Communication method, communication apparatus, and communication system

Abstract

The present application relates to the technical field of communications, and particularly to a communication method, a communication apparatus, and a communication system. The method comprises: receiving a first message on a first channel, wherein the first message comprises a connection establishment request message from a second terminal, and the connection establishment request message is used for requesting to establish a radio resource control (RRC) connection with a network device; and by means of a pre-configured second channel, sending a second message to the network device, wherein the second message comprises the connection establishment request message of the second terminal. Use of the method can reduce the time consumed by a connection establishment procedure of a remote UE.

Description

A communication method, communication device and communication system

[0001] This application claims priority to Chinese Patent Application No. 202410917172.9, filed on July 9, 2024, entitled "A Communication Method, Communication Device and Communication System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and more specifically, to a communication method, communication device, and communication system. Background Technology

[0003] A typical relay technology is a technique where a user equipment (UE) helps another UE communicate with a base station. In this technology, the remote UE communicates with the base station through the cooperation of the relay UE. The remote UE and the relay UE communicate via a sidelink, with the corresponding interface called proximity-based services communication 5 (PC5). The relay UE is directly connected to the base station, i.e., it communicates via the Uu interface.

[0004] In the R17 SL relay, remote UEs can access the network (e.g., base stations) through idle / inactive relay UEs. If a remote UE needs to communicate with the network, after discovering an idle / inactive relay UE, the remote UE establishes a PC5 connection with it. Then, the remote UE sends the first Radio Resource Control (RRC) connection establishment request message (e.g., RRCSetupRequest message, also known as SRB0 message) to the relay UE, thereby triggering the relay UE to enter the connected state.

[0005] However, considering that there are multiple relay UEs acting as relays, some of which may be in idle or inactive states, these idle / inactive relay UEs will store the RRC connection establishment request messages sent by the remote UE until they communicate with the network before forwarding them. If multiple idle / inactive relay UEs exist during the relay process, the remote UE's RRC connection establishment request message can only reach the network side after each relay UE has entered the connected state. In summary, the transmission of SRB0 messages by the remote UE is very time-consuming, resulting in a slow connection establishment process for the remote UE. Summary of the Invention

[0006] This application provides a communication method, communication device, and communication system that can reduce the connection establishment time of a remote UE.

[0007] In a first aspect, embodiments of this application provide a communication method, which can be applied to a first terminal or to components within the first terminal, such as a chip or processor. The method includes:

[0008] A first message is received on the first channel. The first message includes a connection establishment request message from the second terminal. The connection establishment request message is used to request the establishment of a Radio Resource Control (RRC) connection with the network device.

[0009] A second message is sent to the network device through a pre-configured second channel. The second message includes a connection establishment request message from the second terminal.

[0010] In one possible implementation of this application, the first message is transmitted from the second terminal to the first terminal via the first channel. The first channel is a pre-configured channel between terminals. Optionally, the first channel includes a pre-configured PC5 relay radio link control (RLC) channel. Optionally, the aforementioned pre-configuration can refer to default or protocol-defined settings, which can be used when the terminal device needs to transmit information data via the first channel. Optionally, the first message and the second message can be the same or different; the first channel and the second channel can be the same or different. If they are the same, the first channel and the second channel can be a pre-configured PC5 relay RLC channel. If they are different, the first channel can be a pre-configured PC5 relay RLC channel, and the second channel can be a pre-configured Uu relay RLC channel. Of course, the first channel and / or the second channel can also be other channels, and this application embodiment is not limited to these.

[0011] The method provided in this application embodiment, through a pre-configured first channel / passage / bearer between terminals, rapidly transmits the connection establishment request message sent by the remote UE to the relay UE directly connected to the base station via the relay UE, and then rapidly sends the connection establishment request message sent by the remote UE to the network device. This completes the process of interaction between the remote UE and the network device for connection establishment request messages (such as SRB0 messages, which will be described as an example below), preparing for RRC connection establishment and reducing the connection establishment process time of the remote UE. For the first terminal, there is no need to wait for other relay terminals to establish RRC connections sequentially, thus enabling the rapid transmission of SRB0 messages from the second terminal or itself.

[0012] In another alternative implementation, the second channel is a channel between the first terminal and the network device, or the second channel is a channel between the first terminal and the third terminal, and the third terminal is a relay terminal between the first terminal and the network device.

[0013] This implementation method enables fast transmission of SRB0 messages from the second terminal through a pre-configured second channel, which reduces the transmission time of SRB0 messages from the second terminal and thus reduces the connection establishment process time of the remote UE.

[0014] In another alternative implementation, the first terminal provides relay services to the second terminal, and the first message also includes a first local identifier of the second terminal.

[0015] This implementation includes a first local identifier of the second terminal in the first message. This allows the first terminal to clearly identify and distinguish different second terminals, thereby enabling more efficient management of connection requests from multiple second terminals. This helps ensure that each second terminal's connection request is correctly processed in complex network environments and reduces connection failures caused by confusion or misprocessing.

[0016] In another alternative implementation, the first local identifier is generated by the first terminal.

[0017] This implementation allows the first local identifier to be generated by the first terminal itself. For example, in scenarios requiring a fast response, the first terminal can generate and assign the identifier to accelerate the connection establishment process.

[0018] In another alternative implementation, the first local identifier is generated by the second terminal, a relay terminal directly connected to the network device, or a relay terminal directly connected to the second terminal.

[0019] In this embodiment, the second terminal is allowed to generate and carry its own local identifier to ensure identifier security. Furthermore, by allowing a relay terminal (which can be the first terminal) directly connected to the second terminal to generate its own local identifier, the second terminal has a corresponding local identifier from the initial stage of information transmission after joining the relay link. This ensures accurate differentiation of the second terminal, especially in scenarios where multiple remote terminals are connected to the relay link. By having a relay terminal directly connected to the network device generate and distribute local identifiers, all relay terminals in the entire link store their corresponding local identifiers before connecting to remote terminals, preventing duplicate local identifiers.

[0020] In yet another alternative implementation, the method further includes:

[0021] The first local identifier of the second terminal is determined to be the same as the local identifier of other remote terminals;

[0022] A second local identifier is determined for the second terminal, and the first local identifier and the second local identifier are associated.

[0023] In this embodiment, when the first local identifier of the second terminal is detected to be the same as the local identifier of other remote terminals previously stored, the second local identifier can be reassigned to the second terminal, and a second message containing the new identifier can be sent to the network device through a pre-configured second channel. This resolves the identifier conflict problem, ensures that each remote terminal can be uniquely identified by the network device, and successfully establishes an RRC connection.

[0024] In yet another alternative implementation, the second message further includes a second local identifier.

[0025] This embodiment avoids misidentification of the second local identifier of the second terminal during the information transmission of the second terminal by sending a second message containing the second local identifier to the terminal device or network device that is hopped back.

[0026] In yet another alternative implementation, the method further includes:

[0027] Receive a third message, which includes a second local identifier;

[0028] A fourth message is sent to the second terminal, the fourth message including the first local identifier.

[0029] This implementation maintains synchronization and consistency between terminals by adjusting the second local identifier in the third message to the first local identifier.

[0030] In another alternative implementation, the method further includes: generating a first local identifier and sending first indication information, the first indication information being used to indicate the addition of the first local identifier.

[0031] Optionally, the terminal generating the first local identifier is a relay terminal directly connected to a network device (such as a base station). This embodiment provides a mechanism for generating and allocating local identifiers, enabling the first terminal to flexibly manage the second terminals within its service range and avoiding local identifier conflicts.

[0032] In another optional implementation, the method further includes: receiving first indication information, receiving a first local identifier according to the first indication information, the first indication information being used to indicate the addition of the first local identifier, and the first local identifier being used to identify the second terminal.

[0033] In another optional implementation, the method further includes: receiving identifier allocation request information, the identifier allocation request information being used to request the allocation of a local identifier; and allocating a first local identifier according to the identifier allocation request information. It should be understood that the aforementioned actions of allocating or receiving the first local identifier can occur before the second terminal sends the RRC connection request information. This implementation ensures that identifiers can be quickly allocated to new remote terminals when needed by allocating a new identifier.

[0034] In another alternative implementation, the identifier allocation request information includes a target quantity, which indicates the number of local identifiers to be allocated.

[0035] In another optional implementation, the method further includes: sending identifier allocation request information, the identifier allocation request information being used to request the allocation of a local identifier; and receiving a first local identifier.

[0036] In another alternative implementation, the identifier allocation request information includes a target quantity, which indicates the number of local identifiers to be allocated, and receiving the first local identifiers includes receiving the target quantity of the first local identifiers.

[0037] In yet another alternative implementation, the method further includes:

[0038] The local identifiers for the candidates have been used up;

[0039] Receive connection establishment request messages sent by other remote terminals;

[0040] Send a fifth message to other remote terminals. The fifth message is used to indicate that the connection establishment request of other remote terminals is rejected.

[0041] This implementation avoids indefinite waiting or connection failure due to insufficient resources, helps maintain network stability and reliability, and ensures the normal operation of existing connections.

[0042] In yet another alternative implementation, the method further includes:

[0043] Send a configuration request message to the network device. The configuration request message includes the Layer 2 identifier and / or local identifier of the second terminal. The configuration request message is used to request the provision of relay configuration information.

[0044] Receive relay configuration information from the network device. The relay configuration information includes a third local identifier, which is a local identifier reassigned by the network device to the second terminal.

[0045] Send a sixth message, which includes the third local identifier.

[0046] This implementation enables the first terminal to perform configuration updates according to the instructions of the network device, which helps to ensure synchronization and consistency between the first terminal and the network device.

[0047] In another alternative implementation, the first channel includes a pre-configured PC5 relay radio link control (RLC) channel, and the second channel includes a Uu relay RLC channel or a PC5 relay RLC channel.

[0048] Secondly, embodiments of this application provide a communication method, which can be applied to a second terminal or to components within the second terminal, such as a chip or processor. The method includes:

[0049] A first message is sent to the first terminal through a pre-configured first channel. The first message includes a connection establishment request message, which is used to request the establishment of an RRC connection with the network device.

[0050] Relay communication is conducted between the first terminal and network equipment.

[0051] For the second terminal, the connection establishment request message (such as SRB0 message) can be quickly transmitted through the pre-configured channel without waiting for the relay terminals to enter the connection state in turn, thus reducing the connection establishment process time of the second terminal.

[0052] In another alternative implementation, the first terminal provides relay services to the second terminal, and the first message also includes a local identifier of the second terminal, which is generated by the second terminal.

[0053] In yet another alternative implementation, the method further includes:

[0054] A fourth message is received from the first terminal, the fourth message including the first local identifier.

[0055] In yet another alternative implementation, the method further includes:

[0056] A sixth message is received from the first terminal. The sixth message includes a third local identifier, which includes a local identifier reassigned by the network device to the second terminal.

[0057] In another alternative implementation, the first channel includes a PC5 relay RLC channel.

[0058] Thirdly, embodiments of this application provide a communication method applied to a network device, the method comprising:

[0059] On the pre-configured second channel, a second message sent by the first terminal is received. The second message includes a connection establishment request message from the second terminal, which is used by the second terminal to request the establishment of an RRC connection with the network device.

[0060] Relay communication is conducted between the first terminal and the second terminal.

[0061] By receiving connection establishment request messages from second terminals forwarded by the first terminal on a pre-configured second channel, second terminals that were originally unable to establish RRC connections directly with network devices are allowed to connect to the network through a relay terminal (i.e., the first terminal) and the pre-configured second channel. This expands the channels for network access. Furthermore, by quickly accessing and responding to second terminals, network devices reduce resource consumption such as information retention. The resources saved can enable more devices located at the network edge or in signal blind spots to access the network, enhancing the network's connectivity and service breadth. Simultaneously, the network device's rapid reception and transmission of RRC messages (such as RRC connection establishment request messages) through the pre-configured second channel reduces the connection establishment process time for second terminals.

[0062] In yet another alternative implementation, the second message further includes a second local identifier of the second terminal.

[0063] In another optional implementation, the second message includes a second local identifier of the second terminal, which is a local identifier corresponding to the first local identifier. The first local identifier includes the local identifier of the second terminal before reallocation, and the second local identifier includes the local identifier of the second terminal after reallocation.

[0064] In yet another alternative implementation, the method further includes:

[0065] Receive a configuration request message from the first terminal. The configuration request message includes the layer 2 identifier and / or local identifier of the second terminal. The configuration request message is used to request relay configuration information.

[0066] Based on the Layer 2 identifier and / or the local identifier, a local identifier is reassigned to the second terminal;

[0067] The relay configuration information is sent to the first terminal, including a third local identifier that is reassigned to the second terminal.

[0068] In yet another alternative implementation, the method further includes:

[0069] Receive a sixth message from the first terminal, the sixth message including a third local identifier.

[0070] In another alternative implementation, the second channel includes a Uu relay RLC channel.

[0071] Fourthly, embodiments of this application provide a communication method, which can be applied to a first terminal or to components within the first terminal, such as a chip or processor. The method includes:

[0072] Determine the first piece of information;

[0073] Send a second instruction based on the first information, wherein the first information includes one or more of the following: establishing an RRC connection with the network device, the first hop count not exceeding a preset first threshold, the first hop count being the number of terminals between the first terminal and the network device, and the second instruction is used to indicate the provision of relay services;

[0074] Establish a PC5 connection with the second terminal.

[0075] Optionally, the conditions in the first information can be defined by the protocol or preset. For example, the preset first threshold can be defined by the protocol or preset. The relay terminal can determine whether to execute the discovery process based on whether its own state meets the conditions in the first information. If it meets the conditions, the discovery process is executed; otherwise, the discovery process is not executed.

[0076] This embodiment uses a second terminal to send second indication information based on first information (such as establishing an RRC connection with a network device and the first hop count not exceeding a preset first threshold). This avoids relay terminals that might increase latency from joining the link, effectively achieving reliability through relay services under specific conditions (such as insufficient direct connection conditions). The method provided by this embodiment not only improves the flexibility and adaptability of the communication system but also ensures the continuity and stability of communication in complex network environments. Furthermore, establishing a PC5 connection further promotes direct communication between terminals, reduces network latency, and improves overall communication efficiency.

[0077] In yet another alternative implementation, the method further includes:

[0078] Receive third instruction information, which includes the first information and is used to indicate a request for multi-hop relay service.

[0079] In this embodiment, the first information is sent by the second terminal through the third instruction information, which means that the second terminal (remote terminal) can find a relay terminal that meets the requirements by customizing the content of the first information.

[0080] In yet another alternative implementation, the method further includes:

[0081] Receive fourth indication information, which is used to indicate the second hop number of the third terminal. The third terminal is a relay terminal between the first terminal and the network device. The second hop number of the third terminal is the number of terminals between the third terminal and the network device.

[0082] Determine that the number of the first hops does not exceed the preset first threshold.

[0083] Building upon the basic implementation, this implementation, by receiving fourth indication information (indicating the second hop count of the third terminal), enables the second terminal to more accurately assess the current network topology and determine whether it is suitable to act as a relay node. Furthermore, by combining the comparison and judgment between the first hop count and a preset first threshold, the rationality and effectiveness of relay selection are further ensured, avoiding unnecessary waste of communication resources.

[0084] In yet another alternative implementation, sending the second instruction information based on the first information includes:

[0085] Based on the first hop count and / or RRC status information, a second indication message is sent, the RRC status information including the connection state.

[0086] In yet another alternative implementation, the method further includes:

[0087] If the first hop count is less than a preset first threshold and the RRC status information includes an idle state or an inactive state, a fifth indication message is sent. The fifth indication message is used to indicate the hop count of the first terminal.

[0088] In another alternative implementation, the second indication information includes the RRC status information of the first terminal, which includes a connected state.

[0089] This implementation includes RRC status information (such as the status information of establishing an RRC connection with a network device) in the second indication information, enabling the receiver to monitor the sender's connection status and communication capabilities in real time. This improvement helps the receiver more accurately assess the feasibility and quality of relay services, thereby making more reasonable communication decisions. Simultaneously, by sharing RRC status information, it also promotes information exchange and cooperation between network nodes, enhancing the overall network's collaborative working capabilities and fault recovery capabilities.

[0090] Fifthly, embodiments of this application provide a communication method, which can be applied to a second terminal or to components within the second terminal, such as a chip or processor. The method includes:

[0091] The system receives a second instruction message, which is used to instruct the provision of relay services to the second terminal and to instruct the RRC status information of the first terminal, including the status information of establishing an RRC connection with the network device. Alternatively, the system sends a third instruction message and receives the second instruction message, which includes first information. The third instruction message is used to instruct the request for multi-hop relay services. The first information includes one or more of the following: establishing an RRC connection with the network device, and the number of first hops not exceeding a preset first threshold, where the number of first hops is the number of terminals between the first terminal and the network device.

[0092] Establish a PC5 connection with the first terminal.

[0093] The method provided in this embodiment considers the RRC status information of the first terminal, meaning that the first terminal is selected as a relay terminal in the communication link only when it is in a connected state. This state-based selection mechanism ensures the reliability and stability of the relay service, while avoiding the use of an idle or inactive first terminal as a relay, thereby optimizing the utilization of network resources. Furthermore, establishing a PC5 connection facilitates direct communication between the first and second terminals, reducing dependence on network infrastructure, lowering communication latency, and improving the efficiency and security of data transmission. This ability for direct communication between terminals is particularly important in scenarios such as vehicle-to-everything (V2X) and the Internet of Things (IoT), helping to achieve faster and more reliable device interconnection.

[0094] Sixthly, embodiments of this application provide a communication device, which can be the aforementioned first terminal or a component within the first terminal, such as a chip or processor. The communication device includes a processing unit and a transceiver unit, which can respectively perform the following operations:

[0095] The processing unit generates a first message, which includes a connection establishment request message from the second terminal, requesting the establishment of a Radio Resource Control (RRC) connection with the network device. The transceiver unit 1201 receives the first message on a first channel, which includes the connection establishment request message from the second terminal, requesting the establishment of an RRC connection with the network device. The transceiver unit is also configured to send a second message to the network device via a pre-configured second channel, which includes the connection establishment request message from the second terminal.

[0096] In one alternative implementation, the second channel is the channel between the first terminal and the network device, or...

[0097] The second channel is the channel between the first terminal and the third terminal, and the third terminal is the relay terminal between the first terminal and the network device.

[0098] In one alternative implementation, the first terminal provides relay services to the second terminal, and the first message also includes the first local identifier of the second terminal.

[0099] In one alternative implementation, the first local identifier is generated by the first terminal.

[0100] In one alternative implementation, the first local identifier is generated by the second terminal, a relay terminal directly connected to the network device, or a relay terminal directly connected to the second terminal.

[0101] In one optional implementation, the processing unit is further configured to determine that the first local identifier of the second terminal is the same as the local identifier of other remote terminals;

[0102] The processing unit is also used to determine a second local identifier for the second terminal, wherein the first local identifier and the second local identifier are associated.

[0103] In one alternative implementation, the second message also includes a second local identifier.

[0104] In one alternative implementation, the transceiver unit is further configured to receive a third message, the third message including a second local identifier; the transceiver unit is further configured to send a fourth message to the second terminal, the fourth message including a first local identifier.

[0105] In one alternative implementation, the processing unit is further configured to generate a first local identifier and send first indication information, the first indication information being used to indicate the addition of the first local identifier.

[0106] In one optional implementation, the transceiver unit is further configured to receive first instruction information, receive a first local identifier according to the first instruction information, the first instruction information being used to instruct the addition of the first local identifier, and the first local identifier being used to identify the second terminal.

[0107] In one optional implementation, the transceiver unit is further configured to receive identifier allocation request information, which is used to request the allocation of a local identifier.

[0108] The processing unit is also used to allocate a first local identifier based on the identifier allocation request information.

[0109] In one alternative implementation, the identifier allocation request information includes a target quantity, which indicates the number of local identifiers to be allocated.

[0110] In one optional implementation, the transceiver unit is further configured to send an identifier allocation request message, which is used to request the allocation of a local identifier; the transceiver unit is also configured to receive a first local identifier.

[0111] In one alternative implementation, the identifier allocation request information includes a target quantity, which indicates the number of local identifiers to be allocated. Specifically, in receiving the first local identifiers, the transceiver unit is used to receive the target quantity of the first local identifiers.

[0112] In one alternative implementation, the processing unit is also used to determine that the candidate local identifier has been used up;

[0113] This transceiver unit is also used to receive connection establishment request messages sent by other remote terminals;

[0114] The transceiver unit is also used to send a fifth message to other remote terminals, which indicates that the connection establishment request of other remote terminals is rejected.

[0115] In one optional implementation, the transceiver unit is further configured to send a configuration request message to the network device. The configuration request message includes the Layer 2 identifier and / or local identifier of the second terminal. The configuration request message is used to request the provision of relay configuration information.

[0116] The transceiver unit is also used to receive relay configuration information from the network device. The relay configuration information includes a third local identifier, which is a local identifier reassigned by the network device to the second terminal.

[0117] The transceiver unit is also used to send a sixth message, which includes a third local identifier.

[0118] In one alternative implementation, the first channel includes a pre-configured PC5 relay radio link control (RLC) channel, and the second channel includes a Uu relay RLC channel or a PC5 relay RLC channel.

[0119] Seventhly, embodiments of this application provide a communication device, which can be the aforementioned second terminal or a component within the second terminal, such as a chip or processor. The communication device includes a processing unit and a transceiver unit, which can respectively perform the following operations:

[0120] The transceiver unit is used to send a first message to a first terminal through a pre-configured first channel. The first message includes a connection establishment request message, which requests the establishment of an RRC connection with the network device. The processing unit is used to perform relay communication with the network device through the first terminal.

[0121] In one alternative implementation, the first terminal provides relay services to the second terminal, and the first message also includes a local identifier of the second terminal, which is generated by the second terminal.

[0122] In one alternative implementation, the transceiver unit is further configured to receive a fourth message from the first terminal, the fourth message including a first local identifier.

[0123] In one alternative implementation, the transceiver unit is further configured to receive a sixth message from the first terminal, the sixth message including a third local identifier, the third local identifier including a local identifier reassigned by the network device to the second terminal.

[0124] In one alternative implementation, the first channel includes a PC5 relay RLC channel.

[0125] Eighthly, embodiments of this application provide a communication device, which can be a network device mentioned in the third aspect above, or a component within the network device, such as a chip or processor. The communication device includes a processing unit and a transceiver unit, which can respectively perform the following operations:

[0126] The transceiver unit is used to receive a second message sent by the first terminal on a pre-configured second channel. The second message includes a connection establishment request message from the second terminal, which is used by the second terminal to request the establishment of an RRC connection with the network device. The processing unit is used to perform relay communication between the first terminal and the second terminal.

[0127] The second message also includes the local identifier of the second terminal.

[0128] In one alternative implementation, the second message also includes a second local identifier of the second terminal.

[0129] In one optional implementation, the transceiver unit is further configured to receive a configuration request message from the first terminal, the configuration request message including the layer 2 identifier and / or local identifier of the second terminal, the configuration request message being used to request relay configuration information;

[0130] The transceiver unit is also used to reallocate a local identifier for the second terminal based on the Layer 2 identifier and / or the local identifier, thereby obtaining a third local identifier;

[0131] The transceiver unit is also used to send relay configuration information to the first terminal, which includes a third local identifier that is reassigned to the second terminal.

[0132] In one alternative implementation, the transceiver unit is further configured to receive a sixth message from the first terminal, the sixth message including a third local identifier.

[0133] In one alternative implementation, the second channel includes a Uu relay RLC channel.

[0134] Ninthly, embodiments of this application provide a communication device, which can be the first terminal mentioned in the fourth aspect above, or a component within the first terminal, such as a chip or processor. The communication device includes a processing unit and a transceiver unit, which can respectively perform the following operations:

[0135] The transceiver unit is used to send second indication information according to first information, wherein the first information includes one or more of the following: establishing an RRC connection with the network device, the first hop count not exceeding a preset first threshold, the first hop count being the number of terminals between the first terminal and the network device, and the second indication information being used to indicate the provision of relay services. The processing unit is used to establish a PC5 connection with the second terminal.

[0136] In one alternative implementation, the transceiver unit is further configured to receive third indication information, which includes the first information and is used to indicate a request for multi-hop relay service.

[0137] In one optional implementation, the transceiver unit is further configured to receive fourth indication information, which indicates the second hop count of the third terminal, the third terminal being a relay terminal between the first terminal and the network device, and the second hop count of the third terminal being the number of terminals between the third terminal and the network device.

[0138] The processing unit is also used to determine that the first number of hops does not exceed a preset first threshold.

[0139] In one alternative implementation, the transceiver unit is specifically used to send second indication information based on a first hop count and / or RRC status information, the RRC status information including a connection state.

[0140] In one optional implementation, the transceiver unit is further configured to send a fifth indication message when the first hop count is less than a preset first threshold and the RRC status information includes an idle state or an inactive state. The fifth indication message is used to indicate the hop count of the first terminal.

[0141] In one alternative implementation, the second indication information includes RRC status information, which includes a connected state.

[0142] In a tenth aspect, embodiments of this application provide a communication device, which can be the second terminal mentioned in the fifth aspect above, or a component within the second terminal, such as a chip or processor. The communication device includes a processing unit and a transceiver unit, which can respectively perform the following operations:

[0143] The transceiver unit is used to receive second indication information, which indicates that relay service should be provided to the second terminal, and indicates the RRC status information of the first terminal, including the connection status. The processing unit is used to determine the first information.

[0144] Eleventhly, embodiments of this application provide a communication device, which can be a first terminal according to the fourth aspect. The communication device includes a processing unit and a transceiver unit, which can respectively perform the following operations:

[0145] The transceiver unit is used to receive third indication information and send second indication information based on the third indication information; the third indication information includes first information and is used to indicate a request for multi-hop relay service. The processing unit can be used to determine the first information.

[0146] In a twelfth aspect, embodiments of this application provide a communication device, which can be a second terminal as described in the fifth aspect, or a component within the second terminal, such as a chip or processor. The communication device includes a processing unit and a transceiver unit, which can respectively perform the following operations:

[0147] The transceiver unit is used to send third indication information, which includes first information. The third indication information is used to indicate a request for multi-hop relay service. The first information includes one or more of the following: establishing an RRC connection with the network device, and the first hop number not exceeding a preset first threshold. The first hop number is the number of terminals between the first terminal and the network device. The transceiver unit is also used to receive second indication information.

[0148] In a thirteenth aspect, embodiments of this application provide a communication device, which includes a processing unit and a transceiver unit, each capable of performing the following operations:

[0149] The transceiver unit is used to send a ninth message to the second terminal. The ninth message includes a sixth indication information, which indicates the RRC status information of the first terminal. The RRC status information includes the establishment of an RRC connection with the network device. The processing unit is used to establish a PC5 connection with the second terminal.

[0150] In a fourteenth aspect, embodiments of this application provide a communication device, which includes a processing unit and a transceiver unit, each capable of performing the following operations:

[0151] The transceiver unit is used to receive a ninth message from the first terminal. The ninth message includes sixth indication information, which indicates the RRC status information of the first terminal. The RRC status information includes the establishment of an RRC connection with the network device. The processing unit is used to establish a PC5 connection with the first terminal.

[0152] In a fifteenth aspect, embodiments of this application provide a communication device, which includes a processing unit and a transceiver unit, capable of performing the following operations respectively:

[0153] The transceiver unit is used to receive the eleventh message, which includes one or more of the following: an indication of discovering a terminal directly connected to the network device, maximum relay hop count information, and hop count information of the fourth terminal. The hop count information includes a third hop count, which is the number of terminals between the fourth terminal and the second terminal. The transceiver unit is also used to send a second indication message to the second terminal according to the eleventh message. The second indication message is used to indicate that relay service is provided.

[0154] In a sixteenth aspect, embodiments of this application provide a communication device, which includes a processing unit and a transceiver unit, capable of performing the following operations respectively:

[0155] The transceiver unit is used to send a tenth message to the first terminal. The tenth message includes one or more of the following: an indication of the discovery and direct connection of relay terminals to the base station; and maximum relay hop count information, wherein the maximum relay hop count information indicates that network devices can be accessed through multiple hops, but the number of hops cannot exceed the indicated number. The transceiver unit is also used to receive second indication information, which indicates the provision of relay services. The processing unit is used to establish a PC5 connection with the first terminal.

[0156] In a seventeenth aspect, this application provides a computer program product comprising instructions that, when executed on a computer, cause the computer to perform the method of the first aspect or any possible implementation thereof, or to perform the method of the second aspect or any possible implementation thereof, or to perform the method of the third aspect or any possible implementation thereof, or to perform the method of the fourth aspect or any possible implementation thereof, or to perform the method of the fifth aspect or any possible implementation thereof; or to perform the method executable by the communication device corresponding to the eleventh to sixteenth aspects.

[0157] Eighteenthly, this application provides a computer-readable storage medium storing a computer program that, when executed, performs the first aspect or any possible implementation thereof, the second aspect or any possible implementation thereof, the third aspect or any possible implementation thereof, the fourth aspect or any possible implementation thereof, the fifth aspect or any possible implementation thereof; or performs a method executable by the communication device corresponding to the eleventh to sixteenth aspects.

[0158] In a nineteenth aspect, this application provides a communication device, at least one processor, and a memory. The memory is used to store a computer program. The processor is used to execute the computer program stored in the memory, causing the communication device to perform the first aspect or any possible implementation thereof, the second aspect or any possible implementation thereof, the third aspect or any possible implementation thereof, the fourth aspect or any possible implementation thereof, the fifth aspect or any possible implementation thereof; or to perform the methods executable by the communication device corresponding to aspects eleven to sixteen.

[0159] In a twentieth aspect, this application provides a chip that includes at least a processor. The processor is configured to execute computer execution instructions to cause a device on which the chip is mounted to perform the first aspect or any possible implementation thereof, the second aspect or any possible implementation thereof, the third aspect or any possible implementation thereof, the fourth aspect or any possible implementation thereof, or the fifth aspect or any possible implementation thereof; or to perform methods executable by communication devices corresponding to aspects eleven through sixteen.

[0160] In conjunction with aspect 20, in one possible implementation, the chip may further include interface circuitry. This interface circuitry is used to receive computer execution instructions and transmit them to the processor.

[0161] In a twentieth aspect, this application provides a communication system. The communication system includes at least a first terminal, a second terminal, and a network terminal. The first terminal is configured to execute the communication method provided by the first aspect or any possible implementation thereof, the second terminal is configured to execute the communication method provided by the second aspect or any possible implementation thereof, and the network terminal is configured to execute the communication method provided by the third aspect or any possible implementation thereof.

[0162] In a twentieth aspect, this application provides a communication system comprising at least a first terminal and a second terminal. The second terminal is used to execute the communication method provided by the fifth aspect or any possible implementation thereof, and the first terminal executes the communication method provided by the fourth aspect or any possible implementation thereof.

[0163] The beneficial effects of the methods, systems, and apparatus provided in any of the sixth and twenty-second aspects of this application can be found in the beneficial effects of the technical solutions provided in the first aspect, any of the first aspect's possible implementations, the second aspect and any of the second aspect's possible implementations, the third aspect and any of the third aspect's possible implementations, the fourth aspect and any of the fourth aspect's possible implementations, and the fifth aspect and any of the fifth aspect's possible implementations, and will not be repeated here. Attached Figure Description

[0164] Figure 1a is a schematic diagram of a network architecture applicable to an embodiment of this application;

[0165] Figure 1b is a schematic diagram of a network architecture applicable to an embodiment of this application;

[0166] Figure 2 is a schematic diagram of an SL communication scenario;

[0167] Figure 3 is a schematic diagram of the control plane protocol stack architecture for SL radio resource control;

[0168] Figure 4 is a schematic diagram of the communication architecture of U2N relay;

[0169] Figure 5 is a schematic diagram of the L2 U2N relay protocol stack;

[0170] Figure 6 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0171] Figure 7 is a schematic diagram of a scenario in which multiple remote UEs relay data according to an embodiment of this application;

[0172] Figure 8 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0173] Figure 9 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0174] Figure 10 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0175] Figure 11 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0176] Figure 12 is a schematic diagram of the structure of a communication device provided in this application;

[0177] Figure 13 is a schematic diagram of another communication device provided in this application. Detailed Implementation

[0178] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0179] The following explanations of some terms used in this application are provided to facilitate understanding by those skilled in the art.

[0180] The first terminal of the next hop, also known as the next-hop node, can refer to the next terminal in the transmission direction or the next terminal in the uplink (towards the network device) of the relay communication link. Specifically, it can be the first terminal of the subsequent hop. It's understood that the first terminal of the next hop still exists even if no data transmission occurs. For example, when a remote UE sends a message to a relay UE, the next-hop node of the remote UE can be the relay UE; when the relay UE forwards the message to the network device, the next-hop node of the relay UE can be the network device. It should be understood that the term "terminal of the subsequent hop" is a general term used to indicate the relay terminal between the current terminal and the network device.

[0181] The first terminal in the previous hop, also known as the previous hop node, can refer to the terminal in the previous transmission direction, or the next terminal in the downlink (towards the second terminal / remote UE) of the relay communication link. Specifically, it can be the first terminal connected to the current terminal in the preceding hop. For example, when a remote UE sends a message to a network device through a relay UE, the previous hop node of the relay UE is the remote UE, and the previous hop node of the network device is the relay UE. As another example, when a remote UE sends a message to a relay UE, the previous hop node of the relay UE can be the remote UE. It should be understood that the term "previous hop terminal" is a general term used to indicate the relay terminal between the current terminal and the network device.

[0182] Single-hop can refer to data or messages originating from a source node and reaching the destination node via an intermediate node. For example, the source node and destination node of a data packet might be a remote UE and a network device, respectively. The remote UE sends the data packet to a relay UE, which then forwards it to the network device.

[0183] Multi-hop refers to data or messages originating from a source node and passing through two or more intermediate nodes to reach a destination node. For example, if the source node and destination node of a message are a remote UE and a network device, respectively, the remote UE sends a message to relay UE1, relay UE1 forwards the message to relay UE2, and relay UE2 forwards it to the network device.

[0184] To facilitate understanding of the embodiments of this application, the communication system to which the embodiments of this application are applicable is described below.

[0185] The technical solutions provided in this application can be applied to various communication systems, such as 5th generation (5G) or new radio (NR) systems, long-term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, and LTE time division duplex (TDD) systems. The technical solutions provided in this application can also be applied to future communication systems. Furthermore, the technical solutions provided in this application can be applied to device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), and Internet of Things (IoT) communication systems or other communication systems.

[0186] The terminal device in this application embodiment can also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device.

[0187] Terminal devices can be devices that provide voice / data to users, such as handheld devices with wireless connectivity, in-vehicle devices, etc. Currently, some examples of terminals include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, and wireless terminals in transportation safety. The embodiments of this application do not limit the scope to wireless terminals in smart cities, smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, wearable devices, terminal devices in 5G networks, or terminal devices in future evolved public land mobile networks (PLMNs).

[0188] By way of example and not limitation, in this embodiment, the terminal device can also be a wearable device. Wearable devices, also known as wearable smart devices, are a general term for devices that utilize wearable technology to intelligently design and develop everyday wearables, such as glasses, gloves, watches, and shoes. Wearable devices are portable devices that are worn directly on the body or integrated into the user's clothing or accessories. Wearable devices are not merely hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are feature-rich, large in size, and can achieve complete or partial functions without relying on a smartphone, such as smartwatches or smart glasses, as well as those that focus on a specific type of application function and require the use of other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0189] In this embodiment, the device for implementing the functions of the terminal device can be the terminal device itself, or it can be a device that supports the terminal device in implementing the functions, such as a chip system or a chip. This device can be installed in the terminal device. In this embodiment, the chip system can be composed of chips, or it can include chips and other discrete devices.

[0190] The network device in this application embodiment can be a device for communicating with a terminal device. This network device can also be called an access network device or a wireless access network device, such as a base station. In this application embodiment, the network device can refer to a radio access network (RAN) node (or device) that connects the terminal device to the wireless network. A base station can broadly encompass, or be replaced by, various names including: Node B, evolved Node B (eNB), next-generation Node B (gNB), relay station, access point, transmitting and receiving point (TRP), transmitting point (TP), master station, auxiliary station, motorslide retainer (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, or radio unit (RU), etc. A base station can be a macro base station, micro base station, relay node, donor node, or similar entity, or a combination thereof. A base station can also refer to a communication module, modem, or chip installed within the aforementioned equipment or apparatus. A base station can also be a mobile switching center, a device that performs base station functions in D2D, V2X, and M2M communications, or a device that performs base station functions in future communication systems. A base station can support networks using the same or different access technologies. The embodiments of this application do not limit the specific technologies or device forms used in the network equipment.

[0191] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move depending on the location of the mobile base station. In other examples, a helicopter or drone can be configured as a device to communicate with another base station.

[0192] In some deployments, the network devices mentioned in the embodiments of this application may be devices including CU, DU, or CU and DU, or devices with control plane CU nodes (central unit control plane (CU-CP)) and user plane CU nodes (central unit user plane (CU-UP)) and DU nodes. In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU may also be called O-CU (open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples.

[0193] Network devices and terminal devices can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can also be deployed in the air on airplanes, balloons, and satellites. This application does not limit the scenario in which the network devices and terminal devices are located.

[0194] Figures 1a and 1b are schematic diagrams of network architectures applicable to embodiments of this application.

[0195] As shown in Figures 1a and 1b, as an example, the network architecture involved in this application may include terminal devices and network devices. The terminal devices are the first terminal and the second terminal in Figure 1a, or multiple first terminals and second terminals in Figure 1b.

[0196] In Figures 1a and 1b, the second terminal can be a remote UE, and the first terminal can be a relay UE. The second terminal and the first terminal can communicate via communication interface #1, the first terminal and the network device can communicate via communication interface #2, and the second terminal can communicate with the network device through the first terminal. For example, taking the architecture shown in Figure 1a, when the second terminal sends information / data to the network device, it can first send the information / data to the first terminal, which then forwards the information / data to the network device. Therefore, the first terminal is called a relay terminal.

[0197] In remote areas where cell coverage is insufficient, remote UEs may require multiple terminal devices as relay terminals to communicate with network devices, as shown in Figure 1b.

[0198] In Figure 1b, the second terminal communicates with the network device through multiple first terminals. The last relay terminal (the first terminal connected to the network device) can communicate through communication interface 2#, enabling direct communication between the last relay terminal and the network device. Communication between relay terminals (e.g., between the multiple first terminals in Figure 1b) still needs to be done through communication interface #1.

[0199] It should be understood that the multiple first terminals in Figure 1b are some or all of the relay terminals. Figure 1b shows a scenario in which multiple first terminals are all of the relay terminals. In other scenarios, the relay terminals may also include third terminals. The third terminal is the relay terminal between the first terminal and the network device. That is, the last relay terminal mentioned above is the third terminal in this scenario, or the last terminal among the third terminals.

[0200] As an example, communication interface #1 can be a proximity-based services communication 5 (PC5) interface, or an interface not defined by the 3rd generation partnership project (3GPP), such as a proprietary interface, wireless fidelity (WiFi), Bluetooth, or a wired interface, without restriction. As an example, communication interface #2 can be a Uu interface, which refers to the interface for communication between the UE and the network device; correspondingly, the link between the UE and the network device can be called a Uu link. It is understood that the PC5 interface and Uu interface are merely examples and do not constitute any limitation on the scope of protection of this application. The communication interface can also have other names, which will not be elaborated here.

[0201] It is understood that the network architectures shown in Figures 1a and 1b above are merely illustrative examples, and the network architectures applicable to the embodiments of this application are not limited thereto. For example, the above architecture may also include other devices, such as core network devices and / or other terminal devices. As an example, core network devices may include, for example, access and mobility management function (AMF) network elements, session management function (SMF) network elements, user plane function (UPF) network elements, policy control function (PCF) network elements, etc.

[0202] To facilitate understanding of the embodiments of this application, a few basic concepts involved in the embodiments of this application will be briefly explained.

[0203] It is understood that the basic concepts introduced below are simply illustrated using the basic concepts specified in the current protocol as examples, but do not limit the embodiments of this application to be applied only to existing systems. Therefore, the names that appear when describing existing systems are functional descriptions, and the specific names are not limited, but only indicate functions, and can be extended to other systems, such as 4G, 5G or future communication systems.

[0204] 1. Slidelink (SL)

[0205] In wireless communication systems, UEs can communicate with each other via the operator's network (e.g., base stations), or they can communicate directly without going through the operator's network. The interface between UEs can be called a PC5 interface. The link between UEs can be called a sidelink, or a PC5 link. As a possible application scenario, each vehicle can be considered a UE, and vehicles can communicate with each other (i.e., between UEs) via the PC5 interface, without going through the operator's network, thus effectively reducing communication latency.

[0206] For the sake of consistency, this application uses the term SL to refer to the link between UEs and UAs, and Uu to refer to the link between UE and network devices, as an example for illustrative purposes. It is understood that SL and Uu are merely names used for distinction, and their specific naming does not limit the scope of protection of this application. It is also understood that SL and Uu indicate a connection relationship between devices; they are logical concepts rather than physical entities.

[0207] Figure 2 is a schematic diagram of an SL communication scenario.

[0208] As shown in Figure 2, the interface between UE1 and UE2 can be called the PC5 interface, and the direct link between UE1 and UE2 can be called SL. UE1 and UE2 can communicate directly through the PC5 interface.

[0209] Figure 3 is a schematic diagram of the control plane protocol stack architecture of SL radio resource control (RRC).

[0210] As shown in Figure 3, the protocol stack of the SLRRC control plane may include: physical (PHY) layer, media access control (MAC) layer, radio link control (RLC) layer, packet data convergence protocol (PDCP) layer, and RRC layer.

[0211] The PC5 interface supports communication methods such as broadcast, unicast, and multicast. This application mainly involves unicast communication, which is briefly introduced below.

[0212] 2. Unicast communication

[0213] First, a unicast connection is established between two UEs. After the unicast connection is established, the two UEs can communicate data based on a negotiated identifier. This data can be encrypted or unencrypted. Unicast communication is similar to data communication between a UE and a network device after establishing an RRC connection. Compared to broadcast, in unicast communication, only two UEs that have established a unicast connection can conduct this unicast communication.

[0214] In unicast communication, when a UE transmits data, it can send source and destination identifiers, such as a source layer-2 identifier and a destination layer-2 identifier, along with the data and the Service Cell Identifier (SCI), to ensure that the data is transmitted to the correct receiving end. For example, the subheader and SCI of each SL Media Access Control Protocol Data Unit (MACPDU) can contain these source and destination layer-2 identifiers. The source identifier identifies the sending end and can be assigned by the sending UE itself. The destination identifier identifies the receiving end and can be an identifier assigned by the receiving UE for the unicast connection. UEs communicate with each other via the PC5 interface.

[0215] 3. Wireless bearer

[0216] Radio bearer is a collective term for a series of protocol entities and configurations allocated by network devices to UEs. It is a service provided by Layer 2 for transmitting user data between UEs and network devices, including PDCP protocol entities (or PDCP layer), RLC protocol entities (or RLC layer), MAC protocol entities (or MAC layer), and PHY entities (or PHY).

[0217] Radio bearers can be divided into data radio bearers (DRBs) and signaling radio bearers (SRBs). DRBs are used to carry data, while SRBs are used to carry signaling or messages. In SL communication scenarios, the radio bearer corresponding to communication between UEs is called a sidelink radio bearer (SLRB). Similarly, this SLRB includes sidelink data radio bearers (SLDRBs) and sidelink signaling radio bearers (SLSRBs). In the signaling design of the protocol, the RB configuration generally includes configurations above the PDCP layer. Protocol entities below the RLC layer are called RLC bearers, and their corresponding configurations are given in the RLC bearer configuration.

[0218] 4. RLC Bearer

[0219] RLC bearer: refers to the protocol entities and configurations below the RLC layer, which is the lower layer corresponding to the RB, including the RLC layer and a series of resources such as logical channels. An RLC bearer is associated with a logical channel of the MAC layer. An RLC bearer is associated with a PDCP layer, meaning one RLC serves one RB. In SL communication scenarios, the RLC bearer on the SL can also be called a sidelink RLC bearer.

[0220] 5. UE access network relay (UE-to-network relay, U2N relay)

[0221] U2Nrelay, also known as SLU2Nrelay, refers to an architecture where a UE provides network access services to another UE. In a U2Nrelay scenario, unicast communication allows one UE to access the network through another UE, thereby enhancing network coverage. In a U2Nrelay scenario, the node performing the relay function can be called a relay UE, and the node accessing the network through this relay UE can be called a remote UE. It is understood that the terms "remoteUE" and "relayUE" are merely used for distinction and do not limit the scope of protection of the embodiments in this application. For example, remoteUE and relayUE can also be referred to as a first terminal and a second terminal, respectively; or they can also be referred to as a first node and a second node; or they can also be referred to as a first module and a second module, etc.

[0222] Figure 4 is a schematic diagram of the communication architecture of U2Nrelay.

[0223] As shown in Figure 4, remoteUE can communicate with network devices through the cooperation of relayUE. RemoteUE and relayUE communicate through SL, and the corresponding interface can be called PC5. RelayUE and network devices are directly connected, that is, they communicate through the Uu interface.

[0224] It is understood that a relay UE can provide relay services for one remote UE, or it can provide relay services for multiple remote UEs, without restriction. A remote UE can access the network through a one-hop path (i.e., through one relay UE), or it can access the network through a multi-hop path (i.e., through multiple relay UEs), without restriction.

[0225] U2Nrelay technology mainly includes two designs: layer-2 (L2) U2Nrelay and layer-3 (L3) U2Nrelay. The following section uses L2U2Nrelay as an example to introduce the user plane protocol stack and control plane protocol stack during data transmission.

[0226] Figure 5 is a schematic diagram of the L2U2Nrelay protocol stack.

[0227] Figure 5(a) is a schematic diagram of the user plane protocol stack of L2U2Nrelay (i.e., the user plane protocol stack when remoteUE establishes a connection with network device through relayUE to transmit data); Figure 5(b) is a schematic diagram of the control plane protocol stack of L2U2Nrelay (i.e., the control plane protocol stack when remoteUE establishes a connection with network device through relayUE to transmit data).

[0228] As shown in part (a) of Figure 5, the protocol stack of the user plane of L2U2Nrelay may include: a PHY layer (e.g., PC5-PHY and Uu-PHY shown in part (a) of Figure 5), a MAC layer (e.g., PC5-MAC and Uu-MAC shown in part (a) of Figure 5), an RLC layer (e.g., PC5-RLC and Uu-RLC shown in part (a) of Figure 5), a sidelink relay adaptation protocol (SRAP) layer (e.g., PC5-SRAP and Uu-SRAP shown in part (a) of Figure 5), a PDCP layer (e.g., Uu-PDCP shown in part (a) of Figure 5), and an SDAP layer (e.g., Uu-SDAP shown in part (a) of Figure 5). The SRAP layer can also be called an adaptation layer.

[0229] As shown in Figure 5(b), the protocol stack of the control plane of L2U2Nrelay may include: PHY layer (e.g., PC5-PHY and Uu-PHY shown in part (b) of Figure 5), MAC layer (e.g., PC5-MAC and Uu-MAC shown in part (b) of Figure 5), RLC layer (e.g., PC5-RLC and Uu-RLC shown in part (b) of Figure 5), SRAP layer (e.g., PC5-SRAP and Uu-SRAP shown in part (b) of Figure 5), PDCP layer (e.g., Uu-PDCP shown in part (b) of Figure 5) and RRC layer (e.g., Uu-RRC shown in part (b) of Figure 5)).

[0230] As shown in Figure 5, data packets from the remote UE are relayed below the PDCP layer of the relay UE. That is, the relay UE maintains the relay RLC bearer, including the RLC layer (PC5-RLC and Uu-RLC in Figure 5), the MAC layer (PC5-MAC and Uu-MAC in Figure 5), and the PHY layer (PC5-PHY and Uu-PHY in Figure 5). There are end-to-end PDCP, SDAP, and RRC layers between the remote UE and the network device, but no end-to-end RLC, MAC, or PHY layers. In the U2N relay communication scenario, the RLC bearer between the network device and the relay UE can be called the UuRLC bearer or Uu relay RLC channel (Uu RelayRLCchannel), while the RLC bearer between the relay UE and the remote UE is the PC5relayRLC bearer or PC5 relay RLC channel (PC5RelayRLCchannel).

[0231] The SRAP layer (or adaptation layer) lies between the RLC layer and the PDCP layer. Referring to Figure 5, the SRAP layer in the protocol stack at both ends of the PC5 port (i.e., the sidelink) is called the PC5-SRAP layer, and the SRAP layer in the protocol stack at both ends of the Uu port is called the Uu-SRAP layer. The main functions of the SRAP layer include bearer multiplexing and demultiplexing, that is, supporting the multiplexing of different bearers onto a single bearer, or splitting a single bearer into different bearers.

[0232] Currently, when a remote UE accesses the network (e.g., a base station) through an idle / inactive relay UE, the relay UE in the idle / inactive state needs to enter the connected state before it can help the remote UE access the network. If there are multiple relay UEs in the idle / inactive state during the relay process, the remote UE's RRC connection establishment request message can only reach the network side after each relay UE enters the connected state. This undoubtedly makes the connection establishment process of the remote UE very long and time-consuming.

[0233] In view of this, this application provides a communication method. This method mainly transmits the connection establishment request message sent by the remote UE to the relay UE directly connected to the base station through a pre-configured first channel / bearer between terminals. This allows the relay UE directly connected to the base station to enter the connected state and send the connection establishment request message sent by the remote UE to the network device. Alternatively, it can constrain the relay UE to avoid performing the discovery process in the idle state, inactive state, or with excessively high hop count by using the discovery process of the first terminal, thereby reducing the message transmission time and thus reducing the connection establishment process time of the remote UE.

[0234] The method provided in this application can be applied to the scenarios shown in Figures 1a and 1b, and of course, it can also be applied to other scenarios with remote terminal devices and relay terminal devices. For example, a scenario architecture including multiple remote terminals and relay terminals.

[0235] The following example illustrates this method in a multi-hop scenario (as shown in Figure 1b). Figure 1b includes multiple first terminals (relay UEs). In the following embodiment, three first terminals are used as an example to illustrate this method. The three first terminals are first terminal 1, first terminal 2, and first terminal 3. First terminal 1 is directly connected to the second terminal (remote UE), first terminal 2 is connected to first terminal 1, first terminal 2 is connected to first terminal 3, and first terminal 3 is directly connected to the network device. The second terminal can achieve relay communication with the network device through the first terminals (first terminal 1, first terminal 2, and first terminal 3). The direct connection between first terminal 1 and the second terminal (remote UE) can mean that first terminal 1 and second terminal have established a PC5 connection, or that first terminal 1 and second terminal are connected via an SL link; the direct connection between first terminal 3 and the network device can mean that first terminal 3 and the network device are connected via a Uu link. It is easy to understand that the second terminal can also achieve relay communication with the network device through other numbers of first terminals, for example, through N first terminals, where N is a positive integer greater than or equal to 2. This embodiment is described using N as an example.

[0236] Please refer to Figure 6 for details. Figure 6 is a flowchart illustrating a communication method provided in an embodiment of this application. The method includes at least steps S601, S602, S603, S604, and S612. Steps S605 to S611 are optional steps, as detailed below:

[0237] Step S601: The second terminal sends a first message to the first terminal 1. Correspondingly, in step S602: The first terminal 1 receives the first message from the second terminal.

[0238] Optionally, steps S601 and S602 can be the same operation procedure or different operation procedures.

[0239] The first message is transmitted on the first channel, which is a pre-configured channel between terminals. Optionally, the first channel includes a pre-configured PC5 relay radio link control (RLC) channel.

[0240] It should be understood that the above-mentioned pre-configuration may refer to the default or protocol-defined. For example, when the terminal device needs to transmit information data through the first channel, the pre-configured first channel can be used.

[0241] Furthermore, the aforementioned pre-configuration can also be configured by the terminal device (such as the second terminal, the first terminal 1, etc.) after powering on. When a connection establishment message needs to be sent, the pre-configured first channel is activated. Correspondingly, the first channel can be turned off after the terminal device (such as the second terminal) is in the connected state.

[0242] In one alternative implementation, the first channel is dedicated to transmitting connection establishment request messages or messages / information related to connection establishment request messages.

[0243] The first message includes a connection establishment request message from the second terminal. The connection establishment request message is used by the second terminal to request the establishment of a Radio Resource Control (RRC) connection with the network device. For example, the connection establishment request message can be an RRC connection establishment request message, such as an RRC Setup Request message, which can also be called an SRB0 message.

[0244] In one possible scenario, multiple second terminals may access the network through a first terminal (such as first terminal 1). In order for the first terminal to be able to distinguish between different second terminals, the first message includes the first local identifier (local ID) of the second terminal. When first terminal 1 sends a connection request message for the second terminal to the next first terminal (such as first terminal 2) or the network device, it may carry the local identifier so that the first terminal and the network device can identify which second terminal it is when receiving / sending information related to the second terminal.

[0245] In this embodiment, the first local identifier can be an index.

[0246] Optionally, the first message may also include a first local identifier. When sending the first message, the second terminal may add this first local identifier to the header of the adaptation layer at the RLC layer, and then send it along with the second terminal's RRC connection request (first message) to the network device or relay terminal (such as the first terminal 1). This first local identifier is used to identify the second terminal. It can be understood that if the first message sent by the second terminal includes the first local identifier, it means that the first local identifier was generated by the second terminal. Of course, the first message may also not include the first local identifier.

[0247] In one optional implementation, the first message includes a first local identifier, which is generated by the second terminal. After receiving the first message, the first terminal 1 stores the first local identifier of the second terminal in the first message locally, so that when sending downlink information to the second terminal, the data packet of the corresponding second terminal can be identified by the first local identifier. Specifically, the first terminal 1 stores the association relationship between the first local identifier and the second terminal, or stores the association relationship between the first local identifier and the link between the first terminal 1 and the second terminal. It should be noted that the first terminal 1 may also store the local identifiers of other remote terminals and the association relationships between other remote terminals.

[0248] In another alternative implementation, the first local identifier may be generated by the first terminal, meaning the first message does not include the first local identifier. In this case, after receiving the first message, the first terminal 1 generates a second message, which includes the first local identifier and a connection establishment request message from the second terminal. It should be understood that the first local identifier is generated by a relay terminal (such as the first terminal 1) directly connected to the second terminal.

[0249] In another alternative implementation, the local identifier can be generated and distributed by a relay terminal (such as the first terminal 3) directly connected to the network device. Therefore, the first local identifier of the first terminal 1 marking the second terminal can be pre-assigned by the relay terminal (such as the first terminal 3) directly connected to the network device. Taking the first terminal 3 as the generator of the local identifier as an example, the first terminal 3 generates multiple local identifiers, such as ID1, ID2, and ID3, assigns ID1 and ID2 to the first terminal 2, and instructs the first terminal 2 to assign ID1 and / or ID2. The first terminal 2 assigns ID1 to the first terminal 1. After receiving the first message, the first terminal 1 uses ID1 as the first local identifier of the second terminal that sent the first message.

[0250] It is understandable that the above-described generation and allocation process may occur before the method flow shown in Figure 6.

[0251] Step S603: First terminal 1 sends a second message to first terminal 2. Correspondingly, step S604: First terminal 2 receives the second message from first terminal 1.

[0252] In one alternative implementation, the second message sent by the first terminal 1 is sent through a pre-configured second channel, which includes a PC5 relay RLC channel.

[0253] In one optional implementation, after receiving the first message from the second terminal, if the first terminal 1 is in an idle / inactive state, the first terminal 1 may send a connection establishment request message to the first terminal 2. The connection establishment request message is used by the first terminal 1 to request the establishment of an RRC connection with the network device. The connection establishment request message can be transmitted through the second channel.

[0254] In one alternative implementation, the first local identifier is generated by a relay terminal (e.g., the first terminal 1) directly connected to the second terminal, and the second message includes the first local identifier of the second terminal generated by the first terminal 1.

[0255] Optionally, the second message can be the first message, which means that if the first message contains the first local identifier, then the first terminal 1 may not adjust the first local identifier.

[0256] Considering scenarios where multiple second terminals perform relay communication, if the first local identifier is assigned by the second terminal or a relay terminal directly connected to the second terminal, there may be cases where the first local identifier is the same but corresponds to different second terminals. The following explanation uses the example of the first local identifier being generated by the second terminal to illustrate this scenario. Please refer to Figure 7 for details. Figure 7 is a schematic diagram of a scenario where multiple remote UEs perform relay communication according to an embodiment of this application. In Figure 7, the second terminal connected to the first terminal 1 is called second terminal 1, and the second terminal connected to the first terminal 2 is called second terminal 2. In this scenario, the first terminal 2 may receive data packet 1 from the second terminal 2. Data packet 1 includes a connection establishment request message and a first local identifier corresponding to the second terminal 2 (e.g., the first local identifier is ID1, i.e., ID1 in Figure 7). The first terminal 2 also receives the first local identifier corresponding to the second terminal 1, which is also ID1. This indicates that the first terminal 2 received data packet 2 from the first terminal 1. Data packet 2 also includes a connection establishment request message and the first local identifier ID1. The first terminal 2 receives connection establishment request messages from two second terminals (second terminal 1 and second terminal 2), both corresponding to the first local identifier ID1. This may lead to a situation where the first terminal 2 cannot distinguish between the two second terminals. For example, when messages from second terminal 1 and second terminal 2 are exchanged between the first terminal 2 and the first terminal 3, and between the first terminal 3 and the network device, the corresponding data packets will carry the same local identifier. This will cause the first terminal 2, upon receiving a data packet carrying the local identifier, to be unable to determine whether to forward it through the first terminal 1 to the second terminal 1 or to the second terminal 2.

[0257] To address this issue of local identifier conflicts, the first terminal (including first terminals 1, 2, and 3) is enabled to adjust its first local identifier when it receives a local identifier from the second terminal that is duplicated with a previously stored local identifier from another remote terminal. This adjustment prevents duplication and thus avoids identification errors. One possible approach is for first terminal 2 to reallocate the first local identifier of second terminal 1, thus avoiding conflicts during the subsequent hop phase.

[0258] The above-mentioned method for determining the duplication of local identifiers can be that the first terminal 2 determines that the first local identifier of the second terminal 1 is the same as the local identifier of other remote terminals (second terminal 2) (such as the two first local identifiers mentioned above being ID1).

[0259] Optionally, the first terminal 2 can determine whether the first local identifier in the data packet sent by the second terminal 1 conflicts with the stored / maintained local identifier / local identifier correspondence based on the previously stored / maintained correspondence between the local identifier of other remote terminals and the first link, or the previously stored / maintained correspondence between the local identifier of other remote terminals and the other remote terminal. For example, if the first terminal 2 previously stored the local identifier of the second terminal 2 as ID1, and the first local identifier in the newly received data packet sent by the second terminal 1 is also ID1, then it is considered that the first local identifier of the second terminal 1 is the same as the local identifier of another remote terminal (second terminal 2), or that the first local identifier in the data packet sent by the second terminal 1 conflicts with the stored / maintained local identifier / local identifier correspondence.

[0260] To address the issue of duplicate local identifiers, the terminal device / network device can perform actions including reallocating local identifiers. Optionally, this action includes reallocating the first local identifier of a second terminal that accesses the network later than other remote terminals. For example, a second local identifier is determined for second terminal 1, and the first and second local identifiers are associated. In this example, the number of second terminals with relocated local identifiers is one, such as second terminal 1 described above. After the reallocation operation, at first terminal 2, the second local identifier corresponding to second terminal 1 is ID2 (i.e., ID2 in Figure 7), while the local identifier corresponding to second terminal 2 remains ID1 (i.e., ID1 in Figure 7), thereby avoiding conflicts in subsequent communication.

[0261] The values ​​of the local identifiers above are merely examples and are not intended to limit the local identifiers in this application.

[0262] Optionally, to avoid increasing the number of identifier alignment processes between relay terminals, the first terminal 2 can determine / generate a local identifier correspondence based on the first local identifier and the second local identifier. The local identifier correspondence includes the first local identifier and the second local identifier, and the first local identifier and the second local identifier are associated. Specifically, the association relationship can be that the second terminal (remote terminal) corresponding to the first local identifier and the second local identifier are the same.

[0263] The local identifier mapping provided in this embodiment is only an example. In actual applications, the local identifier mapping can be presented in different forms, such as a routing table, which includes a first local identifier and a second local identifier.

[0264] It is understood that the above-described redistribution process can occur at any relay terminal; the redistribution process performed via the first terminal 1 here is merely illustrative. For example, the above-described redistribution process can occur at the first terminal 3. As long as the local identifier of the second terminal received by the first terminal 3 is the same as that stored locally by other remote terminals, the first terminal 3 can also re-determine the local identifier of the second terminal. It is understood that if the above-described redistribution process occurs at the first terminal 1, then the second message also includes the aforementioned second local identifier.

[0265] In an optional implementation, to reduce the overhead of information alignment and avoid confusion in the identification of the local identifier of the second terminal by other terminal devices / network devices, the second local identifier is used in the communication process between the first terminal 2 and the subsequent terminal device (such as the first terminal 3) or network device, while the first local identifier is used in the communication process between the first terminal 2 and the preceding terminal device (such as the first terminal 1). For example, the first terminal 2 receives a third message from the first terminal 3, the third message including the second local identifier; the first terminal 2 can adjust the second local identifier to the first local identifier according to the above-mentioned local identifier correspondence, and send a fourth message to the second terminal / first terminal 1, the fourth message including the first local identifier.

[0266] In another alternative implementation, the first terminal 2 transmits a second local identifier to the forward-jumping terminal device (such as the first terminal 1) so that the forward-jumping terminal device knows that the local identifier of the second terminal has been corrected, and so that the forward-jumping terminal device stores the reallocated local identifier (the second local identifier) ​​to identify the relevant messages of the corresponding second terminal.

[0267] In scenarios with N relay terminals, the connection establishment request message of the second terminal needs to be sent to the network device through these N relay terminals, where N ≥ 2 and is a positive integer. In such scenarios, the method shown in Figure 6 includes steps S605 to S611. It should be understood that steps S605 to S611 are optional. The specific contents of steps S605 to S611 are as follows:

[0268] Step S605: First terminal 2 sends a seventh message to first terminal 3. Correspondingly, step S606: First terminal 3 receives the seventh message from first terminal 2.

[0269] The seventh message includes a connection establishment request message from the second terminal.

[0270] Optionally, the seventh message also includes the first local identifier of the second terminal. This indicates that the first local identifier was not reallocated by the preceding terminal (such as the first terminal 2). Therefore, the local identifier included in the seventh message is the first local identifier, not the reallocated local identifier (such as the second local identifier). It can be understood that the seventh message can be the same as the aforementioned second message or the first message. Whether it is the same as the second message or the first message depends mainly on who generated the first local identifier. If the first local identifier was generated by the second terminal, and the first terminal 1 and the first terminal 2 did not adjust the first local identifier, then the seventh message is the same as the first message. Of course, the second message is also the same as the first message. If the first local identifier was generated by the first terminal 1, and the first terminal 1 did not adjust the first local identifier, then the seventh message is the same as the second message, while the second message is different from the first message (one includes the first local identifier, and the other does not).

[0271] Optionally, the seventh message may also include a second local identifier of the second terminal, which represents the reallocation of the first local identifier by the preceding terminal (such as the first terminal 2).

[0272] Considering that the local identifier (first local identifier or second local identifier) ​​of the second terminal included in the seventh message may also be duplicated / conflicted with the local identifier of other remote terminals connected to the first terminal 3, the relay terminal (including the first terminals 1, 2, and 3) determines that the local identifier (first local identifier or second local identifier) ​​of the second terminal is duplicated / conflicted with the local identifier of other remote terminals. The relay terminal then reallocates the local identifier (first local identifier or second local identifier) ​​of the second terminal. The specific operation process of the reallocation can be found in the relevant description at step S604 of the method corresponding to Figure 6, which will not be repeated here.

[0273] In one optional implementation, the seventh message is transmitted via a pre-configured second channel, which includes a PC5 Relay RLC channel. It should be noted that the second channel has two scenarios: Scenario 1, during the information transmission phase between terminals, the second channel can be a PC5 Relay RLC channel; Scenario 2, during the information transmission phase between a terminal and a network device, the second channel can be a Uu Relay RLC channel.

[0274] Considering that multi-hop scenarios involve multiple relay terminals, in one optional implementation, the second channel is the channel between the first terminal and the third terminal, and the third terminal is the relay terminal between the first terminal and the network device. It should be understood that the third terminal can be the aforementioned first terminal 3, and the first terminal can be the aforementioned first terminal 1 or first terminal 2. The difference here is only in the naming of the terminal devices and has no impact on the flow of this solution.

[0275] Based on the above method, without receiving configuration from the base station, a relay terminal on a multi-hop path can forward SRB0 messages from multiple second terminals. This completes the process of exchanging SRB0 messages between the second terminal and the network device, preparing for the establishment of an RRC connection.

[0276] In an optional implementation, the seventh message further includes a first local identifier or a second local identifier. The local identifier here may be generated by a relay terminal (such as the first terminal 1) directly connected to the second terminal. After receiving the first message from the second terminal 1, the first terminal 1 generates a corresponding first local identifier for the second terminal 1. However, considering that the first terminal 2 may receive a connection establishment request message from other remote terminals (such as the second terminal 3), in this case, the first terminal 2 is the first terminal directly connected to the second terminal 3. The first terminal 2 generates a corresponding local identifier for the second terminal 3 and sends the connection establishment request message of the second terminal 3 and the corresponding local identifier to the first terminal 3. Since the two local identifiers may not have any information exchange regarding the local identifiers, a conflict may occur at the first terminal 3 due to duplicate local identifiers.

[0277] In the event of a conflict caused by duplicate local identifiers, the first terminal 3 can resolve the local identifier conflict by reallocating the first local identifier. For details, please refer to the process described above where the first terminal 2 resolves the local identifier conflict by redetermining the first local identifier. This process will not be repeated here.

[0278] In one alternative implementation, the first local identifier is generated by a relay terminal directly connected to the network device. In this embodiment, the relay terminal directly connected to the network device is the first terminal 3.

[0279] The following uses the first terminal 3 as an example of a relay terminal generating the first local identifier to illustrate the generation process of the first local identifier, which may include:

[0280] The first terminal 3 generates a first local identifier, which is a local identifier that marks the second terminal.

[0281] The first terminal 3 sends a first instruction message to either the first terminal 2 or the first terminal 1. The first instruction message is used to instruct the addition of a first local identifier. The above-mentioned generation action occurs before the second terminal requests to establish an RRC connection, that is, before step S601. It should be understood that the first local identifier here can be the first local identifier corresponding to the second terminal mentioned above, except that in this embodiment, the first local identifier has not yet marked the second terminal.

[0282] It is understandable that the above-described generation and allocation process may occur before the method flow shown in Figure 6.

[0283] Furthermore, the first local identifier can be selected by the first terminal 3 from the ID pool. The first local identifier sent to other first terminals (such as first terminal 1 and first terminal 2) can be some or all of the identifiers in the ID pool. The ID pool is pre-configured by the first terminal 3 or currently generated, and is used to store local identifiers. It is understood that relay terminals on the relay communication link, other than those that generate the first local identifier, can receive the first local identifier assigned by relay terminals directly connected to the network device (such as first terminal 3). For example, the ID pool includes first local identifiers ID1 to ID20. The first terminal 3 assigns ID1 to ID5 to first terminal 1, ID6 to ID10 to first terminal 2, and ID11 to ID15 to itself, leaving 5 IDs as alternatives.

[0284] Correspondingly, the first terminal 2 receives a first local identifier allocated by the first terminal 3, and the first terminal 2 marks the second terminal directly connected to it (as shown in Figure 7) using the first local identifier. The first terminal 1 receives the first local identifier allocated by the first terminal 3 through the first terminal 2. After the allocation is completed, the first terminal (1, 2, 3) receives the message from the second terminal and can attach the first local identifier to the message of the second terminal so that the subsequent first terminal can distinguish between different second terminals. This embodiment can prevent the problem of local identifier conflict when multiple second terminals access the same link.

[0285] Optionally, the producer of the local identifier (such as the first terminal 3) may instruct other relay terminals (such as the first terminal 1 and the first terminal 2) to release the fourth local identifier. For example, the first terminal 3 sends an identifier release message to the first terminal 2. This message releases the fourth local identifier, specifically instructing the first terminal 2 to release it. The first terminal 2 receives the identifier release message and releases the corresponding local identifier (the fourth local identifier) ​​according to the message. For ease of understanding, the fourth local identifier can be explained as follows: if the identifier release message precedes the first message, the fourth local identifier can be any local identifier other than the first local identifier within the receiver (such as the first terminal 2). If the identifier release message follows the connection establishment request message from the second terminal, the fourth local identifier can be some or all of the local identifiers within the receiver.

[0286] Considering the large number of second terminals in a relay communication scenario, if the local identifiers stored in a relay terminal (such as the first terminal 2) are insufficient to meet the demand, the relay terminal (such as the first terminal 2) can request the allocation of new local identifiers from the next-hop relay terminal (such as the first terminal 3). For example, if the number of remote terminals accessed by the first terminal 2 exceeds 5, and the first terminal 2 is only allocated 5 first local identifiers, then the first terminal 2 can send an identifier allocation request message to the first terminal 3. The identifier allocation request message is used to request the allocation of local identifiers. The first terminal 3 allocates a first local identifier to the first terminal 2 according to the identifier allocation request message, and the first terminal 2 receives the first local identifier accordingly.

[0287] Optionally, the identifier allocation request information includes a target quantity, which indicates the number of local identifiers to be allocated. Accordingly, the first terminal 3 allocates the target quantity of first local identifiers to the first terminal 2 according to the identifier allocation request information, and the first terminal 2 receives the target quantity of first local identifiers.

[0288] It should be noted that the actions related to allocating or receiving the first local identifier can occur before the second terminal sends the RRC connection request information.

[0289] In multi-hop scenarios, it's possible that when a relay terminal (e.g., first terminal 1) requests a new local identifier from a next-hop relay terminal (e.g., first terminal 2), the next-hop relay terminal may also lack sufficient local identifiers. In such cases, the relay terminal (e.g., first terminal 2) can continue sending an identifier allocation request to the next-hop relay terminal (e.g., first terminal 3). Since the next-hop relay terminal (e.g., first terminal 3) may still not have enough local identifiers, it can continue to pass the identifier allocation request to subsequent relay terminals until the message reaches the relay terminal that generated the local identifier. After receiving the identifier allocation request, if the number of remaining identifiers in the ID pool is sufficient to meet the demand, the relay terminal that generated the local identifier can allocate the remaining local identifiers that meet the quantity requirement to the local identifier requester. If the number of remaining identifiers in the ID pool is insufficient to meet the quantity requirement, the first terminal (e.g., first terminal 3) can generate a local identifier again and then allocate it.

[0290] To address the issue that an excessive number of second terminals leads to insufficient local identifiers for the first terminals (first terminals 1, 2, and 3) to identify the second terminals, in another optional implementation, if the first terminal has insufficient stored / allocated local identifiers (such as the first local identifier), it can reject the connection request from another remote terminal after receiving a connection establishment request message from that remote terminal.

[0291] Optionally, if the first terminal has insufficient stored / allocated local identifiers (such as the first local identifier), the first terminal may send a fifth message to the other remote terminals mentioned above. The fifth message is used to reject the connection establishment request of the other remote terminal.

[0292] The specific process may include: the first terminal determining that the candidate local identifier has been used up; the first terminal receiving a connection establishment request message sent by another remote terminal; the first terminal sending a fifth message to the other remote terminal, the fifth message being used to reject the connection establishment request from the other remote terminal. The candidate local identifier may be the first local identifier assigned to the first terminal.

[0293] In one alternative implementation, the first terminal in the connected state does not configure a local identifier. For example, if the first terminal 1 is in the connected state, then ID1 to ID5, which are assigned to the first terminal 1, can all be assigned to the first terminal 2.

[0294] Step S607: The first terminal 3 sends the eighth message to the network device.

[0295] Correspondingly, the network device receives the eighth message sent by the first terminal 3.

[0296] Optionally, the eighth message can be the second message. If the eighth message still contains the first local identifier, then the eighth message can be the same as the aforementioned second message, which means that the first terminal 1 and the first terminal 2 have not adjusted the first local identifier of the second terminal.

[0297] The eighth message in this step is transmitted on the pre-configured second channel, which is the Uu relay RLC channel.

[0298] If the first terminal 3 has entered the connected state / established an RRC connection with the network device, then step S609 is executed; if the first terminal 3 is in the idle state / inactive state, then step S608 is executed.

[0299] Step S608: The first terminal 3 establishes an RRC connection with the network device.

[0300] During the establishment of an RRC connection, the first terminal 3 sends a connection establishment request message to the network device. This connection establishment request message can be sent through the Uu relay RLC channel.

[0301] To further reduce the time spent in the connection establishment process, in one optional implementation, the first terminal 3 may send a corresponding RRC message, such as an RRCSetupComplete message, during the process of establishing an RRC connection with the network device. The RRC message may be transmitted through a pre-configured PC5 trunk RLC channel (first channel / second channel).

[0302] Step S609: The first terminal 3 sends a configuration request message to the network device.

[0303] Correspondingly, the network device receives a configuration request message from the first terminal 3.

[0304] The configuration request message includes the Layer 2 identifier and / or local identifier (such as the first local identifier or the second local identifier) ​​of the second terminal. The configuration request message is used to request relay configuration information. The Layer 2 identifier can be used to instruct the second terminal to access the network through the first terminal.

[0305] Optionally, the configuration request message can be sidelink UE information (SUI). This SUI includes relevant information about the second terminal, such as a Layer 2 identifier and / or a local identifier (e.g., a first local identifier or a second local identifier).

[0306] The relay configuration information is used to help the first terminal achieve relay communication between the second terminal and the network device.

[0307] Based on the above steps, even if the second terminal accesses the network via multiple hops and all relay terminals on the path are in an idle / inactive state, all relay terminals on the path (such as the first terminal 1, the first terminal 2, and the first terminal 3) can be simultaneously triggered to enter the connection state process, instead of having each relay terminal sequentially execute the RRC connection establishment process as in the existing process.

[0308] Step S610: The network device sends relay configuration information to the first terminal 3. Correspondingly, in step S611: The first terminal 3 receives the relay configuration information from the network device.

[0309] Optionally, the relay configuration information includes a third local identifier, which is a local identifier reassigned by the network device to the second terminal. Specifically, the network device reassigns a local identifier to the second terminal based on the Layer 2 identifier and / or the local identifier, thereby obtaining a third local identifier corresponding to the second terminal. The following embodiment uses the third local identifier as the local identifier corresponding to the second terminal 1 as an example for illustration.

[0310] Optionally, the relay configuration information includes SRAP configuration information, which may include a third local identifier of the second terminal.

[0311] When the first terminal 3 relays (including sending or receiving) data between the second terminal 1 and the network device, the SRAP entity can determine the destination device based on the SRAP configuration information and the source of the data packet. For example, for uplink data transmission, the SRAP entity can determine to add a local identifier (such as a third local identifier) ​​and / or RB information to the SRAP header based on the PC5RLC bearer or channel from the second terminal where the received data packet originates, and determine the RLC bearer information on the Uu interface based on the local identifier in the SRAP header from the second terminal. Similarly, for downlink data transmission, the SRAP entity can determine which second terminal the data packet should be transmitted to based on the local identifier (such as a third local identifier) ​​in the header of the data packet received from the network device.

[0312] Optionally, the relay configuration information includes a third local identifier corresponding to the second terminal 1. When the first terminal 3 sends information about the second terminal 1 (such as the sixth message) to the first terminal 2, it may attach the third local identifier. For example, the sixth message includes the third local identifier. Optionally, the sixth message may also be sent by a network device, and correspondingly, the network device receives the sixth message.

[0313] It is understandable that if the first terminal 1 and the first terminal 2 are in an idle / inactive state, the first terminal 1 and the first terminal 2 can establish an RRC connection with the network device. Accordingly, after the connection is established, the first terminal 1 and the first terminal 2 can send a configuration request message to the network device through the first terminal 3. The network device then returns relay configuration information, which is used by the first terminal 1 and the first terminal 2 to realize relay communication between the second terminal and the network device.

[0314] Step S612: The second terminal relays communication with the network device through the first terminal 1, the first terminal 2 and the first terminal 3.

[0315] The three first terminals mentioned above are merely examples and are not intended to limit the embodiments provided in this application. In scenarios where more or fewer first terminals participate in relay communication, the first terminals at corresponding locations (such as the first terminal directly connected to the network device, or the first terminal directly connected to the second terminal) can still perform the relevant steps mentioned in the above method, such as the generation and distribution of local identifiers. Furthermore, any device on either side of the above (including the second terminal, first terminal 1, first terminal 2, first terminal 3, and the network device) can individually implement the corresponding method flow.

[0316] The second terminal essentially relays communication with the network device via a relay terminal. Since the embodiment shown in Figure 6 uses three relay terminals as an example, step S612 involves the second terminal relaying communication with the network device through first terminal 1, first terminal 2, and first terminal 3. It should be understood that step S612 can be adapted to different scenarios.

[0317] The method provided in this application embodiment transmits the connection establishment request message sent by the remote UE to the relay UE directly connected to the base station through a pre-configured first channel / bearer between terminals. This allows the relay UE directly connected to the base station to enter the connected state and then send the connection establishment request message sent by the remote UE to the network device, reducing message transmission time and thus reducing the connection establishment process time of the remote UE. Furthermore, it solves the identifier conflict problem caused by an excessive number of accessing second terminals by reallocating local identifiers or generating and distributing local identifiers through the relay UE directly connected to the base station.

[0318] Considering that the time-consuming connection establishment process of the second terminal is mainly due to the relay terminal being in an idle or inactive state, requiring the sequential establishment of RRC connections with network devices, this application provides two communication methods for the relay terminal discovery process. These methods constrain the relay terminals performing the discovery process, allowing relay terminals that meet the conditions to participate in relay communication, thereby reducing the time-consuming connection establishment process of the second terminal.

[0319] First, a brief explanation of the relay terminal discovery process.

[0320] In sidelink communication scenarios, when the signal quality between UEs is poor or the UEs cannot establish a sidelink connection, if the UE supports U2U relay communication, it can initiate a discovery process to find a suitable relay UE in the vicinity and communicate with the peer UE through the relay UE.

[0321] Relays can be discovered using two methods: model A and model B.

[0322] In the model A approach:

[0323] A UE with U2U relay UE capability learns about nearby remote UE information through methods such as eavesdropping, and broadcasts the eavesdropped remote UE information to the surrounding area via an announcement message. After receiving the announcement message sent by the U2U relay UE, the remote UE determines that it can connect to UE2 through the U2U relay UE based on the UE information list contained therein, which includes information about UE2. Subsequently, it triggers the unicast connection establishment procedure to establish an end-to-end connection with UE2.

[0324] In the model B approach:

[0325] End UE1 (or remote UE) broadcasts a Discovery solicitation message. End UE1 uses the L2 ID assigned by the upper layer as the source L2 ID and the L2 ID associated with the solicitation message as the target L2 ID to send the solicitation message.

[0326] After receiving the Discovery solicitation message from End UE1, the U2U Relay UE decides to continue broadcasting the solicitation message as a relay based on the RSC and relay indication. The U2U relay UE uses its own upper-layer assigned L2 ID as the source L2 ID and the L2 ID associated with the solicitation message as the target L2 ID to send the solicitation message.

[0327] When End UE2 receives the End UE user information from the solicitation message and matches it with its own information, it replies with a Discovery response message. End UE2 uses the L2 ID assigned by its upper layer as the source L2 ID, and the U2u relay UE uses the source L2 ID used in sending the solicitation message as the destination L2 ID to send the response message.

[0328] The U2U Relay UE then replies with a response message to End UE1. The U2U relay UE uses its own upper-layer assigned L2 ID as the source L2 ID, receives the source L2 ID used in End UE1's solicitation message as the destination L2 ID, and sends a response message.

[0329] End UE1 may receive Discovery response messages forwarded by multiple relay UEs, indicating that multiple relay UEs are willing to provide relay services. In this case, End UE1 can select a relay UE, determine the relay UE, and establish a relay connection with the peer UE (such as End UE2 mentioned above) through the relay UE.

[0330] Please refer to Figure 8, which is a flowchart illustrating another communication method provided in this application embodiment. The method shown in Figure 8 can be implemented based on model A or model B in the above discovery process. It is easy to understand that the second terminal can also interact with other numbers of first terminals, for example, through N first terminals, where N is a positive integer greater than or equal to 2. The method specifically includes:

[0331] Step S801: The first terminal sends the second instruction information according to the first information.

[0332] The first information includes one or more of the following: establishing an RRC connection (connected state) with the network device, and the first hop count not exceeding a preset first threshold. Optionally, the first hop count may refer to the number of terminals or relay devices between the first terminal and the network device.

[0333] For example, the preset first threshold may be a threshold defined in the protocol of the terminal device, or it may be a default threshold.

[0334] Optionally, before sending the second indication information, the first terminal may first determine the first information. Determining the first information here can be understood as the first terminal determining, based on its own status information, that it meets certain conditions. For example, the first terminal's status information may be its own RRC status information and its first hop count. The conditions in the first information may include being in a connected state and / or the first terminal's hop count being less than a preset first threshold. For example, if the first terminal determines that its RRC status information includes a connected state and / or that its first hop count does not exceed the preset first threshold, the first terminal determines the first information.

[0335] Optionally, the second indication information is used to indicate that relay services are provided to the remote terminal (second terminal).

[0336] In one optional implementation, the second indication information may be an announcement message. The first terminal sends the second indication information according to the first information. Specifically, the first terminal broadcasts the second indication information according to the first information, and the second terminal receives the second indication information. It should be understood that the second terminal here can be used to refer to the remote terminal that received the second indication information. If the second indication information is not received by the remote terminal, then the second indication information has no recipient.

[0337] The first information can be of several kinds, specifically divided into three cases: Case 1, the first information only includes establishing an RRC connection with the network device; Case 2, the first information only includes that the number of first hops does not exceed a preset first threshold; Case 3, the first information includes both establishing an RRC connection with the network device and the number of first hops not exceeding a preset first threshold.

[0338] In one alternative implementation, the first terminal may obtain relevant information about the second terminal based on a message broadcast by the third terminal, where the third terminal is a relay terminal between the first terminal and the network device.

[0339] Specifically, the first terminal receives a fourth indication message from the third terminal. This fourth indication message indicates the second hop count of the third terminal, which is the number of terminals between the third terminal and the network device. It is used by the first terminal to determine whether the first hop count exceeds a preset first threshold. Optionally, if the first terminal determines that the first hop count does not exceed the preset first threshold, it sends a second indication message. Optionally, the second indication message is sent based on the first hop count and / or RRC status information, where the RRC status information includes the connection state.

[0340] In an optional implementation, the third terminal can also be the first terminal. That is, the first terminal can send a fifth indication message to the terminal it hops forward to (the relay terminal closer to the remote terminal in the communication link). The fifth indication message indicates the first terminal's hop count (e.g., the first hop count), allowing the forward-hopping terminal to determine its own hop count and decide whether to execute the discovery process. Optionally, the fifth indication message is sent if the first hop count is less than a preset first threshold and the RRC status information includes an idle state or an inactive state.

[0341] In one optional implementation, the second indication information includes the RRC status information of the first terminal, which includes a connected state. The RRC status information is used by the second terminal to determine and distinguish whether the first terminal has established an RRC connection with the network device. If the second terminal needs to access the network in a timely manner, the first terminal whose RRC status information includes a connected state can be selected to access the network first.

[0342] In one optional implementation, the fifth indication information is further used to instruct relay terminals in an idle or inactive state to execute a discovery procedure (send the second indication information). Optionally, if the fifth indication information is also used to instruct relay terminals in an idle or inactive state to execute a discovery procedure, then the relay terminal receiving the information can determine whether to execute the discovery procedure by judging whether the hop count is less than a preset first threshold. Alternatively, if the fifth indication information is also used to instruct relay terminals in an idle or inactive state to execute a discovery procedure, then the relay terminal receiving the information directly executes the discovery procedure.

[0343] Step S802: The second terminal receives the second instruction information from the first terminal.

[0344] Furthermore, after receiving the second instruction information from the first terminal, the second terminal can establish a PC5 connection with the first terminal according to the second instruction information (correspondingly, the first terminal establishes a PC5 connection with the second terminal), and then execute the RRC connection establishment process. In the RRC connection establishment process of the second terminal, the second terminal can quickly send the connection establishment request message through the PC5 connection with the first terminal. The specific RRC connection establishment process can be referred to the relevant content mentioned in Figure 6 above or the RRC connection establishment process in the prior art, and will not be repeated here.

[0345] In an optional implementation, the first information mentioned above comes from the second terminal. Please refer to Figure 9, which is a flowchart illustrating another communication method provided in this application embodiment. The method shown in Figure 9 is mainly implemented through model B in the above-mentioned discovery process. It is easy to understand that the second terminal can also interact with other numbers of first terminals, for example, through N first terminals, where N is a positive integer greater than or equal to 2. Specifically, it includes:

[0346] Step S901: The second terminal sends the third instruction information.

[0347] Optionally, the third instruction information can be an announcement message. For example, the second terminal sending the third instruction information to the first terminal can be done by the second terminal broadcasting the third instruction information, and the first terminal receiving the third instruction information.

[0348] The third instruction information includes the first information, and the third instruction information is used to indicate a request for multi-hop relay service. This means that the first information can be determined and controlled by the second terminal. The relevant content of the first information can be found in the description of the method shown in Figure 8, and will not be repeated here.

[0349] In one alternative implementation, the second terminal satisfies its relay communication needs by sending instruction information containing first information with various preset conditions.

[0350] Step S902: The first terminal receives the third instruction information from the second terminal.

[0351] The first terminal can determine whether it meets the conditions and requirements of the first information based on the first information in the third instruction information. If it does, it executes the discovery process, which includes sending the second instruction information. If it does not meet the conditions, it abandons the discovery process. Optionally, if the first information includes content related to a preset first threshold, the preset first threshold can be set by the second terminal.

[0352] This application embodiment constrains whether the first terminal establishes a PC5 connection with the second terminal, thereby selecting a better first terminal to access the network for the second terminal and saving the time spent establishing a connection between the second terminal and the network device.

[0353] To further reduce the connection establishment time of the remote UE, in multi-hop scenarios, the second terminal establishes PC5 connections with multiple first terminals, and sends connection establishment request messages through the PC5 interface, without requiring the first terminal of the previous hop to enter the connected state. See Figure 10, which is a flowchart illustrating another communication method provided in this application embodiment. Figure 10 includes two first terminals, namely first terminal 4 and first terminal 5. First terminal 4 is directly connected to the second terminal, and first terminal 5 is directly connected to the network device. It is easy to understand that the second terminal can also achieve relay communication with the network device through other numbers of first terminals, for example, through N first terminals, where N is a positive integer greater than or equal to 2. This embodiment uses N=2 as an example. The method shown in Figure 10 is for model A in the above discovery process.

[0354] It should be noted that the devices on either side (including the second terminal and the first terminal) can implement the corresponding method flow independently.

[0355] The specific process is as follows:

[0356] Step S1001: The first terminal 5 sends the ninth message to the second terminal.

[0357] Correspondingly, the second terminal receives the ninth message from the first terminal 5.

[0358] In this embodiment of the application, the ninth message includes a sixth indication information, which is used to indicate the RRC status information of the first terminal 5. The RRC status information includes establishing an RRC connection with the network device, so that the second terminal can clearly perceive that it can communicate with the network device through the first terminal 5.

[0359] In an optional implementation, the ninth message further includes hop count information, which indicates the number of terminals between the second terminal and the first terminal 5, so that the second terminal knows that it can access the network device through the first terminal 5 only through multi-hop relay.

[0360] It should be understood that the ninth message can be sent from the first terminal 4 to the second terminal, and correspondingly, the second terminal can also receive the ninth message from the first terminal 4.

[0361] Step S1002: The second terminal establishes a PC5 connection with the first terminal 5.

[0362] Furthermore, after establishing the PC5 connection, the second terminal executes the RRC connection establishment process. The specific process can be found in the RRC connection establishment process shown in Figure 6 or the existing RRC connection establishment process, which will not be described in detail here.

[0363] In one alternative implementation, after the second terminal establishes a PC5 connection with the first terminal 5, the second terminal and the first terminal 5 trigger a relay configuration that supports the forwarding of SRB0 messages by the second terminal, for example, a predefined U2U relay RLC channel.

[0364] Furthermore, the second terminal sends a connection establishment request message, such as an SRB0 message, to the first terminal 5 via the U2U relay RLC channel. By carrying the identifier corresponding to SRB0 and the local ID assigned on the PC5 connection in the data packet, the SRB0 message is forwarded via multi-hop relay. The SRB0 identifier can be a protocol-defined identifier, such as index 0. After receiving the SRB0 message from the second terminal, if the first terminal 5 is in a connected state, it reports the information of the second terminal and obtains the forwarding configuration for forwarding the SRB0 message; if it is in an idle / inactive state, it can first establish an RRC connection, report the information of the second terminal, and obtain the configuration for forwarding the SRB0 message.

[0365] Furthermore, when other relay terminals in the link (such as the first terminal 4) receive the SRB0 message on the U2U relay RLC channel, if they are in an idle / inactive state, they can also trigger the RRC connection establishment process. After all relay terminals enter the connected state, the relay terminal directly connected to the second terminal (the first terminal 4) reports a SUI, requesting the network device to configure the second terminal's relay configuration on the path. Therefore, step S1002 can be the second terminal establishing a PC5 connection with the first terminal 4 and the first terminal 5.

[0366] Please refer to Figure 11, which is a flowchart illustrating another communication method provided in this application embodiment. Figure 11 includes two first terminals, namely first terminal 6 and first terminal 7. First terminal 6 is a first terminal directly connected to the second terminal, and first terminal 7 is a first terminal directly connected to the network device. The method shown in Figure 11 is for model B in the above discovery process. It is easy to understand that the second terminal can also achieve relay communication with the network device through other numbers of first terminals, such as through N first terminals, where N is a positive integer greater than or equal to 2. This embodiment is described using N=2 as an example. The specific process is as follows:

[0367] Step S1101: The second terminal sends the tenth message to the first terminal 6.

[0368] Correspondingly, the first terminal 6 receives the tenth message from the second terminal.

[0369] Optionally, the tenth message includes one or more of the following: indication of discovered and directly connected relay terminals, maximum relay hop information, wherein the maximum relay hop information is used to indicate that network devices can be accessed through multiple hops, but the number of hops cannot exceed the indicated number (such as a preset second threshold).

[0370] Step S1102: The first terminal 6 sends the eleventh message.

[0371] In this embodiment, the recipient of the eleventh message is the relay terminal between the first terminal 6 and the network device. In this embodiment, the relay terminal between the first terminal 6 and the network device is the first terminal 7. Therefore, the recipient of the eleventh message is the first terminal 7. Thus, step S1102 can be the first terminal 6 sending the eleventh message to the first terminal 7, and correspondingly, the first terminal 7 receiving the eleventh message from the first terminal 6.

[0372] Optionally, the eleventh message includes one or more of the following: an indication of a terminal directly connected to the network device, maximum relay hop count information, and hop count information between the second terminal and the sender of the eleventh message (such as the fourth terminal, which is the first terminal 6 in this embodiment). The hop count information includes the number of terminals between the second terminal and the sender of the eleventh message (such as the first terminal 6). The hop count information includes a third hop count, which is the number of terminals between the sender of the eleventh message (such as the first terminal 6) and the second terminal. In this embodiment, the third hop count is 0. The hop count information is used to determine the fourth hop count and to determine whether the fourth hop count exceeds the maximum relay hop count information. The fourth hop count is the hop count information corresponding to the receiver of the eleventh message (such as the first terminal 7). For example, the fourth hop count is the number of terminals between the first terminal 7 and the second terminal. In this embodiment, the first terminal 6 is included between the first terminal 7 and the second terminal, so the fourth hop count is 1.

[0373] Optionally, the hop count information between the second terminal and the sender of the eleventh message (such as the first terminal 6) can be replaced with the remaining hop count information. The remaining hop count information is used to indicate the number of hops remaining after the third hop count, based on a preset second threshold. Optionally, the maximum relay hop count information includes a preset second threshold. For example, if the preset second threshold is 5 and the third hop count is 0, then the remaining hop count information indicates that the number of hops remaining after the preset second threshold, after the third hop count, is 5.

[0374] Step S1103: The first terminal 7 sends the second instruction information to the second terminal according to the eleventh message.

[0375] Accordingly, the second terminal receives the second instruction information. The second instruction information is used to instruct the provision of relay services.

[0376] In one alternative implementation, the first terminal 7, based on one or more of the following in the eleventh message: an indication of discovering a relay UE directly connected to the base station, and maximum relay hop count information, wherein the maximum relay hop count information indicates that access to the base station can be achieved through multiple hops, but the number of hops cannot exceed the indicated number (such as a preset second threshold). The relay terminal determines that the requirements of the eleventh message are met, and therefore sends second indication information to the second terminal. It is understood that if the first terminal 7 does not meet the requirements of the eleventh message, a ninth message can be sent to the relay terminal that hops to the next terminal.

[0377] Optionally, the ninth message includes one or more of the following: an indication of the discovery of a terminal directly connected to the network device, maximum relay hop count information, hop count information between the second terminal and the sender of the ninth message (such as the first terminal 7), the hop count information including the number of terminals between the second terminal and the sender of the ninth message (such as the first terminal 7), and the hop count information including a fourth hop count, which is the number of terminals between the sender of the ninth message (such as the first terminal 7) and the second terminal.

[0378] In an optional implementation, after the second terminal establishes a PC5 connection with the first terminal 7, the second terminal and the first terminal 7 trigger a relay configuration to support SRB0 message forwarding for the second terminal, for example, a predefined U2U relay RLC channel. Further details on the RRC connection establishment process for the second terminal can be found in the relevant content of the method shown in Figure 10, and will not be elaborated here.

[0379] Alternatively, the second terminal establishes a PC5 connection with both the first terminal 6 and the first terminal 7.

[0380] It should be noted that the devices on either side (including the second terminal and the first terminal) can implement the corresponding method flow independently.

[0381] The embodiments of this application enable a second terminal to establish a PC5 connection with a relay terminal that can be directly connected to a network device through the method shown in Figures 10 and 11. This allows the second terminal to transmit a connection establishment request message to the relay terminal directly connected to the network device through the PC5 interface, without requiring other relay terminals to enter the connected state, thus reducing the time consumed by the RRC connection establishment process of the second terminal.

[0382] The communication method provided by the embodiments of this application has been described in detail above with reference to Figures 6, 8 to 11. The communication device provided by the embodiments of this application will now be described in detail with reference to Figures 12 and 13. It should be understood that the description of the embodiments of the communication device corresponds to the description of the embodiments of the communication method; therefore, any parts not described in detail can be referred to the foregoing method embodiments.

[0383] Please refer to Figure 12, which is a schematic diagram of a communication device provided in this application. As shown in Figure 12, the communication device 120 may include a transceiver unit 1201 and a processing unit 1202.

[0384] In some feasible implementations, the communication device 120 may correspond to the first terminal in the communication method shown in FIG6 (first terminal 1 to first terminal 3 in FIG6), or a component (such as a circuit, chip or chip system) configured in the first terminal.

[0385] Specifically, processing unit 1202 is used to generate a first message, which includes a connection establishment request message from the second terminal, the connection establishment request message being used to request the establishment of a Radio Resource Control (RRC) connection with the network device. Transceiver unit 1201 is used to receive the first message on the first channel, the first message including a connection establishment request message from the second terminal, the connection establishment request message being used to request the establishment of a Radio Resource Control (RRC) connection with the network device.

[0386] The transceiver unit 1201 is also used to send a second message to the network device through a pre-configured second channel. The second message includes a connection establishment request message from the second terminal. It should be understood that the other functional implementations of each unit can also correspond to the descriptions of the method steps implemented by the first terminal in the communication method shown in FIG6, and will not be repeated here.

[0387] Reusing Figure 12, in some feasible implementations, the communication device 120 may correspond to the second terminal described in the communication method shown in Figure 6, or a component (such as a circuit, chip, or chip system) configured in the second terminal.

[0388] In specific implementation, transceiver unit 1201 is used to send a first message to the first terminal through a pre-configured first channel. The first message includes a connection establishment request message, which is used to request the establishment of an RRC connection with the network device. Processing unit 1202 is used to perform relay communication between the first terminal and the network device. It should be understood that the other functional implementations of each unit can also correspond to the description of the method steps implemented by the second terminal in the communication method shown in Figure 6, which will not be repeated here.

[0389] Reusing Figure 12, in some feasible implementations, the communication device 120 may correspond to the network device described in the communication method shown in Figure 6, or a component (such as a circuit, chip, or chip system) configured in the network device.

[0390] The transceiver unit 1201 is used to receive a second message sent by the first terminal on a pre-configured second channel. The second message includes a connection establishment request message from the second terminal, which is used by the second terminal to request the establishment of an RRC connection with the network device. The processing unit 1202 is used to perform relay communication between the first terminal and the second terminal. It should be understood that the other functional implementations of each unit can also correspond to the descriptions of the method steps implemented by the network device in the communication method shown in Figure 6, and will not be repeated here.

[0391] Reusing Figure 12, in some feasible implementations, the communication device 120 may correspond to the first terminal described in the communication method shown in Figure 8 above, or a component (such as a circuit, chip, or chip system) configured in the first terminal.

[0392] The transceiver unit 1201 is used to send second indication information to the second terminal according to the first information, wherein the first information includes one or more of the following: establishing an RRC connection with the network device, and the first hop count not exceeding a preset first threshold, where the first hop count is the number of terminals between the first terminal and the network device, and the second indication information is used to determine the first information. The processing unit 1202 is used to establish a PC5 connection with the second terminal. It should be understood that the other functional implementations of each unit can also correspond to the description of the method steps implemented by the first terminal in the communication method shown in FIG8, which will not be repeated here.

[0393] Reusing Figure 12, in some feasible implementations, the communication device 120 may correspond to the second terminal described in the communication method shown in Figure 8 above, or a component (such as a circuit, chip, or chip system) configured in the second terminal.

[0394] In specific implementation, the transceiver unit 1201 is used to receive second indication information, which indicates that relay service should be provided to the second terminal, and indicates the RRC status information of the first terminal, including the status information of establishing an RRC connection with the network device. The processing unit 1202 is used to establish a PC5 connection with the first terminal. It should be understood that the other functional implementations of each unit can also correspond to the description of the method steps implemented by the second terminal in the communication method shown in FIG8, which will not be repeated here.

[0395] Reusing Figure 12, in some feasible implementations, the communication device 120 may correspond to the first terminal described in the communication method shown in Figure 9 above, or a component (such as a circuit, chip, or chip system) configured in the first terminal.

[0396] The transceiver unit 1201 is used to receive third indication information and send second indication information according to the third indication information; the third indication information includes first information and is used to indicate a request for multi-hop relay service. The processing unit 1202 is used to determine the first information. It should be understood that the other functional implementations of each unit can also correspond to the description of the method steps implemented by the first terminal in the communication method shown in FIG9, which will not be repeated here.

[0397] Reusing Figure 12, in some feasible implementations, the communication device 120 may correspond to the second terminal described in the communication method shown in Figure 9 above, or a component (such as a circuit, chip, or chip system) configured in the second terminal.

[0398] In specific implementation, the transceiver unit 1201 is used to send third indication information, which includes first information. The third indication information is used to indicate a request for multi-hop relay service. The first information includes one or more of the following: establishing an RRC connection with the network device, and the first hop number not exceeding a preset first threshold. The first hop number is the number of terminals between the first terminal and the network device. The transceiver unit 1201 is also used to receive second indication information. The processing unit 1202 is used to establish a PC5 connection with the first terminal. It should be understood that the other functional implementations of each unit can also correspond to the description of the method steps implemented by the second terminal in the communication method shown in FIG9, which will not be repeated here.

[0399] Reusing Figure 12, in some feasible implementations, the communication device 120 may correspond to the first terminal described in the communication method shown in Figure 10 above, or a component (such as a circuit, chip, or chip system) configured in the first terminal.

[0400] The transceiver unit 1201 is used to send a ninth message to the second terminal. The ninth message includes sixth indication information, which indicates the RRC status information of the first terminal. The RRC status information includes the establishment of an RRC connection with the network device. The processing unit 1202 is used to establish a PC5 connection with the second terminal. It should be understood that the other functional implementations of each unit can also correspond to the descriptions of the method steps implemented by the first terminal in the communication method shown in FIG10, and will not be repeated here.

[0401] Reusing Figure 12, in some feasible implementations, the communication device 120 may correspond to the second terminal described in the communication method shown in Figure 10 above, or a component (such as a circuit, chip, or chip system) configured in the second terminal.

[0402] In specific implementation, the transceiver unit 1201 is used to receive the ninth message from the first terminal. The ninth message includes sixth indication information, which indicates the RRC status information of the first terminal. The RRC status information includes the establishment of an RRC connection with the network device. The processing unit 1202 is used to establish a PC5 connection with the first terminal. It should be understood that the other functional implementations of each unit can also correspond to the descriptions of the method steps implemented by the second terminal in the communication method shown in FIG8, which will not be repeated here.

[0403] Reusing Figure 12, in some feasible implementations, the communication device 120 may correspond to the first terminal described in the communication method shown in Figure 11 above, or a component (such as a circuit, chip, or chip system) configured in the first terminal.

[0404] The transceiver unit 1201 is used to receive an eleventh message, which includes one or more of the following: an indication of discovering a terminal directly connected to the network device, maximum relay hop count information, and hop count information of the fourth terminal. The hop count information includes a third hop count, which is the number of terminals between the fourth terminal and the second terminal. The transceiver unit 1201 is also used to send second indication information to the second terminal according to the eleventh message. The second indication information is used to indicate the provision of relay services. It should be understood that the other functional implementations of each unit can also correspond to the description of the method steps implemented by the first terminal in the communication method shown in FIG11, which will not be repeated here.

[0405] Reusing Figure 12, in some feasible implementations, the communication device 120 may correspond to the second terminal described in the communication method shown in Figure 11 above, or a component (such as a circuit, chip, or chip system) configured in the second terminal.

[0406] In specific implementation, transceiver unit 1201 is used to send a tenth message to the first terminal. The tenth message includes one or more of the following: an indication of discovering a relay terminal directly connected to the base station, and maximum relay hop count information. The maximum relay hop count information indicates that network access can be achieved through multiple hops, but the number of hops cannot exceed the indicated number. Transceiver unit 1201 is also used to receive second indication information, which indicates the provision of relay services. Processing unit 1202 is used to establish a PC5 connection with the first terminal. It should be understood that the other functional implementations of each unit can also correspond to the descriptions of the method steps implemented by the second terminal in the communication method shown in FIG11, and will not be repeated here.

[0407] Please refer to Figure 13, which is a schematic diagram of another communication device provided in this application. This communication device 130 can be used to implement the operations performed by the first terminal and the second terminal in the above embodiments, or, the communication device 130 can be the first terminal or the second terminal described above. The communication device 130 includes: a processor 1301, a memory 1302, and a bus system 1303.

[0408] The memory 1302 is, but is not limited to, RAM, ROM, EPROM, or CD-ROM, and is used to store related instructions and data. The memory 1302 stores executable modules or data structures, or subsets thereof, or extended sets thereof:

[0409] Operation instructions: This includes various operation instructions used to perform various operations.

[0410] Operating system: includes various system programs used to implement various basic business functions and handle hardware-based tasks.

[0411] Figure 13 shows only one memory, but of course, multiple memories can be set as needed.

[0412] The communication device 130 may further include a transceiver 1304. The transceiver 1304 may be a communication module or a transceiver circuit. In the embodiments of this application, the transceiver 1304 is used to perform the message sending and receiving operations involved in the above embodiments.

[0413] Processor 1301 may be a controller, CPU, general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, transistor logic device, hardware component, or any combination thereof. Processor 1301 may also be a combination that implements computing functions, such as including one or more microprocessor combinations, a combination of DSP and microprocessor, etc.

[0414] In specific applications, the various components of the communication device 130 are coupled together through a bus system 1303. This bus system 1303 includes not only a data bus but may also include a power bus, a control bus, and a status signal bus. However, for clarity, all buses are labeled as bus system 1303 in Figure 13. For ease of illustration, Figure 13 is only schematically shown.

[0415] In specific implementation, the communication device 130 can execute the steps of the method performed by the first terminal, the second terminal, or the network device in any of the above embodiments. Specifically, when the communication device 130 is used to implement the various steps performed by the first terminal, the second terminal, or the network device in the communication method provided in any of the above embodiments, the processor 1301 can implement the function of the processing unit 1202, and the transceiver 1304 can implement the function of the transceiver unit 1201.

[0416] It should be noted that in practical applications, the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiments can be completed by the integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above methods.

[0417] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can 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. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, 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), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memories described in the embodiments of this application are intended to include, but are not limited to, these and any other suitable types of memory.

[0418] Referring back to Figure 13, which is a schematic diagram of another communication device provided in this application, the communication device 130 can be used to implement the operations performed by the network device in the above embodiments, or the communication device 130 can be the network device described above.

[0419] This application also provides a computer-readable medium having a computer program stored thereon, which, when executed by a computer, implements the method steps performed by the first terminal, the second terminal, or the network device in the communication methods provided in Figures 6, 8 to 11.

[0420] This application also provides a computer program product that, when executed by a computer, implements the method steps performed by the first terminal, the second terminal, or the network device in the communication methods provided in Figures 6, 8 to 11.

[0421] This application also provides a chip, which includes at least a processor. The processor is used to execute computer execution instructions so that a device on which the chip is installed implements the method steps performed by the first terminal, the second terminal, or the network device in the communication methods provided in Figures 6, 8 to 11.

[0422] Optionally, the chip may also include interface circuitry. This interface circuitry is used to receive computer execution instructions and transmit them to the processor.

[0423] This application also provides a chip system including a processor for supporting the apparatus on which the chip system is installed to implement the method steps performed by the first terminal, the second terminal, or the network device in the communication methods provided in Figures 6, 8 to 11, such as generating or processing the data and / or information involved in the above methods. In one possible design, the chip system also includes a memory for storing program instructions and data necessary for the data transmission device. The chip system may be composed of a chip or may include chips and other discrete devices.

[0424] This application also provides a communication system. The communication system includes at least the first terminal, the second terminal, and the network terminal described above. The first terminal, the second terminal, and the network device work together to implement the communication method shown in Figure 6 above.

[0425] This application also provides a communication system, which includes at least the first terminal and the second terminal described above. The first terminal and the second terminal work together to implement the communication method shown in Figures 8 to 11 above.

[0426] In the above method embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented entirely or partially as a computer program product. This computer program product includes one or more computer instructions. When these computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line, DSL) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be magnetic media (e.g., floppy disk, hard disk, magnetic tape), optical media (e.g., digital video disc, DVD), or semiconductor media (e.g., solid-state disk, SSD, etc.).

[0427] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0428] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

[0429] The above description is merely a preferred embodiment of the technical solution of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A communication method, characterized in that, The method is applied to a first terminal, and the method includes: A first message is received on a first channel, the first message including a connection establishment request message from a second terminal, the connection establishment request message being used to request the establishment of a Radio Resource Control (RRC) connection with a network device; A second message is sent to the network device via a pre-configured second channel. The second message includes a connection establishment request message from the second terminal.

2. The method according to claim 1, characterized in that, The second channel is the channel between the first terminal and the network device, or... The second channel is the channel between the first terminal and the third terminal, and the third terminal is the relay terminal between the first terminal and the network device.

3. The method according to claim 1 or 2, characterized in that, The first terminal provides relay services to the second terminal, and the first message also includes a first local identifier of the second terminal.

4. The method according to claim 3, characterized in that, The first local identifier is generated by the first terminal.

5. The method according to claim 3, characterized in that, The first local identifier is generated by the second terminal, a relay terminal directly connected to the network device, or a relay terminal directly connected to the second terminal.

6. The method according to any one of claims 3-5, characterized in that, The method further includes: It is determined that the first local identifier of the second terminal is the same as the local identifier of other remote terminals; A second local identifier is determined for the second terminal, and the first local identifier and the second local identifier are associated.

7. The method according to claim 6, characterized in that, The second message also includes the second local identifier.

8. The method according to claim 6 or 7, characterized in that, The method further includes: Receive a third message, the third message including the second local identifier; A fourth message is sent to the second terminal, the fourth message including the first local identifier.

9. The method according to claim 3 or 4, characterized in that, The method further includes: Generate the first local identifier and send the first indication information, which is used to indicate the addition of the first local identifier.

10. The method according to claim 3 or 5, characterized in that, The method further includes: Receive first instruction information, and receive the first local identifier according to the first instruction information. The first instruction information is used to instruct the addition of the first local identifier, and the first local identifier is used to identify the second terminal.

11. The method according to claim 3, 4 or 9, characterized in that, The method further includes: Receive identifier allocation request information, the identifier allocation request information being used to request the allocation of a local identifier; The first local identifier is allocated according to the identifier allocation request information.

12. The method according to claim 11, characterized in that, The identifier allocation request information includes a target quantity, which indicates the number of local identifiers to be allocated.

13. The method according to claim 3, 5, or 10, characterized in that, The method further includes: Send an identifier allocation request message, the identifier allocation request message being used to request the allocation of a local identifier; Receive the first local identifier.

14. The method according to claim 13, characterized in that, The identifier allocation request information includes a target quantity, which indicates the number of local identifiers requested for allocation. Receiving the first local identifier includes: Receive the target number of first local identifiers.

15. The method according to any one of claims 3-14, characterized in that, The method further includes: The local identifiers for the candidates have been used up; Receive connection establishment request messages sent by other remote terminals; A fifth message is sent to the other remote terminals, the fifth message indicating that the connection establishment request of the other remote terminals is rejected.

16. The method according to any one of claims 1-15, characterized in that, The method further includes: Send a configuration request message to the network device. The configuration request message includes the Layer 2 identifier and / or local identifier of the second terminal. The configuration request message is used to request relay configuration information. The system receives relay configuration information from the network device, the relay configuration information including a third local identifier, the third local identifier being a local identifier reassigned by the network device for the second terminal; Send a sixth message, which includes the third local identifier.

17. The method according to any one of claims 1-16, characterized in that, The first channel includes a pre-configured PC5 relay radio link control (RLC) channel, and the second channel includes a Uu relay RLC channel or a PC5 relay RLC channel.

18. A communication method, characterized in that, The method is applied to a second terminal, and the method includes: A first message is sent to a first terminal through a pre-configured first channel. The first message includes a connection establishment request message, which is used to request the establishment of an RRC connection with the network device. The first terminal relays communication with the network device.

19. The method according to claim 18, characterized in that, The first terminal provides relay services to the second terminal, and the first message also includes a local identifier of the second terminal, which is generated by the second terminal.

20. The method according to claim 19, characterized in that, The method further includes: A fourth message is received from the first terminal, the fourth message including a first local identifier.

21. The method according to any one of claims 18-20, characterized in that, The method further includes: A sixth message is received from the first terminal, the sixth message including a third local identifier, the third local identifier including a local identifier reassigned by the network device for the second terminal.

22. The method according to any one of claims 18-21, characterized in that, The first channel includes a PC5 relay RLC channel.

23. A communication method, characterized in that, The method is applied to a network device, and the method includes: On a pre-configured second channel, a second message sent by a first terminal is received. The second message includes a connection establishment request message from the second terminal, which is used by the second terminal to request the establishment of an RRC connection with the network device. The first terminal relays communication with the second terminal.

24. The method according to claim 23, characterized in that, The second message also includes a second local identifier for the second terminal.

25. The method according to claim 23 or 24, characterized in that, The method further includes: Receive a configuration request message from the first terminal, the configuration request message including the layer 2 identifier and / or local identifier of the second terminal, the configuration request message being used to request relay configuration information; Based on the Layer 2 identifier and / or the local identifier, a local identifier is reassigned to the second terminal; Relay configuration information is sent to the first terminal, the relay configuration information including a third local identifier reassigned for the second terminal.

26. The method according to claim 25, characterized in that, The method further includes: A sixth message is received from the first terminal, the sixth message including the third local identifier.

27. A communication device, characterized in that, The communication device includes a unit that performs the method as described in any one of claims 1-26.

28. A communication device, characterized in that, Includes a processor for executing computer programs or instructions stored in a memory to implement the method as described in any one of claims 1-26.

29. A communication device, characterized in that, The device includes a processor and an interface circuit, wherein the interface circuit is used to receive signals from other communication devices besides the communication device and transmit them to the processor, or to send signals from the processor to other communication devices besides the communication device, and the processor is used to implement the method as described in any one of claims 1-26 through logic circuits or execution instructions.

30. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions, and when the computer program or instructions are executed by a communication device, the method as described in any one of claims 1-26 is performed.

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