Communication method, communication device, and communication system

Abstract

The present application provides a communication method, a communication device, and a communication system for avoiding interruptions in data communicated by a remote terminal, the method comprising: receiving radio resource control release information sent by a first network device, where the radio resource control release information indicates to release a first radio resource control connection between the first terminal and the first network device; and sending first indication information to a second terminal, where the first terminal is an intermediate device for the second terminal to access the first network device, and the first indication information indicates to release a sidelink between the first terminal and the second terminal, indicates that the first radio resource control connection is released, or indicates that a state of the first radio resource control connection is a connection failure state.

Description

[Technical Field]

[0001] The present application relates to the field of communications, and more particularly to a communication method, a communication device, and a communication system. [Background technology]

[0002] A relay terminal may serve as a relay device and relay data communicated between a remote terminal and a network device. In some cases, the network device may release a radio resource control (RRC) connection between the relay terminal and the network device, causing an interruption in the data communicated by the remote terminal. Summary of the Invention

[0003] The present application provides a communication method, a communication device, and a communication system for avoiding interruptions in data communicated by a remote terminal.

[0004] According to a first aspect, there is provided a communication method comprising: receiving radio resource control release information transmitted by a first network device, wherein the radio resource control release information indicates that a first radio resource control connection between a first terminal and the first network device is to be released; and transmitting first instruction information to a second terminal, wherein the first terminal is an intermediate device for the second terminal to access the first network device, and the first instruction information indicates at least one of: indicating that a sidelink between the first terminal and the second terminal is to be released; indicating that the first radio resource control connection is to be released; or indicating that a state of the first radio resource control connection is a connection failure state.

[0005] When the first radio resource control connection between the first terminal serving as a relay device and the first network device is released, the first terminal sends first indication information to the second terminal serving as a remote device, so that the remote terminal can perform subsequent processing based on the first indication information and avoid interruptions in data communicated by the remote terminal.

[0006] In some possible implementations, the method further includes establishing a second radio resource control connection to the second network device, wherein the second radio resource control connection is used by the second terminal to access the second network device.

[0007] When the first radio resource control connection between the first terminal serving as a relay device and the first network device is released, the first terminal establishes a second radio resource control connection to the second network device, so that the second terminal accesses the second network device through the second radio resource control connection, thereby avoiding interruptions in data communicated by the second terminal.

[0008] In some possible implementations, the method further comprises receiving second instruction information transmitted by the second terminal, wherein the second instruction information indicates to maintain the sidelink.

[0009] When receiving the second indication information sent by the second terminal and instructing to maintain the sidelink, the first terminal establishes a second radio resource control connection to the second network device. In other words, the establishment of the second radio resource control connection depends on the sidelink maintenance response sent by the second terminal in response to the first indication information, which avoids establishing the second radio resource control connection in invalid cases and reduces resource occupancy.

[0010] In some possible implementations, establishing a second radio resource control connection to the second network device includes establishing an RRC connection to the second network device when the sidelink is not disconnected at the detection time, where the detection time includes a time a first length of time after the first indication information is transmitted.

[0011] The fact that the sidelink is not disconnected at the time of detection can be understood as the sidelink maintenance response of the second terminal to the first indication information. In other words, the establishment of the second radio resource control connection depends on the sidelink maintenance response sent by the second terminal to the first indication information, which avoids establishing the second radio resource control connection in invalid cases and reduces resource occupancy.

[0012] In some possible implementations, the method further comprises receiving radio resource control release information when the first terminal satisfies a handover condition and a session belonging to the first terminal does not exist between the first terminal and the first network device.

[0013] For example, the handover condition may be that at least one measurement event is satisfied. After an RRC connection is established between the first terminal and the first network device, the first network device may send the at least one measurement event to the first terminal. The first terminal device may perform measurements periodically or aperiodically. When any one or more of the at least one measurement event is satisfied, the first terminal may send a measurement report to the first network device. Upon receiving the measurement report, the first network device may determine that the handover condition is satisfied.

[0014] The first network device may send at least one measurement event to the first terminal, which may include one or more of the following events: the signal quality of the serving cell falling below a corresponding threshold; the signal quality of the neighboring cell starting to become higher than the signal quality of the serving cell by a certain offset; the signal quality of the neighboring cell rising above a corresponding threshold; the signal quality of the serving cell falling below threshold 1 and the signal quality of the neighboring cell rising above threshold 2; the signal quality of the neighboring cell starting to become higher than the signal quality of a secondary cell (SCell) by a certain offset; the signal quality of an inter-radio access technology (inter-RAT) neighboring cell rising above a corresponding threshold; and the signal quality of a primary cell (PCell) falling below threshold 1 and the signal quality of the inter-RAT neighboring cell rising above threshold 2.

[0015] When the first terminal meets the handover conditions and a session belonging to the first terminal does not exist between the first terminal and the first network device, the first network device may send radio resource control release information to the first terminal and release the first radio resource control connection to the first terminal.

[0016] In some possible implementations, the method further comprises: determining a connection state of the first radio resource control connection; and transmitting state indication information to the second terminal, where the state indication information includes first state information, second state information, or third state information, where the first state information indicates that the connection state is an establishing state, the second state information indicates that the connection state is an established state, and the third state information indicates that the connection state is an establishment failed state.

[0017] The first terminal sends status indication information to the second terminal to indicate the connection status of the first radio resource control connection, so that events related to the first radio resource control connection do not need to be indicated, thereby reducing information redundancy.

[0018] It should be understood that after the first terminal establishes a second radio resource control connection to the second network device, the first terminal may send status indication information to the second terminal to indicate the connection status of the second radio resource control connection. In other words, the status indication information indicates the radio resource control connection between the first terminal and the network device serving the first terminal.

[0019] In some possible implementations, determining the connection state of the first radio resource control connection includes: determining that the connection state is an establishing state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection is restored with a radio link failure occurring; or determining that the connection state is an established state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection is restored with a radio link failure occurring; or determining that the connection state is an establishment failed state when the first terminal device fails to handover, fails to establish the first radio resource control connection, a radio link failure occurs on the first radio resource control connection, fails to restore the first radio resource control connection with a radio link failure occurring, or the first radio resource control connection is released.

[0020] When the state of the radio resource control connection between the first terminal and the network device is the same, multiple events related to the first radio resource control connection can be indicated by using the same information, thereby reducing the number of bits required for the information and reducing information redundancy.

[0021] According to a second aspect, there is provided a communication method, the method comprising: determining a connection status of a first radio resource control connection between a first terminal and a first network device; and transmitting status indication information to a second terminal, where the status indication information includes first status information, second status information, or third status information, where the first status information indicates that the connection status is an establishing status, the second status information indicates that the connection status is an established status, and the third status information indicates that the connection status is an establishment failed status; and the first terminal is an intermediate device for the second terminal to access the first network device.

[0022] The first terminal sends status indication information to the second terminal to indicate the connection status of the first radio resource control connection, so that events related to the first radio resource control connection do not need to be indicated, thereby reducing information redundancy.

[0023] In some possible implementations, determining the connection state of the first radio resource control connection between the first terminal and the first network device includes: determining that the connection state is an establishing state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection is restored with a radio link failure occurring; or determining that the connection state is an established state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection is restored with a radio link failure occurring; or determining that the connection state is an establishment failed state when handover of the first terminal device fails, establishment of the first radio resource control connection fails, a radio link failure occurs on the first radio resource control connection, recovery of the first radio resource control connection with a radio link failure occurs, or the first radio resource control connection is released.

[0024] In some possible implementations, the step of determining the connection state of the first radio resource control connection between the first terminal and the first network device includes: determining that the connection state is in an establishment failure state when receiving radio resource control release information sent by the first network device, where the radio resource control release information indicates that the first radio resource control connection is to be released.

[0025] In some possible implementations, the method further includes establishing a second radio resource control connection to the second network device, wherein the second radio resource control connection is used by the second terminal to access the second network device.

[0026] In some possible implementations, the method further comprises receiving second instruction information transmitted by the second terminal, wherein the second instruction information indicates to maintain the sidelink.

[0027] In some possible implementations, the step of establishing a second radio resource control connection to the second network device includes: establishing an RRC connection to the second network device when the sidelink is not disconnected at the detection time, where the detection time includes a time a first length of time after the first indication information is transmitted.

[0028] In some possible implementations, the radio resource control release information is received when the first terminal meets a handover condition and a session belonging to the first terminal does not exist between the first terminal and the first network device.

[0029] According to a third aspect, there is provided a communication method, comprising: determining that a first terminal satisfies a handover condition and that a session belonging to the first terminal does not exist between the first terminal and a first network device, where the first terminal is an intermediate device for a second terminal to access the first network device, and a first radio resource control connection exists between the first terminal and the first network device; and sending radio resource control release information to the first terminal, where the radio resource control release information indicates to release the first radio resource control connection between the first terminal and the first network device.

[0030] When the first terminal satisfies the handover condition and determines that there is no session belonging to the first terminal, the first network device may instruct the first terminal to release the radio resource control connection, so that the first terminal may send first instruction information to the second terminal, and the second terminal may perform subsequent processing based on the first instruction information to avoid interruptions in the data communicated by the second terminal.

[0031] In some possible implementations, the method further includes: receiving a measurement report from the first terminal, where the measurement report includes information indicating a signal quality obtained by the first terminal through the measurement; and determining, based on the measurement report, that the first terminal satisfies a handover condition.

[0032] The first network device may determine, based on the measurement report from the first terminal, whether the first terminal satisfies a handover condition, and determine whether to send handover indication information to the first terminal.

[0033] In some possible implementations, the method further comprises releasing the first radio resource control connection between the first terminal and the first network device.

[0034] After sending the radio resource control release information to the first terminal, the first network device may release the first radio resource control connection to the first terminal.

[0035] According to a fourth aspect, there is provided a communication method, comprising: determining whether a session belonging to a first terminal exists between the first terminal and a first network device, where the first terminal is an intermediate device for a second terminal to access the first network device; and, when the session belonging to the first terminal does not exist, sending a first radio resource control reconfiguration message to the first terminal, where the first radio resource control reconfiguration message includes information indicating at least one non-measurable cell and / or at least one measurable cell covered by the first network device.

[0036] When there is no session belonging to the first terminal, the first network device may instruct the first terminal to measure only cells covered by the first network device, so that the first terminal may be handed over from its current serving cell to a cell covered by the first network device with better signal quality, thereby avoiding interruptions in data communicated by the second terminal through the first terminal.

[0037] In some possible implementations, the method further comprises: when a session belonging to the first terminal exists, transmitting a second radio resource control reconfiguration message to the first terminal, wherein the second radio resource control reconfiguration message comprises information indicating a cell covered by the first network device and / or another cell, the another cell being a cell other than the cell covered by the first network device.

[0038] When a session belonging to the first terminal exists, the first network device may send a second radio resource control reconfiguration message to the first terminal, so that the first terminal may perform signal measurements based on the second radio resource control reconfiguration message and determine whether a cell with better signal quality exists.

[0039] In some possible implementations, the second radio resource control reconfiguration message includes any one or more of at least one measurement event, a measurable cell whitelist, or a non-measurable cell blacklist, where the measurable cell whitelist includes at least one measurable cell within or outside the coverage of the first network device, and the non-measurable cell blacklist includes at least one non-measurable cell.

[0040] The first network device may send a second radio resource control reconfiguration message to the first terminal, so that when a session belonging to the first terminal exists, the first terminal may be handed over to a network with better signal quality.

[0041] In some possible implementations, the method further comprises receiving a first measurement report from the first terminal, wherein the first measurement report is determined based on the first radio resource control reconfiguration message or the second radio resource control reconfiguration message.

[0042] The first network device may send a different radio resource control reconfiguration message to the first terminal, and may further receive a first measurement report from the first terminal to determine whether to send handover instruction information to the first terminal.

[0043] In some possible implementations, the method further includes a step of receiving a second measurement report from the first terminal, where the second measurement report includes information indicating the signal quality obtained by the first terminal through the measurement; and a step of determining that the first terminal satisfies the handover conditions based on the second measurement report.

[0044] The first network device may determine whether the first terminal satisfies a handover condition based on the second measurement report from the first terminal, and determine whether to send handover indication information to the first terminal. After receiving the second measurement report, the first network device may alternatively determine whether a session belonging to the first terminal exists, and send a first radio resource control reconfiguration message or a second radio resource control reconfiguration message to the first terminal.

[0045] According to a fifth aspect, there is provided a communication method, the method comprising: receiving a first radio resource control reconfiguration message from a first network device when a session belonging to the first terminal does not exist between the first terminal and the first network device, where the first radio resource control reconfiguration message includes information indicating at least one non-measurable cell and / or at least one measurable cell covered by the first network device, and the first terminal is an intermediate device for a second terminal to access the first network device; and performing signal measurement based on the first radio resource control reconfiguration message.

[0046] When there is no session belonging to the first terminal, the first terminal may perform signal measurements based on the first radio resource control reconfiguration message, thereby avoiding a situation where the second terminal cannot transmit data to the first network device through the first terminal because the first terminal is disconnected from the first network device.

[0047] In some possible implementations, when a session belonging to the first terminal exists, a second radio resource control reconfiguration message is received from the first network device, where the second radio resource control reconfiguration message includes information indicating a cell covered by the first network device and / or another cell, the another cell being a cell other than the cell covered by the first network device; and signal measurements are performed based on the second radio resource control reconfiguration message.

[0048] When a session belonging to the first terminal exists, the first terminal 2 Signal measurements may be performed based on the radio resource control reconfiguration message to determine whether there is a cell with better signal quality.

[0049] In some possible implementations, the second radio resource control reconfiguration message includes any one or more of at least one measurement event, a measurable cell whitelist, or a non-measurable cell blacklist, where the measurable cell whitelist includes at least one measurable cell within or outside the coverage of the first network device, and the non-measurable cell blacklist includes at least one non-measurable cell.

[0050] The first terminal is 2 Signal measurements may be performed based on the radio resource control reconfiguration message, so that when a session belonging to the first terminal exists, the first terminal is handed over to a network with better signal quality.

[0051] In some possible implementations, the method further comprises: transmitting a first measurement report to the first network device, wherein the first measurement report is determined based on the first radio resource control reconfiguration message or the second radio resource control reconfiguration message.

[0052] The first terminal may perform signal measurements based on different radio resource control reconfiguration messages and send different measurement reports to the first network device, so that the first network device can obtain information about the signal quality of each cell.

[0053] In some possible implementations, the method further comprises a step of sending a second measurement report to the first network device before receiving the first radio resource control reconfiguration message or the second radio resource control reconfiguration message from the first network device, wherein the second measurement report includes information indicating a signal quality obtained by the first terminal through the measurement.

[0054] The first terminal may send a second measurement report to the first network device to report the signal quality obtained through the measurement to the first network device, allowing the first network device to determine to send the first radio resource control reconfiguration message or the second radio resource control reconfiguration message. Alternatively, the first terminal may send the second measurement report to the first network device, so that the first network device can determine not to send the radio resource control reconfiguration message and not to hand over the first terminal.

[0055] According to a sixth aspect, there is provided a communications device comprising modules configured to perform a method according to the first aspect, the second aspect or the fifth aspect or any one of their implementations.

[0056] According to a seventh aspect, there is provided a communications device comprising modules configured to perform a method according to the third aspect, or the fourth aspect, or any one of their implementations.

[0057] According to an eighth aspect, there is provided a communication device comprising at least one processor and a communication interface, wherein the communication interface is configured to perform information exchange between the communication device and another communication device, and wherein when program instructions are executed by the at least one processor, the communication device is capable of performing a method according to any one of the first aspect, the second aspect, or the fifth aspect, or implementations thereof.

[0058] According to a ninth aspect, there is provided a communication device comprising at least one processor and a communication interface, wherein the communication interface is configured to perform information exchange between the communication device and another communication device, and wherein when program instructions are executed by the at least one processor, the communication device is capable of performing a method according to the third or fourth aspect, or any one of its implementations.

[0059] According to a tenth aspect, there is provided a communication system comprising a second terminal, a communication device according to the sixth or eighth aspect, and a communication device according to the seventh or ninth aspect.

[0060] According to an eleventh aspect, there is provided a computer-readable medium storing program code for execution by a device, the program code being for performing a method according to any one of the first, second, third, fourth or fifth aspects or implementations thereof.

[0061] According to a twelfth aspect, there is provided a computer program product comprising instructions which, when executed on a computer, enable the computer to perform a method according to any one of the first, second, third, fourth or fifth aspects or implementations thereof.

[0062] According to a thirteenth aspect, there is provided a chip including a processor and a data interface, wherein the processor reads instructions stored in a memory through the data interface to perform a method according to any one of the first, second, third, fourth, or fifth aspects, or implementations thereof.

[0063] Optionally, in the implementation, the chip may further include a memory, the memory storing instructions, and the processor configured to execute the instructions stored in the memory, such that when the instructions are executed, the processor is configured to perform a method according to any one of the first, second, third, fourth, or fifth aspects, or implementations thereof.

[0064] The chip may specifically be a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). [Brief explanation of the drawings]

[0065] [Figure 1] 1 is a diagram of a scenario of a communication method between devices.

[0066] [Figure 2] 1 is a schematic flowchart of a communication method.

[0067] [Figure 3] 1 is a schematic flowchart of a communication method according to an embodiment of the present application;

[0068] [Figure 4] 4 is a schematic flowchart of another communication method according to an embodiment of the present application;

[0069] [Figure 5] 4 is a schematic flowchart of yet another communication method according to an embodiment of the present application;

[0070] [Figure 6] 1 is a schematic flowchart of a communication method according to an embodiment of the present application;

[0071] [Figure 7] 4 is a schematic flowchart of another communication method according to an embodiment of the present application;

[0072] [Figure 8] 1 is a diagram of the structure of a communication device according to an embodiment of the present application;

[0073] [Figure 9] FIG. 2 is a diagram of the structure of another communication device according to an embodiment of the present application;

[0074] [Figure 10] 1 is a diagram of the structure of a communication device according to an embodiment of the present application;

[0075] [Figure 11] FIG. 2 is a diagram of the structure of another communication device according to an embodiment of the present application;

[0076] [Figure 12] FIG. 10 is a diagram of the structure of yet another communication device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0077] The technical solutions of the present application will be described below with reference to the accompanying drawings.

[0078] The technical solutions in the embodiments of the present application may be applied to various communication systems, such as a global system for mobile communications (GSM), a code division multiple access (CDMA) system, a wideband code division multiple access (WCDMA) system, a general packet radio service (GPRS) system, a long term evolution (LTE) system, an LTE frequency division duplex (FDD) system, an LTE time division duplex (TDD) system, a universal mobile telecommunications system (UMTS), a worldwide interoperability for microwave access (WiMAX) communication system, a fifth generation (5G) system, or a new radio (NR) system.

[0079] FIG. 1 is a diagram of a scenario of a communication method between devices. In the scenario 100 shown in FIG. 1, there are mainly two types of communication interfaces: a communication interface (Uu interface) between a terminal 121 and a network device 110, and a communication interface (PC5 interface) between a terminal 121 and a terminal 122. The Uu interface is used for communication between a user equipment and a base station or a roadside unit, and the PC5 interface is used for sidelink communication between terminals. On the Uu interface, a link through which a terminal transmits data to a base station is called an uplink, and a link through which a terminal receives data transmitted by a base station is called a downlink. The communication interface between terminals is called a PC5 interface. On the PC5 interface, a link for data transmission between terminals is called a sidelink or a direct link. The sidelink is generally used in scenarios such as a device-to-device (D2D) scenario in which devices can communicate directly with each other. In this scenario, data transmission between devices does not need to be performed through a base station. Vehicle-to-everything (V2X) communication can be considered as a special case of D2D communication.

[0080] On the Uu interface, data transmission and radio resource control (RRC) signaling are performed between a terminal and a base station through radio bearers. A radio bearer for data transmission is called a data radio bearer (DRB), and a bearer for RRC signaling transmission is called a signaling radio bearer (SRB). A radio bearer includes a packet data convergence protocol (PDCP) entity and a radio link control (RLC) bearer. An RLC bearer includes an RLC entity and a corresponding logical channel (LCH). A radio bearer configuration is the configuration of the PDCP entity, RLC entity, and logical channel of a radio bearer. The radio bearer configuration must ensure the quality of service (QoS) requirements of the service whose transmission is performed over the radio bearer. On the Uu interface, a radio bearer is configured for a terminal by a network device.

[0081] Data transmission and RRC signaling also need to be performed between terminals over the PC5 interface through radio bearers. The radio bearers over the PC5 interface may be referred to as sidelink radio bearers (SL RBs). In a Long Term Evolution (LTE) V2X system, the radio bearers over the PC5 interface are established separately by the transmitting terminal and the receiving terminal, and the configuration of the radio bearers is predefined in a standard or determined by the transmitting terminal and the receiving terminal.

[0082] A terminal may communicate with a network device. The terminal may be an access terminal, a subscriber unit, a subscriber station, a mobile station, a mobile console, a remote station, a remote terminal, a mobile device, a subscriber terminal, a user equipment (UE), a wireless communication device, a user agent, or a user device. The user equipment may alternatively be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication capabilities, a computing device, another processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal in a 5G network, any form of user equipment in a future network, or the like. This is not particularly limited in this embodiment of the present application.

[0083] A network device in this embodiment of the present application may be a device configured to communicate with a terminal and enable the terminal to access a radio access network (RAN). The network device may also be referred to as an access network device, an access network node, or a base station. It may be understood that in systems using different radio access technologies, the name of a device having the functionality of a base station may be different. For ease of explanation, in this embodiment of the present application, devices providing wireless communication access functionality for terminals are collectively referred to as a network device. The network device may be a base transceiver station (BTS) in a global system for mobile communications (GSM) or code division multiple access (CDMA) system, a Node B (Node B, NB) in a wideband code division multiple access (WCDMA) system, an evolved Node B (eNB, or eNodeB) in an LTE system, or a radio controller in a cloud radio access network (CRAN) scenario. Alternatively, the network device may be a relay station, an access point, an in-vehicle device, a wearable device, a network device in a 5G network, a network device in a future evolved PLMN network, or one antenna panel or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or may be a network node forming a next generation Node Base station (gNB) or a transmission point, for example a baseband unit (BBU) or a distributed unit (DU).This is not limited to this embodiment of the present application.

[0084] In an embodiment of the present application, a terminal or network device includes a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. The hardware layer includes hardware such as a central processing unit (CPU), a memory management unit (MMU), and memory (also referred to as main memory). The operating system may be any one or more types of computer operating systems that implement service processing through processes, such as the Linux operating system, Unix operating system, Android operating system, iOS operating system, or Windows operating system. The application layer includes applications such as a browser, an address book, word processing software, and instant messaging software. In addition, the specific structure of the executing entity of the method provided in the embodiment of the present application is not specifically limited in the embodiment of the present application, as long as it can execute a program recording code for the method provided in the embodiment of the present application to perform communication according to the method provided in the embodiment of the present application. For example, the method provided in the embodiment of the present application may be executed by the terminal or network device, or may be executed by a functional module in the terminal or network device, such as a chip or processor, that can call and execute a program.

[0085] Furthermore, aspects or features of the present application may be implemented as a method, apparatus, or article of manufacture using standard programming and / or engineering techniques. For example, computer-readable media may include, but are not limited to, magnetic storage components (e.g., hard disks, floppy disks, or magnetic tapes), optical disks (e.g., compact discs (CDs) or digital versatile discs (DVDs)), smart cards, and flash memory components (e.g., erasable programmable read-only memory (EPROM), cards, sticks, or key drives). Furthermore, various storage media described herein may represent one or more devices configured to store information and / or other machine-readable media. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, storing, and / or conveying instructions and / or data.

[0086] To improve network performance, D2D communication supports user equipment-to-network relay (UE-to-network relay, U2N Relay). A relay terminal as a relay device may relay data whose transmission is performed between a remote terminal and a network device. In scenario 100, terminal 121 may be used as a relay terminal, and terminal 121 may be used as a remote terminal.

[0087] 2 is a schematic flowchart of a communication method 200. The method 200 includes steps S201 to S208.

[0088] S201: A source base station sends a first RRC reconfiguration message to a terminal, where the first RRC reconfiguration message is used to configure at least one measurement event for the terminal to measure signals of each base station.

[0089] The first RRC reconfiguration message may be used to configure at least one measurement event, for example, one of the at least one measurement events being when the signal strength of the serving cell is below a threshold and the signal strength of the target cell is below a threshold. strength may be higher than a threshold.

[0090] An RRC connection is established between the terminal and the source base station, the serving cell is one of at least one cell covered by the source base station, and the target cell may be one of at least one cell covered by the target base station.

[0091] The terminal may perform measurements based on at least one measurement event. For example, one of the at least one measurement event may be that the signal strength of the source base station is lower than a threshold and the signal strength of the target base station is higher than or equal to a threshold. In this case, the terminal may measure the signal strength of each base station.

[0092] For example, the source base station may send a first RRC reconfiguration message to the terminal after establishing an RRC connection to the terminal. The terminal may periodically perform measurements and determine whether the measurement results satisfy any one of at least one measurement event.

[0093] S202: When the measurement result satisfies any measurement event, the terminal sends a measurement report (MR) to the source base station.

[0094] The MR may include a measurement event in at least one measurement event that the measurement result satisfies. The MR may further include a target cell or target base station that allows the measurement result to satisfy the measurement event. The target cell may be a cell covered by the target base station.

[0095] S203: The source base station sends a handover request message to the target base station based on the MR sent by the terminal.

[0096] After receiving the MR sent by the terminal, the source base station may send a handover request message to the target base station when the terminal has service.

[0097] S204: The target base station may send a handover acknowledgement message to the source base station.

[0098] The target base station determines whether to grant the terminal access based on the number of other terminals connected to the target base station and the like. If the target base station determines to grant the terminal access, the target base station may send a handover acknowledgement message to the source base station.

[0099] The handover acknowledgement message may include target cell-related information and related configuration parameters required by the terminal to access the target cell. The target cell-related information may include one or more of the following: a physical cell identifier (PCI) of the target cell, frequency information corresponding to the target cell, a cell radio network temporary identifier (C-RNTI) of the target cell assigned to the terminal by the target base station, and the like. The related configuration parameters required by the terminal to access the target cell include one or more of random access channel (RACH) resource information (e.g., dedicated RACH resources and / or common RACH resources) required to access the target cell, security-related algorithms of the target base station, and the like.

[0100] S205: The source base station may send a handover command message to the terminal.

[0101] The handover command message (or may be understood as a second RRC reconfiguration message) may include relevant information of the target cell and relevant configuration parameters required by the terminal to access the target cell.

[0102] S206: The terminal initiates random access to the target base station based on the handover command and establishes an RRC connection to the target base station.

[0103] After disconnecting the RRC connection to the source base station, the terminal may initiate random access to the target base station, and establish an RRC connection to the target base station after accessing the target base station.

[0104] S207: The terminal sends an RRC reconfiguration complete message to the target base station.

[0105] The terminal may send an RRC reconfiguration complete message to the target base station when the RRC connection between the terminal and the target base station is successfully established.

[0106] S208: The target base station sends an RRC connection release message to the source base station.

[0107] The source base station may release the context of the terminal after receiving the context release message.

[0108] According to method 200, a terminal may complete a handover (HO) between cells.

[0109] When the base station releases the RRC connection to the relay terminal, the data of the remote terminal may be interrupted. For example, when the terminal in FIG. 2 is a relay terminal and a protocol data unit (PDU) session of the terminal does not exist between the terminal and the source base station, the source base station does not execute S203 after receiving the MR. As a result, the data of the remote terminal may be interrupted.

[0110] To solve the data interruption problem of the remote terminal that occurs in the scenario in FIG. 2 or another scenario, the embodiment of the present application provides a communication method.

[0111] 3 is a schematic flowchart of a communication method according to an embodiment of the present application. The method 300 includes steps S310 to S330. The device that performs steps S320 and S330 may be a first terminal, or may be a component such as a chip in the first terminal.

[0112] S310: The first network device determines that the first terminal satisfies a handover condition and that there is no session belonging to the first terminal.

[0113] The first network device may determine whether the first terminal satisfies a handover condition, and may further determine whether a session belonging to the first terminal exists between the first network device and the first terminal. The first terminal is an intermediate device for a second terminal to access the first network device. A first radio resource control connection (i.e., a first RRC connection) exists between the first terminal and the first network device.

[0114] For example, the handover condition may be that at least one measurement event is satisfied. After an RRC connection is established between the first terminal and the first network device, the first network device may send the at least one measurement event to the first terminal. The first terminal device may perform measurements periodically or aperiodically. When any one or more of the at least one measurement event is satisfied, the first terminal may send a measurement report to the first network device. Upon receiving the measurement report, the first network device may determine that the handover condition is satisfied.

[0115] For example, the measurement report may indicate at least one measurement event that is met.

[0116] The first network device may send at least one measurement event to the first terminal, which may include one or more of the following events: the signal quality of the serving cell falling below a corresponding threshold; the signal quality of the neighboring cell starting to become higher than the signal quality of the serving cell by a certain offset; the signal quality of the neighboring cell rising above a corresponding threshold; the signal quality of the serving cell falling below threshold 1 and the signal quality of the neighboring cell rising above threshold 2; the signal quality of the neighboring cell starting to become higher than the signal quality of a secondary cell (SCell) by a certain offset; the signal quality of an inter-radio access technology (inter-RAT) neighboring cell rising above a corresponding threshold; and the signal quality of a primary cell (PCell) falling below threshold 1 and the signal quality of the inter-RAT neighboring cell rising above threshold 2.

[0117] When the first network device determines that the first terminal satisfies the handover condition, the first network device may further determine whether a session belonging to the first terminal exists. When a session belonging to the first terminal does not exist, the first network device may send a connection release message to the first terminal. The connection release message indicates that the first RRC connection between the first terminal and the first network device is to be released.

[0118] Before the first network device determines whether the first terminal satisfies the handover condition, the first network device may receive a measurement report from the first terminal. The measurement report includes information indicating a signal quality obtained by the first terminal through the measurement. The first network device may determine whether the first terminal satisfies the handover condition based on the measurement report.

[0119] After the first network device sends the radio resource control release information to the first terminal, the first network device may further release the first radio resource control connection to the first terminal.

[0120] S320: Receive connection release instruction information sent by the first network device.

[0121] The connection release instruction information instructs to release the connection between the first terminal and the first network device.

[0122] The connection release indication information may be, for example, a radio resource control release message, which indicates that a first radio resource control connection between the first terminal and the first network device is to be released.

[0123] The connection release indication information may be carried in an RRC message sent by the first network device to the first terminal. In other words, before releasing the first radio resource control connection between the first terminal and the first network device, the first network device may send the connection release indication information to the first terminal through the first radio resource control connection.

[0124] The first network device may release the first radio resource control connection and send a radio resource control release message to the first terminal when at least one of the following occurs: network-side RRC connection release information is received; the load of the first network device exceeds a preset value; a higher layer authentication fails; a lower layer error (e.g., a media access control (MAC) layer link failure or a radio link control (RLC) layer link failure) occurs; the radio link control is restored and no session belonging to the first terminal exists; a timer corresponding to the first radio resource control connection expires; a message exchange performed over the first radio resource control connection fails; a handover condition is met; and no session belonging to the first terminal exists, and the like.

[0125] S330: Send first instruction information to a second terminal, where the first terminal is an intermediate device for the second terminal to access the first network device, and the first instruction information instructs at least one of: instructing to release a sidelink between the first terminal and the second terminal; instructing to release a first radio resource control connection; or instructing that the state of the first radio resource control connection is a connection failure state.

[0126] The first indication information may be carried in an RRC message transmitted by the first terminal to the second terminal via a sidelink. The sidelink between the first terminal and the second terminal may be an RRC connection established between the first terminal and the second terminal. The RRC message transmitted by the first terminal to the second terminal via the sidelink may also be referred to as a PC5-RRC message.

[0127] The first indication information may be used as a field of a PC5-RRC message and carried in the PC5-RRC message. Alternatively, the first indication information may be used as a PC5-RRC message.

[0128] According to the method 300, when a radio resource control connection between a first terminal serving as a relay device and a network device is released, first indication information is sent to a second terminal serving as a remote terminal, so that the second terminal can perform subsequent operations based on the first indication information and avoid data interruption.

[0129] The first indication information may indicate that the sidelink between the first terminal and the second terminal is to be released. In this case, after receiving the first indication information, the second terminal may perform relay reselection or initiate random access to the network device and establish an RRC connection to the network device.

[0130] The first indication information may further indicate that the first radio resource control connection is released, or may indicate that the state of the first radio resource control connection is a connection failure state.

[0131] The first indication information indicating the state of the radio resource control connection can reduce redundancy of the first indication information compared to a specific event in which the first indication information indicates that the first radio resource control connection has been released.

[0132] Specifically, the relay service is configured to provide a relay service for a second terminal and a network device when a radio link failure (RLF) occurs on a radio resource control connection between the first terminal and the network device, a radio resource control release message is received, an RLF recovery fails, an RRC connection establishment fails, a handover fails, or the like. 1 The terminal may send third state information to the second terminal to indicate a state of the radio resource control connection between the first terminal and the network device. Thus, after receiving the third state information, the second terminal may perform relay reselection or initiate random access to the network device to establish an RRC connection to the network device. The first terminal sends the third state information to the second terminal, so that different specific events regarding the connection state of the radio resource control connection between the first terminal and the network device can be indicated by using the same information, thereby reducing the redundancy of the first indication information.

[0133] In some embodiments, after transmitting the first indication information, the first terminal may release the sidelink between the first terminal and the second terminal.

[0134] In some other embodiments, the first terminal may perform a subsequent action based on the second terminal's response to the first indication information.

[0135] When the response of the second terminal indicates that the sidelink should be maintained, the first terminal may establish a second radio resource control connection to the second network device. The second radio resource control connection is used by the second terminal to access the second network device. In other words, the first terminal reselects a network device for the second terminal to provide service for the second terminal.

[0136] After receiving the first instruction information, the second terminal may transmit second instruction information to the first terminal. The second instruction information instructs the first terminal to maintain the sidelink. The second instruction information may be understood as the second terminal's response to the first instruction information. The first terminal receives the second instruction information, i.e., obtains the second terminal's response instructing the first terminal to maintain the sidelink.

[0137] After receiving the first indication, the second terminal may disconnect or maintain the sidelink with the first terminal. The first terminal may detect the sidelink at a detection time point that is a first length of time after the first indication is transmitted. If the detection result at the detection time point indicates that the sidelink still exists, i.e., the sidelink has not been released by the second terminal but is maintained by the second terminal, the first terminal receives a response from the second terminal indicating that the sidelink will be maintained.

[0138] It should be understood that the first time length may be set in advance, may be determined by the second terminal and the first terminal through an agreement, or may be determined by the first terminal based on information such as communication quality of the sidelink, etc. This is not limited to this embodiment of the present application.

[0139] After the first terminal receives a response from the second terminal indicating that the sidelink is maintained, the first terminal may establish a second radio resource control connection to the second network device. Conversely, if the first terminal does not receive the second indication information sent by the second terminal, or if the sidelink at the time of detection is released by the second terminal, the first terminal may no longer establish the second radio resource control connection to the second terminal.

[0140] The first terminal not receiving the second instruction information transmitted by the second terminal may mean that the first terminal does not receive the second instruction information transmitted by the second terminal within a second time period after the first instruction information is transmitted. The second time period may be preset, or may be determined by the second terminal and the first terminal through an agreement, or may be determined by the first terminal based on information such as communication quality of the sidelink.

[0141] For example, after S320, the first terminal may establish a second radio resource control connection to the second network device. The establishment of the second radio resource control connection may be independent of S330.

[0142] The second radio resource control connection is established so as to avoid data interruption for the second terminal.

[0143] Additionally, the apparatus performing the method 300 may determine a connection status of the radio resource control connection between the first terminal and the first network device, and send status indication information to the second terminal. The status indication information includes first status information, second status information, or third status information. The first status information indicates that the connection status is an establishing status, the second status information indicates that the connection status is an established status, and the third status information indicates that the connection status is an establishment failed status. The first terminal is an intermediate device for the second terminal to access the first network device.

[0144] Specifically, the establishing state indicates that a connection is established or that connection establishment is being performed. The connection state is determined to be the establishing state when the first terminal is being handed over, the radio resource control connection is being established, the radio resource control connection that experiences a radio link failure is being restored (Uu-RLF recovery), or the like.

[0145] The established state indicates that the connection is established or has been successfully established. The connection state is determined to be the established state when the first terminal is handed over, the radio resource control connection is established, the radio resource control connection that experiences a radio link failure is restored (Uu-RLF recovery), or the like.

[0146] The establishment failure state indicates that the establishment of the connection has failed or that the connection is unavailable. The connection state is determined to be the establishment failure state when the handover of the first terminal device fails (HO failure), the establishment of the radio resource control connection fails, a radio link failure occurs on the radio resource control connection, the recovery of the radio resource control connection fails resulting in a radio link failure (Uu-RLF failure), the radio resource control connection is released, or the like.

[0147] For example, when radio resource control release information sent by the first network device is received, and the radio resource control release information indicates that the radio resource control connection is to be released, the connection state is determined to be an establishment failure state.

[0148] 4 is a schematic flowchart of a communication method according to an embodiment of the present application. The communication method 400 includes steps S410 to S460.

[0149] An RRC connection is established between the first terminal and the first network device.

[0150] After an RRC connection is established between the first terminal and the first network device, the first network device may send at least one measurement event to the first terminal.

[0151] The first terminal detects the signal of each cell and determines whether the detection result satisfies at least one measurement event. If the detection result satisfies any measurement event, S410 may be executed.

[0152] S410: The first terminal sends a measurement report to the first network device.

[0153] For example, the measurement report may include measurement events satisfied by the first terminal.

[0154] S420: The first network device determines that there is no session belonging to the first terminal.

[0155] The at least one measurement event may include at least one of measurement event A2, measurement event A3, measurement event A4, measurement event A5, measurement event A6, measurement event B1, and measurement event B2.

[0156] Measurement event A2 is when the signal quality of the serving cell falls below the corresponding threshold.

[0157] Measurement event A3 is when the signal quality of the neighboring cell starts to become higher than the signal quality of the serving cell by a certain offset.

[0158] Measurement event A4 is when the signal quality of the neighboring cell becomes higher than the corresponding threshold.

[0159] Measurement event A5 is when the signal quality of the serving cell falls below threshold 1 and the signal quality of the neighboring cell rises above threshold 2.

[0160] Measurement event A6 is when the signal quality of the neighboring cell starts to become higher than the signal quality of the secondary cell (SCell) by a certain offset.

[0161] Measurement event B1 is that the signal quality of an Inter-RAT neighboring cell is higher than a corresponding threshold.

[0162] Measurement event B2 occurs when the signal quality of the primary cell (PCell) becomes lower than threshold 1 and the signal quality of the inter-RAT neighbor cell becomes higher than threshold 2.

[0163] It should be understood that both the primary cell and the secondary cell are cells covered by the first network device and configured to serve the first terminal. The primary cell and the secondary cell correspond to different frequency bands. The neighboring cell is a cell other than the serving cell, and the serving cell is a cell covered by the first network device. The serving cell serves the first terminal.

[0164] After receiving the measurement report, the first network device may determine whether a session of the first terminal exists. When the first network device determines that a session of the first terminal does not exist, the first network device may release the RRC context of the first terminal and execute S430. The first network device may release the RRC context of the first terminal, i.e., the first access network device disconnects the RRC connection from the first terminal.

[0165] When determining that a session belonging to the first terminal does not exist, the first network device may determine whether a protocol data unit (PDU) session belonging to the first terminal exists. When the first network device determines that a PDU session for the first terminal does not exist, the first network device may perform S430 and disconnect the RRC connection from the first terminal.

[0166] S430: The first network device sends RRC release information to the first terminal, where the RRC release information indicates that the first network device releases the RRC connection of the first terminal.

[0167] After receiving the RRC release information, the first terminal may enter an RRC idle mode (RRC_IDLE) and perform any one of S440, S450, and S460.

[0168] S440: The first terminal transmits sidelink release instruction information to the second terminal.

[0169] The sidelink release instruction information instructs the second terminal to disconnect the sidelink connection from the first terminal.

[0170] After receiving the sidelink release indication, the second terminal may disconnect the sidelink connection from the first terminal, i.e., release the sidelink context.

[0171] After disconnecting the sidelink connection from the first terminal, the second terminal may perform relay reselection or cell (re)selection, i.e., the second terminal may redetermine a relay terminal, or the second terminal may initiate random access to the second network device and establish an RRC connection to the second network device.

[0172] S450 includes S451 to S453.

[0173] S451: The first terminal may send Uu interface RRC release information to the second terminal.

[0174] The Uu interface RRC release information indicates that the RRC connection between the first terminal and the first network device is terminated, for example, the Uu interface RRC release information indicates that the first network device releases the RRC context of the first terminal.

[0175] After receiving the Uu interface RRC release information sent by the first terminal, the second terminal may release the sidelink with the first terminal.

[0176] Alternatively, the second terminal may maintain a sidelink with the first terminal, i.e., maintain a connection with the first terminal.

[0177] In some embodiments, when the second terminal decides to maintain the sidelink, it may send sidelink maintenance information to the first terminal.

[0178] S452: The first terminal acquires a sidelink maintenance response from the second terminal.

[0179] For example, the first terminal receiving sidelink maintenance information transmitted by the second terminal may be understood as the first terminal obtaining a sidelink maintenance response from the second terminal.

[0180] For example, a timer may be set in the first terminal. The first terminal may start the timer when transmitting the Uu interface RRC release information. After the timer is started, the timer expires after a first period of time. The first period of time may be preset, determined by the second terminal and the first terminal through an agreement, or determined by the first terminal based on information such as the communication quality of the sidelink. When the timer expires, the first terminal may determine whether the sidelink with the second terminal remains connected. If the first terminal determines that the sidelink with the second terminal remains connected, the first terminal obtains a sidelink maintenance response from the second terminal. In other words, if the first terminal determines that the sidelink with the second terminal has not been disconnected at the time of detecting a preset period of time since the transmission of the Uu interface RRC release information, the first terminal obtains a sidelink maintenance response from the second terminal.

[0181] S453: The first terminal establishes an RRC connection to the second network device.

[0182] After accessing the second network device, the first terminal may camp on a cell covered by the second network device.

[0183] It should be understood that the second network device may be the first network device or may be a network device other than the first network device.

[0184] When the second network device is the first network device, the cell on which the first terminal camps after performing random access may be a cell different from the serving cell of the first terminal before S410.

[0185] After the first terminal establishes an RRC connection to the second network device, the first terminal, as a relay terminal of the second terminal, may relay data between the second terminal and the second network device.

[0186] If the first terminal does not obtain a sidelink maintenance response from the second terminal after S451, the first terminal may release the sidelink with the second terminal.

[0187] S460 includes S461 to S463.

[0188] S461: The first terminal may send status indication information to the second terminal.

[0189] When an RRC connection state between the first terminal and the network device changes, the first terminal may send state indication information to the second terminal.

[0190] The state of the RRC connection between the first terminal and the network device may be one of an establishing state, an established state, or a failed state.

[0191] Before S410, the RRC connection state between the first terminal and the first network device is in an established state. The first network device may send RRC release information to the first terminal to release the RRC connection to the first terminal. 3 In step S460, when receiving the RRC release information sent by the first network device, the first terminal may determine that the RRC connection status between the first terminal and the first network device changes to a failed status and execute step S461.

[0192] Alternatively, when receiving the RRC release information sent by the first network device, the first terminal may detect the RRC connection status between the first terminal and the first network device. When detecting that the RRC connection status between the first terminal and the first network device is in a failed state, the first terminal may execute S461.

[0193] S462: The first terminal acquires a sidelink maintenance response from the second terminal.

[0194] Similarly to S452, when the first terminal receives the sidelink maintenance information transmitted by the second terminal, or when the first terminal determines that the sidelink with the second terminal has not been disconnected at the time of detecting the predetermined period since the transmission of the status indication information in S461, the first terminal may obtain a sidelink maintenance response from the second terminal. Then, the first terminal may execute S463.

[0195] S463: The first terminal establishes an RRC connection to the second network device.

[0196] If the first terminal does not receive a sidelink maintenance response from the second terminal after S461, the first terminal may release the sidelink with the second terminal.

[0197] Optionally, after S440, alternatively, the first terminal may not release the sidelink and may establish an RRC connection to the second network device after obtaining a sidelink maintenance response of the second terminal.

[0198] FIG. 5 is a schematic flowchart of a communication method according to an embodiment of the present application.

[0199] When the first terminal is an intermediate device for a second terminal to access a network device, the first terminal may transmit event information to the second terminal to indicate an event related to the radio resource control connection between the first terminal and the network device. For example, after the first terminal determines that an RLF occurs on the radio resource control connection to the network device, the first terminal may transmit event information to the second terminal to indicate that an RLF occurs on the radio resource control connection. In other words, different times may correspond to different event information.

[0200] After receiving different event information, the second terminal may perform the same operation. For example, event 1 is that handover of the first terminal fails, and event 2 is that RLF occurs on the radio resource control connection between the first terminal and the network device. The event information corresponding to event 1 is different from that corresponding to event 2. However, after the second terminal receives the event information corresponding to event 1 and the event information corresponding to event 2, both operations performed by the second terminal may be to release the sidelink with the first terminal.

[0201] In other words, the first terminal sends event information to the second terminal to indicate an event related to the radio resource control connection between the first terminal and the network device. Because there are a large number of events related to the radio resource control connection between the first terminal and the network device, more bits are needed in the event information to distinguish different event information, which causes information redundancy. To solve the above problem, an embodiment of the present application may provide a communication method 500. The method 500 includes S510 and S520.

[0202] S510: Determine a connection status of a radio resource control connection between a first terminal and a network device.

[0203] Specifically, the connection state may be determined to be an establishing state when the first terminal is being handed over, a radio resource control connection is being established, or a radio resource control connection in which a radio link failure occurs is being restored.

[0204] When the first terminal is handed over, a radio resource control connection is established, or a radio resource control connection in which a radio link failure occurs is restored, the connection state may be determined to be an established state.

[0205] The connection state may be determined to be an establishment failure state when handover of the first terminal device fails, establishment of a radio resource control connection fails, a radio link failure occurs on the radio resource control connection, recovery of the radio resource control connection resulting in a radio link failure fails, or the radio resource control connection is released.

[0206] S520: Send status indication information to the second terminal, where the status indication information includes first status information, second status information, or third status information, where the first status information indicates that the connection status is an establishing status, the second status information indicates that the connection status is an established status, and the third status information indicates that the connection status is an establishment failed status; the first terminal is an intermediate device for the second terminal to access the network device.

[0207] For events corresponding to the same connection state of the radio resource control connection between the first terminal and the network device, the operation of the second terminal may be the same. According to the method 500, the first terminal sends state indication information to the second terminal to indicate the connection state of the radio resource control connection between the first terminal and the network device. The number of connection states of the radio resource control connection is smaller than the number of events related to the radio resource control connection. Therefore, the number of information bits can be reduced, information redundancy can be avoided, and the processing of the first terminal and the second terminal becomes simpler.

[0208] It should be understood that the first terminal may periodically or non-periodically detect the status of the radio resource control connection between the first terminal and the network device, determine the connection status of the radio resource control connection between the first terminal and the network device, and send status indication information to the second terminal.

[0209] Alternatively, when determining that the connection status of the radio resource control connection between the first terminal and the network device changes, the first terminal may send status indication information to the second terminal.

[0210] Specifically, when receiving the radio resource control release information sent by the first network device, the first terminal may determine that the connection state is an establishment failure state, and the radio resource control release information indicates that the radio resource control connection is to be released.

[0211] The radio resource control release information indicates that the connection state of the radio resource control connection changes.

[0212] After receiving the radio resource control release information sent by the first network device, the first terminal may establish a second radio resource control connection to the second network device, which is used by the second terminal to access the second network device.

[0213] For example, after receiving second indication information sent by the second terminal, the first terminal may establish a second radio resource control connection to the second network device, the second indication information indicating that the sidelink is to be maintained.

[0214] The second instruction information can be understood as response information to the first instruction information.

[0215] For example, if the sidelink is not disconnected at the detection time, the first terminal may establish an RRC connection to the second network device, the detection time including a first time length after the first indication information is transmitted.

[0216] 6 is a schematic flowchart of a communication method according to an embodiment of the present application. The communication method 600 includes steps S610 to S630.

[0217] S610: It is determined that there is no session belonging to the first terminal.

[0218] The first network device may determine whether a session belonging to the first terminal exists between the first terminal and the first network device, and may further send the same radio resource control reconfiguration message or a different radio resource control reconfiguration message to the first terminal depending on whether a session belonging to the first terminal exists. The first terminal is an intermediate device for a second terminal to access the first network device, and the first terminal communicates with the second terminal through a sidelink. A first radio resource control connection exists between the first terminal and the first network device.

[0219] For example, the first network device may periodically determine whether a session belonging to the first terminal exists. Alternatively, after receiving indication information, the first network device may determine whether a session belonging to the first terminal exists. The indication information instructs the first network device to determine whether a session belonging to the first terminal exists. Alternatively, after determining that the first terminal satisfies a handover condition, the first network device may determine whether a session belonging to the first terminal exists. This is not limited to this embodiment of the present application.

[0220] When determining whether a session belonging to the first terminal exists, the first network device may determine whether a PDU session of the first terminal exists.

[0221] In some embodiments, after determining that there is no session belonging to the first terminal, the first network device may perform step S620.

[0222] In some other embodiments, after determining that there is no session belonging to the first terminal, the first network device may not perform step S620 and may maintain the first RRC connection to the first terminal. In other words, when there is no session belonging to the first terminal, the first network device may not send an RRC reconfiguration message or handover indication information to the first terminal when the first terminal satisfies a handover condition, so that the second terminal can continue to maintain a connection to the first network device through the first terminal and avoid interruptions in data transmission.

[0223] S620: Send a first RRC reconfiguration message to the first terminal.

[0224] When the first network device determines that a session belonging to the first terminal does not exist between the first terminal and the first network device, the first network device may send a first RRC reconfiguration message (i.e., a first radio resource control reconfiguration message) to the first terminal, wherein the first RRC reconfiguration message includes information indicating at least one non-measurable cell and / or at least one measurable cell covered by the first network device.

[0225] For example, the at least one unmeasurable cell may be an unmeasurable cell covered by the first network device or another unmeasurable cell, which is an unmeasurable cell covered by a network device other than the first network device.

[0226] For example, the information indicating at least one non-measurable cell in the first RRC reconfiguration message may be expressed in the form of a non-measurable cell blacklist, and the information indicating at least one measurable cell covered by the first network device in the first RRC reconfiguration message may be expressed in the form of a measurable cell whitelist. In other words, the first RRC reconfiguration message may include a measurable cell whitelist and / or a non-measurable cell blacklist.

[0227] In some embodiments, when the first network device determines that a session belonging to the first terminal exists between the first terminal and the first network device, the first network device may send a second RRC reconfiguration message (i.e., a second radio resource control reconfiguration message) to the first terminal, the second RRC reconfiguration message including information indicating cells covered by the first network device and / or another cell.

[0228] For example, the second RRC reconfiguration message may include any one or more of at least one measurement event, a measurable cell whitelist, or a non-measurable cell blacklist. The measurable cell whitelist in the second RRC reconfiguration message includes at least one measurable cell covered by the first network device and / or another measurable cell. The other measurable cell is a measurable cell covered by a network device other than the first network device. The non-measurable blacklist in the second RRC reconfiguration message includes at least one non-measurable cell. The at least one non-measurable cell may be an non-measurable cell covered by the first network device or another non-measurable cell. The other non-measurable cell is an non-measurable cell covered by a network device other than the first network device.

[0229] For example, the at least one measurement event in the second RRC reconfiguration message may include: the signal quality of the serving cell becoming higher than a corresponding threshold; the signal quality of the serving cell becoming lower than a corresponding threshold; the signal quality of the neighboring cell starting to be higher than the signal quality of the serving cell by a certain offset; the signal quality of the neighboring cell becoming higher than a corresponding threshold; the signal quality of the serving cell becoming lower than threshold 1 and the signal quality of the neighboring cell becoming higher than threshold 2; the signal quality of the neighboring cell starting to be higher than the signal quality of the secondary cell by a certain offset; and the like. This is not limited to this embodiment of the present application.

[0230] In some embodiments, if the first network device determines at a first point in time that a session belonging to the first terminal exists and the first network device determines at a second point in time that a session belonging to the first terminal does not exist, the first network device may send a first RRC reconfiguration message to the first terminal at the second point in time, where the first point in time is different from the second point in time and the first point in time is earlier than the second point in time.

[0231] In some other embodiments, if the first network device determines at a third point in time that a session belonging to the first terminal does not exist, and the first network device determines at a fourth point in time that a session belonging to the first terminal exists, the first network device may send a second RRC reconfiguration message to the first terminal at the fourth point in time, where the third point in time is different from the fourth point in time and the third point in time is earlier than the fourth point in time.

[0232] S630: Perform signal measurement based on the first RRC reconfiguration message.

[0233] After the first terminal receives the first RRC reconfiguration message from the first network device, the first terminal may perform signal measurement based on the first RRC reconfiguration message.

[0234] For example, if the first RRC reconfiguration message includes information indicating at least one measurable cell covered by the first network device, the first terminal may measure the signal strength of each measurable cell in the at least one measurable cell.

[0235] For example, if the first RRC reconfiguration message includes information indicating at least one unmeasurable cell, the first terminal may not measure the signal strength of a cell included in the at least one unmeasurable cell, and in this case, the first terminal may further measure the signal strength of a cell other than the at least one unmeasurable cell.

[0236] In some embodiments, after the first terminal receives the second RRC reconfiguration message from the first network device, the first terminal may perform signal measurements based on the second RRC reconfiguration message.

[0237] For example, if the second RRC reconfiguration message includes at least one measurement event, the first terminal may perform measurements based on the at least one measurement event. For example, if one of the at least one measurement events may be measurement event A3, the first terminal may measure the signal strength of the serving cell and the signal strength of a cell other than the serving cell.

[0238] For example, if the second RRC reconfiguration message includes a measurable cell whitelist, the first terminal may measure the signal strength of the cells included in the measurable cell whitelist.

[0239] For example, if the second RRC reconfiguration message includes a non-measurable cell blacklist, the first terminal may not measure the signal strength of the cells included in the non-measurable cell blacklist, and in this case, the first terminal may further measure the signal strength of cells other than the cells included in the non-measurable cell blacklist.

[0240] In some embodiments, the first terminal may send a first measurement report to the first network device based on the signal quality obtained through the measurement, the first measurement report being determined based on the first RRC reconfiguration message or the second RRC reconfiguration message.

[0241] In some other embodiments, the first network device may determine whether to send handover indication information to the first terminal based on the first measurement report received from the first terminal.

[0242] The first network device may send the same or different RRC reconfiguration messages to the first terminal depending on whether a session belonging to the first terminal exists. When a session belonging to the first terminal does not exist, the first RRC reconfiguration message sent by the first network device to the first terminal may enable the first terminal to maintain a connection to the first network device, so that the second terminal can transmit data to the first network device through the first terminal and avoid interruptions in the data communicated by the second terminal.

[0243] 7 is a schematic flowchart of a communication method according to an embodiment of the present application. The communication method 700 includes steps S710 to S740.

[0244] S710: Determine whether a session belonging to the first terminal exists.

[0245] A first radio resource control connection exists between a first network device and a first terminal, the first terminal being an intermediate device for a second terminal to access the first network device, and the first terminal communicating with the second terminal through a sidelink.

[0246] For example, the first network device may periodically determine whether a session belonging to the first terminal exists. Alternatively, after a preset condition is met, the first network device may determine whether a session belonging to the first terminal exists. The preset condition may include: receiving indication information, where the indication information indicates determining whether a session belonging to the first terminal exists; determining that the first terminal satisfies a handover condition; or the like. This is not limited to this embodiment of the present application.

[0247] The specific implementation of the first network device determining that there is no session belonging to the first terminal is similar to the implementation of step S610, and the details will not be described again here.

[0248] S720: Send a first RRC reconfiguration message or a second RRC reconfiguration message to the first terminal.

[0249] When determining that there is no session belonging to the first terminal, the first network device may send a first RRC reconfiguration message to the first terminal. The first RRC reconfiguration message includes information indicating at least one unmeasurable cell and / or at least one measurable cell covered by the first network device. A specific implementation of the first network device sending the first RRC reconfiguration message to the first terminal is similar to step S620. Details will not be described again here.

[0250] When the first network device determines that a session belonging to the first terminal does not exist, the first network device may send a second RRC reconfiguration message to the first terminal, the second RRC reconfiguration message including information indicating a cell covered by the first network device and / or another cell, the another cell being a cell other than the cell covered by the first network device.

[0251] For example, the second RRC reconfiguration message includes any one or more of at least one measurement event, a measurable cell whitelist, or a non-measurable cell blacklist, where the measurable cell whitelist includes at least one measurable cell within or outside the coverage of the first network device, and the non-measurable cell blacklist includes at least one non-measurable cell.

[0252] S730: The first terminal performs signal measurement based on the first RRC reconfiguration message or the second RRC reconfiguration message. Step S730 is the same as step S630. Details will not be described again here.

[0253] S740: Send a first measurement report to a first network device.

[0254] The first terminal may perform signal measurement based on the first RRC reconfiguration message or the second RRC reconfiguration message and send a first measurement report to the first network device. The first measurement report may include information indicating a signal quality obtained by the first terminal through the measurement.

[0255] For example, if the first RRC reconfiguration message includes at least one measurable cell covered by the first network device, the first measurement report may include the signal quality of each cell in the at least one measurable cell covered by the first network device.

[0256] For example, if the first RRC reconfiguration message includes at least one unmeasurable cell, the first measurement report may include signal quality of a cell other than the cell included in the at least one unmeasurable cell.

[0257] For example, if the second RRC reconfiguration message includes at least one measurement event, the first measurement report may include measurement events that the measurement results satisfy and that are in the at least one measurement event. Alternatively, the first measurement report may include a target cell or target base station that enables the measurement results to satisfy the measurement event. The target cell is a cell covered by the target base station. Alternatively, the first measurement report may include signal quality of the cell for the at least one measurement event.

[0258] For example, if the second RRC reconfiguration message includes a measurable cell whitelist, the first measurement report may include the signal quality of the cells included in the measurable cell whitelist.

[0259] For example, if the second RRC reconfiguration message includes an unmeasurable cell blacklist, the first measurement report may include signal quality of cells other than the cells included in the unmeasurable cell blacklist.

[0260] In some embodiments, after receiving the first measurement report from the first terminal, the first network device may determine that the first terminal meets a handover condition and send handover indication information to the first terminal.

[0261] For example, when the first network device determines that there is no session belonging to the first terminal, the first network device may determine a target cell list or a target frequency list that satisfies a handover condition based on the received first measurement report, and determine a first cell or a first frequency from the target cell list or the target frequency list. The cells or frequencies included in the target cell list or the target frequency list are cells or frequencies covered by the first network device. The first network device may send handover indication information to the first terminal. The handover indication information indicates that the first terminal will be handed over from the current serving cell to the first cell. The first cell is a cell that can serve the first terminal and has the best signal quality among the cells in the target cell list. The first frequency is a frequency whose corresponding cell can serve the first terminal and has the best signal quality among one or more frequencies in the target frequency list. The cell corresponding to the first frequency may be the first cell.

[0262] For example, when the first network device determines that a session belonging to the first terminal exists, the first network device may determine a target cell list or a target frequency list that satisfies a handover condition based on the received first measurement report. The cells or frequencies included in the target cell list or the target frequency list may be cells or frequencies covered by the first network device, or may be cells or frequencies covered by a network device other than the first network device. The first network device may further determine a first cell or a first frequency from the target cell list or the target frequency list. The first cell may be a cell covered by the first network device, or may be a cell covered by a network device other than the first network device. The first cell is a cell that can serve the first terminal and has the best signal quality among the cells in the target cell list. The first frequency is a frequency whose corresponding cell can serve the first terminal and has the best signal quality among one or more frequencies in the target frequency list. The cell corresponding to the first frequency may be the first cell.

[0263] When the first cell is a cell covered by the first network device, the first network device may send handover indication information to the first terminal, where the handover indication information indicates that the first terminal is handed over from the current serving cell to the first cell.

[0264] If the first cell is a cell covered by a network device other than the first network device, and the network device to which the first cell belongs is a second network device, the first network device may send a handover request message to the second network device to assist the first terminal in being handed over from the current serving cell to the first cell covered by the second network device.

[0265] In some embodiments, after the first network device sends the handover indication information to the first terminal, the first terminal may establish a second RRC connection to the second network device, and the first terminal may act as a relay terminal for the second terminal to relay data between the second terminal and the second network device. After accessing the second network device, the first terminal may camp on a cell covered by the second network device.

[0266] The process in which the first terminal is handed over from the current serving cell to the first cell may be a coverage-based intra-frequency handover process or a coverage-based inter-frequency handover process.

[0267] When a partial overlap area exists between the signal range of the current serving cell and the signal range of the first cell, and the current serving cell and the first cell have the same frequency, the process by which the first terminal is handed over from the current serving cell to the first cell is a coverage-based intra-frequency handover.

[0268] In some embodiments of coverage-based intra-frequency handover, when determining that no session belonging to the first terminal exists, the first network device may send a first RRC reconfiguration message to the first terminal, the first RRC reconfiguration message including information indicating at least one non-measurable cell and / or at least one measurable cell covered by the first network device.

[0269] Alternatively, when determining that a session belonging to the first terminal exists, the first network device may send a second RRC reconfiguration message to the first terminal. The second RRC reconfiguration message may include any one or more of at least one measurement event, a measurable cell whitelist, or a non-measurable cell blacklist. For example, the second RRC reconfiguration message may include measurement event A3.

[0270] For example, after receiving the first RRC reconfiguration message or the second RRC reconfiguration message, the first terminal may perform signal measurement based on the first RRC reconfiguration message or the second RRC reconfiguration message. In addition, the first terminal may send a first measurement report to the first network device. The first measurement report is determined based on the first RRC reconfiguration message or the second RRC reconfiguration message. For example, when the second RRC reconfiguration message includes measurement event A3, the first measurement report may include at least one target cell or target frequency that satisfies measurement event A3.

[0271] For example, after receiving a first measurement report from the first terminal, the first network device may generate a target cell list or a target frequency list based on the first measurement report. The first network device may determine the first cell from the target cell list or the target frequency list. When there is no session belonging to the first terminal, the first cell is a cell covered by the first network device. When there is a session belonging to the first terminal, the first cell may be a cell covered by the first network device or a cell covered by a network device other than the first network device.

[0272] When there is a partial overlap area between the signal range of the current serving cell and the signal range of the first cell, and the current serving cell and the first cell have different frequencies, the process by which the first terminal is handed over from the current serving cell to the first cell is a coverage-based inter-frequency handover.

[0273] In some embodiments of coverage-based inter-frequency handover, before performing S710, the first network device may receive a second measurement report from the first terminal. In other words, the method 700 may further include S701.

[0274] S701: The first terminal sends a second measurement report to the first network device.

[0275] The second measurement report includes information indicating the signal quality obtained by the first terminal through the measurements.

[0276] For example, the second measurement report may be determined based on RRC configuration information recently received by the first terminal. The RRC configuration information recently received by the first terminal may include any one of RRC configuration information received when a connection is established between the first terminal and the first network device, a first RRC reconfiguration message, or a second RRC reconfiguration message. The RRC configuration information received when a connection is established between the first terminal and the first network device may include at least one measurement event.

[0277] For example, if the RRC configuration information recently received by the first terminal is the RRC configuration information received when a connection is established between the first terminal and the first network device, and the RRC configuration information received when a connection is established between the first terminal and the first network device includes measurement event A2, the second measurement report may include information indicating that a reference signal received power (RSRP) or a reference signal received quality (RSRQ) of a second cell or a second frequency satisfies measurement event A2. The second cell or the second frequency may be a cell or frequency covered by the first network device, or may be a cell or frequency covered by a network device other than the first network device.

[0278] For example, if the RRC configuration information recently received by the first terminal is the first RRC reconfiguration message or the second RRC reconfiguration message, the second measurement report may be the same as the first measurement report.

[0279] In some embodiments of coverage-based inter-frequency handover, after receiving the second measurement report from the first terminal, the first network device may determine whether a session belonging to the first terminal exists. Alternatively, the first network device may periodically determine whether a session belonging to the first terminal exists, or the like. This is not limited to this embodiment of the present application.

[0280] In some embodiments of coverage-based inter-frequency handover, when determining that no session belonging to the first terminal exists, the first network device may send a first RRC reconfiguration message to the first terminal, the first RRC reconfiguration message including information indicating at least one non-measurable cell and / or at least one measurable cell covered by the first network device.

[0281] Alternatively, when determining that a session belonging to the first terminal exists, the first network device may send a second RRC reconfiguration message to the first terminal. The second RRC reconfiguration message includes any one or more of at least one measurement event, a measurable cell whitelist, or a non-measurable cell blacklist. For example, the second RRC reconfiguration message may include measurement event A5 and measurement event A1, or the second RRC reconfiguration message may include measurement event A3 and measurement event A1. Measurement event A1 is when the signal quality of the serving cell becomes higher than a corresponding threshold.

[0282] In some embodiments of coverage-based inter-frequency handover, when the first network device receives the second measurement report and determines that a session belonging to the first terminal exists, it may determine the specific content of the second RRC reconfiguration message based on the cell configuration information or the frequency related to the second measurement report.

[0283] For example, when the second measurement report includes information indicating that the RSRP or RSRQ of the second cell or second frequency satisfies measurement event A2 and it is determined that a session belonging to the first terminal exists, the first network device may determine at least one measurement event to be included in the second RRC reconfiguration message based on the configuration information of the second cell or second frequency.

[0284] If the configuration information of the second cell or the second frequency is event A5, the second RRC reconfiguration message may include measurement event A5 and measurement event A1. If the configuration information of the second cell or the second frequency is event A3, the second RRC reconfiguration message may include measurement event A3 and measurement event A1.

[0285] Optionally, the configuration information of the second cell or the second frequency may be information stored in the first network device. Alternatively, the configuration information of the second cell or the second frequency may be information transmitted by the first terminal to the first network device. This is not limited in this embodiment of the present application.

[0286] For example, after receiving the first RRC reconfiguration message or the second RRC reconfiguration message, the first terminal may perform signal measurement based on the first RRC reconfiguration message or the second RRC reconfiguration message. In addition, the first terminal may send a first measurement report to the first network device. The first measurement report is determined based on the first RRC reconfiguration message or the second RRC reconfiguration message. For example, when the second RRC reconfiguration message includes measurement event A5 and measurement event A1, the first measurement report may include at least one target cell or target frequency that satisfies measurement event A5 and measurement event A1.

[0287] For example, after receiving a first measurement report from the first terminal, the first network device may generate a target cell list or a target frequency list based on the first measurement report. The first network device may determine the first cell from the target cell list or the target frequency list. When there is no session belonging to the first terminal, the first cell is a cell covered by the first network device. When there is a session belonging to the first terminal, the first cell may be a cell covered by the first network device or a cell covered by a network device other than the first network device.

[0288] In some other embodiments of coverage-based inter-frequency handover, when the first network device receives the second measurement report from the first terminal and determines that no session belonging to the first terminal exists, the first network device may not send a first RRC reconfiguration message to the first terminal and may maintain the first RRC connection to the first terminal. In this case, the second terminal may continue to maintain a connection to the first network device through the first terminal, avoiding interruption of data transmission.

[0289] When a session belonging to the first terminal exists, the first network device may send a second RRC reconfiguration message to the first terminal, so that the first terminal may perform signal measurements based on the second RRC reconfiguration message to determine whether a cell with better signal quality exists. When a session belonging to the first terminal does not exist, the first network device may alternatively send a first RRC reconfiguration message to the first terminal, so that the first terminal maintains its connection to the first network device and avoids interruptions in data communicated by the second terminal.

[0290] FIG. 8 is a diagram of the structure of a communication device according to an embodiment of the present application.

[0291] The communication device 800 includes a receiving module 810 and a transmitting module 820 .

[0292] The receiving module 810 is configured to receive radio resource control release information sent by a first network device, the radio resource control release information indicating that a first radio resource control connection between the first terminal and the first network device is to be released. The first terminal may include the apparatus 800.

[0293] The sending module 820 is configured to send first indication information to a second terminal, the first terminal being an intermediate device for the second terminal to access the first network device, the first indication information indicating that a sidelink between the first terminal and the second terminal is to be released, indicating that a first radio resource control connection is to be released, or indicating that a state of the first radio resource control connection is a connection failed state.

[0294] Optionally, the communication apparatus 800 further includes an establishment module configured to establish a second radio resource control connection to the second network device, where the second radio resource control connection is used by the second terminal to access the second network device.

[0295] Optionally, the receiving module 810 is further configured to receive second indication information sent by the second terminal, the second indication information indicating to maintain the sidelink.

[0296] Optionally, the establishment module is specifically configured to establish an RRC connection to the second network device when the sidelink is not disconnected at a detection time point, wherein the detection time point comprises a first time length after the first indication information is transmitted.

[0297] Optionally, the radio resource control release information is received when the first terminal satisfies a handover condition and no session belonging to the first terminal exists between the first terminal and the first network device.

[0298] Optionally, the communications device 800 further includes a processing module configured to determine a connection state of the first radio resource control connection.

[0299] The sending module 820 is further configured to send status indication information to the second terminal, the status indication information including first status information, second status information, or third status information, where the first status information indicates that the connection status is an establishing status, the second status information indicates that the connection status is an established status, and the third status information indicates that the connection status is an establishment failed status.

[0300] Optionally, the processing module is specifically configured to determine that the connection state is an establishing state when the first terminal is being handed over, the first radio resource control connection is being established, or the first radio resource control connection in which a radio link failure occurs is being restored.

[0301] The processing module is specifically configured to determine that the connection state is an established state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection in which a radio link failure occurs is restored.

[0302] The processing module is specifically configured to determine that the connection state is an establishment failure state when handover of the first terminal device fails, establishment of the first radio resource control connection fails, a radio link failure occurs on the first radio resource control connection, recovery of the first radio resource control connection where a radio link failure occurs fails, or the first radio resource control connection is released.

[0303] FIG. 9 is a diagram of the structure of a communication device according to an embodiment of the present application.

[0304] The communications device 900 includes a processing module 910 and a transceiver module 920 .

[0305] The processing module 910 is configured to determine a connection state of a first radio resource control connection between a first terminal and a first network device. The communications apparatus 900 may be located at the first terminal.

[0306] The transceiver module 920 is configured to send status indication information to the second terminal. The status indication information includes first status information, second status information, or third status information. The first status information indicates that the connection status is an establishing status, the second status information indicates that the connection status is an established status, and the third status information indicates that the connection status is an establishment failed status. The first terminal is an intermediate device for the second terminal to access the first network device.

[0307] Optionally, the processing module 910 is specifically configured to determine that the connection state is an establishing state when the first terminal is being handed over, the first radio resource control connection is being established, or the first radio resource control connection in which a radio link failure occurs is being restored.

[0308] The processing module 910 is specifically configured to determine that the connection state is an established state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection in which a radio link failure occurs is restored.

[0309] The processing module 910 is specifically configured to determine that the connection state is an establishment failure state when handover of the first terminal device fails, establishment of the first radio resource control connection fails, a radio link failure occurs on the first radio resource control connection, recovery of the first radio resource control connection where a radio link failure occurs fails, or the first radio resource control connection is released.

[0310] Optionally, the processing module 910 is specifically configured to determine that the connection state is an establishment failure state when radio resource control release information sent by the first network device is received, wherein the radio resource control release information indicates to release the first radio resource control connection.

[0311] Optionally, the processing module 910 is further configured to establish a second radio resource control connection to the second network device, the second radio resource control connection being used by the second terminal to access the second network device.

[0312] Optionally, the transceiver module 920 is configured to receive second indication information sent by the second terminal, the second indication information indicating to maintain the sidelink.

[0313] Optionally, the processing module 910 is specifically configured to establish an RRC connection to the second network device when the sidelink is not disconnected at a detection time point, the detection time point comprising a first time length after the first indication information is transmitted.

[0314] Optionally, the processing module 910 is specifically configured to receive radio resource control release information when the first terminal satisfies a handover condition and a session belonging to the first terminal does not exist between the first terminal and the first network device.

[0315] In some embodiments, the transceiver module 920 may receive a first radio resource control reconfiguration message from the first network device when a session belonging to the first terminal does not exist between the first terminal and the first network device, or may receive a second radio resource control reconfiguration message from the first network device when a session belonging to the first terminal exists. The transceiver module 920 may further transmit the first measurement report or the second measurement report to the first network device. The transceiver module 920 may perform step S620 of the method in FIG. 6 or steps S701, S720, and S740 of the method in FIG. 7.

[0316] In some embodiments, the processing module 910 may perform signal measurements based on the first radio resource control reconfiguration message or the second radio resource control reconfiguration message. The processing module 910 may perform step S630 in the method of FIG. 6 or step S730 in the method of FIG. 7.

[0317] In some embodiments, the transceiver module 920 may alternatively transmit the second measurement report to the first network device before receiving the first radio resource control reconfiguration message or the second radio resource control reconfiguration message from the first network device. The second measurement report includes information indicating the signal quality obtained by the first terminal through the measurements.

[0318] FIG. 10 is a diagram of the structure of a communication device according to an embodiment of the present application.

[0319] The communications device 1000 includes a processing module 1010 and a transceiver module 1020 .

[0320] The processing module 1010 is configured to determine that when the first terminal satisfies a handover condition, and a session belonging to the first terminal does not exist between the first terminal and the first network device, the first terminal is an intermediate device for a second terminal to access the first network device, and a first radio resource control connection exists between the first terminal and the first network device.

[0321] The transceiver module 1020 is configured to transmit radio resource control release information to the first terminal, the radio resource control release information indicating a release of a first radio resource control connection between the first terminal and the first network device.

[0322] In some embodiments, the transceiver module 1020 is further configured to receive a measurement report from the first terminal, the measurement report including information indicating a signal quality obtained by the first terminal through the measurement.

[0323] In some embodiments, the processing module 1010 is further configured to determine, based on the measurement report received from the first terminal, that the first terminal satisfies a handover condition. The processing module 1010 may be further configured to release a first radio resource control connection between the first terminal and the first network device.

[0324] In some embodiments, the processing module 1010 may determine whether a session belonging to the first terminal exists between the first terminal and the first network device. The first terminal is an intermediate device for a second terminal to access the first network device. The processing module 1010 may perform step S610 in the method in FIG. 6 or step S710 in the method in FIG. 7.

[0325] In some embodiments, the transceiver module 1020 may send a first radio resource control reconfiguration message to the first terminal when a session belonging to the first terminal does not exist, or may send a second radio resource control reconfiguration message to the first terminal when a session belonging to the first terminal exists. The transceiver module 1020 may further receive a first measurement report or a second measurement report from the first terminal. The transceiver module 1020 may perform step S620 of the method in FIG. 6 or steps S701, S720, and S740 of the method in FIG. 7.

[0326] In some embodiments, the processing module 1010 may further determine that the first terminal meets a handover condition based on the second measurement report.

[0327] FIG. 11 is a diagram of the structure of a communication device according to an embodiment of the present application.

[0328] The communication device 2000 includes at least one processor 2010 and a communication interface 2020. The communication interface 2020 is configured to perform information exchange between a terminal and another communication device, and when program instructions are executed by the at least one processor, the terminal is capable of performing the above-mentioned communication method. A first terminal may include the communication device 2000.

[0329] Specifically, in some embodiments, the at least one processor 2010 may be configured to receive radio resource control release information sent by the first network device through the communication interface 2020. The radio resource control release information indicates that a first radio resource control connection between the first terminal and the first network device is to be released.

[0330] The at least one processor 2010 may further be configured to send first indication information to the second terminal through the communication interface 2020. The first terminal is an intermediate device for the second terminal to access the first network device, and the first indication information indicates that a sidelink between the first terminal and the second terminal is to be released, indicates that the first radio resource control connection is to be released, or indicates that the state of the first radio resource control connection is a connection failure state.

[0331] Optionally, the at least one processor 2010 is further configured to establish a second radio resource control connection to the second network device, the second radio resource control connection being used by the second terminal to access the second network device.

[0332] Optionally, the at least one processor 2010 is further configured to receive, through the communication interface 2020, second indication information sent by the second terminal, the second indication information indicating to maintain the sidelink.

[0333] Optionally, the at least one processor 2010 is specifically configured to establish an RRC connection to the second network device when the sidelink is not disconnected at a detection time point, the detection time point comprising a first time length after the first indication information is transmitted.

[0334] Optionally, the radio resource control release information is received when the first terminal satisfies a handover condition and no session belonging to the first terminal exists between the first terminal and the first network device.

[0335] Optionally, the at least one processor 2010 is specifically configured to determine a connection state of the first radio resource control connection.

[0336] The at least one processor 2010 is further configured to send status indication information to the second terminal through the communication interface 2020. The status indication information includes first status information, second status information, or third status information, where the first status information indicates that the connection status is an establishing status, the second status information indicates that the connection status is an established status, and the third status information indicates that the connection status is an establishment failed status.

[0337] Optionally, the at least one processor 2010 is specifically configured to determine that the connection state is in an establishing state when the first terminal is being handed over, the first radio resource control connection is being established, or the first radio resource control connection in which a radio link failure occurs is being restored.

[0338] The at least one processor 2010 is specifically configured to determine that the connection state is an established state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection in which a radio link failure occurs is restored.

[0339] The at least one processor 2010 is specifically configured to determine that the connection state is an establishment failure state when handover of the first terminal device fails, establishment of the first radio resource control connection fails, a radio link failure occurs on the first radio resource control connection, recovery of the first radio resource control connection where a radio link failure occurs fails, or the first radio resource control connection is released.

[0340] In some other embodiments, the at least one processor 2010 is configured to determine a connection state of a first radio resource control connection between the first terminal and the first network device.

[0341] The communication interface 2020 is configured to transmit status indication information to the second terminal. The status indication information includes first status information, second status information, or third status information. The first status information indicates that the connection status is an establishing status, the second status information indicates that the connection status is an established status, and the third status information indicates that the connection status is an establishment failed status. The first terminal is an intermediate device for the second terminal to access the first network device.

[0342] Optionally, the at least one processor 2010 is specifically configured to determine that the connection state is in an establishing state when the first terminal is being handed over, the first radio resource control connection is being established, or the first radio resource control connection in which a radio link failure occurs is being restored.

[0343] The at least one processor 2010 is specifically configured to determine that the connection state is an established state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection in which a radio link failure occurs is restored.

[0344] The at least one processor 2010 is specifically configured to determine that the connection state is an establishment failure state when handover of the first terminal device fails, establishment of the first radio resource control connection fails, a radio link failure occurs on the first radio resource control connection, recovery of the first radio resource control connection where a radio link failure occurs fails, or the first radio resource control connection is released.

[0345] Optionally, the at least one processor 2010 is specifically configured to determine that the connection state is an establishment failure state when radio resource control release information sent by the first network device is received, the radio resource control release information indicating to release the first radio resource control connection.

[0346] Optionally, the at least one processor 2010 is specifically configured to establish a second radio resource control connection to the second network device, the second radio resource control connection being used by the second terminal to access the second network device.

[0347] Optionally, the communication interface 2020 is further configured such that the method further comprises receiving second indication information sent by the second terminal, the second indication information indicating to maintain the sidelink.

[0348] Optionally, the at least one processor 2010 is specifically configured to establish an RRC connection to the second network device when the sidelink is not disconnected at a detection time point, the detection time point comprising a first time length after the first indication information is transmitted.

[0349] Optionally, the radio resource control release information is received when the first terminal satisfies a handover condition and no session belonging to the first terminal exists between the first terminal and the first network device.

[0350] In some embodiments, the at least one processor 2010 may be configured to receive a first radio resource control reconfiguration message from the first network device through the communication interface 2020 when a session belonging to the first terminal does not exist between the first terminal and the first network device.

[0351] In some embodiments, the at least one processor 2010 may be further configured to receive a second radio resource control reconfiguration message from the first network device through the communication interface 2020 when a session belonging to the first terminal exists.

[0352] In some embodiments, the at least one processor 2010 may be further configured to perform signal measurements based on the first radio resource control reconfiguration message or the second radio resource control reconfiguration message.

[0353] In some embodiments, the at least one processor 2010 may be further configured to transmit the first measurement report or the second measurement report to the first network device via the communication interface 2020.

[0354] In some embodiments, the at least one processor 2010 may be further configured to establish a second RRC connection to the second network device, the second radio resource control connection being used by the second terminal to access the second network device.

[0355] FIG. 12 is a diagram of the structure of a communication device according to an embodiment of the present application.

[0356] The communication device 3000 includes at least one processor 3010 and a communication interface 3020. The communication interface 3020 is configured to perform information exchange between the communication device and another communication device, and when program instructions are executed by the at least one processor, the communication device is capable of performing the above-mentioned communication method. A first network device may include the communication device 3000.

[0357] In some embodiments, the at least one processor 3010 may be configured to determine that the first terminal satisfies a handover condition and that a session belonging to the first terminal does not exist between the first terminal and the first network device, the first terminal is an intermediate device for a second terminal to access the first network device, and a first radio resource control connection exists between the first terminal and the first network device.

[0358] In some embodiments, the at least one processor 3010 may be further configured to send radio resource control release information to the first terminal through the communication interface 3020. The radio resource control release information indicates a release of a first radio resource control connection between the first terminal and the first network device.

[0359] In some embodiments, the at least one processor 3010 may be further configured to receive a measurement report from the first terminal through the communication interface 3020. The measurement report includes information indicating a signal quality obtained by the first terminal through the measurement.

[0360] In some embodiments, the at least one processor 3010 may be further configured to determine, based on the measurement report received from the first terminal, that the first terminal satisfies a handover condition.

[0361] In some embodiments, the at least one processor 3010 may be further configured to release the first radio resource control connection between the first terminal and the first network device.

[0362] In some embodiments, the at least one processor 3010 may be configured to determine whether a session belonging to the first terminal exists between the first terminal and the first network device, the first terminal being an intermediate device for a second terminal to access the first network device.

[0363] In some embodiments, the at least one processor 3010 may be further configured to transmit a first radio resource control reconfiguration message to the first terminal through the communication interface 3020 when there is no session belonging to the first terminal.

[0364] In some embodiments, the at least one processor 3010 may be further configured to transmit a second radio resource control reconfiguration message to the first terminal through the communication interface 3020 when there is no session belonging to the first terminal.

[0365] In some embodiments, the at least one processor 3010 may be further configured to receive, via the communication interface 3020, the first measurement report or the second measurement report from the first terminal.

[0366]

[0010] An embodiment of the present application further provides a communication system including a first terminal, a second terminal, and a first network device. In some embodiments, the communication system may further include a second network device.

[0367] An embodiment of the present application further provides a computer program storage medium having program instructions thereon, which, when executed, perform the aforementioned method.

[0368] An embodiment of the present application further provides a chip system, which includes at least one processor, and performs the aforementioned method when the program instructions are executed by the at least one processor.

[0369] It should be understood that the processor in this embodiment of the present application may be a central processing unit (CPU). The processor may alternatively be another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or another programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The general-purpose processor may be a microprocessor, or the processor may be any conventional processor or the like.

[0370] It may be understood that in this embodiment of the present application, memory may be volatile memory or nonvolatile memory, or may include volatile and nonvolatile memory. Nonvolatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may be random access memory (RAM) used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) may be used, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchlink dynamic random access memory (SLDRAM), and direct rambus random access memory (DR RAM).

[0371] All or some of the above-described embodiments may be implemented using software, hardware, firmware, or any combination thereof. When software is used to implement an embodiment, the aforementioned embodiment may be implemented, entirely or partially, in the form of a computer program product. A computer program product includes one or more computer instructions or computer programs. When the program instructions or computer programs are loaded and executed on a computer, the procedures or functions according to the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from a computer-readable storage medium to another computer-readable storage medium. For example, computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center. Wireless The information may be transmitted in a variety of ways (e.g., infrared, radio, or electromagnetic waves). The computer-readable storage medium may be any available medium that can be accessed by a computer or data storage device, such as a server or data center that includes one or more available media sets. The available medium may be magnetic media (e.g., floppy disks, hard disks, or magnetic tapes), optical media (e.g., DVDs), or semiconductor media. The semiconductor media may be a solid-state drive.

[0372] It should be understood that the term "and / or" herein describes only a correspondence relationship between related objects and indicates that three relationships may exist. For example, A and / or B may represent three cases: when only A is present, when both A and B are present, and when only B is present. A and B may be singular or plural. In addition, the character " / " herein usually indicates an "or" relationship between related objects, but may also indicate an "and / or" relationship. For further details, please refer to the context for understanding.

[0373] As used herein, "at least one" means one or more, and "more" means two or more. "At least one" of the following items (elements) or similar expressions refers to any combination of these items, including any combination of one item (element) or more than one item (element). For example, "at least one" of a, b, or c may refer to a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be singular or plural.

[0374] It should be understood that the sequence numbers of the above processes do not refer to the execution sequence in various embodiments of the present application, and the execution order of the processes should be determined according to the functions and internal logic of the processes, and should not be construed as any limitation on the implementation process of the embodiments of the present application.

[0375] In combination with the examples described in the embodiments disclosed herein, those skilled in the art can recognize that the units and algorithm steps can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific application and the design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered as going beyond the scope of this application.

[0376] For the purpose of simple and concise description, for the detailed operation processes of the above-mentioned systems, devices and units, please refer to the corresponding processes in the above-mentioned method embodiments, which can be clearly understood by those skilled in the art, and the details will not be described again here.

[0377] In some embodiments provided herein, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the described device embodiments are merely examples. For example, the division of units is merely a division of logical functions, and other divisions may occur in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be omitted or not implemented. In addition, the shown or described mutual couplings or direct couplings or communication connections may be implemented using some interfaces. Indirect couplings or communication connections between devices or units may be implemented in electronic, mechanical, or other forms.

[0378] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, and may be located in one location or distributed across multiple network units, some or all of which may be selected based on actual requirements for realizing the objectives of the solutions of the embodiments.

[0379] Furthermore, each functional unit in the embodiments of the present application may be integrated into one processing unit, each of these units may exist physically alone, or two or more units may be integrated into one unit.

[0380] When these functions are implemented in the form of software functional units and sold or used as independent products, these functions may be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the present application may essentially be implemented in the form of a software product, or a portion of the technical solutions may be implemented in the form of a software product. The computer software product is stored in a storage medium and includes instructions for instructing a computer device (which may be a personal computer, a server, or a network device) to perform all or part of the steps of the methods described in the embodiments of the present application. The storage medium includes any medium capable of storing program code, such as a USB flash drive, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0381] The above description is merely a specific implementation form of the present application and is not intended to limit the scope of protection of the present application. Any modifications or replacements that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application shall be included in the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the scope of protection of the claims. (Other possible items) [Item 1] 1. A communication method comprising: receiving radio resource control release information sent by a first network device, where the radio resource control release information indicates releasing a first radio resource control connection between a first terminal and the first network device; and sending first indication information to a second terminal, where the first terminal is an intermediate device for the second terminal to access the first network device, and the first indication information indicates at least one of: indicating that a sidelink between the first terminal and the second terminal is to be released; indicating that the first radio resource control connection is to be released; or indicating that a state of the first radio resource control connection is a connection failure state; A method for providing [Item 2] The method further comprises: establishing a second radio resource control connection to a second network device, wherein the second radio resource control connection is used by the second terminal to access the second network device. The method of item 1, comprising: [Item 3] The method further comprises: receiving second indication information transmitted by the second terminal, wherein the second indication information indicates that the sidelink is maintained; 3. The method according to item 1 or 2, comprising: [Item 4] Establishing a second radio resource control connection to a second network device includes: establishing an RRC connection to the second network device when the sidelink is not disconnected at a detection time, wherein the detection time comprises a first time length after the first indication information is transmitted. Item 3. The method according to item 2, comprising: [Item 5] 5. The method according to any one of items 1 to 4, wherein the radio resource control release information is received when the first terminal satisfies a handover condition and a session belonging to the first terminal does not exist between the first terminal and the first network device. [Item 6] The method further comprises: determining a connection status of the first radio resource control connection; and sending status indication information to the second terminal, where the status indication information includes first status information, second status information, or third status information, the first status information indicating that the connection status is an establishing status, the second status information indicating that the connection status is an established status, and the third status information indicating that the connection status is an establishment failed status; The method of item 1, comprising: [Item 7] The step of determining a connection state of the first radio resource control connection comprises: determining that the connection state is the establishing state when the first terminal is being handed over, the first radio resource control connection is being established, or the first radio resource control connection is being restored after a radio link failure occurs; or determining that the connection state is the established state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection is restored after a radio link failure occurs; or determining that the connection state is an establishment failure state when the first terminal fails to handover, fails to establish the first radio resource control connection, a radio link failure occurs on the first radio resource control connection, fails to recover the first radio resource control connection after the radio link failure occurs, or the first radio resource control connection is released; Item 7. The method according to item 6, comprising: [Item 8] 1. A communication method comprising: determining a connection status of a first radio resource control connection between the first terminal and the first network device; and sending status indication information to a second terminal, where the status indication information includes first status information, second status information, or third status information, where the first status information indicates that the connection status is an establishing status, the second status information indicates that the connection status is an established status, and the third status information indicates that the connection status is an establishment failed status; and the first terminal is an intermediate device for the second terminal to access the first network device. A method for providing [Item 9] The step of determining a connection status of a first radio resource control connection between a first terminal and a first network device comprises: determining that the connection state is the establishing state when the first terminal is being handed over, the first radio resource control connection is being established, or the first radio resource control connection is being restored after a radio link failure occurs; or determining that the connection state is the established state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection is restored after a radio link failure occurs; or determining that the connection state is the establishment failure state when handover of the first terminal device fails, establishment of the first radio resource control connection fails, a radio link failure occurs on the first radio resource control connection, recovery of the first radio resource control connection fails after the radio link failure occurs, or the first radio resource control connection is released. Item 9. The method according to item 8, comprising: [Item 10] The step of determining a connection state of a first radio resource control connection between a first terminal and a first network device includes: determining that the connection state is the establishment failure state when receiving radio resource control release information sent by the first network device, where the radio resource control release information indicates to release the first radio resource control connection; 10. The method according to item 8 or 9, comprising: [Item 11] The method further comprises: establishing a second radio resource control connection to a second network device, wherein the second radio resource control connection is used by the second terminal to access the second network device; Item 11. The method of item 10, comprising: [Item 12] Item 12. The method according to item 10 or 11, further comprising receiving second indication information transmitted by the second terminal, wherein the second indication information indicates that the sidelink is to be maintained. [Item 13] Item 13. The method of claim 11 or 12, wherein the step of establishing a second radio resource control connection to a second network device comprises: establishing an RRC connection to the second network device when the sidelink is not disconnected at a detection time, wherein the detection time comprises a time a first length of time after first indication information is transmitted. [Item 14] 14. The method according to any one of items 10 to 13, wherein the radio resource control release information is received when the first terminal satisfies a handover condition and a session belonging to the first terminal does not exist between the first terminal and the first network device. [Item 15] 1. A communication method comprising: determining that a first terminal satisfies a handover condition and that a session belonging to the first terminal does not exist between the first terminal and a first network device, where the first terminal is an intermediate device for a second terminal to access the first network device, and a first radio resource control connection exists between the first terminal and the first network device; and sending radio resource control release information to the first terminal, where the radio resource control release information indicates that the first radio resource control connection is to be released; A method for providing [Item 16] The method further comprises: receiving a measurement report from the first terminal, wherein the measurement report includes information indicating a signal quality obtained by the first terminal through measurements; and determining that the first terminal satisfies the handover condition based on the measurement report; Item 16. The method of item 15, comprising: [Item 17] The method further comprises: Releasing the first radio resource control connection between the first terminal and the first network device. 17. The method according to item 15 or 16, comprising: [Item 18] 1. A communication method comprising: determining whether a session belonging to a first terminal exists between the first terminal and a first network device, wherein the first terminal is an intermediate device for a second terminal to access the first network device; and sending a first radio resource control reconfiguration message to the first terminal when the session belonging to the first terminal does not exist, wherein the first radio resource control reconfiguration message includes information indicating at least one non-measurable cell and / or at least one measurable cell covered by the first network device; A method for providing [Item 19] The method further comprises: transmitting a second radio resource control reconfiguration message to the first terminal when the session belonging to the first terminal exists, wherein the second radio resource control reconfiguration message includes information indicating a cell covered by the first network device and / or another cell, the another cell being a cell other than the cell covered by the first network device; Item 19. The method of item 18, comprising: [Item 20] 20. The method of claim 19, wherein the second radio resource control reconfiguration message includes any one or more of at least one measurement event, a measurable cell whitelist, or a non-measurable cell blacklist, wherein the measurable cell whitelist includes at least one measurable cell within or outside the coverage of the first network device, and the non-measurable cell blacklist includes at least one non-measurable cell. [Item 21] The method further comprises: receiving a first measurement report from the first terminal, wherein the first measurement report is determined based on the second radio resource control reconfiguration message or the first radio resource control reconfiguration message; 21. The method of any one of items 18 to 20, comprising: [Item 22] Prior to the step of determining that a session belonging to a first terminal exists between the first terminal and a first network device, the method further comprises: receiving a second measurement report from the first terminal, wherein the second measurement report includes information indicating a signal quality obtained by the first terminal through measurements; and determining that the first terminal satisfies a handover condition based on the second measurement report; 22. The method of any one of items 18 to 21, comprising: [Item 23] 1. A communication method comprising: receiving a first radio resource control reconfiguration message from the first network device when a session belonging to the first terminal does not exist between the first terminal and the first network device, wherein the first radio resource control reconfiguration message includes information indicating at least one non-measurable cell and / or at least one measurable cell covered by the first network device, and the first terminal is an intermediate device for a second terminal to access the first network device; and performing signal measurements based on the first radio resource control reconfiguration message. A method for providing [Item 24] receiving a second radio resource control reconfiguration message from the first network device when the session belonging to the first terminal exists, wherein the second radio resource control reconfiguration message includes information indicating a cell covered by the first network device and / or another cell, the another cell being a cell other than the cell covered by the first network device; and performing signal measurements based on the second radio resource control reconfiguration message. 24. The method of claim 23, further comprising: [Item 25] Item 25. The method of item 24, wherein the second radio resource control reconfiguration message includes one or more of at least one measurement event, a measurable cell whitelist, or a non-measurable cell blacklist, wherein the measurable cell whitelist includes at least one measurable cell within or outside the coverage of the first network device, and the non-measurable cell blacklist includes at least one non-measurable cell. [Item 26] The method further comprises: sending a first measurement report to the first network device, wherein the first measurement report is determined based on the second radio resource control reconfiguration message or the first radio resource control reconfiguration message; 26. The method of any one of items 23 to 25, comprising: [Item 27] The method further comprises: sending a second measurement report to the first network device before receiving the second radio resource control reconfiguration message or the first radio resource control reconfiguration message from the first network device, wherein the second measurement report includes information indicating a signal quality obtained by the first terminal through measurements. 27. The method of any one of items 23 to 26, comprising: [Item 28] A communication device, a receiving module configured to receive radio resource control release information sent by the first network device, where the radio resource control release information indicates that a first radio resource control connection between a first terminal and the first network device is to be released; and a sending module configured to send first indication information to a second terminal, where the first terminal is an intermediate device for the second terminal to access the first network device, and the first indication information indicates at least one of: indicating that a sidelink between the first terminal and the second terminal is to be released; indicating that the first radio resource control connection is to be released; or indicating that a state of the first radio resource control connection is a connection failure state; An apparatus comprising: [Item 29] The apparatus of item 28, further including an establishment module, wherein the establishment module is configured to establish a second radio resource control connection to a second network device, wherein the second radio resource control connection is used by the second terminal to access the second network device. [Item 30] 30. The apparatus of claim 28 or 29, wherein the receiving module is further configured to receive second instruction information transmitted by the second terminal, the second instruction information indicating that the sidelink is to be maintained. [Item 31] 30. The apparatus of claim 29, wherein the establishment module is configured to establish an RRC connection to the second network device when the sidelink is not disconnected at a detection time, wherein the detection time comprises a first time length after the first indication information is transmitted. [Item 32] 32. The apparatus of any one of items 28 to 31, wherein the radio resource control release information is received when the first terminal satisfies a handover condition and a session belonging to the first terminal does not exist between the first terminal and the first network device. [Item 33] The apparatus further comprises a processing module, wherein the processing module is configured to determine a connection state of the first radio resource control connection; and 29. The device of claim 28, wherein the transmitting module is further configured to transmit status indication information to the second terminal, wherein the status indication information includes first status information, second status information, or third status information, wherein the first status information indicates that the connection status is an establishing status, the second status information indicates that the connection status is an established status, and the third status information indicates that the connection status is an establishment failed status. [Item 34] Specifically, the processing module: Determine that the connection state is the establishing state when the first terminal is being handed over, the first radio resource control connection is being established, or the first radio resource control connection is being restored after a radio link failure occurs; or determining that the connection state is the established state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection after a radio link failure occurs is restored; or Determine that the connection state is the establishment failure state when handover of the first terminal device fails, establishment of the first radio resource control connection fails, a radio link failure occurs on the first radio resource control connection, recovery of the first radio resource control connection after the radio link failure occurs fails, or the first radio resource control connection is released. Item 34. The device according to item 33, configured as follows: [Item 35] A communication device, a processing module configured to determine a connection state of a first radio resource control connection between the first terminal and the first network device; and a transceiver module configured to send status indication information to a second terminal, wherein the status indication information includes first status information, second status information, or third status information, wherein the first status information indicates that the connection status is an establishing status, the second status information indicates that the connection status is an established status, and the third status information indicates that the connection status is an establishment failed status; and the first terminal is an intermediate device for the second terminal to access the first network device. An apparatus comprising: [Item 36] Specifically, the processing module: Determine that the connection state is the establishing state when the first terminal is being handed over, the first radio resource control connection is being established, or the first radio resource control connection is being restored after a radio link failure occurs; or determining that the connection state is the established state when the first terminal is handed over, the first radio resource control connection is established, or the first radio resource control connection after a radio link failure occurs is restored; or Determine that the connection state is the establishment failure state when handover of the first terminal device fails, establishment of the first radio resource control connection fails, a radio link failure occurs on the first radio resource control connection, recovery of the first radio resource control connection after the radio link failure occurs fails, or the first radio resource control connection is released. Item 36. The device according to item 35, configured as follows: [Item 37] The processing module is specifically configured to determine that the connection state is the establishment failure state when radio resource control release information sent by the first network device is received, wherein the radio resource control release information indicates that the first radio resource control connection is to be released. [Item 38] Item 38. The apparatus of item 37, wherein the processing module is further configured to establish a second radio resource control connection to a second network device, wherein the second radio resource control connection is used by the second terminal to access the second network device. [Item 39] Item 39. The apparatus of item 37 or 38, wherein the transceiver module is further configured to receive second instruction information transmitted by the second terminal, wherein the second instruction information indicates that a sidelink is to be maintained. [Item 40] Item 39. The apparatus of item 38 or 39, wherein the processing module is further configured to: establish an RRC connection to the second network device when the sidelink is not disconnected at a detection time, wherein the detection time comprises a first time length after first indication information is transmitted. [Item 41] 41. The apparatus of any one of items 37 to 40, wherein the radio resource control release information is received when the first terminal satisfies a handover condition and a session belonging to the first terminal does not exist between the first terminal and the first network device. [Item 42] A communication device, a processing module configured to determine that a first terminal satisfies a handover condition and that a session belonging to the first terminal does not exist between the first terminal and a first network device, where the first terminal is an intermediate device for a second terminal to access the first network device, and a first radio resource control connection exists between the first terminal and the first network device; and a transceiver module configured to transmit radio resource control release information to the first terminal, wherein the radio resource control release information indicates that the first radio resource control connection is to be released; An apparatus comprising: [Item 43] The transceiver module is further configured to receive a measurement report from the first terminal, wherein the measurement report includes information indicating a signal quality obtained by the first terminal through measurements; and The processing module is further configured to determine, based on the measurement report, that the first terminal satisfies the handover condition. Item 43. The device according to item 42. [Item 44] Item 44. The apparatus of item 42 or 43, wherein the processing module is further configured to release the first radio resource control connection between the first terminal and the first network device. [Item 45] A communication device, a processing module configured to determine whether a session belonging to a first terminal exists between the first terminal and a first network device, where the first terminal is an intermediate device for a second terminal to access the first network device; and a transceiver module configured to send a first radio resource control reconfiguration message to the first terminal when the session belonging to the first terminal does not exist, wherein the first radio resource control reconfiguration message includes information indicating at least one non-measurable cell and / or at least one measurable cell covered by the first network device; An apparatus comprising: [Item 46] The transceiver module further comprises: configured to send a second radio resource control reconfiguration message to the first terminal when the session belonging to the first terminal exists, wherein the second radio resource control reconfiguration message includes information indicating a cell covered by the first network device and / or another cell, and the another cell is a cell other than the cell covered by the first network device. Item 46. The device according to item 45. [Item 47] Item 47. The apparatus of item 46, wherein the second radio resource control reconfiguration message includes any one or more of at least one measurement event, a measurable cell whitelist, or a non-measurable cell blacklist, wherein the measurable cell whitelist includes at least one measurable cell within or outside the coverage of the first network device, and the non-measurable cell blacklist includes at least one non-measurable cell. [Item 48] 48. The apparatus of any one of items 45 to 47, wherein the transceiver module is further configured to receive a first measurement report from the first terminal, wherein the first measurement report is determined based on the second radio resource control reconfiguration message or the first radio resource control reconfiguration message. [Item 49] The transceiver module is further configured to: receive a second measurement report from the first terminal before the session belonging to the first terminal is determined to exist between the first terminal and the first network device, wherein the second measurement report includes information indicating a signal quality obtained by the first terminal through measurements; and The processing module is further configured to determine, based on the second measurement report, that the first terminal satisfies a handover condition. 49. The device according to any one of items 45 to 48. [Item 50] A communication device, a transceiver module configured to receive a first radio resource control reconfiguration message from a first network device when a session belonging to the first terminal does not exist between the first terminal and the first network device, wherein the first radio resource control reconfiguration message includes information indicating at least one non-measurable cell and / or at least one measurable cell covered by the first network device, and the first terminal is an intermediate device for a second terminal to access the first network device; and a processing module configured to perform signal measurements based on the first radio resource control reconfiguration message. An apparatus comprising: [Item 51] The transceiver module is further configured to: receive a second radio resource control reconfiguration message from the first network device when the session belonging to the first terminal exists, where the second radio resource control reconfiguration message includes information indicating a cell covered by the first network device and / or another cell, and the another cell is a cell other than the cell covered by the first network device; and the processing module is further configured to perform signal measurements based on the second radio resource control reconfiguration message. Item 51. The device according to item 50. [Item 52] 52. The apparatus of claim 51, wherein the second radio resource control reconfiguration message includes any one or more of at least one measurement event, a measurable cell whitelist, or a non-measurable cell blacklist, wherein the measurable cell whitelist includes at least one measurable cell within or outside the coverage of the first network device, and the non-measurable cell blacklist includes at least one non-measurable cell. [Item 53] 53. The apparatus of any one of items 50 to 52, wherein the transceiver module is further configured to send a first measurement report to the first network device, wherein the first measurement report is determined based on the second radio resource control reconfiguration message or the first radio resource control reconfiguration message. [Item 54] The apparatus of any one of items 50 to 53, wherein the transceiver module is further configured to: send a second measurement report to the first network device before receiving the second radio resource control reconfiguration message or the first radio resource control reconfiguration message from the first network device, wherein the second measurement report includes information indicating the signal quality obtained by the first terminal through measurements. [Item 55] 28. A communication device comprising at least one processor and a communication interface, the communication interface being configured to perform information exchange between the communication device and another communication device, wherein when program instructions are executed by the at least one processor, the communication device is capable of performing the method of any one of items 1 to 14 or 23 to 27. [Item 56] A communication device comprising at least one processor and a communication interface, the communication interface being configured to perform information exchange between the terminal and another communication device, and wherein, when program instructions are executed by the at least one processor, the communication device is capable of performing the method according to any one of items 15 to 17 or 18 to 22. [Item 57] 28. A computer program product comprising program instructions, which when executed perform the method of any one of items 1 to 27. [Item 58] 28. A computer-readable storage medium storing program code that is executed by a device, the program instructions of which, when executed, perform the method of any one of items 1 to 27. [Item 59] 28. A chip comprising at least one processor, wherein program instructions, when executed by the at least one processor, perform the method of any one of items 1 to 27. [Item 60] A communication system comprising the communication device according to item 55, the communication device according to item 56, and a second terminal.

Claims

1. 1. A communication method comprising: determining that a first terminal satisfies a handover condition and that a session belonging to the first terminal does not exist between the first terminal and a first network device, where the first terminal is an intermediate device for a second terminal to access the first network device, and a first radio resource control connection exists between the first terminal and the first network device; and sending radio resource control release information to the first terminal, wherein the radio resource control release information indicates that the first radio resource control connection is to be released; A method for providing

2. The method further comprises: receiving a measurement report from the first terminal, wherein the measurement report includes information indicating a signal quality obtained by the first terminal through measurements; and determining that the first terminal satisfies the handover condition based on the measurement report; The method of claim 1 , comprising:

3. The method further comprises: Releasing the first radio resource control connection between the first terminal and the first network device. The method of claim 1 , comprising:

4. The method of claim 1 , wherein the first terminal meeting a handover condition includes the first terminal meeting at least one measurement event.

5. The at least one measurement event is one of the following events: The signal quality of the serving cell falls below a corresponding threshold; the signal quality of the neighboring cell begins to become higher than the signal quality of the serving cell by a specific offset; the signal quality of the neighboring cell rises above a corresponding threshold; the signal quality of the serving cell falls below threshold 1 and the signal quality of the neighboring cell rises above threshold 2; the signal quality of the neighboring cell begins to become higher than the signal quality of a secondary cell by a specific offset; the signal quality of an inter-radio access technology neighboring cell rises above a corresponding threshold; and the signal quality of the primary cell falls below threshold 1 and the signal quality of an inter-RAT neighboring cell rises above threshold 2. including one or more of: The method of claim 4.

6. The method further comprises: transmitting the at least one measurement event to the first terminal; The method of claim 4 comprising:

7. The step of determining that the first terminal satisfies the handover condition and that the session belonging to the first terminal does not exist between the first terminal and a first network device comprises: determining that the first terminal satisfies the handover condition and that a protocol data unit (PDU) session belonging to the first terminal does not exist between the first terminal and the first network device; The method of claim 1 , comprising:

8. The step of determining that the first terminal satisfies the handover condition and that the session belonging to the first terminal does not exist between the first terminal and a first network device comprises: determining that the first terminal satisfies the handover condition, radio link control is restored, and the session belonging to the first terminal does not exist between the first terminal and the first network device; The method of claim 1 , comprising:

9. A communication device, a processing module configured to determine that a first terminal satisfies a handover condition and that a session belonging to the first terminal does not exist between the first terminal and a first network device, where the first terminal is an intermediate device for a second terminal to access the first network device, and a first radio resource control connection exists between the first terminal and the first network device; and a transceiver module configured to transmit radio resource control release information to the first terminal, wherein the radio resource control release information indicates that the first radio resource control connection is to be released; An apparatus comprising:

10. The transceiver module is further configured to receive a measurement report from the first terminal, wherein the measurement report includes information indicating a signal quality obtained by the first terminal through measurements; and The processing module is further configured to determine, based on the measurement report, that the first terminal satisfies the handover condition.

10. The apparatus of claim 9.

11. The apparatus of claim 9 , wherein the processing module is further configured to release the first radio resource control connection between the first terminal and the first network device.

12. The apparatus of claim 9 , wherein the first terminal satisfying a handover condition includes the first terminal satisfying at least one measurement event.

13. The at least one measurement event is one of the following events: The signal quality of the serving cell falls below a corresponding threshold; the signal quality of the neighboring cell begins to become higher than the signal quality of the serving cell by a specific offset; the signal quality of the neighboring cell rises above a corresponding threshold; the signal quality of the serving cell falls below threshold 1 and the signal quality of the neighboring cell rises above threshold 2; the signal quality of the neighboring cell begins to become higher than the signal quality of a secondary cell by a specific offset; the signal quality of an inter-radio access technology neighboring cell rises above a corresponding threshold; and the signal quality of the primary cell falls below threshold 1 and the signal quality of an inter-RAT neighboring cell rises above threshold 2. including one or more of:

13. The apparatus of claim 12.

14. The apparatus of claim 12 , wherein the transceiver module is further configured to transmit the at least one measurement event to the first terminal.

15. The apparatus of claim 9, wherein the processing module is configured to determine that the first terminal satisfies the handover condition and that a protocol data unit (PDU) session belonging to the first terminal does not exist between the first terminal and the first network device.

16. The apparatus described in Claim 9, wherein the processing module is configured to determine that the first terminal satisfies the handover condition, radio link control is restored, and the session belonging to the first terminal does not exist between the first terminal and the first network device.

17. 9. A communication device comprising at least one processor and a communication interface, the communication interface being configured to perform information exchange between the communication device and another communication device, the communication device being capable of performing the method of any one of claims 1 to 8 when program instructions are executed by the at least one processor.

18. A program comprising program instructions that are executed by a device, the program instructions causing the device to perform a method according to any one of claims 1 to 8 when executed by the device.

19. A chip comprising at least one processor, wherein program instructions, when executed by said at least one processor, perform the method of any one of claims 1 to 8.

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