Communication method and device

Abstract

An embodiment of the present application provides a communication method and apparatus. The method includes: a relay device obtains handover conditions of a plurality of preset cells from a first cell. For any cell i among the plurality of preset cells, the handover condition of the cell i is the handover condition for the relay device to hand over from the first cell to the cell i; when the relay device meets the handover condition of a second cell, the relay device establishes a connection with the second cell, and the second cell is any one of the plurality of preset cells; the relay device sends first indication information to a terminal device, and the first indication information indicates that the relay device establishes a connection with the second cell. The solution of the embodiment of the present application can enable the terminal device to know the completion status of the cell handover of the relay device and the finally selected target cell, so that the terminal device can interact with the switched second cell through the relay device.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of communication technologies, and in particular, to a communication method and apparatus. Background Art

[0002] In a wireless communication system, in order to improve the transmission coverage range, a relay device may be introduced between a terminal and a base station. The relay device can forward the data of the terminal to the base station and forward the data of the base station to the terminal.

[0003] Since the relay device is movable, when the connection between the relay device and the terminal remains unchanged and the relay device and the base station move relative to each other, the relay device and the terminal need to perform a group handover, switching from one base station to another base station while maintaining the connection relationship between the relay device and the terminal unchanged. When a group handover is required, the signals of the relay device and the base station are usually already poor. To avoid the relay device not receiving the handover command, the current solution is to use conditional handover, that is, to send the handover command to the relay device in advance, and the handover command includes multiple possible target base stations and corresponding handover conditions. The relay device does not immediately perform the handover operation, but performs the handover only when the handover condition is met.

[0004] The above solution can avoid the problem of handover failure caused by the relay device not receiving the handover command. However, since both the trigger of the handover and the selection of the target base station are determined by the relay device, the terminal cannot know which target base station is finally selected. Summary of the Invention

[0005] Embodiments of the present application provide a communication method and apparatus to solve the problem that the terminal device cannot know which target cell is finally selected during the group handover process.

[0006] In a first aspect, embodiments of the present application provide a communication method, including:

[0007] The relay device obtains handover conditions of multiple preset cells from a first cell. For any cell i among the multiple preset cells, the handover condition of the cell i is the handover condition for the relay device to switch from the first cell to the cell i;

[0008] When the relay device meets the handover condition of a second cell, the relay device establishes a connection with the second cell, and the second cell is any one of the multiple preset cells;

[0009] The relay device sends first indication information to the terminal device, and the first indication information indicates that the relay device establishes a connection with the second cell.

[0010] In a possible implementation manner, the first indication information includes an identifier of the second cell.

[0011] In a possible implementation, the relay device obtains handover conditions of a plurality of preset cells from a first cell, including:

[0012] The relay device obtains a Radio Resource Control (RRC) message from the first cell, and the handover conditions of the plurality of preset cells are included in the RRC message.

[0013] In a possible implementation, configuration information of each of the plurality of preset cells is further included in the RRC message; establishing a connection between the relay device and the second cell includes:

[0014] The relay device obtains the configuration information of the second cell according to the RRC message;

[0015] The relay device establishes a connection with the second cell according to the configuration information of the second cell.

[0016] In a possible implementation, before the relay device establishes a connection with the second cell, the method further includes:

[0017] The relay device sends second indication information to the terminal device, and the second indication information indicates that the relay device starts to perform an operation of handing over from the first cell to one of the plurality of preset cells.

[0018] In a possible implementation, the handover condition of the second cell is:

[0019] The signal strength between the relay device and the second cell is greater than or equal to a preset strength.

[0020] In a possible implementation, the method further includes:

[0021] The relay device receives data from the terminal device and sends the data to the second cell.

[0022] In a second aspect, an embodiment of the present application provides a communication method, including:

[0023] The terminal device receives first indication information from the relay device, and the first indication information indicates that the relay device hands over from a first cell to a second cell and establishes a connection with the second cell;

[0024] The terminal device sends data to the second cell through the relay device according to the first indication information.

[0025] In a possible implementation, an identifier of the second cell is included in the first indication information.

[0026] In a possible implementation, before the terminal device receives the first indication information from the relay device, the method further includes:

[0027] The terminal device receives second indication information from the relay device, where the second indication information indicates that the relay device starts to perform an operation of switching from the first cell to one of a plurality of preset cells, and the second cell is one of the plurality of preset cells.

[0028] In a third aspect, an embodiment of the present application provides a communication method, including:

[0029] The relay device obtains handover conditions of a plurality of preset cells from the first cell. For any cell i among the plurality of preset cells, the handover condition of the cell i is the handover condition for the relay device to switch from the first cell to the cell i;

[0030] When the relay device meets any one of the handover conditions of the plurality of preset cells, the relay device sends second indication information to the terminal device, where the second indication information indicates that the relay device starts to perform an operation of switching from the first cell to one of a plurality of preset cells;

[0031] The relay device establishes a connection with a second cell, where the second cell is one of the plurality of preset cells, and the relay device meets the handover condition of the second cell.

[0032] In a possible implementation, the relay device obtaining handover conditions of a plurality of preset cells from the first cell includes:

[0033] The relay device obtains a radio resource control (RRC) message from the first cell, and the RRC message includes the handover conditions of the plurality of preset cells.

[0034] In a possible implementation, the RRC message further includes configuration information of each cell among the plurality of preset cells; and the relay device establishing a connection with the second cell includes:

[0035] The relay device obtains the configuration information of the second cell according to the RRC message;

[0036] The relay device establishes a connection with the second cell according to the configuration information of the second cell.

[0037] In a possible implementation, the handover condition of the second cell is:

[0038] The signal strength between the relay device and the second cell is greater than or equal to a preset strength.

[0039] In a possible implementation manner, after the relay device establishes a connection with the second cell, the method further includes:

[0040] The relay device sends first indication information to the terminal device, and the first indication information indicates that the relay device establishes a connection with the second cell.

[0041] In a possible implementation manner, the identifier of the second cell is included in the first indication information.

[0042] In a possible implementation manner, the method further includes:

[0043] Receive data from the terminal device and send the data to the second cell.

[0044] In a fourth aspect, an embodiment of the present application provides a communication method, including:

[0045] The terminal device receives second indication information from the relay device, and the second indication information indicates that the relay device starts to perform an operation of switching from the first cell to one of a plurality of preset cells;

[0046] The terminal device stops sending data to the first cell through the relay device according to the second indication information.

[0047] In a possible implementation manner, the method further includes:

[0048] The terminal device receives first indication information from the relay device, and the first indication information indicates that the relay device switches from the first cell to the second cell and establishes a connection with the second cell, and the second cell is one of the plurality of preset cells;

[0049] The terminal device sends data to the second cell through the relay device according to the first indication information.

[0050] In a possible implementation manner, the identifier of the second cell is included in the first indication information.

[0051] In a fifth aspect, an embodiment of the present application provides a communication device, including:

[0052] An acquisition module, configured to acquire handover conditions of a plurality of preset cells from a first cell. For any cell i among the plurality of preset cells, the handover condition of the cell i is the handover condition for the relay device to switch from the first cell to the cell i;

[0053] A connection module, configured to enable the relay device to establish a connection with the second cell when the relay device meets the handover condition of the second cell, and the second cell is any one of the plurality of preset cells;

[0054] A sending module, configured to send first indication information to a terminal device, where the first indication information indicates that the relay device establishes a connection with the second cell.

[0055] In a possible implementation manner, the second cell identifier is included in the first indication information.

[0056] In a possible implementation manner, the obtaining module is specifically configured to:

[0057] Obtain a Radio Resource Control (RRC) message from a first cell, where the RRC message includes handover conditions of the multiple preset cells.

[0058] In a possible implementation manner, the RRC message further includes configuration information of each of the multiple preset cells; the connection module is specifically configured to:

[0059] Obtain the configuration information of the second cell according to the RRC message;

[0060] Establish a connection with the second cell according to the configuration information of the second cell.

[0061] In a possible implementation manner, before the relay device establishes a connection with the second cell, the sending module is further configured to:

[0062] Send second indication information to the terminal device, where the second indication information indicates that the relay device starts to perform an operation of handing over from the first cell to one of the multiple preset cells.

[0063] In a possible implementation manner, the handover condition of the second cell is:

[0064] The signal strength between the relay device and the second cell is greater than or equal to a preset strength.

[0065] In a possible implementation manner, the obtaining module is further configured to:

[0066] Receive data from the terminal device and send the data to the second cell.

[0067] In a sixth aspect, an embodiment of the present application provides a communication device, including:

[0068] A receiving module, configured to receive first indication information from a relay device, where the first indication information indicates that the relay device hands over from a first cell to a second cell and establishes a connection with the second cell;

[0069] A sending module, configured to send data to the second cell through the relay device according to the first indication information.

[0070] In a possible implementation manner, the identification of the second cell is included in the first indication information.

[0071] In a possible implementation manner, the receiving module is further configured to, before the terminal device receives the first indication information from the relay device:

[0072] Receive second indication information from the relay device, where the second indication information indicates that the relay device starts to perform an operation of switching from the first cell to one of a plurality of preset cells, and the second cell is one of the plurality of preset cells.

[0073] In a seventh aspect, an embodiment of the present application provides a communication device, including:

[0074] An obtaining module, configured to obtain handover conditions of a plurality of preset cells from a first cell. For any cell i among the plurality of preset cells, the handover condition of the cell i is the handover condition for the relay device to switch from the first cell to the cell i;

[0075] A sending module, configured to, when the relay device meets any one of the handover conditions of the plurality of preset cells, the relay device sends second indication information to the terminal device, where the second indication information indicates that the relay device starts to perform an operation of switching from the first cell to one of the plurality of preset cells;

[0076] A connection module, configured to establish a connection between the relay device and a second cell, where the second cell is one of the plurality of preset cells, and the relay device meets the handover condition of the second cell.

[0077] In a possible implementation manner, the obtaining module is specifically configured to:

[0078] Obtain a Radio Resource Control (RRC) message from the first cell, where the RRC message includes the handover conditions of the plurality of preset cells.

[0079] In a possible implementation manner, the RRC message further includes configuration information of each cell among the plurality of preset cells; the connection module is specifically configured to:

[0080] Obtain the configuration information of the second cell according to the RRC message;

[0081] Establish a connection with the second cell according to the configuration information of the second cell.

[0082] In a possible implementation manner, the handover condition of the second cell is:

[0083] The signal strength between the relay device and the second cell is greater than or equal to a preset strength.

[0084] In a possible implementation, the sending module is further configured to, after the relay device establishes a connection with the second cell:

[0085] Send first indication information to the terminal device, where the first indication information indicates that the relay device establishes a connection with the second cell.

[0086] In a possible implementation, the second cell identifier is included in the first indication information.

[0087] In a possible implementation, the obtaining module is further configured to:

[0088] Receive data from the terminal device and send the data to the second cell.

[0089] In an eighth aspect, an embodiment of the present application provides a communication device, including:

[0090] A receiving module, configured to receive second indication information from a relay device, where the second indication information indicates that the relay device starts to perform an operation of switching from the first cell to one of a plurality of preset cells;

[0091] A processing module, configured to stop sending data to the first cell through the relay device according to the second indication information.

[0092] In a possible implementation, the receiving module is further configured to:

[0093] Receive first indication information from the relay device, where the first indication information indicates that the relay device switches from the first cell to the second cell and establishes a connection with the second cell, and the second cell is one of the plurality of preset cells;

[0094] The terminal device sends data to the second cell through the relay device according to the first indication information.

[0095] In a possible implementation, the second cell identifier is included in the first indication information.

[0096] In a ninth aspect, an embodiment of the present application provides a relay device, including: at least one processor and a memory;

[0097] The memory stores computer-executable instructions;

[0098] The at least one processor executes the computer-executable instructions stored in the memory, such that the at least one processor executes the communication method according to any one of the first aspect, or such that the at least one processor executes the communication method according to any one of the third aspect.

[0099] In a tenth aspect, an embodiment of the present application provides a terminal device, including: at least one processor and a memory;

[0100] The memory stores computer-executable instructions;

[0101] The at least one processor executes the computer-executable instructions stored in the memory, such that the at least one processor executes the communication method according to any one of the second aspect, or such that the at least one processor executes the communication method according to any one of the fourth aspect.

[0102] In an eleventh aspect, an embodiment of the present application provides a computer-readable storage medium, in which computer-executable instructions are stored, and when a processor executes the computer-executable instructions, the communication method according to any one of the first aspect to the fourth aspect is implemented.

[0103] In the communication method and apparatus provided in the embodiments of the present application, first, a relay device obtains handover conditions of a plurality of preset cells from a first cell. For any cell i in the plurality of preset cells, the handover condition of cell i is the handover condition for the relay device to hand over from the first cell to cell i; when the relay device meets the handover condition of a second cell, the relay device establishes a connection with the second cell, and the second cell is any one of the plurality of preset cells; finally, the relay device sends first indication information to a terminal device, indicating that the relay device has established a connection with the second cell. In the solution of the embodiments of the present application, after the relay device establishes a connection with the second cell, the relay device informs the terminal device through the first indication information that a connection has been established with the second cell, so that the terminal device can know the timing when the relay device has completed the handover and the target cell selected for the handover, so that the terminal device can interact with the switched second cell through the relay device. BRIEF DESCRIPTION OF THE DRAWINGS

[0104] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0105] Figure 1 It is a schematic diagram of uplink, downlink, and sidelink provided in an embodiment of the present application;

[0106] Figure 2 Schematic diagram of link connection of the relay provided by an embodiment of the present application;

[0107] Figure 3 Schematic diagram of group handover provided by an embodiment of the present application;

[0108] Figure 4 Schematic diagram of group handover of a relay device provided by the prior art;

[0109] Figure 5 Schematic flow chart of a communication method provided by an embodiment of the present application;

[0110] Figure 6 Signaling diagram of the communication method provided by an embodiment of the present application;

[0111] Figure 7 Schematic flow chart of a communication method provided by another embodiment of the present application;

[0112] Figure 8 Schematic flow chart of a communication method provided by another embodiment of the present application;

[0113] Figure 9 Schematic flow chart of a communication method provided by another embodiment of the present application;

[0114] Figure 10 Schematic structural diagram of a communication device provided by an embodiment of the present application;

[0115] Figure 11 Schematic structural diagram of a communication device provided by an embodiment of the present application;

[0116] Figure 12 Schematic structural diagram of a communication device provided by an embodiment of the present application;

[0117] Figure 13 Schematic structural diagram of a communication device provided by an embodiment of the present application;

[0118] Figure 14 Schematic hardware structure diagram of a relay device provided by an embodiment of the present application;

[0119] Figure 15 Schematic hardware structure diagram of a terminal device provided by an embodiment of the present application. Detailed implementation manners

[0120] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Apparently, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the scope of protection of this application.

[0121] For ease of understanding, first, the concepts involved in this application will be described.

[0122] Terminal device: Usually having wireless transceiver functions, the terminal device can be deployed on land, including indoor or outdoor, handheld, wearable or vehicle-mounted; it can also be deployed on the water surface (such as a ship, etc.); it can also be deployed in the air (such as an airplane, a balloon, a satellite, etc.). The terminal device can be a mobile phone, a tablet computer (Pad), a computer with wireless transceiver functions, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a vehicle-mounted terminal device, a wireless terminal in self-driving, a wireless terminal device in remote medical, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, a wireless terminal device in a smart home, a wearable terminal device, etc. The terminal device involved in the embodiments of this application can also be referred to as a terminal, a user equipment (UE), an access terminal device, a vehicle-mounted terminal, an industrial control terminal, a UE unit, a UE station, a mobile station, a mobile device, a remote station, a remote terminal device, a mobile device, a UE terminal device, a wireless communication device, a UE agent, or a UE device, etc. The terminal device can also be fixed or mobile.

[0123] RRC: radio resource control, wireless resource control.

[0124] CHO: conditional handover, that is, the handover command will be sent in advance to the device that needs to perform a cell handover, including the configuration information of multiple possible cells and the respective handover conditions. The device does not immediately perform the handover operation but waits for the conditions to be met before executing the handover operation.

[0125] Relay device: Also known as a relay, it is a transmission path between two switching centers. In this application, to increase the transmission coverage, a relay device can be introduced between the sending end and the receiving end. The relay device can forward the received data to the receiving end, thereby expanding the sending range of the sending end.

[0126] For example, in a cellular system, a relay device can be introduced between the base station and the terminal device. The relay device is responsible for forwarding the data of the terminal device to the base station or forwarding the data of the base station to the terminal device.

[0127] Sidelink (SL) communication technology, also known as device-to-device direct communication technology, is a communication technology that is different from ordinary wireless cellular network communication. In a traditional cellular network, the terminal device communicates with the network device. At this time, the link between the terminal device and the network device is called the uplink or downlink, and the interface is called the Uu interface. In device-to-device direct communication, the terminal device communicates directly with the terminal device. The link between the terminal device and the terminal device is called the direct link, and the interface is called the PC5 interface. The sidelink can also be called the direct link.

[0128] Figure 1 Schematic diagrams of the uplink / downlink and sidelink provided for the embodiments of this application, as Figure 1 shown, including base station 10, terminal 11, and terminal 12. Among them, there are uplink and downlink between base station 10 and terminal 11. Base station 10 can send downlink data to terminal 11 through the downlink, and terminal 11 can send uplink data to base station 10 through the uplink.

[0129] Between terminal 11 and terminal 12, there is a direct link. Through this direct link, terminal 11 can send data to terminal 12, and terminal 12 can also send data to terminal 11.

[0130] The introduction of the sidelink was initially to enable nearby terminal devices to communicate directly, without the need for the data to be forwarded by the base station, reducing the transmission delay. Later, based on the introduction of the sidelink, sidelink relay was designed. The previous relay used the uplink and downlink for communication between the relay and the terminal device, while the sidelink relay uses the sidelink technology for the link between the relay device and the terminal device.

[0131] Figure 2 Schematic diagram of the link connection of the relay provided for the embodiments of this application, as Figure 2 shown, including base station 20, relay device 21, and terminal device 22.

[0132] The communication technology adopted between the relay device 21 and the base station 20 is the uplink and downlink for communication. The base station 20 can send downlink data to the relay device 21 through the downlink, and the relay device 21 can send uplink data to the base station 20 through the uplink.

[0133] On the left side of Figure 2 , the communication technology adopted between the relay device 21 and the terminal device 22 is also the uplink and downlink for communication. The relay device 21 can send the downlink data sent by the base station 20 to the terminal device 22 through the downlink, and the terminal device 22 can send uplink data to the relay device 22 through the uplink and forward it to the base station 20 by the relay device 22.

[0134] On the right side of Figure 2 , the communication technology adopted between the relay device 21 and the terminal device 22 is the direct link for communication, and direct data transmission is performed.

[0135] In a wireless communication system, when the base station is directly connected to the terminal device, since the terminal device can move and may move from the coverage area of one base station to the coverage area of another base station, the terminal device needs to perform a handover at this time. Similarly, for the relay device, the relay device can also move. When the connection between the relay device and the terminal device remains unchanged, but the relay device and the base station or cell move, a phenomenon of group handover will occur, that is, both the relay device and the terminal device switch from one base station to another base station, or both the relay device and the terminal device switch from one cell to another cell, and the connection relationship between the relay device and the terminal device remains unchanged.

[0136] Figure 3 This is a schematic diagram of group handover provided by the embodiment of the present application. As Figure 3 shown, it includes a terminal device 31, a relay device 32, a base station 33, and a base station 34. The connection between the terminal device 31 and the relay device 32 remains unchanged. When the terminal device 31 and the relay device 32 move, they switch from the base station 33 to the base station 34, that is, a group handover occurs.

[0137] In a communication system including only a base station and a terminal device, when a handover is required, the source base station sends a handover command to the terminal device. When the terminal device receives the handover command, it will immediately start to perform the handover operation. However, since when the terminal device needs to perform a handover, it generally occurs when the signal between the terminal device and the source base station is already poor, so it may happen that the handover command sent by the source base station cannot be successfully received by the terminal device, and at this time, the handover cannot be performed. If the handover command is sent to the terminal device in advance when the signal between the terminal device and the source base station is relatively good, it may cause the terminal device to perform a handover prematurely.

[0138] Therefore, when studying 5G, 3GPP introduced a conditional handover solution. The source base station will send the handover command to the terminal device in advance. The handover command includes the configuration information of multiple possible target base stations and the respective handover conditions for each target base station. After receiving the handover command, the terminal device does not immediately perform the handover operation, but judges whether it meets the handover conditions. Only when the handover conditions corresponding to a certain target base station are met, the handover is performed.

[0139] For example, the handover command includes 5 cells, namely Cell 1 - 5. When the terminal device receives the handover command, it continuously monitors the signal strengths of these 5 cells. When the signal strength of Cell 3 is greater than the preset threshold (at this time, the handover condition for Cell 3 is that the signal strength of Cell 3 is greater than the preset threshold), and the signal strength of the current cell is lower than the preset threshold, the operation of handing over to Cell 3 is performed.

[0140] In the group handover of relay devices, when the relay device and the terminal device hand over from one cell to another cell together, the conditional handover method can also be adopted. The relay device receives the configuration information of multiple target cells and their respective handover conditions. When the relay device meets the handover conditions, it selects a target cell to complete the handover.

[0141] Figure 4 Schematic diagram of the group handover of the relay device provided by the prior art, as Figure 4 shown, including:

[0142] S41, the relay device sends the measurement result to the first cell.

[0143] S42, the first cell sends a handover request to the second cell.

[0144] S43, the second cell sends a handover command to the first cell.

[0145] After allowing the relay device to hand over to the second cell, the second cell will send a handover command to the first cell.

[0146] S44, the first cell sends a handover command to the relay device.

[0147] S45, the relay device sends a handover command to the terminal device.

[0148] S46, the terminal device sends a handover command response to the relay device.

[0149] S47, the relay device establishes a connection with the second cell.

[0150] For example, the connection with the second cell can be established through random access.

[0151] In the current group handover process, since the handover condition is generally that the signal strength between the relay device and the potential target cell meets a certain threshold, the final handover trigger and the selection of the target cell are both determined by the relay device. For the terminal device, it does not know when to trigger the cell handover, nor which target cell is selected for the handover. Therefore, the embodiments of the present application provide a solution that enables the terminal device to know the trigger of the cell handover and the selected target cell. The following will be introduced.

[0152] Figure 5 It is a schematic flowchart of a communication method provided by the embodiments of the present application, as Figure 5 shown, including:

[0153] S51, the relay device obtains the handover conditions of multiple preset cells from the first cell. For any cell i among the multiple preset cells, the handover condition of the cell i is the handover condition for the relay device to switch from the first cell to the cell i.

[0154] In the embodiments of the present application, the relay device is initially connected to the first cell. Through this relay device, data transmission can be carried out between the terminal device and the first cell. The distance between the relay device and the terminal device is maintained within a certain range, so that the connection between the relay device and the terminal device can be maintained without handover.

[0155] When the terminal device and the relay device move, cell handover may be required. For example, when the terminal device and the relay device move out of the coverage range of the first cell, at this time, the terminal device and the relay device need to switch to other cells, that is, the second cell. At this time, the connection relationship maintained between the terminal device and the relay device remains unchanged, and both the relay device and the terminal device need to switch from the first cell to the second cell, that is, perform a group handover.

[0156] Before the relay device needs to perform cell handover, the first cell will send the handover conditions of multiple preset cells to the relay device. When the relay device meets the handover condition of any cell i among the multiple preset cells, the relay device will switch from the first cell to the cell i.

[0157] S52, when the relay device meets the handover condition of the second cell, the relay device establishes a connection with the second cell, and the second cell is any one of the multiple preset cells.

[0158] The second cell is one of the multiple preset cells, and the relay device meets the handover condition of the second cell, then the relay device will switch from the first cell to the second cell. When the relay device starts to perform cell handover, the relay device will disconnect from the first cell and attempt to establish a connection with the second cell.

[0159] S53, the relay device sends first indication information to the terminal device, and the first indication information indicates that the relay device establishes a connection with the second cell.

[0160] After the relay device successfully establishes a connection with the second cell, the relay device sends first indication information to the terminal device, indicating that the relay device has successfully established a connection with the second cell. After receiving the first indication information, the terminal device can know that the relay device has switched to the second cell according to the first indication information. At this time, the terminal device can stop communicating with the first cell through the relay device and can start communicating with the second cell through the relay device.

[0161] In the communication method provided by the embodiments of the present application, first, the relay device obtains the handover conditions of multiple preset cells from the first cell. For any cell i among the multiple preset cells, the handover condition of cell i is the handover condition for the relay device to switch from the first cell to cell i; when the relay device meets the handover condition of the second cell, the relay device establishes a connection with the second cell, and the second cell is any one of the multiple preset cells; finally, the relay device sends first indication information to the terminal device, indicating that the relay device establishes a connection with the second cell. In the solution of the embodiments of the present application, after the relay device and the second cell establish a connection, the relay device uses the first indication information to inform the terminal device that it has established a connection with the second cell, so that the terminal device can know the timing when the relay device completes the handover and the target cell selected for the handover, so that the terminal device can interact with the switched second cell through the relay device.

[0162] The solution of the present application will be described in detail below with reference to the accompanying drawings.

[0163] When the relay device and the terminal device need to perform cell handover due to reasons such as position change, the relay device needs to receive a handover command from the first cell. Among them, when the relay device needs to switch from the first cell to the second cell, the first cell sends a handover request to the second cell. If the second cell allows the relay device to switch, the second cell will send a handover command to the first cell, and the first cell will send the handover command to the relay device.

[0164] Optionally, the first indication information includes the identifier of the second cell. After receiving the first indication information, the terminal device can know that the relay device switches from the first cell to the second cell according to the identifier of the second cell included in the first indication information.

[0165] Optionally, the relay device can obtain an RRC message from the first cell, and the RRC message includes the handover conditions of multiple preset cells.

[0166] Optionally, the RRC message further includes configuration information of each cell in a plurality of preset cells. Through the RRC message, the relay device can obtain the configuration information of the second cell and establish a connection with the second cell according to the configuration information of the second cell.

[0167] Optionally, the handover condition of the second cell is that the signal strength between the relay device and the second cell is greater than or equal to a preset strength. For any cell i in the plurality of preset cells, the handover condition of cell i is that the signal strength between the relay device and cell i is greater than or equal to a certain signal strength, and the magnitudes of this signal strength corresponding to different cells may be the same or different.

[0168] Optionally, before the relay device establishes a connection with the second cell, the relay device may further send second indication information to the terminal device to indicate that the relay device starts to perform an operation of handing over from the first cell to one of the plurality of preset cells.

[0169] After the relay device obtains the handover conditions of the plurality of preset cells from the first cell, the terminal device does not know when the relay device is ready to perform cell handover at this time, nor which cell is selected. The first indication information is sent by the relay device to the terminal device after the connection between the relay device and the second cell is successfully established. Before that, the second indication information is used to inform the relay device that it is about to start the operation of cell handover, that is, the second indication information indicates that the relay device starts to perform an operation of handing over from the first cell to one of the plurality of preset cells. The terminal device stops communicating with the first cell through the relay device according to the second indication information and stops sending data for the first cell to the first cell through the relay device.

[0170] The second indication information only informs the relay device that it is about to perform the operation of cell handover, but does not include the identifier of the target cell to which the relay device is about to hand over. This is because when the relay device meets the handover condition of a certain cell i and attempts to establish a connection with cell i, it may fail to connect. At this time, the relay device will select a cell that meets the conditions in other cells and try to establish a connection again. It is not until the connection between the relay device and the second cell is successfully established that the relay device will inform the terminal device through the first indication information that the target cell for handover is the second cell.

[0171] After the terminal device receives the first indication information, it can send data to the second cell through the relay device according to the first indication information.

[0172] The solution of the present application will be described in detail below with reference to the accompanying drawings.

[0173] Figure 6 A signaling diagram of the communication method provided by the embodiment of the present application is as Figure 6 shown, including:

[0174] S601, The relay device reports the measurement results to the first cell.

[0175] The relay device can obtain the measurement results of one or more nearby cells and report them to the first cell.

[0176] S602, The first cell receives the measurement results.

[0177] After the relay device reports the measurement results to the first cell, the first cell receives the measurement results and determines multiple preset cells, as well as the configuration information and various handover conditions of each preset cell.

[0178] S603, The relay device sends an RRC message (i.e., handover command) to the terminal device.

[0179] The RRC message includes the handover conditions of multiple preset cells and the configuration information of multiple preset cells.

[0180] After receiving the RRC message, the terminal device can learn the handover conditions of multiple preset cells and the configuration information of multiple preset cells.

[0181] S604, The terminal device sends a handover command response to the relay device.

[0182] S605, The relay device determines that the handover conditions of the second cell are met.

[0183] S606, The relay device sends second indication information to the terminal device.

[0184] S607, The terminal device receives the second indication information.

[0185] The second indication information instructs the relay device to start performing the operation of switching from the first cell to one of the multiple preset cells. At this time, the terminal device does not yet know which target cell the relay device has selected, but can learn that the relay device has disconnected from the first cell and started trying to access other cells. Therefore, after receiving the second indication information, the terminal device can stop sending data for the first cell to the relay device and stop communicating with the first cell through the relay device.

[0186] S608, The relay device establishes a connection with the second cell.

[0187] S609, The relay device sends first indication information to the terminal device.

[0188] S610, The terminal device receives the first indication information.

[0189] The first indication information includes the identifier of the second cell. According to the first indication information, the terminal device can learn that the relay device has completed cell handover and has switched to the second cell.

[0190] Figure 7 It is a schematic flowchart of a communication method provided by another embodiment of this application, as Figure 7 shown, including:

[0191] S71, the terminal device receives first indication information from the relay device, and the first indication information indicates that the relay device switches from the first cell to the second cell and establishes a connection with the second cell;

[0192] S72, the terminal device sends data to the second cell through the relay device according to the first indication information

[0193] In a possible implementation manner, the first indication information includes the identifier of the second cell.

[0194] In a possible implementation manner, before the terminal device receives the first indication information from the relay device, the method further includes:

[0195] The terminal device receives second indication information from the relay device, and the second indication information indicates that the relay device starts to perform an operation of switching from the first cell to one of multiple preset cells, and the second cell is one of the multiple preset cells.

[0196] Figure 7 The solution of the exemplary embodiment is Figures 5 - 6 The method on the terminal device side corresponding to the exemplary solution, its steps and principles have been introduced in the above embodiments. For specific implementation, reference can be made to the above embodiments, and details will not be elaborated here.

[0197] Figure 8 It is a schematic flowchart of a communication method provided by another embodiment of this application, as Figure 8 shown, including:

[0198] S81, the relay device obtains the handover conditions of multiple preset cells from the first cell. For any cell i among the multiple preset cells, the handover condition of the cell i is the handover condition for the relay device to switch from the first cell to the cell i.

[0199] In the embodiments of this application, the relay device is initially connected to the first cell. Through this relay device, data transmission can be performed between the terminal device and the first cell. The distance between the relay device and the terminal device is kept within a certain range, so that the connection between the relay device and the terminal device can be maintained without handover.

[0200] When the terminal device and the relay device move, cell handover may be required. For example, when the terminal device and the relay device move out of the coverage area of the first cell, at this time, the terminal device and the relay device need to switch to another cell, that is, the second cell. At this time, the connection relationship maintained between the terminal device and the relay device remains unchanged, and both the relay device and the terminal device need to switch from the first cell to the second cell, that is, perform a group handover.

[0201] S82. When the relay device meets any one of the handover conditions of the multiple preset cells, the relay device sends second indication information to the terminal device, and the second indication information indicates that the relay device starts to perform the operation of switching from the first cell to one of the multiple preset cells.

[0202] Before the relay device performs cell handover, the relay device first sends second indication information to the terminal device, indicating to the terminal device that the relay device is about to perform cell handover and disconnect from the first cell. After receiving the second indication information, the terminal device can stop communicating with the first cell through the relay device and stop sending data to the first cell through the relay device.

[0203] S83. The relay device establishes a connection with the second cell, where the second cell is one of the multiple preset cells and the relay device meets the handover condition of the second cell.

[0204] The second cell is one of the multiple preset cells, and the relay device meets the handover condition of the second cell, then the relay device will switch from the first cell to the second cell. After the relay device starts to perform cell handover, the relay device will disconnect from the first cell and attempt to establish a connection with the second cell.

[0205] Optionally, the way for the relay device to obtain the handover conditions of the multiple preset cells from the first cell can be:

[0206] The relay device obtains a Radio Resource Control (RRC) message from the first cell, and the RRC message includes the handover conditions of the multiple preset cells.

[0207] Optionally, the RRC message further includes the configuration information of each cell in the multiple preset cells; the way for the relay device to establish a connection with the second cell can be:

[0208] The relay device obtains the configuration information of the second cell according to the RRC message;

[0209] The relay device establishes a connection with the second cell according to the configuration information of the second cell.

[0210] Optionally, the handover condition of the second cell is:

[0211] The signal strength between the relay device and the second cell is greater than or equal to a preset strength.

[0212] Optionally, after the relay device establishes a connection with the second cell, the relay device may send first indication information to the terminal device, where the first indication information indicates that the relay device establishes a connection with the second cell. After receiving the first indication information, the terminal device can learn that the relay device has switched from the first cell to the second cell, and the terminal device can communicate with the second cell through the relay device according to the configuration information of the second cell in the RRC cell.

[0213] Optionally, the first indication information includes the identifier of the second cell, and the terminal device learns that the target cell selected by the relay device is the second cell according to the identifier of the second cell.

[0214] Optionally, after the terminal device receives the first indication information, the relay device may receive data from the terminal device and send the data to the second cell.

[0215] Figure 9 A schematic flow chart of a communication method provided by another embodiment of this application is as Figure 9 shown, including:

[0216] S91, the terminal device receives second indication information from the relay device, where the second indication information indicates that the relay device starts to perform an operation of switching from the first cell to one of a plurality of preset cells;

[0217] S92, the terminal device stops sending data to the first cell through the relay device according to the second indication information.

[0218] In a possible implementation manner, the method further includes:

[0219] The terminal device receives first indication information from the relay device, where the first indication information indicates that the relay device switches from the first cell to the second cell and establishes a connection with the second cell, and the second cell is one of the plurality of preset cells;

[0220] The terminal device sends data to the second cell through the relay device according to the first indication information.

[0221] In a possible implementation manner, the first indication information includes the identifier of the second cell.

[0222] Figure 9 The solution of the exemplary embodiment is Figure 8For the method on the terminal device side corresponding to the exemplary solution, the steps and principles have been introduced in the foregoing embodiments. For the specific implementation, refer to the foregoing embodiments and details are not described herein again.

[0223] For the communication method and apparatus provided in the embodiments of the present application, first, a relay device obtains handover conditions of a plurality of preset cells from a first cell. For any cell i among the plurality of preset cells, the handover condition of cell i is the handover condition for the relay device to hand over from the first cell to cell i; when the relay device meets the handover condition of a second cell, the relay device establishes a connection with the second cell, and the second cell is any one of the plurality of preset cells; finally, the relay device sends a first indication message to a terminal device to indicate that the relay device has established a connection with the second cell. In the solution of the embodiments of the present application, after the relay device and the second cell establish a connection, the relay device notifies the terminal device through the first indication message that a connection has been established with the second cell, so that the terminal device can know the timing when the relay device completes the handover and the target cell selected for the handover, so that the terminal device can interact with the switched second cell through the relay device. Further, before the relay device starts to perform cell handover, the relay device may send a second indication message to the terminal device to indicate that the relay device is about to start cell handover. After receiving the second indication message, the terminal device may stop communicating with the first cell through the relay device, saving signaling resources.

[0224] Figure 10 is a schematic structural diagram of the communication apparatus provided in the embodiments of the present application, as Figure 10 shown, the communication apparatus 100 includes an obtaining module 101, a connection module 102, and a sending module 103, where:

[0225] The obtaining module 101 is configured to obtain handover conditions of a plurality of preset cells from a first cell. For any cell i among the plurality of preset cells, the handover condition of cell i is the handover condition for the relay device to hand over from the first cell to cell i;

[0226] The connection module 102 is configured to, when the relay device meets the handover condition of a second cell, establish a connection between the relay device and the second cell, and the second cell is any one of the plurality of preset cells;

[0227] The sending module 103 is configured to send a first indication message to a terminal device, and the first indication message indicates that the relay device has established a connection with the second cell.

[0228] In a possible implementation manner, the first indication message includes an identifier of the second cell.

[0229] In a possible implementation manner, the obtaining module 101 is specifically configured to:

[0230] Obtain a Radio Resource Control (RRC) message from a first cell, where the RRC message includes handover conditions for the multiple preset cells.

[0231] In a possible implementation manner, the RRC message further includes configuration information for each of the multiple preset cells; specifically, the connection module 102 is configured to:

[0232] Obtain the configuration information of the second cell according to the RRC message;

[0233] Establish a connection with the second cell according to the configuration information of the second cell.

[0234] In a possible implementation manner, before the relay device establishes a connection with the second cell, the sending module 103 is further configured to:

[0235] Send second indication information to the terminal device, where the second indication information indicates that the relay device starts to perform an operation of handing over from the first cell to one of the multiple preset cells.

[0236] In a possible implementation manner, the handover condition for the second cell is:

[0237] The signal strength between the relay device and the second cell is greater than or equal to a preset strength.

[0238] In a possible implementation manner, the obtaining module 101 is further configured to:

[0239] Receive data from the terminal device and send the data to the second cell.

[0240] The device provided in the embodiments of the present application can be used to execute the technical solutions of the above method embodiments, and its implementation principles and technical effects are similar, which will not be elaborated here.

[0241] Figure 11 It is a schematic structural diagram of a communication device provided in the embodiments of the present application. As Figure 11 shown, the communication device 110 includes a receiving module 111 and a sending module 112, where:

[0242] The receiving module 111 is configured to receive first indication information from a relay device, where the first indication information indicates that the relay device hands over from a first cell to a second cell and establishes a connection with the second cell;

[0243] The sending module 112 is configured to send data to the second cell through the relay device according to the first indication information.

[0244] In a possible implementation manner, the identity of the second cell is included in the first indication information.

[0245] In a possible implementation manner, before the receiving module 111 receives the first indication information from the relay device, the receiving module 111 is further configured to:

[0246] Receive second indication information from the relay device, where the second indication information indicates that the relay device starts to perform an operation of switching from the first cell to one of a plurality of preset cells, and the second cell is one of the plurality of preset cells.

[0247] The device provided in the embodiments of the present application can be used to execute the technical solutions of the above method embodiments. The implementation principles and technical effects are similar and will not be elaborated here.

[0248] Figure 12 As shown in the schematic structural diagram of the communication device provided in the embodiments of the present application, Figure 12 The communication device 120 includes an acquisition module 121, a sending module 122, and a connection module 123, where:

[0249] The acquisition module 121 is configured to acquire the handover conditions of a plurality of preset cells from the first cell. For any cell i among the plurality of preset cells, the handover condition of the cell i is the handover condition for the relay device to switch from the first cell to the cell i;

[0250] The sending module 122 is configured to, when the relay device meets any one of the handover conditions of the plurality of preset cells, the relay device sends second indication information to the terminal device, where the second indication information indicates that the relay device starts to perform an operation of switching from the first cell to one of the plurality of preset cells;

[0251] The connection module 123 is configured to establish a connection between the relay device and a second cell, where the second cell is one of the plurality of preset cells, and the relay device meets the handover condition of the second cell.

[0252] In a possible implementation manner, the acquisition module 121 is specifically configured to:

[0253] Acquire a Radio Resource Control (RRC) message from the first cell, where the RRC message includes the handover conditions of the plurality of preset cells.

[0254] In a possible implementation manner, the RRC message further includes the configuration information of each cell among the plurality of preset cells; the connection module 123 is specifically configured to:

[0255] Acquire the configuration information of the second cell according to the RRC message;

[0256] Establish a connection with the second cell according to the configuration information of the second cell.

[0257] In a possible implementation manner, the handover condition of the second cell is:

[0258] The signal strength between the relay device and the second cell is greater than or equal to a preset strength.

[0259] In a possible implementation manner, the sending module 122 is further configured to, after the relay device establishes a connection with the second cell:

[0260] Send first indication information to the terminal device, where the first indication information indicates that the relay device establishes a connection with the second cell.

[0261] In a possible implementation manner, the first indication information includes an identifier of the second cell.

[0262] In a possible implementation manner, the obtaining module 121 is further configured to:

[0263] Receive data from the terminal device and send the data to the second cell.

[0264] The device provided in the embodiments of the present application can be used to execute the technical solutions of the above method embodiments, and its implementation principles and technical effects are similar, which will not be elaborated here.

[0265] Figure 13 It is a schematic structural diagram of a communication device provided in an embodiment of the present application. As Figure 13 shown, the communication device 130 includes a receiving module 131 and a processing module 132, where:

[0266] The receiving module 131 is configured to receive second indication information from the relay device, where the second indication information indicates that the relay device starts to execute an operation of switching from the first cell to one of a plurality of preset cells;

[0267] The processing module 132 is configured to stop sending data to the first cell through the relay device according to the second indication information.

[0268] In a possible implementation manner, the receiving module 131 is further configured to:

[0269] Receive first indication information from the relay device, where the first indication information indicates that the relay device switches from the first cell to the second cell and establishes a connection with the second cell, and the second cell is one of the plurality of preset cells;

[0270] The terminal device sends data to the second cell through the relay device according to the first indication information.

[0271] In a possible implementation manner, the second cell identifier is included in the first indication information.

[0272] The device provided in the embodiments of the present application can be used to execute the technical solutions in the above method embodiments. The implementation principles and technical effects are similar and will not be elaborated here.

[0273] Figure 14 It is a schematic hardware structure diagram of the relay device provided in the embodiments of the present application. As Figure 14 shown, the relay device includes at least one processor 141 and a memory 142. Among them, the processor 141 and the memory 142 are connected through a bus 143.

[0274] Optionally, the model determination further includes a communication component. For example, the communication component may include a receiver and / or a transmitter.

[0275] In a specific implementation process, at least one processor 141 executes the computer execution instructions stored in the memory 142, so that at least one processor 141 executes the above communication method.

[0276] The specific implementation process of the processor 141 can be referred to in the above method embodiments. The implementation principles and technical effects are similar and will not be elaborated in this embodiment.

[0277] Figure 15 It is a schematic hardware structure diagram of the terminal device provided in the embodiments of the present application. As Figure 15 shown, the terminal device includes at least one processor 151 and a memory 152. Among them, the processor 151 and the memory 152 are connected through a bus 153.

[0278] Optionally, the model determination further includes a communication component. For example, the communication component may include a receiver and / or a transmitter.

[0279] In a specific implementation process, at least one processor 151 executes the computer execution instructions stored in the memory 152, so that at least one processor 151 executes the above communication method.

[0280] The specific implementation process of the processor 151 can be referred to in the above method embodiments. The implementation principles and technical effects are similar and will not be elaborated in this embodiment.

[0281] In the above Figure 14 or Figure 15In the illustrated embodiments, it should be understood that the processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in connection with the application can be directly implemented by the execution of a hardware processor, or can be implemented by a combination of hardware and software modules in the processor.

[0282] The memory may include high-speed RAM memory and may also include non-volatile storage NVM, such as at least one disk memory.

[0283] The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the buses in the drawings of this application are not limited to only one bus or one type of bus.

[0284] This application also provides a computer-readable storage medium storing computer-executable instructions, and when the processor executes the computer-executable instructions, the communication method described above is implemented.

[0285] For the above-mentioned computer-readable storage medium, the readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, a disk or an optical disc. The readable storage medium can be any available medium accessible by a general or special-purpose computer.

[0286] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an Application Specific Integrated Circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in a device.

[0287] The division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Additionally, the couplings or direct couplings or communication connections shown or discussed among each other can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0288] The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0289] Furthermore, in each embodiment of the present application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0290] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0291] Those of ordinary skill in the art will understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments; and the aforementioned storage medium includes various media such as ROM, RAM, magnetic disks, or optical discs that can store program codes.

[0292] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A communication method, characterized in that, Including: The relay device obtains handover conditions of multiple preset cells from a first cell. For any cell i among the multiple preset cells, the handover condition of the cell i is the handover condition for the relay device to hand over from the first cell to the cell i. When the relay device meets the handover condition of a second cell, the relay device establishes a connection with the second cell, where the second cell is any one of the multiple preset cells; the handover condition of the second cell is that the signal strength between the relay device and the second cell is greater than or equal to a preset strength. The relay device sends first indication information to the terminal device, and the first indication information indicates that the relay device establishes a connection with the second cell. The first indication information includes an identifier of the second cell. The relay device obtaining handover conditions of multiple preset cells from a first cell includes: The relay device obtains a radio resource control (RRC) message from the first cell, and the RRC message includes the handover conditions of the multiple preset cells.

2. The method according to claim 1, characterized in that, The RRC message further includes configuration information of each cell among the multiple preset cells; the relay device establishing a connection with the second cell includes: The relay device obtains the configuration information of the second cell according to the RRC message. The relay device establishes a connection with the second cell according to the configuration information of the second cell.

3. The method according to any one of claims 1-2, characterized in that, Before the relay device establishes a connection with the second cell, the method further includes: The relay device sends second indication information to the terminal device, and the second indication information indicates that the relay device starts to perform an operation of handing over from the first cell to one of the multiple preset cells.

4. The method according to any one of claims 1-2, characterized in that, The method further includes: The relay device receives data from the terminal device and sends the data to the second cell.

5. A communication method, characterized in that, Including: The terminal device receives first indication information from the relay device. The first indication information indicates that the relay device hands over from a first cell to a second cell and establishes a connection with the second cell. The first indication information includes an identifier of the second cell. The first indication information is sent by the relay device when it meets the handover condition of the second cell. The handover condition of the second cell is determined by the relay device according to the handover conditions of multiple preset cells included in a radio resource control (RRC) message obtained from the first cell. The handover condition of the second cell is that the signal strength between the relay device and the second cell is greater than or equal to a preset strength. The terminal device sends data to the second cell through the relay device according to the first indication information. The relay device obtaining handover conditions of multiple preset cells from a first cell includes: The relay device obtains a radio resource control (RRC) message from the first cell, and the RRC message includes the handover conditions of the multiple preset cells.

6. The method according to claim 5, characterized in that, Before the terminal device receives the first indication information from the relay device, the method further includes: The terminal device receives second indication information from the relay device, where the second indication information instructs the relay device to start performing an operation of switching from the first cell to one of a plurality of preset cells, and the second cell is one of the plurality of preset cells.

7. A communication device, characterized in that, Comprising: An obtaining module, configured to obtain handover conditions of a plurality of preset cells from a first cell. For any cell i among the plurality of preset cells, the handover condition of the cell i is the handover condition for the relay device to switch from the first cell to the cell i; A connection module, configured to establish a connection between the relay device and a second cell when the relay device meets the handover condition of the second cell, where the second cell is any one of the plurality of preset cells; the handover condition of the second cell is that the signal strength between the relay device and the second cell is greater than or equal to a preset strength; A sending module, configured to send first indication information to the terminal device, where the first indication information instructs the relay device to establish a connection with the second cell, and the first indication information includes an identifier of the second cell; Specifically, the obtaining module is configured to obtain a radio resource control (RRC) message from the first cell, and the RRC message includes the handover conditions of the plurality of preset cells.

8. A communication device, characterized in that, Comprising: A receiving module, configured to receive first indication information from the relay device, where the first indication information instructs the relay device to switch from a first cell to a second cell and establish a connection with the second cell, and the first indication information includes an identifier of the second cell; the first indication information is sent by the relay device when the relay device meets the handover condition of the second cell, and the handover condition of the second cell is determined by the relay device according to the handover conditions of the plurality of preset cells included in the radio resource control (RRC) message obtained from the first cell, and the handover condition of the second cell is that the signal strength between the relay device and the second cell is greater than or equal to a preset strength; A sending module, configured to send data to the second cell through the relay device according to the first indication information.

9. A relay device, characterized in that, Comprising: At least one processor and a memory; The memory stores computer-executable instructions; The at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor executes the communication method according to any one of claims 1 to 4.

10. A terminal device, characterized in that, Comprising: At least one processor and a memory; The memory stores computer-executable instructions; The at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor executes the communication method according to any one of claims 5 to 6.

11. A computer-readable storage medium, characterized in that, Computer-executable instructions are stored in the computer-readable storage medium, and when the processor executes the computer-executable instructions, the communication method according to any one of claims 1 to 6 is implemented.

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