCGI is used for the first DU to establish a first key for encrypted communication of the F1 connection with other CUs, or the physical cell identifier PCI of the cell in the first DU.

In one possible implementation, the transceiver unit 1202 sends a third message when at least one of the following items is met, including: the processing unit 1201 determines that the cell switching execution condition is met, and the target cell corresponding to the cell switching is located in the other CU; the processing unit 1201 determines to establish an F1 connection with the other CU; or the processing unit 1201 determines that the PCI of any cell under the first DU conflicts with other PCIs.

In a possible implementation, the transceiver unit 1202 is also used to send fourth indication information to the first CU, where the fourth indication information is used to indicate that the third configuration information of the first DU has taken effect, or to instruct the first CU to send a switching command to a terminal device connected to the first DU.

In a possible implementation, the third message includes an SSB sent by the first DU to the terminal device, or an F1 connection establishment request message sent by the first DU to other CUs.

It should be noted that the information execution process and other contents of the units of the above-mentioned communication device 1200 can be specifically referred to the description in the method embodiment shown in the above-mentioned application, and will not be repeated here.

Please refer to Fig. 13, which is another schematic structural diagram of a communication device 1300 provided in the present application. The communication device 1300 at least includes an input and output interface 1302. The communication device 1300 may be a chip or an integrated circuit.

Optionally, the communication device also includes a logic circuit 1301.

The transceiver unit 1202 shown in Figure 12 may be a communication interface, which may be the input/output interface 1302 in Figure 13, which may include an input interface and an output interface. Alternatively, the communication interface may also be a transceiver circuit, which may include an input interface circuit and an output interface circuit.

Optionally, when the communication device 1300 is a terminal device (or a component in a terminal device) in the aforementioned embodiment, the input-output interface 1302 is used to receive a first message, the first message including switching configuration information of N cells, N being a positive integer, wherein the switching configuration information is used for a cell switching process triggered by a second message; and the logic circuit 1301 is used to perform cell switching based on the switching configuration information after the input-output interface 1302 receives the second message.

Optionally, when the communication device 1300 is a terminal device (or a component in a terminal device) in the aforementioned embodiment, the input-output interface 1302 is used to receive a first message, which includes switching configuration information of N cells, where N is a positive integer; the logic circuit 1301 is used to ignore or delete the switching configuration information after determining that a second message is not received (the second message is used to trigger the cell switching process corresponding to the switching configuration information) or determining that an indication message indicating cancellation of the cell switching process corresponding to the switching configuration information is received.

Optionally, when the communication device 1300 is the source CU (or a component in the source CU) in the aforementioned embodiment, the logic circuit 1301 is used to determine a first message, which includes switching configuration information of N cells, N is a positive integer, and the switching configuration information is used for a cell switching process triggered by a second message; wherein the N cells are located in the target DU; the input-output interface 1302 is used to send the first message to the terminal device through an access backhaul integrated IAB node.

Optionally, when the communication device 1300 is the target CU (or a component in the target CU) in the aforementioned embodiment, the logic circuit 1301 is used to determine a third indication information after determining that an F1 connection has been established with the target distributed unit DU, and the third indication information instructs the terminal device to perform cell switching based on the switching configuration information, and the target DU includes N cells, where N is a positive integer; wherein the switching configuration information is used for a cell switching process triggered by a second message; and the input-output interface 1302 is used to send the third indication information to the source CU.

Optionally, when the communication device 1300 is the first CU (or a component in the first CU) in the aforementioned embodiment, the logic circuit 1301 is used to determine the third configuration information, and the third configuration information includes the third configuration information of the first centralized unit DU; wherein the first DU is located at the access and backhaul integrated IAB node, and the IAB node also includes a second DU and a mobile terminal MT; the input and output interface 1302 is used to send the third configuration information to the IAB node.

Optionally, when the communication device 1300 is the IAB node (or a component in the IAB node) in the aforementioned embodiment, the input-output interface 1302 is used to receive third configuration information, and the third configuration information includes the third configuration information of the first DU; the logic circuit 1301 is used to determine a third message, and the third message is obtained based on the third configuration information; the input-output interface 1302 is also used to send a third message.

The logic circuit 1301 and the input/output interface 1302 can also execute other steps executed by the network device in any embodiment and implement The corresponding beneficial effects are now omitted here.

In a possible implementation, the processing unit 1201 shown in FIG. 12 may be the logic circuit 1301 in FIG. 13 .

Optionally, the logic circuit 1301 may be a processing device, and the functions of the processing device may be partially or completely implemented by software. The functions of the processing device may be partially or completely implemented by software.

Optionally, the processing device may include a memory and a processor, wherein the memory is used to store a computer program, and the processor reads and executes the computer program stored in the memory to perform corresponding processing and/or steps in any one of the method embodiments.

Alternatively, the processing device may include only a processor. A memory for storing a computer program is located outside the processing device, and the processor is connected to the memory via a circuit/wire to read and execute the computer program stored in the memory. The memory and the processor may be integrated together, or may be physically independent of each other.

Optionally, the processing device may be one or more chips, or one or more integrated circuits. For example, the processing device may be one or more field-programmable gate arrays (FPGA), application specific integrated circuits (ASIC), system on chip (SoC), central processor unit (CPU), network processor (NP), digital signal processor (DSP), microcontroller unit (MCU), programmable logic device (PLD) or other integrated chips, or any combination of the above chips or processors.

Please refer to FIG. 14 , which shows a communication device 1400 involved in the above embodiments provided in an embodiment of the present application. The communication device 1400 may specifically be a communication device as a terminal device in the above embodiments.

Herein, a possible logical structure diagram of the communication device 1400 is shown. The communication device 1400 may include but is not limited to at least one processor 1401 and a communication port 1402 .

Further optionally, the device may also include at least one of a memory 1403 and a bus 1404 . In an embodiment of the present application, the at least one processor 1401 is used to control and process the actions of the communication device 1400 .

In addition, the processor 1401 can be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a transistor logic device, a hardware component or any combination thereof. It can implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. The processor can also be a combination that implements a computing function, such as a combination of one or more microprocessors, a combination of a digital signal processor and a microprocessor, and the like. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the above-described system, device and unit can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

It should be noted that the communication device 1400 shown in Figure 14 can be specifically used to implement the steps implemented by the terminal device in the aforementioned method embodiment, and to achieve the corresponding technical effects of the terminal device. The specific implementation methods of the communication device shown in Figure 14 can refer to the description in the aforementioned method embodiment, and will not be repeated here.

Please refer to FIG. 15, which is a schematic diagram of the structure of the communication device 1500 involved in the above embodiments provided in the embodiments of the present application. The communication device 1500 may specifically be a communication device as a network device (e.g., source CU, target CU, first CU, IAB node, etc.) in the above embodiments. The structure of the communication device may refer to the structure shown in FIG. 15.

The communication device 1500 includes at least one processor 1511 and at least one network interface 1514. Further optionally, the communication device also includes at least one memory 1512, at least one transceiver 1513 and one or more antennas 1515. The processor 1511, the memory 1512, the transceiver 1513 and the network interface 1514 are connected, for example, through a bus. In an embodiment of the present application, the connection may include various interfaces, transmission lines or buses, etc., which are not limited in this embodiment. The antenna 1515 is connected to the transceiver 1513. The network interface 1514 is used to enable the communication device to communicate with other communication devices through a communication link. For example, the network interface 1514 may include a network interface between the communication device and the core network device, such as an S1 interface, and the network interface may include a network interface between the communication device and other communication devices (such as other network devices or core network devices), such as an X2 or Xn interface.

The processor 1511 is mainly used to process the communication protocol and communication data, and to control the entire communication device, execute the software program, and process the data of the software program, for example, to support the communication device to perform the actions described in the embodiment. The communication device may include a baseband processor and a central processing unit. The baseband processor is mainly used to process the communication protocol and communication data, and the central processing unit is mainly used to The processor 1511 in FIG. 15 can integrate the functions of the baseband processor and the central processor. It can be understood by those skilled in the art that the baseband processor and the central processor can also be independent processors, which are interconnected through technologies such as buses. It can be understood by those skilled in the art that the terminal device can include multiple baseband processors to adapt to different network formats, and the terminal device can include multiple central processors to enhance its processing capabilities. The various components of the terminal device can be connected through various buses. The baseband processor can also be described as a baseband processing circuit or a baseband processing chip. The central processor can also be described as a central processing circuit or a central processing chip. The function of processing the communication protocol and the communication data can be built into the processor, or it can be stored in the memory in the form of a software program, and the processor executes the software program to realize the baseband processing function.

The memory is mainly used to store software programs and data. The memory 1512 can be independent and connected to the processor 1511. Optionally, the memory 1512 can be integrated with the processor 1511, for example, integrated into a chip. Among them, the memory 1512 can store program codes for executing the technical solutions of the embodiments of the present application, and the execution is controlled by the processor 1511. The various types of computer program codes executed can also be regarded as drivers of the processor 1511.

FIG15 shows only one memory and one processor. In an actual terminal device, there may be multiple processors and multiple memories. The memory may also be referred to as a storage medium or a storage device, etc. The memory may be a storage element on the same chip as the processor, i.e., an on-chip storage element, or an independent storage element, which is not limited in the embodiments of the present application.

The transceiver 1513 can be used to support the reception or transmission of radio frequency signals between the communication device and the terminal, and the transceiver 1513 can be connected to the antenna 1515. The transceiver 1513 includes a transmitter Tx and a receiver Rx. Specifically, one or more antennas 1515 can receive radio frequency signals, and the receiver Rx of the transceiver 1513 is used to receive the radio frequency signal from the antenna, and convert the radio frequency signal into a digital baseband signal or a digital intermediate frequency signal, and provide the digital baseband signal or the digital intermediate frequency signal to the processor 1511, so that the processor 1511 further processes the digital baseband signal or the digital intermediate frequency signal, such as demodulation processing and decoding processing. In addition, the transmitter Tx in the transceiver 1513 is also used to receive a modulated digital baseband signal or a digital intermediate frequency signal from the processor 1511, and convert the modulated digital baseband signal or the digital intermediate frequency signal into a radio frequency signal, and send the radio frequency signal through one or more antennas 1515. Specifically, the receiver Rx can selectively perform one or more stages of down-mixing and analog-to-digital conversion processing on the RF signal to obtain a digital baseband signal or a digital intermediate frequency signal, and the order of the down-mixing and analog-to-digital conversion processing is adjustable. The transmitter Tx can selectively perform one or more stages of up-mixing and digital-to-analog conversion processing on the modulated digital baseband signal or digital intermediate frequency signal to obtain a RF signal, and the order of the up-mixing and digital-to-analog conversion processing is adjustable. The digital baseband signal and the digital intermediate frequency signal can be collectively referred to as a digital signal.

The transceiver 1513 may also be referred to as a transceiver unit, a transceiver, a transceiver device, etc. Optionally, a device in the transceiver unit for implementing a receiving function may be regarded as a receiving unit, and a device in the transceiver unit for implementing a sending function may be regarded as a sending unit, that is, the transceiver unit includes a receiving unit and a sending unit, and the receiving unit may also be referred to as a receiver, an input port, a receiving circuit, etc., and the sending unit may be referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

It should be noted that the communication device 1500 shown in Figure 15 can be specifically used to implement the steps implemented by the network equipment in the aforementioned method embodiment, and to achieve the corresponding technical effects of the network equipment. The specific implementation methods of the communication device 1500 shown in Figure 15 can refer to the description in the aforementioned method embodiment, and will not be repeated here one by one.

An embodiment of the present application further provides a computer-readable storage medium storing one or more computer-executable instructions. When the computer-executable instructions are executed by a processor, the processor executes the method described in the possible implementation manner of the terminal device in the aforementioned embodiment.

An embodiment of the present application also provides a computer-readable storage medium storing one or more computer-executable instructions. When the computer-executable instructions are executed by a processor, the processor executes the method described in the possible implementation method of the network device (e.g., source CU, target CU, first CU, IAB node, etc.) in the aforementioned embodiment.

An embodiment of the present application also provides a computer program product (or computer program) storing one or more computers. When the computer program product is executed by the processor, the processor executes the method of the possible implementation mode of the above-mentioned terminal device.

An embodiment of the present application also provides a computer program product storing one or more computers. When the computer program product is executed by the processor, the processor executes a method of possible implementation of the above-mentioned network device (such as a source CU, a target CU, a first CU, an IAB node, etc.).

The embodiment of the present application also provides a chip system, which includes at least one processor for supporting a communication device to implement the functions involved in the possible implementation of the above communication device. Optionally, the chip system also includes an interface circuit, which provides program instructions and/or data to the at least one processor. In a possible design, the chip system may also include a memory, The memory is used to store the necessary program instructions and data of the communication device. The chip system can be composed of a chip, or can include a chip and other discrete devices, wherein the communication device can specifically be the terminal device in the above method embodiment.

An embodiment of the present application also provides a chip system, which includes at least one processor for supporting a communication device to implement the functions involved in the possible implementation methods of the above-mentioned communication device. Optionally, the chip system also includes an interface circuit, which provides program instructions and/or data for the at least one processor. In one possible design, the chip system may also include a memory, which is used to store the necessary program instructions and data for the communication device. The chip system may be composed of chips, or may include chips and other discrete devices, wherein the communication device may specifically be a network device (such as a source CU, a target CU, a first CU, an IAB node, etc.) in the aforementioned method embodiment.

An embodiment of the present application also provides a communication system, which includes the terminal device and network device in any of the above embodiments (including at least one of a source CU, a target CU, a first CU, an IAB node, etc.).

In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit. If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a disk or an optical disk.

Claims

A communication method, comprising:

receiving a first message, where the first message includes handover configuration information of N cells, where N is a positive integer, wherein the handover configuration information is used for a cell handover process triggered by a second message;

After receiving the second message, a cell handover is performed based on the handover configuration information.
The method according to claim 1, wherein the second message includes first information, and the first information is carried in any one of the following:

The short message field in the downlink control information DCI of the physical downlink control channel PDCCH scrambled by the paging radio network temporary identifier P-RNTI;

The information in the pager PO; or,

Any broadcast information of the N cells.
The method according to claim 1 or 2, characterized in that the first message further includes at least one of the following:

first indication information, indicating that the switching configuration information is used for a cell switching process triggered by a second message; or,

The second indication information indicates to monitor the second message on all POs.
The method according to claim 3 is characterized in that the second message is a broadcast message.
The method according to any one of claims 1 to 4, characterized in that the value of N is 1.
The method according to any one of claims 1 to 5, characterized in that the switching configuration information is conditional switching CHO configuration information.
A communication method, comprising:

Determine a first message, wherein the first message includes handover configuration information of N cells, where N is a positive integer, and the handover configuration information is used for a cell handover process triggered by the second message; wherein the N cells are located in a target DU;

The first message is sent to the terminal device via the access backhaul integrated IAB node.
The method according to claim 7, characterized in that the target DU is located at the IAB node.
The method according to claim 7 or 8, characterized in that the method further comprises:

After determining that the target DU has established an F1 connection with a target centralized unit CU, sending a handover request message of the terminal to the target CU;

A handover response message is received from the target CU, where the handover response message includes the handover configuration information.
The method according to any one of claims 7 to 9, characterized in that the method further comprises:

Send the second message to the terminal device.
The method according to claim 10, characterized in that when at least one of the following is satisfied, sending the second message to the terminal device comprises:

Determining that the target DU has established an F1 connection with the target CU;

Determine that the mobile terminal MT in the IAB node is to be switched to the target CU; or,

Receiving the indication from the target CU allows the terminal device to perform a cell switch based on the switching configuration information.
The method according to any one of claims 7 to 11, characterized in that sending the first message when any of the following conditions is met comprises:

After sending a first handover request message to the target CU, receiving a first handover response message from the target CU, where the first handover response message includes handover configuration information of the N cells;

After sending a second handover request message to the target CU, receiving a second handover response message from the target CU, where the second handover request message includes identifiers of the N cells and the N cells are unactivated cells; or,

After receiving the first configuration information from the target DU and sending the first configuration information to the target CU, the switching configuration information of the N cells is received from the target CU, and the switching configuration information of the N cells includes the first configuration information and the second configuration information.
The method according to claim 12 is characterized in that the first configuration information includes radio link control RLC layer configuration information and/or media access control MAC layer configuration information, and the second configuration information includes packet data convergence protocol PDCP layer configuration information and/or service data adaptation protocol SDAP layer configuration information.
The method according to any one of claims 9 to 13, characterized in that the determining that the target DU has established an F1 connection with the target CU comprises:

Based on the third indication information from the target CU, it is determined that the target DU has established an F1 connection with the target CU, and the third indication information instructs the terminal device to perform cell switching based on the switching configuration information.
The method according to any one of claims 7 to 14, characterized in that the second message includes first information, and the first information is carried in any one of the following:

The short message field in the downlink control information DCI of the physical downlink control channel PDCCH scrambled by the paging radio network temporary identifier P-RNTI;

The information in the pager PO; or,

Any broadcast information of the N cells.
The method according to any one of claims 7 to 15, characterized in that the first message further includes at least one of the following:

first indication information, indicating that the switching configuration information is used for a cell switching process triggered by a second message; or,

The second indication information indicates to monitor the second message on all POs.
The method according to claim 16, characterized in that the second message is a broadcast message.
The method according to any one of claims 7 to 17, characterized in that the value of N is 1.
The method according to any one of claims 7 to 18, characterized in that the method further comprises:

Send indication information to the terminal device indicating cancellation of the cell switching process corresponding to the switching configuration information.
A communication method, comprising:

After determining that an F1 connection has been established with the target distributed unit DU, determining third indication information, wherein the third indication information instructs the terminal device to perform cell switching based on the switching configuration information, the target DU includes the N cells, N is a positive integer; wherein the switching configuration information is used for a cell switching process triggered by the second message;

Send the third indication information to the source CU.
The method according to claim 20, characterized in that the sending the third indication information to the source CU comprises:

After determining that the target DU has configured the context of the terminal device, the third indication information is sent to the source CU.
The method according to claim 20 or 21, characterized in that before sending the third indication information to the source CU, the method further comprises:

receiving a second handover request message from a source centralized unit CU, wherein the second handover request message includes identifiers of N cells and the N cells are unactivated cells; wherein the N cells are located in the target DU;

A second handover response message is sent to the source CU, where the second handover response message includes handover configuration information of the N cells.
The method according to claim 20 or 21, characterized in that before sending the third indication information to the source CU, the method further comprises:

After receiving the first configuration information from a source centralized unit CU, the switching configuration information of the N cells is sent to the source CU, where the switching configuration information of the N cells includes the first configuration information and the second configuration information.
The method according to claim 23 is characterized in that the first configuration information includes radio link control RLC layer configuration information and/or media access control MAC layer configuration information, and the second configuration information includes packet data convergence protocol PDCP layer configuration information and/or service data adaptation protocol SDAP layer configuration information.
A communication device, characterized in that it comprises a processing unit and a transceiver unit;

Wherein, the processing unit and the transceiver unit are used to execute the method described in any one of claims 1 to 24.
A communication device, characterized in that it comprises at least one processor, wherein the at least one processor is coupled to a memory;

The memory is used to store programs or instructions;

The at least one processor is configured to execute the program or instruction so that the communication device implements the method according to any one of claims 1 to 24.
A communication system, characterized in that the system includes at least two communication devices among a communication device for executing the method described in any one of claims 1 to 6, a communication device for executing the method described in any one of claims 7 to 19, and a communication device for executing the method described in any one of claims 20 to 24.
A computer-readable storage medium, characterized in that the readable storage medium stores instructions, and when the instructions are executed by a computer, the method according to any one of claims 1 to 24 is implemented.
A computer program product, characterized in that the program product comprises instructions, and when the instructions are executed on a computer, the computer is caused to execute the method according to any one of claims 1 to 24.