Relay method, routing table generation method and device, terminal and storage medium

Abstract

The invention discloses a relay method, a routing table generation method and device, a terminal and a storage medium, and relates to the field of wireless communication. The method is applied to the relay terminal, the relay terminal comprises a relay protocol stack, the relay protocol stack is located between a PDCP layer and a layer 2 protocol stack of a PC5 interface, or the relay protocol stack is an MAC layer protocol stack, and the relay protocol stack comprises a relay receiving entity and a relay sending entity. The method comprises the following steps: a relay receiving entity receives a relay protocol data unit (PDU) sent by a previous hop node; forwarding the relay PDU to a relay sending entity; the relay sending entity sends the relay PDU to the next hop node according to the protocol head of the relay PDU; wherein the relay PDU is a PDU sent between at least two remote terminals. At least two remote terminals can realize indirect communication through the relay terminal, and one or more relay terminals can provide relay service.

Description

[0001] The present invention is a divisional application of the invention patent application with application number 202080096156.8 filed on February 24, 2020 and invention name “Relay method, routing table generation method, device, terminal and storage medium”. Technical Field

[0002] The present application relates to the field of wireless communications, and in particular to a relay method, a routing table generation method, a device, a terminal and a storage medium. Background Art

[0003] In the fifth generation wireless systems (5G), a remote UE can be connected to another remote UE through one or more relay UEs, thereby achieving communication between remote UEs.

[0004] In the related art, the remote terminal and the relay terminal can be connected through a PC5 interface. In implementation, the mapping relationship between the local index and the wireless bearer identifier can be configured by a network device, and the configuration relationship can be sent to the relay terminal, wherein the local index is used to identify the remote terminal, and the wireless bearer identifier is used to identify the wireless bearer. In this way, the remote terminal sends a relay protocol data unit (PDU) to the relay terminal, and the relay PDU carries the local index of the remote terminal. The relay terminal receives the relay PDU, and determines the corresponding wireless bearer based on the local index and the above mapping relationship, and sends the relay PDU to another remote terminal through the wireless bearer.

[0005] However, in the solutions provided by the related technologies, the mapping relationship between the remote terminal and the wireless bearer needs to be configured by the network equipment through additional signaling to realize the communication between the two remote terminals. The transmission overhead is large, resulting in delays in the remote terminal services. Summary of the invention

[0006] The embodiment of the present application provides a relay method, a routing table generation method, an apparatus, a terminal and a storage medium, by introducing a relay protocol layer in the protocol stack of the relay terminal, so that the relay sending entity and the relay receiving entity can send and receive the relay PDU of the adjacent node, and can autonomously determine the next hop node according to the protocol header of the relay PDU. The technical solution is as follows.

[0007] According to one aspect of the present application, a relay method is provided, which is applied to a relay terminal, wherein the relay terminal includes a relay protocol stack, the relay protocol stack is located between a packet data convergence protocol (PDCP) layer and a layer 2 protocol stack of a PC5 interface, or the relay protocol stack is a media access control (MAC) layer protocol stack, and the relay protocol stack includes a relay receiving entity and a relay sending entity, and the method includes:

[0008] The relay receiving entity receives a relay protocol data unit (PDU) sent by a previous hop node; forwards the relay PDU to the relay sending entity;

[0009] The relay sending entity sends the relay PDU to a next hop node according to a protocol header of the relay PDU;

[0010] The relay PDU is a PDU sent between at least two remote terminals.

[0011] According to one aspect of the present application, a relay method is provided, which is applied to a first remote terminal, wherein the first remote terminal includes a relay protocol stack, the relay protocol stack is located between a PDCP layer and a layer 2 protocol stack of a PC5 interface, or the relay protocol stack is a MAC layer protocol stack, and the relay protocol stack includes a relay sending entity, the method comprising:

[0012] The relay sending entity receives the PDCP PDU transmitted by the PDCP layer protocol stack, generates a relay protocol data unit (PDU) according to the PDCP PDU; and sends the relay PDU to a next hop node;

[0013] The relay PDU is a PDU sent between at least two remote terminals.

[0014] According to one aspect of the present application, a relay method is provided, which is applied to a second remote terminal, wherein the second remote terminal includes a relay protocol stack, wherein the relay protocol stack is located between a PDCP layer and a layer 2 protocol stack of a PC5 interface, or the relay protocol stack is a MAC layer protocol stack, and the relay protocol stack includes a relay sending entity, wherein the method includes:

[0015] The relay receiving entity receives a relay protocol data unit (PDU) from a previous hop node, and delivers a first PDCP PDU in the relay PDU to the PDCP layer;

[0016] The relay PDU is a PDU sent between at least two remote terminals.

[0017] According to one aspect of the present application, a method for generating a routing table is provided, the method comprising:

[0018] Receive a relay protocol data unit (PDU) sent by a previous hop node, wherein a protocol header of the relay PDU includes a first source identifier, and the first source identifier includes a terminal identifier of a first remote terminal;

[0019] In a case where there is no routing relationship corresponding to the first source identifier in the relay routing table, establishing a second routing relationship in the relay routing table based on the first source identifier and the node identifier of the previous hop node;

[0020] The relay PDU is a PDU sent between two remote terminals, and the second routing relationship is a routing relationship when the terminal identifier of the first remote terminal is used as the destination identifier.

[0021] According to one aspect of the present application, a relay device is provided, which is applied to a relay device, wherein the relay device includes a relay protocol stack, wherein the relay protocol stack is located between a packet data convergence protocol (PDCP) layer and a layer 2 protocol stack of a PC5 interface, or the relay protocol stack is a media access control (MAC) layer protocol stack, and the relay protocol stack includes a relay receiving module and a relay sending module:

[0022] The relay receiving module is used to receive a relay protocol data unit (PDU) sent by a previous hop node; forward the relay PDU to the relay sending module;

[0023] The relay sending module is used to send the relay PDU to the next hop node according to the protocol header of the relay PDU;

[0024] The relay PDU is a PDU sent between at least two remote terminals.

[0025] According to one aspect of the present application, a relay device is provided, which is applied to a first remote terminal, wherein the first remote terminal includes a relay protocol stack, wherein the relay protocol stack is located between a packet data convergence protocol (PDCP) layer and a layer 2 protocol stack of a PC5 interface, or the relay protocol stack is a MAC layer protocol stack, and the relay protocol stack includes a relay sending module:

[0026] The relay sending module receives the PDCP PDU transmitted by the PDCP layer protocol stack, generates a relay protocol data unit (PDU) according to the PDCP PDU; and sends the relay PDU to a next hop node;

[0027] The relay PDU is a PDU sent between at least two remote terminals.

[0028] According to one aspect of the present application, a relay device is provided, which is applied to a second remote terminal, wherein the second remote terminal includes a relay protocol stack, wherein the relay protocol stack is located between a packet data convergence protocol PDCP layer and a layer 2 protocol stack of a PC5 interface, or the relay protocol stack is a media access control (MAC) layer protocol stack, and the relay protocol stack includes a relay receiving module:

[0029] The relay receiving module is used to receive a relay protocol data unit (PDU) from a previous hop node, and transfer a first PDCP PDU in the relay PDU to the PDCP layer;

[0030] The relay PDU is a PDU sent between at least two remote terminals.

[0031] According to one aspect of the present application, a device for generating a routing table is provided, the device comprising:

[0032] A receiving module, configured to receive a relay protocol data unit (PDU) sent by a previous hop node, wherein a protocol header of the relay PDU includes a first source identifier, and the first source identifier includes a terminal identifier of a first remote terminal;

[0033] An establishing module, configured to establish a second routing relationship in the relay routing table based on the first source identifier and the node identifier of the previous hop node when there is no routing relationship corresponding to the first source identifier in the relay routing table;

[0034] The relay PDU is a PDU sent between two remote terminals, and the second routing relationship is a routing relationship when the terminal identifier of the first remote terminal is used as the destination identifier.

[0035] According to one aspect of the present application, a terminal is provided, comprising: a processor; a transceiver connected to the processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to load and execute the executable instructions to implement the relay method as described in the above aspects, or the routing table generation method.

[0036] According to one aspect of the present application, a computer-readable storage medium is provided, in which executable instructions are stored. The executable instructions are loaded and executed by a processor to implement the relay method described in the above aspects, or the routing table generation method.

[0037] The technical solution provided by the embodiments of the present application includes at least the following beneficial effects:

[0038] In the indirect communication mode between two remote terminals, the present application introduces a relay protocol layer in the protocol stack of the relay terminal, so that the relay sending entity and the relay receiving entity can send and receive relay PDUs of adjacent nodes, and can autonomously determine the next hop node based on the protocol header of the relay PDU, without having to determine the next hop node identifier based on the corresponding mapping relationship configured according to the network device, and then relay the PDU to the next hop node indicated by the next hop node identifier, thereby saving transmission overhead and improving transmission efficiency.

[0039] At the same time, the present application also provides two possible locations of the relay protocol stack. The relay protocol stack can be located between the PDCP layer and the layer 2 protocol stack, or can be implemented through the original MAC layer, thereby improving the flexibility of the relay method configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 is a block diagram of a communication system provided by an exemplary embodiment of the present application;

[0042] Figure 2 is a schematic diagram of a relay protocol stack provided by an exemplary embodiment of the present application;

[0043] Figure 3 is a schematic diagram of the format of a relay PDU provided by an exemplary embodiment of the present application;

[0044] Figure 4 is a flow chart of a relay method provided by an exemplary embodiment of the present application;

[0045] Figure 5 is a flow chart of a relay method provided by an exemplary embodiment of the present application;

[0046] Figure 6 is a flow chart of a relay method provided by an exemplary embodiment of the present application;

[0047] Figure 7 is a flow chart of a relay method provided by an exemplary embodiment of the present application;

[0048] Figure 8 is a flow chart of a method for generating a routing table provided by an exemplary embodiment of the present application;

[0049] Fig. 9is a schematic diagram of communication between remote terminals provided by an exemplary embodiment of the present application;

[0050] Fig.10 is a schematic diagram of a relay device provided by an exemplary embodiment of the present application;

[0051] Fig.11 is a schematic diagram of a relay device provided by an exemplary embodiment of the present application;

[0052] Fig.12 is a schematic diagram of a relay device provided by an exemplary embodiment of the present application;

[0053] Fig.13 is a schematic diagram of a routing table generating device provided by an exemplary embodiment of the present application;

[0054] Fig.14 It is a schematic diagram of the structure of a terminal provided by an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0055] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0056] First, the nouns involved in the embodiments of the present application are briefly introduced:

[0057] Different protocol entities in the protocol stack of the wireless access network:

[0058] 1) Service Data Adaptation Protocol (SDAP): Responsible for mapping QoS bearers to radio bearers according to Quality-of-Service (QoS) requirements. This protocol layer does not exist in the Long Term Evolution (LTE) system, but in the New Radio (NR) when connected to the 5G core network, the new QoS processing requires this protocol entity.

[0059] 2) Packet Data Convergence Protocol (PDCP): implements IP header compression, encryption and integrity protection. It also handles retransmission, in-order delivery and deduplication during switching. For dual connections with separate bearers, PDCP can provide routing and replication, that is, configure a PDCP entity for each radio bearer of the terminal.

[0060] 3) Radio Link Control (RLC): Responsible for data segmentation and retransmission. RLC provides services to PDCP in the form of RLC signaling. Each RLC channel (corresponding to each radio bearer) configures an RLC entity for each terminal. In order to reduce latency, compared with Long Term Evolution (LTE), the RLC in the New Radio (NR) does not support in-sequence delivery of data to higher protocol layers.

[0061] 4) Medium-Access Control (MAC): Responsible for logical channel multiplexing, Hybrid Automatic Repeat reQuest (HARQ), and scheduling and scheduling-related functions. The scheduling functions for uplink and downlink are located in the network equipment. MAC provides services to RLC in the form of logical channels. NR changes the header structure of MAC, so that it can support low-latency processing more effectively than LTE.

[0062] 5) Physical Layer (PHY): Responsible for encoding and decoding, modulation, demodulation, multi-antenna mapping and other typical physical layer functions. The physical layer provides services to the MAC layer in the form of transmission channels.

[0063] As an example, when three IP packets are given: packet 1, packet 2, and packet 3, where packet 1 and packet 2 are on one radio bearer a, and packet 3 is on another radio bearer b. The SDAP protocol maps IP packets to different bearers, packet 1 and packet 2 are mapped to radio bearer a, and packet 3 is mapped to radio bearer b. Generally, data entities from or to higher protocol layers are called service data units (SDUs), while data entities from or to lower protocol layers are called protocol data units (PDUs). Therefore, the output of SDAP is SDAP PDU, which is equivalent to PDCP SDU.

[0064] The PDCP protocol performs (optional) IP header compression for each radio bearer and then encrypts it. Depending on the configuration, it is decided whether to add a PDCP header, which contains the information required by the terminal for decryption and a sequence number for retransmission and in-order delivery. The output of PDCP is forwarded to RLC.

[0065] If necessary, the RLC protocol segments the PDCP PDU and adds an RLC header containing a sequence number for retransmission handling. Unlike LTE, the RLC in NR does not provide data order delivery services to higher protocol layers. Because the reordering mechanism will cause additional latency, this latency may cause damage to services that require very low latency. If it is really necessary, the PDCP layer can provide in-sequence delivery.

[0066] The RLC PDU is sent to the MAC layer, which multiplexes multiple RLC PDUs and adds a MAC header to form a new transport block. The physical layer provides services to the MAC layer in the form of transport channels. The transport channel is defined by the way and characteristics of information transmission over the radio interface. The data on the transport channel is organized into transport blocks. In each transmission time interval (TTI), at most one transport block of dynamically variable size is sent to or from the terminal over the radio interface.

[0067] To support priority processing, the MAC layer can multiplex multiple logical channels onto a transport channel, where each logical channel has its own RLC entity. At the receiving end, the MAC layer is responsible for the corresponding demultiplexing and forwarding of the RLC PDU to their respective RLC entities. In order to support demultiplexing at the receiving end, the MAC header is required, and the subheader of each MAC SDU is placed before the SDU, so that the PDU can be pre-processed before receiving the scheduling decision. Among them, the subheader contains the logical channel identifier (Logical Channel Index, LCID) of the logical channel receiving the RLC PDU and the length of the PDU (in bytes), and may also contain reserved bits for demand or future use.

[0068] Radio bearer: is a collection of wireless logical resources, which is divided into signaling radio bearer (SRB) and data radio bearer (DRB). DRB is further divided into default bearer and dedicated bearer.

[0069] Communication links between communication devices, such as between a terminal and a network device, between two terminals, and between two network devices, can be facilitated by using one or more radio bearers.

[0070] PC5 interface: It is an interface introduced between communication devices. Currently, PC5 interface can be used to transmit device to device discovery (D2D Discovery), device to device communication (D2D Communication) and vehicle to everything (V2X).

[0071] Relay PDU: It is the PDU corresponding to the relay protocol stack. The relay PDU can contain information from the upper layer of the relay protocol stack and the information of the relay protocol stack itself.

[0072] Direct communication (Sidelink): It is an important branch of cellular IoT technology, namely, object-to-object communication technology. It can meet the direct communication between two user equipment (UE). Before transmission, there is no need for pre-connection between UEs. Sidelink is used to meet the faster and more efficient connection between UEs.

[0073] Figure 1 A block diagram of a communication system provided by an exemplary embodiment of the present application is shown, and the communication system may include: a first remote terminal 111, a second remote terminal 112, and several relay terminals 12. In the communication system shown in the figure, no network device may be required to participate in the communication process.

[0074] The relay terminal 12 is a terminal device deployed in a communication system for providing a relay service for communication between remote terminals. The first remote terminal 111 and the relay terminal 12 can be connected via a PC5 interface of the Third Generation Partnership Project (3GPP) system, and the second remote terminal 112 and the relay terminal 12 can also be connected via a PC5 interface.

[0075] The communication process between the first remote terminal 111 and the second remote terminal 112 may be: the first remote terminal 111 sends a relay PDU to the relay terminal, the relay terminal receives the relay PDU and forwards the relay PDU to the second remote terminal 112 .

[0076] The relay terminal 12 (or the first remote terminal 111, or the second remote terminal 112) may include various handheld devices, vehicle-mounted devices, wearable devices, computing devices or other processing devices connected to a wireless modem with wireless communication functions, as well as various forms of user equipment, mobile stations (Mobile Station, MS), terminals (terminal device), etc.

[0077] It should be understood that Figure 1 The number of relay terminals 12 shown is for illustrative purposes only and is not intended to be limiting. The communication system may include any suitable number of relay terminals.

[0078] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: Global System of Mobile Communication (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD) system, Advanced Long Term Evolution (LTE-A) system, New Radio (NR) system, NR system evolution system, LTE on unlicensed spectrum (LTE-based access to Unlicensed spectrum, LTE-U) system, NR-U system, Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication system, Wireless Local Area Network (WLAN) system. Networks, WLAN), Wireless Fidelity (WiFi), next generation communication systems or other communication systems, etc.

[0079] Generally speaking, the number of connections supported by traditional communication systems is limited and easy to implement. However, with the development of communication technology, mobile communication systems will not only support traditional communications, but also support, for example, device to device (Device to Device, D2D) communication, machine to machine (Machine to Machine, M2M) communication, machine type communication (Machine Type Communication, MTC), vehicle to vehicle (V2V) communication and vehicle to everything (V2X) system, etc. The embodiments of the present application can also be applied to these communication systems.

[0080] based on Figure 1 In the communication system shown, the first remote terminal, the relay terminal and the second remote terminal all include a relay protocol stack, and the function of the relay protocol stack is to help realize the transmission of data packets between the two remote terminals through the relay terminal. Regarding the position of the relay protocol stack in the protocol stack, the present application shows two possible examples: the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface; or, the relay protocol stack is a media access control (MAC) layer protocol stack.

[0081] Exemplary, with reference to Figure 2 In (a), the relay protocol stack is the RELAY layer. The RELAY layer is between the PDCP layer and the layer 2 protocol stack of the PC5 interface. The layer 2 protocol stack includes the RLC layer protocol stack and the MAC layer protocol stack.

[0082] Exemplary, with reference to Figure 2 In (b), the relay protocol stack implements its functions through the MAC layer. The MAC layer is between the PDCP layer and the layer 2 protocol stack of the PC5 interface.

[0083] Figure 3 The format diagram of the relay PDU provided by an exemplary embodiment of the present application is shown. In addition to the R bit indicating the reserved bit (Reserved bit), the relay PDU may also include a logical channel identifier LCID, a source identifier SOURCEID and a destination identifier DESTINATION ID.

[0084] The SOURCE ID and DESTINATION ID are unique identifiers of the remote terminal or relay terminal. When the relay protocol layer receives the relay PDU, the source of the relay PDU can be determined based on the source ID contained in the relay PDU. The destination of the relay PDU can be determined based on the destination ID contained in the relay PDU.

[0085] In the format of the above relay PDU, a special DESTINATION ID can be reserved to be used as a broadcast identifier, which means that the transmitted relay PDU is broadcast by the first remote terminal to all connected relay terminals and other remote terminals. This DESTINATION ID cannot be occupied by the relay terminal and other remote terminals.

[0086] Optionally, the logical channel identifier LCID in the format of the above relay PDU may also be replaced by a radio bearer identifier DRB ID or SRB ID.

[0087] In the embodiments of the present application, two types of relay PDUs are exemplarily described. One is a relay PDU sent by a first remote terminal to other remote terminals, and the relay PDU can be a broadcast relay PDU broadcasted by the first remote terminal, or a first relay PDU unicasted by the first remote terminal to the second remote terminal. The other is a second relay PDU sent by the second remote terminal to the first remote terminal, and both of the above relay PDUs rely on the relay service of one or more relay terminals.

[0088] In the present application, the relay protocol stack includes a relay receiving entity and a relay sending entity. For the relay PDU, the working principles of the relay receiving entity and the relay sending entity are as follows.

[0089] 1) The working principle of the relay receiving entity is as follows:

[0090] For each received relay PDU, if Figure 3 The relay protocol can obtain the source identifier, destination identifier, radio bearer identifier, and PDCP PDU in the relay PDU format shown. Except for the PDCP PDU, the other parts are all located in the protocol header of the relay PDU. The identifier of the node receiving the relay PDU is the neighbor ID Prior ID.

[0091] Processing for source identification:

[0092] If the source ID in the relay PDU is not in the relay routing table that the node has established, then the source ID is used as the destination ID in the opposite direction. If the source ID of the relay PDU is Source ID, and the neighboring point that receives the relay PDU is Prior ID, then a route is recorded: (Source ID, Prior ID). If this is a relay terminal directly connected to the remote terminal, then the Prior ID in the route is the same as the Source ID.

[0093] Processing of purpose identification:

[0094] If the destination identifier is the same as the identifier of this node, or this destination identifier is reserved for broadcast messages or data packets, the radio bearer identifier and PDCP PDU are delivered to the upper layer protocol. If the destination identifier is not the same as the identifier of this node, or this destination identifier is reserved for broadcast messages or data packets, it is delivered to the relay sending entity of the relay protocol, and the relay sending entity sends the broadcast message or data packet to all other nodes connected to the relay terminal.

[0095] 2) The working principle of the relay sending entity is as follows:

[0096] Processing of SDU from higher layers:

[0097] The upper layer protocol passes the information required to generate the relay PDU to the relay protocol stack, including the PDCP PDU, source identifier, destination identifier, and radio bearer identifier, which are all passed to the relay sending entity of the relay protocol. The relay sending entity can Figure 3 The Relay PDU format shown generates a Relay PDU.

[0098] Processing of relay PDU:

[0099] Regardless of the relay PDU generated by the relay sending entity or the relay PDU obtained from the relay receiving entity, the relay sending entity will obtain the destination identifier of the next hop node according to the existing relay routing table. If the destination identifier is not in the relay routing table, the default next hop node is selected.

[0100] It should be noted that in the related art, a local index is used to identify the remote terminal, and a wireless bearer identifier is used to distinguish the wireless bearers. The first remote terminal establishes at least one wireless bearer to send a relay PDU to the relay terminal, and the relay PDU carries the local index of the first remote terminal. The relay terminal receives the relay PDU, and determines the wireless bearer used for communication between the relay terminal and the second remote terminal based on the local index and the mapping relationship between the stored local index and the wireless bearer identifier, and then sends the relay PDU to the second remote terminal through the wireless bearer. Among them, the mapping relationship between the local index and the wireless bearer identifier needs to be configured by the network device, and the configuration result is notified to the relay terminal.

[0101] In the present application, the generation of address information and relay routing table in the relay protocol adopts a distributed autonomous manner, that is, the generation and maintenance of address information and relay routing table can be dynamically maintained as data packets are transmitted, rather than being configured by network devices.

[0102] The first remote terminal is a terminal that sends a relay PDU. Next, a relay method applied to the first remote terminal side is described.

[0103] Figure 4 A flowchart of a relay method provided by an exemplary embodiment of the present application is shown. The method can be applied to Figure 1 In the first remote terminal 111 in the communication system shown. The method includes:

[0104] Step 410, the relay sending entity receives the PDCP PDU transmitted by the PDCP layer protocol stack, generates a relay protocol data unit (PDU) according to the PDCP PDU; and sends the relay PDU to the next hop node;

[0105] The relay PDU is a PDU sent between at least two remote terminals.

[0106] The first remote terminal refers to a terminal device that performs point-to-point communication with the relay terminal, and then can communicate with other remote terminals (such as the second remote terminal) through the relay terminal. Different from the direct communication between the first remote terminal and the second remote terminal through a direct communication link, in this case, the communication between the first remote terminal and the second remote terminal is an indirect communication mode.

[0107] The first remote terminal includes a relay protocol stack, which includes a relay sending entity. Optionally, the functions of the relay protocol stack include but are not limited to: generating a routing table, forwarding a data packet whose destination address is not the local node, processing a data packet whose destination address is the local node, and processing a broadcast data packet.

[0108] Regarding the position of the relay protocol stack in the protocol stack of the first remote terminal, such as Figure 2 As shown, the present application shows two possible examples: the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface; or, the relay protocol stack is a MAC layer protocol stack.

[0109] Optionally, the PDCP layer protocol stack is an upper layer protocol stack of the relay protocol stack. When the relay protocol stack receives the PDCP PDU transmitted by the PDCP layer protocol stack, the relay sending entity will add a header of the relay protocol stack to the PDCP PDU to generate a new transmission block, i.e., a relay PDU, and send the relay PDU to the next hop node. Optionally, the next hop node is a relay terminal around the first remote terminal.

[0110] The relay PDU may be a first relay PDU unicasted by the first remote terminal to the second remote terminal, or a broadcast relay PDU broadcasted by the first remote terminal to other remote terminals. The following is an exemplary description of these two possible situations.

[0111] Case 1: The relay PDU includes: a first relay PDU; the first relay PDU is a PDU sent by the first remote terminal to the second remote terminal.

[0112] The first remote terminal attempts to perform unicast communication with the second remote terminal and sends a first relay PDU to the second remote terminal.

[0113] Optionally, the protocol header of the first relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote terminal; the first destination identifier includes: a terminal identifier of the second remote terminal.

[0114] The source ID is an identifier used to identify the source of the relay PDU. After receiving the first relay PDU, other terminals (relay terminals or other remote terminals) can determine that the first relay PDU is a relay PDU sent by the first remote terminal based on the first source ID in the first relay PDU.

[0115] Among them, the destination identifier (DESTINATION ID) is an identifier used to identify the destination terminal of the relay PDU. After receiving the first relay PDU, other terminals (relay terminals or other remote terminals) can determine whether the relay PDU is for their own relay PDU based on the first destination identifier. Exemplarily, when the first destination identifier is the terminal identifier of the second remote terminal, after receiving the first relay PDU, the relay terminal determines through the first destination identifier that the relay PDU is not for its own PDU, and then forwards the first relay PDU.

[0116] Optionally, sending the relay PDU to the next hop node includes: when the relay sending entity has a first routing relationship corresponding to the first destination identifier in the relay routing table, sending the first relay PDU to the next hop node according to the first routing relationship; wherein the first routing relationship includes: the terminal identifier of the second remote terminal, and, the node identifier of the next hop node, and the first routing relationship is the routing relationship when the terminal identifier of the second remote terminal is used as the destination identifier.

[0117] Exemplarily, the first destination identifier (i.e., the terminal identifier of the second remote terminal) is RMUE2, and there is a first routing relationship (RMUE2, RLUE2) in the relay routing table, and the destination identifier in the first routing relationship is the terminal identifier RMUE2 of the second remote terminal. The first destination identifier corresponds to the first routing relationship, and the node Relay UE2 corresponding to the identifier RLUE2 is the next hop node.

[0118] Optionally, the first relay PDU also includes: a first PDCP PDU; wherein the first PDCP PDU includes: at least one of a first signaling and a first data packet, the first signaling is a related signaling sent by the first remote terminal as the sender, and the first data packet is a related data packet sent by the first remote terminal as the sender.

[0119] The first relay PDU may include a first PDCP PDU. Since the first relay PDU is the first relay PDU sent by the first remote terminal to the second remote terminal, the first PDCP PDU may include signaling related to the first remote terminal and may also include a data packet related to the first remote terminal. The embodiment of the present application does not limit the specific content of the first signaling and the first data packet.

[0120] Case 2: Relay PDU includes: broadcast relay PDU; broadcast relay PDU is a PDU that the first remote terminal broadcasts to other remote terminals. The first remote terminal attempts to perform broadcast communication with other remote terminals and sends broadcast relay PDUs to several other remote terminals.

[0121] Optionally, the protocol header of the broadcast relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote terminal; and the first destination identifier includes: a broadcast identifier.

[0122] The source ID is an identifier used to identify the source of the relay PDU. After receiving the broadcast relay PDU, other terminals (relay terminals or other remote terminals) can determine that the broadcast relay PDU is a relay PDU sent by the first remote terminal according to the first source ID.

[0123] Among them, the destination identifier (DESTINATION ID) is an identifier used to identify the destination terminal of the relay PDU. Optionally, when the destination identifier is a broadcast identifier, the broadcast identifier can be agreed upon between communication devices, such as "0XFFFFFF". Since the destination identifier is a broadcast identifier, the destination terminals of the broadcast relay PDU are multiple other terminals (relay terminals or other remote terminals). After receiving the broadcast relay PDU, other terminals can determine that the broadcast relay PDU is the PDU broadcast and sent by the first remote terminal based on the destination identifier, and can parse the broadcast relay PDU and pass part of the content in the broadcast relay PDU to the upper layer protocol.

[0124] Optionally, the relay receiving entity receives a second relay PDU, which is a PDU sent by the second remote terminal to the first remote terminal, and the second source identifier of the second relay PDU includes the terminal identifier of the second remote terminal; if the relay receiving entity does not have a routing relationship corresponding to the second source identifier in the relay routing table, the relay receiving entity establishes a first routing relationship in the relay routing table.

[0125] After receiving a second source identifier, when the relay receiving entity finds that the second source identifier is a new source identifier, it may add a record in the relay routing table to create a new routing relationship.

[0126] Exemplarily, the second source identifier (i.e., the terminal identifier of the second remote terminal) is RMUE2, the current node is the first remote terminal, the previous hop node is the relay terminal Relay UE2, and the node identifier of the previous hop node is RLUE2. The routing relationship corresponding to the second source identifier refers to the routing relationship in which the destination identifier of the routing relationship is the same as the second source identifier, such as the routing relationship (RMUE2, RLUE1). RLUE1 is the node identifier of the relay terminal Relay UE1. If there is no routing relationship corresponding to the second source identifier in the relay routing table, the relay receiving entity will use the second source identifier as the destination identifier in the reverse direction and establish a second routing relationship (RMUE2, RLUE2) in the relay routing table.

[0127] Optionally, the broadcast relay PDU also includes: a first PDCP PDU; wherein the first PDCP PDU includes: at least one of a broadcast data packet and a broadcast signaling.

[0128] The broadcast relay PDU may include a first PDCP PDU. Since the broadcast relay PDU is a broadcast relay PDU sent by the first remote terminal to other remote terminals, the first PDCP PDU may include broadcast signaling and may also include a broadcast data packet. The embodiment of the present application does not limit the specific content of the broadcast signaling and the broadcast data packet.

[0129] In one example, when the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the relay PDU also includes: a first radio bearer identifier; when the relay protocol stack is a MAC layer protocol stack, the relay PDU also includes: a first logical channel identifier.

[0130] Among them, the first radio bearer identifier is an identifier used to distinguish the radio bearers between remote terminals. The radio bearer can be a signaling radio bearer (SRB) or a data radio bearer (DRB). Because the first remote terminal is in a direct communication (Sidelink, SL) communication mode, the SRB is a direct communication signaling radio bearer SL SRB, and the DRB is a direct communication data radio bearer SL DRB, and the corresponding first radio bearer identifiers are SL SRB ID and SL DRB ID respectively. In the case where the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the destination end of the relay PDU (i.e., the second remote terminal) can determine the radio bearer between the two remote terminals through the above-mentioned first radio bearer identifier.

[0131] Among them, the first logical channel identifier (LCID) is an identifier used to distinguish the logical channel between the MAC layer and the RLC layer. When the relay protocol stack is implemented in the MAC layer, the first logical channel identifier (LCID) is associated with the PDCP PDU multiplexed in the MAC layer. There is a one-to-one mapping relationship between the radio bearer and the first logical channel identifier. The destination end of the relay PDU (i.e., the second remote terminal) can determine the radio bearer between the two remote terminals through the above-mentioned first logical channel identifier.

[0132] In one example, the end-to-end protocol stack between at least two remote terminals includes: a PDCP layer protocol stack of a PC5 interface, and other protocol layers located above the PDCP protocol layer.

[0133] Optionally, other protocol layers above the PDCP protocol layer include other user plane protocol layers, such as SDAP and IP protocol layers, and other control plane protocol layers, such as RRC layer and Non-Access Stratum (NAS).

[0134] In one example, the point-to-point protocol stack between the first remote terminal and the next hop node includes: a layer 2 protocol stack and a layer 1 protocol stack of a 3GPP PC5 interface, the layer 2 protocol stack includes an RLC layer protocol stack and a MAC layer protocol stack, and the layer 1 protocol stack includes a PHY layer protocol stack.

[0135] Optionally, the next hop node refers to a relay terminal around the first remote terminal. It should be noted that the above layer 1 protocol stack and layer 2 protocol stack include but are not limited to: RLC layer protocol stack, MAC layer protocol stack and PHY layer protocol stack, which are not limited in the embodiments of the present application.

[0136] In one example, the relay protocol stack further includes a relay receiving entity; the relay receiving entity receives a second relay PDU, where the second relay PDU is a relay PDU sent by the second remote terminal to the first remote terminal.

[0137] After the first remote terminal successfully sends the relay PDU to the second remote terminal, a route from the first remote terminal to the second remote terminal is established and stored in the relay routing table of the relay terminal and the second remote terminal. When the second remote terminal sends the second relay PDU to the first remote terminal, the second relay PDU can be sent to the first remote terminal through the established route. The first remote terminal can receive the second relay PDU through the relay receiving entity.

[0138] Optionally, the second relay PDU includes: a second PDCP PDU; the relay receiving entity transfers the second PDCP PDU to an upper layer protocol.

[0139] Optionally, when the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the second relay PDU also includes: a second radio bearer identifier, and the relay receiving entity passes the second radio bearer identifier to the PDCP layer protocol stack; or, when the relay protocol stack is a MAC layer protocol stack, the second relay PDU also includes: a second logical channel identifier, and the relay receiving entity passes the second logical channel identifier to the PDCP layer protocol stack.

[0140] After the first remote terminal receives the second relay PDU, the second PDCP PDU and the second radio bearer identifier (or the second logical channel identifier) ​​in the second relay PDU may be transferred to the PDCP layer protocol stack.

[0141] In one example, when a direct communication link exists between the first remote terminal and the second remote terminal, the relay PDU is directly sent to the second remote terminal through the direct communication link.

[0142] Optionally, when the first remote terminal finds that it can communicate directly with the second remote terminal, the bypass of the relay terminal is omitted, that is, data packets are sent and received through the point-to-point PC5 connection. In this process, the source identifier and destination identifier of the relay PDU can remain unchanged.

[0143] In summary, the method provided in this embodiment, the first remote terminal includes a relay protocol stack, and the relay protocol stack includes a relay sending entity. The relay sending entity can receive the PDCP PDU sent by the PDCP layer, generate a relay PDU according to the PDCP PDU, and send the relay PDU to the next hop node. The relay PDU is a PDU sent by the first remote terminal to other remote terminals. In the indirect communication mode between two remote terminals, the present application introduces a relay protocol layer in the protocol stack of the first remote terminal, so that the relay sending entity can generate and send a relay PDU, and in the process of sending, the first remote terminal can autonomously determine the route of transmitting the relay PDU, without determining the next hop node identifier according to the corresponding mapping relationship configured by the network device, and then sending the relay PDU to the relay terminal indicated by the next hop node identifier, thereby saving the transmission overhead and improving the transmission efficiency.

[0144] The method provided in this embodiment provides two possible locations of the relay protocol stack. The relay protocol stack can be located between the PDCP layer and the layer 2 protocol stack, or can be implemented through the original MAC layer, thereby improving the flexibility of the relay method configuration.

[0145] The relay terminal can receive and forward the relay PDU from the first remote terminal or other relay terminals. Next, the relay method applied to the relay terminal side is described.

[0146] Figure 5 A flowchart of a relay method provided by an exemplary embodiment of the present application is shown. The method can be applied to Figure 1 In the relay terminal 12 in the communication system shown. The method includes:

[0147] Step 510: The relay receiving entity receives the relay PDU sent by the previous hop node; and forwards the relay PDU to the relay sending entity;

[0148] The relay PDU is a PDU sent between at least two remote terminals.

[0149] A relay terminal is a terminal that provides relay services for communication between at least two remote terminals. There may be one or more relay terminals that assist in communication between at least two remote terminals. In this embodiment, only one of the relay terminals is used to illustrate the relay method.

[0150] The relay terminal includes a relay protocol stack, which includes: a relay receiving entity and a relay sending entity. Optionally, the functions of the relay protocol stack include but are not limited to: generating a routing table, forwarding a data packet whose destination address is not the current node, processing a data packet whose destination address is the current node, and processing a broadcast data packet.

[0151] Regarding the position of the relay protocol stack in the protocol stack of the first remote terminal, such as Figure 2 As shown, the present application shows two possible examples: the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface; or, the relay protocol stack is a MAC layer protocol stack.

[0152] Optionally, the previous hop node of the relay terminal may be the first remote terminal, or may be another relay terminal between the first remote terminal and the relay terminal. Exemplarily, the first remote terminal is connected to the second remote terminal via a Relay UE1, and the relay terminal refers to Relay UE1, then the previous hop node of the relay terminal is the first remote terminal. Exemplarily, the first remote terminal is connected to the second remote terminal via Relay UE1 and Relay UE2 in sequence, and the relay terminal refers to Relay UE2, then the previous hop node of the relay terminal is Relay UE1.

[0153] The relay PDU may be a first relay PDU unicasted by the first remote terminal to the second remote terminal, or a broadcast relay PDU broadcasted by the first remote terminal to other remote terminals. The following is an exemplary description of these two possible situations.

[0154] Case 1: The relay PDU includes: a first relay PDU; the first relay PDU is a PDU sent by the first remote terminal to the second remote terminal.

[0155] The first remote terminal attempts to perform unicast communication with the second remote terminal and sends a first relay PDU to the second remote terminal.

[0156] Optionally, the protocol header of the first relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote terminal; the first destination identifier includes: a terminal identifier of the second remote terminal.

[0157] The first source ID is an identifier used to identify the source of the relay PDU. After receiving the first relay PDU, other terminals (relay terminals or other remote terminals) can determine that the first relay PDU is a relay PDU sent by the first remote terminal based on the first source ID.

[0158] The first destination ID is used to identify the destination terminal of the first relay PDU. After receiving the first relay PDU, other terminals (relay terminals or other remote terminals) can determine whether the relay PDU is sent to themselves according to the first destination ID.

[0159] Optionally, forwarding the relay PDU to the relay sending entity includes: when the first destination identifier is not equal to the terminal identifier of the relay terminal, forwarding the first relay PDU to the relay sending entity.

[0160] Exemplarily, when the first destination identifier is the terminal identifier of the second remote terminal, after the relay terminal receives the first relay PDU through the relay receiving entity, it determines through the destination identifier that the first relay PDU is not for its own PDU, and then it forwards the first relay PDU to the relay sending entity, but does not pass the first relay PDU to the upper layer through the relay receiving entity.

[0161] Optionally, the first relay PDU also includes: a first PDCP PDU; wherein the first PDCP PDU includes: at least one of a first signaling and a first data packet, the first signaling is a signaling sent by the first remote terminal, and the first data packet is a data packet sent by the first remote terminal.

[0162] The first relay PDU may include a first PDCP PDU. Since the first relay PDU is a PDU sent by the first remote terminal to the second remote terminal, the first PDCP PDU may include signaling related to the first remote terminal and may also include a data packet related to the first remote terminal. The embodiment of the present application does not limit the specific content of the first signaling and the first data packet.

[0163] Case 2: Relay PDU includes: broadcast relay PDU; broadcast relay PDU is a PDU that the first remote terminal broadcasts to other remote terminals. The first remote terminal attempts to perform broadcast communication with other remote terminals and sends broadcast relay PDUs to several other remote terminals.

[0164] Optionally, the protocol header of the broadcast relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote terminal; and the first destination identifier includes: a broadcast identifier.

[0165] The first source ID is an identifier used to identify the source of the relay PDU. After receiving the relay PDU, other terminals (relay terminals or other remote terminals) can determine that the relay PDU is sent by the first remote terminal according to the first source ID.

[0166] The first destination identifier (DESTINATION ID) is an identifier used to identify the destination terminal of the relay PDU. Optionally, when the first destination identifier is a broadcast identifier, the broadcast identifier may be an identifier agreed upon between communication devices, such as "0XFFFFFF".

[0167] Optionally, forwarding the relay PDU to the relay sending entity includes: when the first destination identifier includes a broadcast identifier, forwarding the broadcast relay PDU to the relay sending entity.

[0168] Exemplarily, since the first destination identifier is a broadcast identifier, after receiving the relay PDU, other terminals (relay terminals or other remote terminals) can determine that the relay PDU is a PDU broadcast and sent by the first remote terminal based on the broadcast identifier, and can process the relay PDU, such as uploading it to a high-level protocol stack. In addition, the relay terminal will forward the broadcast relay PDU to the relay sending entity, and then forward the broadcast relay PDU to other terminals (relay terminals or other remote terminals) through the relay sending entity.

[0169] Optionally, the broadcast relay PDU also includes: a first PDCP PDU; wherein the first PDCP PDU includes: at least one of a broadcast data packet and a broadcast signaling.

[0170] The broadcast relay PDU may include the first PDCP PDU. Since the relay PDU is a broadcast relay PDU sent by the first remote terminal to other remote terminals, the first PDCP PDU may include broadcast signaling and may also include broadcast data packets. The embodiment of the present application does not limit the specific content of the broadcast signaling and broadcast data packets.

[0171] Step 520, the relay sending entity sends the relay PDU to the next hop node according to the protocol header of the relay PDU;

[0172] Optionally, the relay protocol header may include a first source identifier and a first destination identifier. The relay sending entity may forward the relay PDU to the next hop node based on the relevant information of the first source identifier and the first destination identifier. The next hop node may be another relay terminal or a remote terminal (such as a second remote terminal). The above-mentioned relay PDU may be a first relay PDU unicast sent by the first remote terminal to the second remote terminal, or it may be a broadcast relay PDU broadcasted by the first remote terminal to other remote terminals. Below, exemplary descriptions are given for these two possible situations.

[0173] Case 1: The relay PDU is the first relay PDU

[0174] Optionally, step 520 is alternatively implemented as the following steps:

[0175] Step: When the relay sending entity has a first routing relationship corresponding to the first destination identifier in the relay routing table, the relay sending entity sends the first relay PDU to the next hop node according to the first routing relationship; wherein the first routing relationship includes: the terminal identifier of the second remote terminal, and, the node identifier of the next hop node, and the first routing relationship is the routing relationship when the terminal identifier of the second remote terminal is used as the destination identifier.

[0176] The relay routing table is a table containing routing relationships. Optionally, the relay routing table is generated in a distributed autonomous manner, that is, the generation and maintenance of the relay routing table can be dynamically maintained as the data packet is transmitted. As an example, the format of the routing table is shown in Table 1 below.

[0177] Table 1

[0178]

[0179] When the relay PDU is the first relay PDU, the protocol header of the first relay PDU may include a first destination identifier, which is a terminal identifier of the second remote terminal, indicating that the destination to which the first relay PDU is sent is the second remote terminal.

[0180] Exemplarily, the first destination identifier (i.e., the terminal identifier of the second remote terminal) is RMUE2, and there is a first routing relationship (RMUE2, RLUE2) in the relay routing table, and the destination identifier in the first routing relationship is the terminal identifier RMUE2 of the second remote terminal. The first destination identifier corresponds to the first routing relationship, and the node Relay UE2 corresponding to the identifier RLUE2 is the next hop node.

[0181] In one example, when there is no first routing relationship corresponding to the first destination identifier in the relay routing table, the relay sending entity sends the first relay PDU to a default next hop node, and there is at least one default next hop node.

[0182] Optionally, a default next hop node is reserved in the routing table. If the first routing relationship cannot be found in the relay routing table, the default next hop node is selected and the first relay PDU is sent to the default next hop node. The embodiment of the present application does not limit the number of default next hop nodes.

[0183] Case 2: The relay PDU is a broadcast relay PDU

[0184] Optionally, step 520 is alternatively implemented as the following steps:

[0185] Step: When the first destination identifier includes a broadcast identifier, the relay sending entity sends the broadcast relay PDU to the next hop node.

[0186] Since the first destination identifier is a broadcast identifier, it indicates that the relay PDU is a broadcast relay PDU. The relay terminal will send the broadcast relay PDU to one or more other nodes. In this case, the present application does not limit the number of next-hop nodes.

[0187] In one example, when there is no routing relationship corresponding to the first source identifier in the relay routing table, the relay receiving entity establishes a second routing relationship in the relay routing table; wherein the second routing relationship includes: the terminal identifier of the first remote terminal, and, the node identifier of the previous hop node; the second routing relationship is the routing relationship when the terminal identifier of the first remote terminal is used as the destination identifier.

[0188] The relay receiving entity receives a new first source identifier, which may be a source identifier in the first relay PDU or a source identifier in the broadcast relay PDU. The relay terminal may add a record in the relay routing table to create a new routing relationship, namely, a second routing relationship.

[0189] Exemplarily, the first source identifier (i.e., the terminal identifier of the first remote terminal) is RMUE1, the current node is the relay terminal Relay UE3, the previous hop node is the relay terminal Relay UE2, and the node identifier of the previous hop node is RLUE2. The routing relationship corresponding to the first source identifier refers to the routing relationship in which the destination identifier in the routing relationship is the same as the first source identifier, such as the routing relationship (RMUE1, RLUE1). If there is no routing relationship corresponding to the first source identifier in the relay routing table, the relay receiving entity will use the second source identifier as the destination identifier in the reverse direction and establish a second routing relationship (RMUE1, RLUE2) in the relay routing table.

[0190] In one example, a relay receiving entity receives a second relay PDU, which is a PDU sent by a second remote terminal to a first remote terminal, and a second source identifier of the second relay PDU includes a terminal identifier of the second remote terminal; when there is no routing relationship corresponding to the second source identifier in the relay routing table, the relay receiving entity establishes a first routing relationship in the relay routing table; wherein the first routing relationship includes: the terminal identifier of the second remote terminal, and, the node identifier of the next hop node; the first routing relationship is a routing relationship when the terminal identifier of the second remote terminal is used as the destination identifier.

[0191] After receiving a new source identifier, the relay receiving entity can add a record in the relay routing table to create a new routing relationship.

[0192] Exemplarily, the second source identifier (i.e., the terminal identifier of the second remote terminal) is RMUE2, the current node is the relay terminal Relay UE1, the next hop node is the relay terminal Relay UE2, and the node identifier of the next hop node is RLUE2. The routing relationship corresponding to the second source identifier refers to the routing relationship in which the destination identifier of the routing relationship is the same as the second source identifier, such as the routing relationship (RMUE2, RLUE1). If there is no routing relationship corresponding to the second source identifier in the relay routing table, the relay receiving entity will use the second source identifier as the destination identifier in the reverse direction and establish the first routing relationship (RMUE2, RLUE2) in the relay routing table.

[0193] In an optional example, when the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the relay PDU also includes: a first radio bearer identifier; when the relay protocol stack is a MAC layer protocol stack, the relay PDU also includes: a first logical channel identifier.

[0194] Among them, the first radio bearer identifier is an identifier used to distinguish the radio bearers between remote terminals. The radio bearer can be a signaling radio bearer (SRB) or a data radio bearer (DRB). Because the first remote terminal is in a direct communication mode, the SRB is a direct communication signaling radio bearer SL SRB, and the DRB is a direct communication data radio bearer SLDRB, and the corresponding first radio bearer identifiers are SL SRB ID and SL DRB ID, respectively. In the case where the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the destination end of the relay PDU (i.e., the second remote terminal) can determine the radio bearer between the two remote terminals through the above-mentioned first radio bearer identifier.

[0195] Among them, the first logical channel identifier (LCID) is an identifier used to distinguish the logical channel between the MAC layer and the RLC layer. When the relay protocol stack is implemented in the MAC layer, the logical channel identifier (LCID) is associated with the PDCP PDU multiplexed in the MAC layer. There is a one-to-one mapping relationship between the radio bearer and the first logical channel identifier. The destination end of the relay PDU (i.e., the second remote terminal) can determine the radio bearer between the two remote terminals through the above-mentioned first logical channel identifier.

[0196] In an optional example, the end-to-end protocol stack between at least two remote terminals includes: a PDCP layer protocol stack of a PC5 interface, and other protocol layers located above the PDCP protocol layer.

[0197] Optionally, other protocol layers above the PDCP protocol layer include other user plane protocol layers, such as SDAP and IP protocol layers, and other control plane protocol layers, such as RRC layer and Non-Access Stratum (NAS).

[0198] In an optional example, the point-to-point protocol stack between the relay terminal and the previous hop node includes: layer 2 protocol stack and layer 1 protocol stack of the PC5 interface, the layer 2 protocol stack includes the RLC layer protocol stack and the MAC layer protocol stack, and the layer 1 protocol stack includes the PHY layer protocol stack.

[0199] Optionally, the previous hop node may be the first remote terminal, or may be another relay terminal between the first remote terminal and the relay terminal. It should be noted that the above-mentioned layer 1 protocol stack and layer 2 protocol stack include but are not limited to: RLC layer protocol stack, MAC layer protocol stack and PHY layer protocol stack, which are not limited in the embodiments of the present application.

[0200] In summary, the method provided in this embodiment, the relay terminal includes a relay protocol stack, and the relay protocol stack includes a relay receiving entity and a relay sending entity. The relay receiving entity can receive the relay PDU sent by the previous hop node, pass the relay PDU to the relay sending entity, and the relay sending entity relays the PDU to the next hop node. In the indirect communication mode between two remote terminals, the present application introduces a relay protocol layer in the protocol stack of the relay terminal, so that the relay sending entity and the relay receiving entity can send and receive relay PDUs of adjacent nodes, and can autonomously determine the next hop node according to the protocol header of the relay PDU, without determining the next hop node identifier according to the corresponding mapping relationship configured by the network device, and then relaying the PDU to the next hop node indicated by the next hop node identifier, saving the transmission overhead, thereby improving the transmission efficiency.

[0201] The method provided in this embodiment provides two possible locations of the relay protocol stack. The relay protocol stack can be located between the PDCP layer and the layer 2 protocol stack, or can be implemented through the original MAC layer, thereby improving the flexibility of the relay method configuration.

[0202] The second remote terminal is a destination end of the relay PDU and can receive the relay PDU forwarded by the relay terminal. The relay method applied to the second remote terminal side is described below.

[0203] Figure 6 A flowchart of a relay method provided by an exemplary embodiment of the present application is shown. The method can be applied to Figure 1 In the second remote terminal 112 in the communication system shown. The method includes:

[0204] Step 610: The relay receiving entity receives a relay PDU from a previous hop node; and delivers the first PDCP PDU in the relay PDU to the PDCP layer.

[0205] The relay PDU is a PDU sent between at least two remote terminals.

[0206] The second remote terminal refers to a terminal device that performs point-to-point communication with the relay terminal, and then can communicate with the first remote terminal through the relay terminal. Different from the direct communication between the first remote terminal and the second remote terminal through a direct communication link, in this case, the communication between the first remote terminal and the second remote terminal is an indirect communication mode.

[0207] The second remote terminal includes a relay protocol stack. Optionally, the functions of the relay protocol stack include but are not limited to: generating a routing table, forwarding data packets whose destination address is not the current node, processing data packets whose destination address is the current node, and processing broadcast data packets.

[0208] Regarding the position of the relay protocol stack in the protocol stack of the second remote terminal, such as Figure 2 As shown, the present application shows two possible examples: the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, or the relay protocol stack is a MAC layer protocol stack.

[0209] Optionally, the relay protocol stack includes a relay receiving entity. The relay receiving entity may receive a relay protocol data unit (PDU) from a relay terminal (ie, a previous hop node), and then transfer the first PDCP PDU in the relay PDU to the PDCP layer.

[0210] The relay PDU may be a first relay PDU unicasted by the first remote terminal to the second remote terminal, or a broadcast relay PDU broadcasted by the first remote terminal to other remote terminals. The following describes examples of these two possibilities.

[0211] Case 1: The relay PDU includes: a first relay PDU; the first relay PDU is a PDU sent by the first remote terminal to the second remote terminal.

[0212] The first remote terminal attempts to perform unicast communication with the second remote terminal and sends a first relay PDU to the second remote terminal.

[0213] Optionally, the protocol header of the first relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote terminal; the first destination identifier includes: a terminal identifier of the second remote terminal.

[0214] The first source ID is an identifier used to identify the source of the relay PDU. After receiving the first relay PDU, other terminals (relay terminals or other remote terminals) can determine that the relay PDU is sent by the first remote terminal based on the first source ID.

[0215] The first destination ID is used to identify the destination terminal of the relay PDU. After receiving the relay PDU, other terminals (relay terminals or other remote terminals) can determine whether the relay PDU is for themselves according to the first destination ID.

[0216] Optionally, when the first destination identifier in the first relay PDU is the same as the terminal identifier of the second remote terminal, the relay receiving entity passes the first PDCP PDU to the PDCP layer; wherein the first PDCP PDU includes: at least one of a first signaling and a first data packet, the first signaling is related signaling with the first remote terminal as the sender, and the first data packet is related data packet with the first remote terminal as the sender.

[0217] Exemplarily, when the first destination identifier is the terminal identifier of the second remote terminal, after receiving the first relay PDU, the second remote terminal determines through the destination identifier that the first relay PDU is for its own PDU, and then passes the first PDCP PDU in the first relay PDU to the upper layer.

[0218] The first relay PDU may include a first PDCP PDU. Since the first relay PDU is a PDU sent by the first remote terminal to the second remote terminal, the first PDCP PDU may include signaling related to the first remote terminal and may also include a data packet related to the first remote terminal. The embodiment of the present application does not limit the specific content of the first signaling and the first data packet.

[0219] Case 2: Relay PDU includes: broadcast relay PDU; broadcast relay PDU is a PDU broadcasted by the first remote terminal to other remote terminals. The first remote terminal attempts to perform broadcast communication with other remote terminals and sends broadcast relay PDU to several other remote terminals (including the second remote terminal).

[0220] Optionally, the protocol header of the broadcast relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote terminal; and the first destination identifier includes: a broadcast identifier.

[0221] The first source ID is an identifier used to identify the source of the relay PDU. After receiving the broadcast relay PDU, other terminals (relay terminals or other remote terminals) can determine that the broadcast relay PDU is a relay PDU sent by the first remote terminal according to the source ID.

[0222] The first destination identifier (DESTINATION ID) is an identifier used to identify the destination terminal of the relay PDU. Optionally, when the first destination identifier is a broadcast identifier, the broadcast identifier may be an identifier agreed upon between communication devices, such as "0XFFFFFF".

[0223] Optionally, in a case where the first destination identifier includes a broadcast identifier, the relay receiving entity delivers the first PDCP PDU to the PDCP layer; wherein the PDCP PDU includes: at least one of a broadcast data packet and a broadcast signaling.

[0224] Since the first destination identifier is a broadcast identifier, after receiving the broadcast relay PDU, other terminals (relay terminals or other remote terminals) can determine based on the broadcast identifier that the broadcast relay PDU is the PDU broadcast and sent by the first remote terminal, and can pass the first PDCP PDU in the relay PDU to the upper layer protocol.

[0225] The broadcast relay PDU may include a first PDCP PDU. Since the broadcast relay PDU is a broadcast relay PDU sent by the first remote terminal to other remote terminals, the first PDCP PDU may include broadcast signaling and may also include a broadcast data packet. The embodiment of the present application does not limit the specific content of the broadcast signaling and the broadcast data packet.

[0226] In an optional example, the relay protocol stack also includes a relay sending entity, which receives a PDCP PDU sent by the PDCP layer, generates a second relay PDU according to the PDCP PDU, and sends the second relay PDU to a next-hop node.

[0227] The second relay PDU is a relay PDU sent by the second remote terminal to the first remote terminal.

[0228] After receiving the relay PDU sent by the second remote terminal, the second remote terminal establishes a route from the first remote terminal to the second remote terminal, which is stored in the relay routing table of the relay terminal and the second remote terminal. When the second remote terminal is interested in the service of the relay PDU sent by the first remote terminal, it can send the second relay PDU to the first remote terminal. The second remote terminal can send the second relay PDU to the first remote terminal through the established relay path. The second remote terminal can send the second relay PDU through the relay sending entity in the relay protocol stack.

[0229] In an optional example, when the relay receiving entity does not have a routing relationship corresponding to the first source identifier in the relay routing table, a second routing relationship is established in the relay routing table; wherein the second routing relationship includes: the terminal identifier of the first remote terminal, and, the node identifier of the previous hop node; the second routing relationship is the routing relationship when the terminal identifier of the first remote terminal is used as the destination identifier.

[0230] The relay receiving entity receives a new first source identifier, which may be a source identifier in the first relay PDU or a source identifier in the broadcast relay PDU. The relay receiving entity may add a record in the relay routing table to create a new routing relationship, namely, a second routing relationship.

[0231] Exemplarily, the first source identifier (i.e., the terminal identifier of the first remote terminal) is RMUE1, the current node is the second remote terminal, the previous hop node is the relay terminal Relay UE1, and the node identifier of the previous hop node is RLUE1. The routing relationship corresponding to the first source identifier refers to the routing relationship in which the destination identifier in the routing relationship is the same as the first source identifier, such as the routing relationship (RMUE1, RLUE2). If there is no routing relationship corresponding to the first source identifier in the relay routing table, the relay receiving entity will use the second source identifier as the destination identifier in the reverse direction and establish a second routing relationship (RMUE1, RLUE1) in the relay routing table.

[0232] In an optional example, when the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the relay PDU also includes: a first wireless bearer identifier, and the relay receiving entity passes the wireless bearer identifier to the PDCP layer protocol stack; or, when the relay protocol stack is a MAC layer protocol stack, the relay PDU also includes: a first logical channel identifier, and the relay receiving entity passes the logical channel identifier to the PDCP layer protocol stack.

[0233] Among them, the first radio bearer identifier is an identifier used to distinguish the radio bearers between remote terminals. The radio bearer can be a signaling radio bearer (SRB) or a data radio bearer (DRB). Because the first remote terminal is in a sidelink communication mode, the SRB is a sidelink signaling radio bearer SL SRB, and the DRB is a sidelink data radio bearer SL DRB. The corresponding first radio bearer identifiers are SL SRB ID and SL DRB ID, respectively. In the case where the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the second remote terminal can pass the first radio bearer identifier to the upper layer protocol through the relay receiving entity, thereby determining the radio bearer between the two remote terminals.

[0234] Among them, the first logical channel identifier (LCID) is used to distinguish the logical channel between the MAC layer and the RLC layer. When the relay protocol stack is implemented in the MAC layer, the first logical channel identifier (LCID) is associated with the PDCP PDU multiplexed in the MAC layer. There is a one-to-one mapping relationship between the radio bearer and the logical channel identifier. The second remote terminal can pass the first logical channel identifier to the upper layer protocol through the relay receiving entity, thereby determining the radio bearer between the two remote terminals.

[0235] In an optional example, the end-to-end protocol stack between at least two remote terminals includes: a PDCP layer protocol stack of a PC5 interface, and other protocol layers located above the PDCP protocol layer.

[0236] Optionally, other protocol layers above the PDCP protocol layer include other user plane protocol layers, such as SDAP and IP protocol layers, and other control plane protocol layers, such as RRC layer and NAS layer.

[0237] In an optional example, the point-to-point protocol stack between the second remote terminal and the previous hop node includes: layer 2 protocol stack and layer 1 protocol stack of the PC5 interface, the layer 2 protocol stack includes the RLC layer protocol stack and the MAC layer protocol stack, and the layer 1 protocol stack includes the PHY layer protocol stack.

[0238] Optionally, the previous hop node refers to a relay terminal around the second remote terminal. It should be noted that the above layer 1 protocol stack and layer 2 protocol stack include but are not limited to: RLC layer protocol stack, MAC layer protocol stack and PHY layer protocol stack, which are not limited in the embodiments of the present application.

[0239] In summary, the method provided in this embodiment, the second remote terminal includes a relay protocol stack, and the relay protocol stack includes a relay receiving entity. The relay receiving entity can receive the relay PDU from the previous hop node; and pass the first PDCP PDU in the relay PDU to the PDCP layer. In the indirect communication mode between two remote terminals, the present application introduces a relay protocol layer in the protocol stack of the second remote terminal, so that the relay receiving entity can receive the relay PDU from the previous hop node. The previous hop node does not need to receive the configuration of the network device, which saves the transmission overhead and improves the transmission efficiency.

[0240] The method provided in this embodiment provides two possible locations of the relay protocol stack. The relay protocol stack can be located between the PDCP layer and the layer 2 protocol stack, or can be implemented through the original MAC layer, thereby improving the flexibility of the relay method configuration.

[0241] Next, the process of the first remote terminal communicating with the second remote terminal via the relay terminal in the present application is explained.

[0242] like Figure 7 As shown, Figure 7 is a flowchart of a relay method according to another exemplary embodiment of the present application, the method is applied to the above Figure 1 In the communication system shown. The communication system includes a first remote terminal, a relay terminal, and a second remote terminal, and the first remote terminal, the relay terminal, and the second remote terminal all include a relay protocol stack, the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, or the relay protocol stack is a MAC layer protocol stack, and the relay protocol stack includes a relay receiving entity and a relay sending entity. The relay method may include at least part of the following contents:

[0243] Step 710: The relay sending entity of the first remote terminal receives the PDCP PDU transmitted by the PDCP layer, generates a first relay PDU according to the PDCP PDU, and sends the first relay PDU to the next hop node.

[0244] The first relay PDU is a PDU sent by the first remote terminal to the second remote terminal.

[0245] Step 720: The relay receiving entity of the relay terminal receives the first relay PDU sent by the previous hop node, and transmits the first relay PDU to the relay sending entity.

[0246] Exemplarily, the previous hop node is the first remote terminal.

[0247] Optionally, the point-to-point protocol stack between the relay terminal and the previous hop node includes: a layer 2 protocol stack and a layer 1 protocol stack of a 3GPP PC5 interface, the layer 2 protocol stack includes an RLC layer protocol stack and a MAC layer protocol stack, and the layer 1 protocol stack includes a PHY layer protocol stack.

[0248] Step 730: The relay sending entity of the relay terminal sends the first relay PDU to the next hop node according to the protocol header of the first relay PDU.

[0249] Exemplarily, the next hop node is the second remote terminal.

[0250] Optionally, the protocol header of the first relay PDU may include a source identifier and a destination identifier.

[0251] Step 740: The relay receiving entity of the second remote terminal receives the first relay PDU from the previous hop node, and transfers the first PDCP PDU in the first relay PDU to the PDCP layer.

[0252] Optionally, the previous hop node is a relay terminal.

[0253] Step 750: The relay sending entity of the second remote terminal receives the PDCP PDU sent by the PDCP layer, generates a second relay PDU according to the PDCP PDU, and sends the second relay PDU to the next hop node.

[0254] The second relay PDU is a relay PDU sent by the second remote terminal to the first remote terminal. The next hop node is a relay terminal directly connected to the network device.

[0255] Step 760: The relay receiving entity of the relay terminal receives the second relay PDU, and transmits the second relay PDU to the relay sending entity.

[0256] The previous hop node is the second remote terminal, or the previous hop node is another relay terminal between the relay terminal and the second remote terminal.

[0257] It should be noted that, when the relay receiving entity determines that the protocol header of the second relay PDU also includes a broadcast identifier, the second relay PDU is delivered to the upper layer.

[0258] Step 770: The relay sending entity of the relay terminal sends the second relay PDU to the next hop node.

[0259] The next hop node is a remote terminal, or the next hop node is another relay terminal between the relay terminal and the remote terminal.

[0260] Step 780: The relay receiving entity of the first remote terminal receives the second relay PDU.

[0261] Optionally, when determining that the second destination identifier in the protocol header of the second relay PDU is the same as the terminal identifier of the first remote terminal, the relay receiving entity delivers the second relay PDU to the upper layer.

[0262] It should be noted that, in this embodiment, the relay method is exemplarily described by taking the first relay PDU received by the second remote terminal as an example, and the first relay PDU is a PDU unicasted by the first remote terminal to the second remote terminal. In other implementations, the second remote terminal may also receive a PDU broadcasted by the first remote terminal, i.e., a broadcast PDU.

[0263] In addition, the relay method in the present application can be implemented not only by introducing a new relay protocol stack between the PDCP layer and the layer 2 protocol stack, but also by implementing it through the MAC layer.

[0264] Figure 8 A flowchart of a route generation method according to an exemplary embodiment of the present application is shown. The method can be applied to a relay terminal or a remote terminal. The method includes:

[0265] Step 810, receiving a relay protocol data unit (PDU) sent by a previous hop node, wherein a protocol header of the relay PDU includes a first source identifier;

[0266] The relay PDU is a PDU sent between two remote terminals, and the first source identifier includes a terminal identifier of the first remote terminal.

[0267] Exemplarily, the first remote terminal Remote UE1 is connected to the second remote terminal Remote UE2 via Relay UE1 and Relay UE2 in sequence. The implementation subject of step 810 is Relay UE2, and the previous hop node is Relay UE1. The first source identifier is the terminal identifier "RMUE1" of the first remote terminal.

[0268] Exemplarily, the first remote terminal Remote UE1 is connected to the second remote terminal Remote UE2 via Relay UE1 and Relay UE2 in sequence. The implementation subject of step 810 is Remote UE2, and the previous hop node is Relay UE2. The first source identifier is the terminal identifier "RMUE1" of the first remote terminal.

[0269] The relay PDU may be a first relay PDU unicasted by the first remote terminal to the second remote terminal, or a broadcast relay PDU broadcasted by the first remote terminal to other remote terminals. The following is an exemplary description of these two possible situations.

[0270] Case 1: the relay PDU includes: a first relay PDU; the first relay PDU is a PDU sent by the first remote terminal to the second remote terminal.

[0271] The first remote terminal attempts to perform unicast communication with the second remote terminal and sends a first relay PDU to the second remote terminal.

[0272] Optionally, the protocol header of the first relay PDU also includes: a first destination identifier; the first destination identifier includes: a terminal identifier of the second remote terminal.

[0273] After receiving the first relay PDU, the relay terminal (or other remote terminal) can determine whether the relay PDU is a PDU for itself according to the first destination identifier.

[0274] Optionally, the first relay PDU also includes: a first PDCP PDU; wherein the first PDCP PDU includes: at least one of a first signaling and a first data packet, the first signaling is a related signaling sent by the first remote terminal as the sender, and the first data packet is a related data packet sent by the first remote terminal as the sender.

[0275] Case 2: The relay PDU includes: a broadcast relay PDU; the broadcast relay PDU is a PDU that is broadcasted by the first remote terminal to other remote terminals.

[0276] The first remote terminal attempts to perform broadcast communication with other remote terminals, and sends a broadcast relay PDU to several other remote terminals.

[0277] Optionally, the protocol header of the broadcast relay PDU also includes: a first destination identifier; the first destination identifier includes: a broadcast identifier.

[0278] Since the destination identifier is a broadcast identifier, the destination terminals of the broadcast relay PDU are multiple other terminals (relay terminals or other remote terminals).

[0279] Optionally, the broadcast relay PDU also includes: a first PDCP PDU; wherein the first PDCP PDU includes: at least one of a broadcast data packet and a broadcast signaling.

[0280] In one example, when the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the relay PDU also includes: a first radio bearer identifier; when the relay protocol stack is a MAC layer protocol stack, the relay PDU also includes: a first logical channel identifier.

[0281] Step 820: If there is no routing relationship corresponding to the first source identifier in the relay routing table, a second routing relationship is established in the relay routing table based on the first source identifier and the node identifier of the previous hop node.

[0282] The second routing relationship is a routing relationship when the terminal identifier of the first remote terminal is used as the destination identifier.

[0283] The relay receiving entity receives a new first source identifier, which may be a source identifier in the first relay PDU or a source identifier in the broadcast relay PDU. The relay terminal may add a record in the relay routing table to create a new routing relationship, namely, a second routing relationship.

[0284] Exemplarily, the first source identifier (i.e., the terminal identifier of the first remote terminal) is RMUE1, the current node is the relay terminal Relay UE1, and the node identifier of the previous hop node is RMUE1, i.e., the previous hop node is the first remote terminal. The routing relationship corresponding to the first source identifier refers to the routing relationship in which the destination identifier in the routing relationship is the same as the first source identifier, such as the routing relationship (RMUE1, RLUE1). If there is no routing relationship corresponding to the first source identifier in the relay routing table, the relay receiving entity will use the second source identifier as the destination identifier in the reverse direction and establish a second routing relationship (RMUE1, RMUE1) in the relay routing table.

[0285] In an optional example, the method also includes: receiving a second relay PDU, the second relay PDU is a PDU sent by the second remote terminal to the first remote terminal, and the second source identifier of the second relay PDU includes the terminal identifier of the second remote terminal; when there is no routing relationship corresponding to the second source identifier in the relay routing table, establishing a first routing relationship in the relay routing table based on the second source identifier and the node identifier of the next hop node; wherein the first routing relationship includes: the terminal identifier of the second remote terminal, and, the node identifier of the next hop node; the first routing relationship is the routing relationship when the terminal identifier of the second remote terminal is used as the destination identifier.

[0286] After receiving a new source identifier, the relay receiving entity can add a record in the relay routing table to create a new routing relationship.

[0287] Exemplarily, the second source identifier (i.e., the terminal identifier of the second remote terminal) is RMUE2, the current node is the first remote terminal, the next hop node is the relay terminal Relay UE1, and the node identifier of the next hop node is RLUE1. If the destination identifier of the routing relationship (RMUE2, RLUE3) is the same as the second source identifier, then the routing relationship is the routing relationship corresponding to the second source identifier. RLUE3 is the node identifier of the relay terminal Relay UE3. If there is no routing relationship corresponding to the second source identifier in the relay routing table, the relay receiving entity will use the second source identifier as the destination identifier in the reverse direction and establish the first routing relationship (RMUE2, RLUE1) in the relay routing table.

[0288] To sum up, the method provided in this embodiment is that when a relay PDU is received, the relay terminal (or remote terminal) can establish a new routing relationship based on the source identifier of the relay PDU and the routing relationship in the relay routing table, thereby dynamically updating the relay routing table, and the transmission route of the relay PDU can be defined according to the relay routing table, so that the relay solution is more flexible and efficient.

[0289] It should be noted that the above-mentioned method for generating a routing table is not only applicable to the relay terminal, but also applicable to the first remote terminal and the second remote terminal.

[0290] Fig. 9 A schematic diagram of communication between two remote terminals provided by an exemplary embodiment of the present application is shown. In this embodiment, Remote UE1 is a first remote terminal, Remote UE2 is a second remote terminal, and Relay UE1 and Relay UE2 are two relay terminals.

[0291] Remote UE1 communicates with Remote UE2 through Relay UE1 and Relay UE2. When Remote UE1 finds that it cannot communicate directly with Remote UE2 through direct connection and there is a Relay UE1 nearby, Remote UE1 sends a Direct Communication Request (DCR) message to Relay UE1, trying to find Remote UE2 and establish an indirect connection with Remote UE2. Specifically, the following steps are included:

[0292] Step 1: A point-to-point PC5 connection is established between Remote UE1 and Relay UE1, and a radio bearer for sending and receiving relay PDUs is established.

[0293] Step 2: Remote UE1 sends a DCR message to Relay UE1. In the protocol header of the relay PDU, SOURCE ID = RMUE1, DESTINATION ID = 0XFFFFFF. 0XFFFFFF is the agreed DESTINATION ID for broadcast purposes. Relay UE1 and the surrounding terminals establish a PC5 connection and a radio bearer for sending and receiving relay PDUs. When Relay UE1 receives the relay PDU from Remote UE1, it finds that RMUE1 is a new SOURCE ID, and a point-to-point PC5 connection is established between Remote UE1 and Relay UE1, so Relay UE1 establishes a routing record (RMUE1, RMUE1) locally.

[0294] Step 3: Relay UE2 and Relay UE1 behave in the same way. Relay UE2 establishes PC5 connections and radio bearers for sending and receiving relay PDUs with the surrounding terminals. If the SOURCE ID (RMUE1) in the relay PDU is not in the relay routing table, Relay UE2 uses this SOURCE ID as the DESTINATION ID in the opposite direction and records (SOURCEID, PRIOR ID). The PRIOR ID is RLUE1, i.e., a routing record (RMUE1, RLUE1) is established locally.

[0295] Step 4: When Remote UE2 receives the DCR message, it finds that it is the terminal that Remote UE1 is looking for, or it is interested in the service described in the DCR message, so it sends a Direct Communication Accept (DCA) message in response. Based on the same algorithm, if the SOURCE ID (RMUE1) in the relay PDU is not in the relay routing table, Remote UE2 uses this SOURCE ID as the DESTINATION ID in the opposite direction and records (SOURCE ID, PRIOR ID). The PRIOR ID is RLUE2, that is, a routing record (RMUE1, RLUE2) is established locally. In the relay PDU containing the DCA message, SOURCE ID = RMUE2, DETINATION ID = RMUE1. This DCA message is contained in a PDCP PDU, and the identifier of the radio bearer is set to the identifier of the SL SRB.

[0296] Step 5: After receiving the relay PDU containing the DCA message, Relay UE2 finds that SOURCE ID = RMUE2 is a new source identifier, and a point-to-point PC5 connection is established between Remote UE2 and Relay UE2, so it establishes a routing record (RMUE2, RMUE2). Then, Relay UE2 finds that DETINATION ID = RMUE1 based on the existing routing record (RMUE1, RLUE1), and sends this relay PDU to the relay terminal Relay UE1 whose address is RLUE1.

[0297] Step 6: After Relay UE1 receives the relay PDU containing the DCA message, it finds that SOURCE ID = RMUE2 is the new source ID. Relay UE1 uses this SOURCE ID as the DESTINATION ID in the opposite direction and records (SOURCE ID, PRIOR ID). The PRIOR ID is RLUE2, that is, it creates a routing record (RMUE2, RLUE2). Then, Relay UE1 finds that DETINATION ID = RMUE1 based on the existing routing record (RMUE1, RMUE1), and sends this relay PDU to the first remote terminal Remote UE1 whose address is RMUE1.

[0298] Step 7: After receiving the relay PDU, Remote UE1 finds that SOURCE ID = RMUE2 is a new source identifier. Remote UE1 uses this SOURCE ID as the DESTINATION ID in the opposite direction and records (SOURCE ID, PRIOR ID). The PRIOR ID is RLUE1, that is, a routing record (RMUE2, RLUE1) is established locally. Because DESTINATION ID = RMUE1, the PDCP PDU and radio bearer identifier contained in the relay PDU are delivered to the upper layer protocol. The PDCP PDU here contains the DCA message.

[0299] After the above 7 steps, the routing between Remote UE1 and Remote UE2 through Relay UE1 and Relay UE2 is established. After that, for other relay PDUs between Remote UE1 and Remote UE2, Relay UE1 and Relay UE2 can perform routing according to the local relay routing table.

[0300] Fig.10A block diagram of a relay device provided by an exemplary embodiment of the present application is shown. The relay device includes a relay protocol stack, the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, or the relay protocol stack is a MAC layer protocol stack, the relay protocol stack includes: a relay receiving module 1020 and a relay sending module 1040, and the device includes:

[0301] The relay receiving module 1020 is used to receive the relay protocol data unit (PDU) sent by the previous hop node; forward the relay PDU to the relay sending module;

[0302] The relay sending module 1040 is used to send the relay PDU to the next hop node according to the protocol header of the relay PDU;

[0303] The relay PDU is a PDU sent between at least two remote terminals.

[0304] In an optional embodiment, the relay PDU includes: a first relay PDU; the first relay PDU is a PDU sent by the first remote terminal to the second remote terminal.

[0305] In an optional embodiment, the protocol header of the first relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote terminal; the first destination identifier includes: a terminal identifier of the second remote terminal.

[0306] In an optional embodiment, the relay receiving module 1020 is configured to forward the first relay PDU to the relay sending module when the first destination identifier is not equal to the terminal identifier of the relay terminal.

[0307] In an optional embodiment, the relay sending module 1040 is used to send the first relay PDU to the next hop node according to the first routing relationship when there is a first routing relationship corresponding to the first destination identifier in the relay routing table; wherein the first routing relationship includes: the terminal identifier of the second remote terminal, and, the node identifier of the next hop node, and the first routing relationship is the routing relationship when the terminal identifier of the second remote terminal is used as the destination identifier.

[0308] In an optional embodiment, the relay sending module 1040 is used to send the first relay PDU to a default next hop node when there is no first routing relationship corresponding to the first destination identifier in the relay routing table, and the default next hop node is at least one.

[0309] In an optional embodiment, the first relay PDU also includes: a first PDCP PDU; wherein the first PDCP PDU includes: at least one of a first signaling and a first data packet, the first signaling is a signaling sent by the first remote terminal, and the first data packet is a data packet sent by the first remote terminal.

[0310] In an optional embodiment, the relay PDU includes: a broadcast relay PDU; the broadcast relay PDU is a PDU that is broadcasted by the first remote terminal to other remote terminals.

[0311] In an optional embodiment, the protocol header of the broadcast relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote terminal; and the first destination identifier includes: a broadcast identifier.

[0312] In an optional embodiment, the relay receiving module 1020 is used to forward the broadcast relay PDU to the relay sending module when the first destination identifier includes a broadcast identifier.

[0313] In an optional embodiment, the relay sending module 1040 is configured to send the broadcast relay PDU to the next hop node when the first destination identifier includes a broadcast identifier.

[0314] In an optional embodiment, the broadcast relay PDU further includes: a first PDCP PDU, and a relay receiving module 1020, configured to transfer the first PDCP PDU to the PDCP layer when the first destination identifier includes a broadcast identifier. The first PDCP PDU includes: at least one of a broadcast data packet and a broadcast signaling.

[0315] In an optional embodiment, the relay receiving module 1020 is used to receive a second relay PDU, which is a PDU sent by the second remote terminal to the first remote terminal, and the second source identifier of the second relay PDU includes the terminal identifier of the second remote terminal; the relay receiving module 1020 is used to establish a first routing relationship in the relay routing table when there is no routing relationship corresponding to the second source identifier in the relay routing table; wherein the first routing relationship includes: the terminal identifier of the second remote terminal, and, the node identifier of the next hop node, and the first routing relationship is the routing relationship when the terminal identifier of the second remote terminal is used as the destination identifier.

[0316] In an optional embodiment, the relay receiving module 1020 is used to establish a second routing relationship in the relay routing table when there is no routing relationship corresponding to the first source identifier in the relay routing table;

[0317] The second routing relationship includes: the terminal identifier of the first remote terminal, and the node identifier of the previous hop node; the second routing relationship is the routing relationship when the terminal identifier of the first remote terminal is used as the destination identifier.

[0318] In an optional embodiment, when the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the relay PDU also includes: a first radio bearer identifier; when the relay protocol stack is a MAC layer protocol stack, the relay PDU also includes: a first logical channel identifier.

[0319] In an optional embodiment, the end-to-end protocol stack between at least two remote terminals includes: a PDCP layer protocol stack of a PC5 interface, and other protocol layers located above the PDCP protocol layer.

[0320] In an optional embodiment, the point-to-point protocol stack between the relay terminal and the previous hop node includes: a layer 2 protocol stack and a layer 1 protocol stack of a PC5 interface, the layer 2 protocol stack includes a radio link control (RLC) layer protocol stack and a (MAC) layer protocol stack, and the layer 1 protocol stack includes a physical (PHY) layer protocol stack.

[0321] Fig.11 A block diagram of a first remote device provided by an exemplary embodiment of the present application is shown. The first remote device includes a relay protocol stack, the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, or the relay protocol stack is a MAC layer protocol stack, the relay protocol stack includes a relay sending module 1120, and the device includes:

[0322] The relay sending module 1120 is used to receive the PDCP PDU transmitted by the PDCP layer protocol stack, generate a relay protocol data unit (PDU) according to the PDCP PDU, and send the relay PDU to the next hop node;

[0323] The relay PDU is a PDU sent between at least two remote devices.

[0324] In an optional embodiment, the relay PDU includes: a first relay PDU; the first relay PDU is a PDU sent by the first remote device to the second remote device.

[0325] In an optional embodiment, the protocol header of the first relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote device; the first destination identifier includes: a terminal identifier of the second remote device.

[0326] In an optional embodiment, the relay sending module 1120 is used to send the first relay PDU to the next hop node according to the first routing relationship when there is a first routing relationship corresponding to the first destination identifier in the relay routing table; wherein the first routing relationship includes: the terminal identifier of the second remote device, and the node identifier of the next hop node, and the first routing relationship is the routing relationship when the terminal identifier of the second remote device is used as the destination identifier.

[0327] In an optional embodiment, the first relay PDU also includes: a first PDCP PDU; wherein the first PDCP PDU includes: at least one of a first signaling and a first data packet, the first signaling is a signaling sent by the first remote device, and the first data packet is a data packet sent by the first remote device.

[0328] In an optional embodiment, the relay PDU includes: a broadcast relay PDU; the broadcast relay PDU is a PDU that is broadcasted by the first remote device to other remote devices.

[0329] In an optional embodiment, the protocol header of the broadcast relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote device; and the first destination identifier includes: a broadcast identifier.

[0330] In an optional embodiment, the broadcast relay PDU further includes: a first PDCP PDU; wherein the first PDCP PDU includes: at least one of a broadcast data packet and a broadcast signaling.

[0331] In an optional embodiment, the device also includes: a relay receiving module 1140, used to receive a second relay PDU, the second relay PDU is a PDU sent by the second remote device to the first remote device, and the second source identifier of the second relay PDU includes the terminal identifier of the second remote device; the relay receiving module 1140 is used to establish a first routing relationship in the relay routing table when there is no routing relationship corresponding to the second source identifier in the relay routing table; wherein the first routing relationship includes: the terminal identifier of the second remote device, and, the node identifier of the next hop node, and the first routing relationship is the routing relationship when the terminal identifier of the second remote device is used as the destination identifier.

[0332] In an optional embodiment, when the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the relay PDU also includes: a first radio bearer identifier; when the relay protocol stack is a MAC layer protocol stack, the relay PDU also includes: a first logical channel identifier.

[0333] In an optional embodiment, the end-to-end protocol stack between at least two remote devices includes: a PDCP layer protocol stack of a PC5 interface, and other protocol layers located above the PDCP protocol layer.

[0334] In an optional embodiment, the point-to-point protocol stack between the first remote device and the next hop node includes: a layer 2 protocol stack and a layer 1 protocol stack of a PC5 interface, the layer 2 protocol stack includes a radio link control (RLC) layer protocol stack and a (MAC) layer protocol stack, and the layer 1 protocol stack includes a physical (PHY) layer protocol stack.

[0335] In an optional embodiment, the relay protocol stack further includes a relay receiving module, and the device further includes: a relay receiving module 1140, configured to receive a second relay PDU, where the second relay PDU is a relay PDU sent by the second remote device to the first remote device.

[0336] In an optional embodiment, the second relay PDU includes: a second PDCP PDU; and a relay receiving module 1140, configured to transfer the second PDCP PDU to an upper layer protocol.

[0337] In an optional embodiment, when the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the second relay PDU also includes: a second radio bearer identifier, a relay receiving module 1140, used to pass the second radio bearer identifier to the PDCP layer protocol stack; or, when the relay protocol stack is a MAC layer protocol stack, the second relay PDU also includes: a second logical channel identifier, a relay receiving module 1140, used to pass the second logical channel identifier to the PDCP layer protocol stack.

[0338] In an optional embodiment, when a direct communication link exists between the first remote device and the second remote device, the relay PDU is directly sent to the second remote device through the direct communication link.

[0339] Fig.12 A block diagram of a second remote device provided by an exemplary embodiment of the present application is shown. The second remote device includes a relay protocol stack, the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, or the relay protocol stack is a MAC layer protocol stack, and the relay protocol stack includes a relay receiving module 1220:

[0340] The relay receiving module 1220 is configured to receive a relay protocol data unit (PDU) from a previous hop node and deliver a first PDCP PDU in the relay PDU to the PDCP layer;

[0341] The relay PDU is a PDU sent between at least two remote devices.

[0342] In an optional embodiment, the relay PDU includes: a first relay PDU, where the first relay PDU is a PDU sent by the first remote device to the second remote device.

[0343] In an optional embodiment, the protocol header of the first relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote device; the first destination identifier includes: a terminal identifier of the second remote device.

[0344] In an optional embodiment, the relay receiving module 1220 is used to pass the first PDCP PDU to the PDCP layer when the first destination identifier in the first relay PDU is the same as the terminal identifier of the second remote device; wherein the first PDCP PDU includes: at least one of a first signaling and a first data packet, the first signaling is a related signaling sent by the first remote device as the sender, and the first data packet is a related data packet sent by the first remote device as the sender.

[0345] In an optional embodiment, the relay PDU includes: a broadcast relay PDU, which is a PDU that is broadcasted by the first remote device to other remote devices.

[0346] In an optional embodiment, the protocol header of the broadcast relay PDU includes: a first source identifier and a first destination identifier; the first source identifier includes: a terminal identifier of the first remote device; and the first destination identifier includes: a broadcast identifier.

[0347] In an optional embodiment, the relay receiving module 1220 is used to pass the first PDCP PDU to the PDCP layer when the first destination identifier includes a broadcast identifier; wherein the first PDCP PDU includes: at least one of a broadcast data packet and a broadcast signaling.

[0348] In an optional embodiment, the relay protocol stack also includes a relay sending module 1240; the relay sending module 1240 is used to receive the PDCP PDU sent by the PDCP layer, generate a second relay PDU based on the PDCP PDU, and send the second relay PDU to the next hop node, the second relay PDU is a relay PDU sent by the second remote device to the first remote device.

[0349] In an optional example, the relay receiving module 1220 is used to establish a second routing relationship in the relay routing table when there is no routing relationship corresponding to the first source identifier in the relay routing table; wherein the second routing relationship includes: the terminal identifier of the first remote terminal, and the node identifier of the previous hop node; the second routing relationship is the routing relationship when the terminal identifier of the first remote terminal is used as the destination identifier.

[0350] In an optional embodiment, when the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the relay PDU also includes: a first wireless bearer identifier, a relay receiving module 1220, used to pass the first wireless bearer identifier to the PDCP layer protocol stack; or, when the relay protocol stack is a MAC layer protocol stack, the relay PDU also includes: a first logical channel identifier, a relay receiving module 1220, used to pass the first logical channel identifier to the PDCP layer protocol stack.

[0351] In an optional embodiment, the end-to-end protocol stack between at least two remote devices includes: a PDCP layer protocol stack of a PC5 interface, and other protocol layers located above the PDCP protocol layer.

[0352] In an optional embodiment, the point-to-point protocol stack between the second remote device and the previous hop node includes: a layer 2 protocol stack and a layer 1 protocol stack of a PC5 interface, the layer 2 protocol stack includes a radio link control (RLC) layer protocol stack and a (MAC) layer protocol stack, and the layer 1 protocol stack includes a physical (PHY) layer protocol stack.

[0353] Fig.13 A block diagram of a device for generating a routing table provided in an exemplary embodiment of the present application is shown. The device includes:

[0354] The receiving module 1320 is configured to receive a relay protocol data unit (PDU) sent by a previous hop node, wherein a protocol header of the relay PDU includes a first source identifier, and the first source identifier includes a terminal identifier of a first remote terminal;

[0355] Establishing module 1340, configured to establish a second routing relationship in the relay routing table based on the first source identifier and the node identifier of the previous hop node if there is no routing relationship corresponding to the first source identifier in the relay routing table;

[0356] The relay PDU is a PDU sent between two remote terminals, and the second routing relationship is a routing relationship when the terminal identifier of the first remote terminal is used as the destination identifier.

[0357] In an optional embodiment, the relay PDU includes: a first relay PDU; the first relay PDU is a PDU sent by the first remote terminal to the second remote terminal.

[0358] In an optional embodiment, the protocol header of the first relay PDU further includes: a first destination identifier;

[0359] The first destination identifier includes: a terminal identifier of the second remote terminal.

[0360] In an optional embodiment, the first relay PDU also includes: a first packet data convergence protocol PDCP PDU; wherein the first PDCP PDU includes: at least one of a first signaling and a first data packet, the first signaling is a related signaling sent by the first remote terminal as the sender, and the first data packet is a related data packet sent by the first remote terminal as the sender.

[0361] In an optional embodiment, the relay PDU includes: a broadcast relay PDU; the broadcast relay PDU is a PDU that is broadcasted by the first remote terminal to other remote terminals.

[0362] In an optional embodiment, the protocol header of the broadcast relay PDU further includes: a first destination identifier;

[0363] The first purpose identifier includes: a broadcast identifier.

[0364] In an optional embodiment, the broadcast relay PDU further includes: a first Packet Data Convergence Protocol PDCP PDU; wherein the first PDCP PDU includes: at least one of a broadcast data packet and a broadcast signaling.

[0365] In an optional embodiment, when the relay protocol stack is located between the PDCP layer and the layer 2 protocol stack of the PC5 interface, the relay PDU also includes: a first wireless bearer identifier; when the relay protocol stack is a MAC layer protocol stack, the relay PDU also includes: a first logical channel identifier.

[0366] In an optional embodiment, the receiving module 1320 is also used to receive a second relay PDU, which is a PDU sent by the second remote terminal to the first remote terminal, and the second source identifier of the second relay PDU includes the terminal identifier of the second remote terminal; the establishing module 1340 is also used to establish a first routing relationship in the relay routing table based on the second source identifier and the node identifier of the previous hop node when there is no routing relationship corresponding to the second source identifier in the relay routing table; wherein the first routing relationship includes: the terminal identifier of the second remote terminal, and, the node identifier of the previous hop node; the first routing relationship is the routing relationship when the terminal identifier of the second remote terminal is used as the destination identifier.

[0367] Fig.14 A schematic diagram of the structure of a terminal device (relay terminal or first remote terminal or second remote terminal) provided by an exemplary embodiment of the present application is shown. The terminal device includes: a processor 101, a receiver 102, a transmitter 103, a memory 104 and a bus 105.

[0368] The processor 101 includes one or more processing cores. The processor 101 executes various functional applications and information processing by running software programs and modules.

[0369] The receiver 102 and the transmitter 103 may be implemented as a communication component, which may be a communication chip.

[0370] The memory 104 is connected to the processor 101 via a bus 105 .

[0371] The memory 104 may be used to store at least one instruction, and the processor 101 may be used to execute the at least one instruction to implement each step in the above method embodiment.

[0372] In addition, the memory 104 can be implemented by any type of volatile or non-volatile storage device or a combination thereof. The volatile or non-volatile storage device includes but is not limited to: a magnetic disk or an optical disk, an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a static random access memory (SRAM), a read-only memory (ROM), a magnetic memory, a flash memory, and a programmable read-only memory (PROM).

[0373] In an exemplary embodiment, a computer-readable storage medium is also provided, in which at least one instruction, at least one program, a code set or an instruction set is stored, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by a processor to implement the relay method performed by the terminal device provided by the above-mentioned various method embodiments, or the routing table generation method.

[0374] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0375] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A relay method, characterized in that: Applied in a relay terminal, the relay terminal includes a relay protocol stack, the relay protocol stack is located between a packet data convergence protocol layer and a layer 2 protocol stack of a PC5 interface, or the relay protocol stack is a media access control layer protocol stack, the relay protocol stack includes a relay receiving entity and a relay sending entity, and the method includes: The relay receiving entity receives a relay protocol data unit sent by a previous hop node; and forwards the relay protocol data unit to the relay sending entity; The relay sending entity sends the relay protocol data unit to a next hop node according to a protocol header of the relay protocol data unit; The relay protocol data unit is a protocol data unit sent between at least two remote terminals.

2. The method according to claim 1, characterized in that The relay protocol data unit includes: a first relay protocol data unit; The first relay protocol data unit is a protocol data unit sent by the first remote terminal to the second remote terminal.

3. The method according to claim 2, characterized in that The protocol header of the first relay protocol data unit includes: a first source identifier and a first destination identifier; The first source identifier includes: a terminal identifier of the first remote terminal; The first destination identifier includes: a terminal identifier of the second remote terminal.

4. The method according to claim 3, characterized in that The relay sending entity sends the relay protocol data unit to a next hop node according to a protocol header of the relay protocol data unit, including: When there is a first routing relationship corresponding to the first destination identifier in the relay routing table, the relay sending entity sends the first relay protocol data unit to the next hop node according to the first routing relationship; The first routing relationship includes: the terminal identifier of the second remote terminal, and the node identifier of the next hop node. The first routing relationship is a routing relationship when the terminal identifier of the second remote terminal is used as the destination identifier.

5. The method according to claim 2, characterized in that: The first relay protocol data unit also includes: a first packet data convergence protocol data unit; The first packet data convergence protocol data unit includes: at least one of a first signaling and a first data packet, the first signaling is a signaling sent by the first remote terminal, and the first data packet is a data packet sent by the first remote terminal.

6. The method according to claim 2, characterized in that In the case where the relay protocol stack is located between the packet data convergence protocol layer and the layer 2 protocol stack of the PC5 interface, the relay protocol data unit further includes: a first radio bearer identifier; In the case that the relay protocol stack is the media access control layer protocol stack, the relay protocol data unit further includes: a first logical channel identifier.

7. The method according to claim 1, characterized in that The end-to-end protocol stack between the at least two remote terminals includes: The packet data convergence protocol layer protocol stack of the PC5 interface, and other protocol layers located above the packet data convergence protocol layer protocol stack.

8. The method according to claim 1, characterized in that The point-to-point protocol stack between the relay terminal and the previous hop node includes: The PC5 interface has a layer 2 protocol stack and a layer 1 protocol stack, wherein the layer 2 protocol stack includes a radio link control layer protocol stack and a media access control layer protocol stack, and the layer 1 protocol stack includes a physical layer protocol stack.

9. A relay device, characterized in that: The relay device includes a relay protocol stack, the relay protocol stack is located between the packet data convergence protocol layer and the layer 2 protocol stack of the PC5 interface, or the relay protocol stack is a media access control layer protocol stack, and the relay protocol stack includes a relay receiving module and a relay sending module: The relay receiving module is used to receive the relay protocol data unit sent by the previous hop node; forward the relay protocol data unit to the relay sending module; The relay sending module is used to send the relay protocol data unit to the next hop node according to the protocol header of the relay protocol data unit; The relay protocol data unit is a protocol data unit sent between at least two remote terminals.

10. The device according to claim 9, characterized in that The relay protocol data unit includes: a first relay protocol data unit; The first relay protocol data unit is a protocol data unit sent by the first remote terminal to the second remote terminal.

11. The device according to claim 10, characterized in that The protocol header of the first relay protocol data unit includes: a first source identifier and a first destination identifier; The first source identifier includes: a terminal identifier of the first remote terminal; The first destination identifier includes: a terminal identifier of the second remote terminal.

12. The device according to claim 11, characterized in that The relay sending module is used to send the first relay protocol data unit to the next hop node according to the first routing relationship when there is a first routing relationship corresponding to the first destination identifier in the relay routing table; The first routing relationship includes: the terminal identifier of the second remote terminal, and the node identifier of the next hop node. The first routing relationship is a routing relationship when the terminal identifier of the second remote terminal is used as the destination identifier.

13. The device according to claim 10, characterized in that The first relay protocol data unit also includes: a first packet data convergence protocol data unit; The first packet data convergence protocol data unit includes: at least one of a first signaling and a first data packet, the first signaling is a signaling sent by the first remote terminal, and the first data packet is a data packet sent by the first remote terminal.

14. The device according to claim 10, characterized in that In the case where the relay protocol stack is located between the packet data convergence protocol layer and the layer 2 protocol stack of the PC5 interface, the relay protocol data unit further includes: a first radio bearer identifier; In the case that the relay protocol stack is the media access control layer protocol stack, the relay protocol data unit further includes: a first logical channel identifier.

15. The device according to claim 9, characterized in that The end-to-end protocol stack between the at least two remote terminals includes: The packet data convergence protocol layer protocol stack of the PC5 interface, and other protocol layers located above the packet data convergence protocol layer protocol stack.

16. The device according to claim 9, characterized in that The point-to-point protocol stack between the relay terminal and the previous hop node includes: The PC5 interface has a layer 2 protocol stack and a layer 1 protocol stack, wherein the layer 2 protocol stack includes a radio link control layer protocol stack and a media access control layer protocol stack, and the layer 1 protocol stack includes a physical layer protocol stack.

17. A terminal, characterized in that: The terminal comprises: processor; a transceiver connected to the processor; a memory for storing processor-executable instructions; Wherein, the processor is configured to implement the relay method as described in any one of claims 1 to 8 above.

18. A computer-readable storage medium, characterized in that: The storage medium stores at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor to implement the relay method as described in any one of claims 1 to 8.

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