Relay communication method and terminal

Abstract

The invention relates to a relay communication method and a terminal, and the method comprises the steps that a first terminal sends first information, and the first information is used for indicating relay state information; in the embodiment of the invention, the appropriate relay can be selected for the terminal based on the relay state information indicated by the first information in the relay scene, so that the communication quality is improved.

Description

Relay communication method and terminal Technical Field The present application relates to the field of communications, and more specifically, to a relay communication method and terminal. Background Art With the development of wireless communication technology, the 3rd Generation Partnership Project (3GPP) introduced relays. Remote terminals can be connected to the network through relay terminals. Source terminals and target terminals can also be connected through relay terminals. Communication based on relay terminals can extend the communication distance and improve communication reliability. Summary of the invention The embodiments of the present application provide a relay communication method and a terminal, which avoid the signaling interaction process of a traditional user equipment (UE) that only supports single-hop relay and is connected to a multi-hop relay. The present application provides a relay communication method, including: The first terminal sends first information, where the first information is used to indicate relay state information. The present application provides a relay communication method, including: The second terminal receives first information, where the first information is used to indicate relay state information. An embodiment of the present application provides a first terminal, including: The first sending unit is used to send first information, where the first information is used to indicate relay state information. An embodiment of the present application provides a second terminal, including: The first receiving unit is used to receive first information, where the first information is used to indicate relay state information. The embodiment of the present application provides a terminal device, including a processor and a memory. The memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory, so that the terminal device executes the above-mentioned relay communication method. The embodiment of the present application provides a chip for implementing the above-mentioned relay communication method. Specifically, the chip includes: a processor for calling and running a computer program from a memory so that a device equipped with the chip executes the above-mentioned relay communication method. An embodiment of the present application provides a computer-readable storage medium for storing a computer program. When the computer program is executed by a device, the device executes the above-mentioned relay communication method. An embodiment of the present application provides a computer program product, including computer program instructions, which enable a computer to execute the above-mentioned relay communication method. An embodiment of the present application provides a computer program, which, when executed on a computer, enables the computer to execute the above-mentioned relay communication method. The embodiment of the present application provides a relay communication method, which can select a suitable relay for a terminal based on relay status information indicated by first information in a relay scenario, thereby improving communication quality. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an application scenario according to an embodiment of the present application. FIG. 2A is a schematic diagram of 3GPP transmission mode A. FIG. FIG. 2B is a schematic diagram of 3GPP transmission mode B. FIG3 is a schematic flowchart of a relay communication method according to an embodiment of the present application. FIG4 is a schematic flowchart of a relay communication method according to another embodiment of the present application. FIG5 is a schematic flowchart of a relay communication method according to another embodiment of the present application. FIG6 is a schematic flowchart of a relay communication method according to another embodiment of the present application. FIG. 7 is a schematic flowchart of a relay communication method according to another embodiment of the present application. FIG8 is a schematic flowchart of a relay communication method according to an embodiment of the present application. FIG. 9 is a schematic flowchart of a relay communication method according to another embodiment of the present application. FIG. 10 is a schematic flowchart of a relay communication method according to another embodiment of the present application. FIG. 11 is a schematic flowchart of a relay communication method according to another embodiment of the present application. FIG. 12 is a schematic flowchart of a relay communication method according to another embodiment of the present application. FIG13A is a schematic flowchart of relay between a network and a terminal according to Example 1 of the present application. Figure 13B is a schematic flowchart of relaying between terminals according to Example 1 of the present application. FIG14A is a schematic flowchart of relay between a network and a terminal according to Example 2 of the present application. Figure 14B is a schematic flowchart of relaying between terminals according to Example 2 of the present application. Figure 15A is a schematic flowchart of relay between the network and the terminal according to Example 3 of the present application. Figure 15B is a schematic flowchart of relaying between terminals according to Example 3 of the present application. FIG16 is a schematic block diagram of a first terminal according to an embodiment of the present application. FIG. 17 is a schematic flowchart of a first terminal according to another embodiment of the present application. FIG18 is a schematic block diagram of a second terminal according to an embodiment of the present application. FIG. 19 is a schematic flowchart of a second terminal according to another embodiment of the present application. FIG. 20 is a schematic structural diagram of a communication device according to an embodiment of the present application. FIG. 21 is a schematic structural diagram of a chip according to an embodiment of the present application. Figure 22 is a schematic block diagram of a communication system according to an embodiment of the present application. DETAILED DESCRIPTION The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. 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, 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 on unlicensed spectrum (NR-based access to unlicensed spectrum, NR-U) system, Non-Terrestrial Networks (NTN) system, Universal Mobile Telecommunication System (UMTS), Wireless Local Area Networks (WLAN), Wireless Fidelity (Wireless Fidelity) system. Fidelity, WiFi), fifth-generation communication (5th-Generation, 5G) system or other communication systems, etc. Generally speaking, traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, mobile communication systems will not only support traditional communications, but will also support, for example, device to device (D2D) communication, machine to machine (M2M) communication, machine type communication (MTC) communication, vehicle to vehicle (V2V) communication, or vehicle to everything (V2X) communication, etc. The embodiments of the present application can also be applied to these communication systems. In one implementation, the communication system in the embodiment of the present application can be applied to a carrier aggregation (CA) scenario, a dual connectivity (DC) scenario, or a standalone (SA) networking scenario. In one embodiment, the communication system in the embodiment of the present application can be applied to an unlicensed spectrum, wherein the unlicensed spectrum can also be considered as a shared spectrum; or, the communication system in the embodiment of the present application can also be applied to an authorized spectrum, wherein the authorized spectrum can also be considered as an unshared spectrum. The embodiments of the present application describe various embodiments in conjunction with network devices and terminal devices, wherein the terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal (remote terminal), mobile device, user terminal, terminal, wireless communication device, user agent or user device, etc. The terminal device can be a station (STAION, ST) in a WLAN, a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA) device, a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a next-generation communication system such as an NR network, or a terminal device in a future evolved Public Land Mobile Network (PLMN) network, etc. In the embodiments of the present application, the terminal device can be deployed on land, including indoors or outdoors, handheld, wearable or vehicle-mounted; it can also be deployed on the water surface (such as ships, etc.); it can also be deployed in the air (for example, on airplanes, balloons and satellites, etc.). In the embodiment of the present application, the terminal device may be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self driving, a wireless terminal device in remote medical, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, or a wireless terminal device in a smart home, etc. As an example but not limitation, in the embodiments of the present application, the terminal device may also be a wearable device. Wearable devices may also be referred to as wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also powerful functions achieved through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include full-featured, large-sized, and fully or partially independent of smartphones, such as smart watches or smart glasses, as well as devices that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various types of smart bracelets and smart jewelry for vital sign monitoring. In the embodiment of the present application, the network device may be a device for communicating with a mobile device, and the network device may be an access point (AP) in a WLAN, a base station (BTS) in a GSM or CDMA, or a WCDMA It can be a base station (NodeB, NB) in LTE, or an evolved base station (Evolutional Node B, eNB or eNodeB) in LTE, or a relay station or access point, or a vehicle-mounted device, a wearable device, and a network device (gNB) in the NR network, or a network device in the future evolved PLMN network, or a network device in the NTN network, etc. As an example but not limitation, in an embodiment of the present application, the network device may have a mobile characteristic, for example, the network device may be a mobile device. Optionally, the network device may be a satellite or a balloon station. For example, the satellite may be a low earth orbit (LEO) satellite, a medium earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, a high elliptical orbit (HEO) satellite, etc. Optionally, the network device may also be a base station set up in a location such as land or water. In an embodiment of the present application, the network device can provide services for a cell, and the terminal device communicates with the network device through the transmission resources used by the cell (for example, frequency domain resources, or spectrum resources). The cell can be a cell corresponding to the network device (for example, a base station), and the cell can belong to a macro base station or a base station corresponding to a small cell. The small cells here may include: metro cells, micro cells, pico cells, femto cells, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services. Fig. 1 exemplarily shows a communication system 100. The communication system includes a network device 110 and two terminal devices 120. In one embodiment, the communication system 100 may include multiple network devices 110, and each network device 110 may include other number of terminal devices 120 within its coverage area, which is not limited in the embodiment of the present application. In one implementation, the communication system 100 may also include other network entities such as a mobility management entity (MME) and an access and mobility management function (AMF), which is not limited in this embodiment of the present application. Among them, the network equipment may include access network equipment and core network equipment. That is, the wireless communication system also includes multiple core networks for communicating with the access network equipment. The access network equipment may be an evolutionary base station (evolutional node B, referred to as eNB or e-NodeB) macro base station, micro base station (also called "small base station"), micro-micro base station, access point (AP), transmission point (TP) or new generation base station (new generation Node B, gNodeB), etc. in a long-term evolution (LTE) system, a next-generation (mobile communication system) (next radio, NR) system or an authorized auxiliary access long-term evolution (LAA-LTE) system. It should be understood that the device with communication function in the network / system in the embodiment of the present application can be called a communication device. Taking the communication system shown in Figure 1 as an example, the communication device may include a network device and a terminal device with communication function, and the network device and the terminal device may be specific devices in the embodiment of the present application, which will not be repeated here; the communication device may also include other devices in the communication system, such as other network entities such as a network controller and a mobile management entity, which is not limited in the embodiment of the present application. It should be understood that the terms "system" and "network" are often used interchangeably in this article. The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship. It should be understood that the "indication" mentioned in the embodiments of the present application can be a direct indication, an indirect indication, or an indication of an association relationship. For example, A indicates B, which can mean that A directly indicates B, for example, B can be obtained through A; it can also mean that A indirectly indicates B, for example, A indicates C, and B can be obtained through C; it can also mean that there is an association relationship between A and B. In the description of the embodiments of the present application, the term "corresponding" may indicate a direct or indirect correspondence between two items, or an association relationship between the two items, or a relationship between indication and being indicated, configuration and being configured, and the like. To facilitate understanding of the technical solutions of the embodiments of the present application, the relevant technologies of the embodiments of the present application are described below. The following related technologies can be arbitrarily combined with the technical solutions of the embodiments of the present application as optional solutions, and they all belong to the protection scope of the embodiments of the present application. 1. Long Term Evolution (LTE) Device to Device (D2D) / Vehicle to X (V2X) Device-to-device communication is a sidelink (SL) transmission technology based on D2D. Unlike the traditional cellular system where communication data is received or sent by base stations, sidelink communication systems such as the Internet of Vehicles system can use terminal-to-terminal direct communication, thus having higher spectrum efficiency and lower transmission latency. 3GPP includes two transmission modes: Mode A and Mode B. Mode A: As shown in Figure 2A, the transmission resources of the terminal are allocated by the base station, and the terminal sends data on the sidelink according to the resources allocated by the base station. The base station can allocate resources for a single transmission to the terminal, or it can allocate resources for a semi-static transmission to the terminal. Mode B: As shown in FIG2B , the vehicle terminal selects a resource in the resource pool for data transmission. In 3GPP, D2D includes different stages: (1) Proximity based service (ProSe): In Rel-12 / 13, device-to-device communication is studied for ProSe scenarios, which mainly targets public safety services. In ProSe, by configuring the location of the resource pool in the time domain, for example, the resource pool is non-contiguous in the time domain, so that the UE can The data is sent / received discontinuously to save power. (2) Internet of Vehicles: In Rel-14 / 15, the Internet of Vehicles system studied the scenarios of vehicle-to-vehicle communication, which mainly targets the services of vehicle-to-vehicle and vehicle-to-person communication at relatively high speeds. In V2X, since the on-board system has a continuous power supply, power efficiency is not the main issue, but the delay of data transmission is the main issue, so the system design requires the terminal equipment to perform continuous transmission and reception. (3) Wearable devices, Further Enhancement to Device-to-Device (FeD2D): In Rel-14, this topic studies the scenarios in which wearable devices access the network through mobile phones, mainly targeting scenarios with low mobile speeds and low power access. In FeD2D, in the pre-research stage, 3GPP concluded that the base station can configure the discontinuous reception (DRX) parameters of the remote terminal through a relay terminal. However, since the subject has not entered the standardization stage, the specific details of how to configure DRX have not been concluded. Multi-carrier: In Rel-15LTE V2X, a multi-carrier mechanism is introduced. Specifically, the multi-carrier mechanism is reflected in that the UE can support packet segmentation, transmit packets using multiple carriers to improve data transmission rate; packet replication, copy an identical packet twice and send it using two carriers to improve transmission reliability; and multi-carrier reception enhancement at the receiving end. Specifically, for packet replication: V2X sidelink communication supports sidelink packet replication and is executed at the Packet Data Convergence Protocol (PDCP) layer of the UE. For sidelink packet replication for transmission, the PDCP protocol data unit (PDU) is replicated at the PDCP entity. The replicated Packet Data Protocol (PDP) PDU of the same PDCP entity is submitted to two different Radio Link Control (RLC) entities and associated with two different sidelink logical channels respectively. The replicated PDP PDU of the same PDCP entity is only allowed to be transmitted on different sidelink carriers. The UE can activate or deactivate sidelink packet replication based on (pre) configuration. Sidechain packet replication does not work with Rel-14 transport profile (TS 23.285

[0072] ) transmission. The Prose Per-Packet Reliability (PPPR) value of the neighboring service supporting sidelink packet replication can be (pre-)configured via a PPPR threshold. For UE autonomous resource selection and scheduled resource allocation, the UE shall perform sidelink packet replication for data with configured PPPR values ​​until the packet replication configuration is canceled for these PPPR values. For scheduled resource allocation, the UE reports the amount of data associated with one or more PPPR values ​​and the destination to which the data belongs via a sidelink buffer status report (Buffer Status Report, BSR). The mapping of PPPR values ​​to logical channel groups can be configured by the eNB, and the PPPR value is reflected by the associated logical channel group identifier (IDentity, ID) included in the sidelink BSR. A list of one or more PPPR values ​​can be reported by an RRC connected UE in the sidelink UE information. NR V2X Based on LTE V2X, NR V2X is not limited to broadcast scenarios, but is further expanded to unicast and multicast scenarios, and the application of V2X is studied in these scenarios. Similar to LTE V2X, NR V2X also includes two resource authorization modes: mode-1 / 2. Furthermore, the user may be in a mixed mode, that is, it can use mode-1 to acquire resources and mode-2 to acquire resources at the same time. The resource acquisition is indicated by the sidelink authorization, that is, the sidelink authorization indicates the time-frequency position of the corresponding PSCCH and PSSCH resources. Different from LTE V2X, in addition to the feedback-free, UE-initiated Hybrid Automatic Repeat-reQuest (HARQ) retransmission, NR V2X introduces feedback-based HARQ retransmission, which is not limited to unicast communication but also includes multicast communication. Similar to LTE V2X, in NR V2X, since the on-board system has continuous power supply, power efficiency is not the main issue, but the latency of data transmission is the main issue, so the system design requires the terminal equipment to perform continuous transmission and reception. For example, the sidelink terminal triggers the sidelink RRC reconfiguration process in the following scenarios: releasing sidelink data bearers in unicast communications; Establishing a sidelink data bearer in unicast communication; Modifying the configuration of the sidelink data bearer in unicast communication; In the terminal-to-network relay scenario, the PC5 relay RLC channel between the layer 2 relay terminal and the remote terminal is released; In the terminal-to-network relay scenario, a PC5 relay RLC channel is established between the layer 2 relay terminal and the remote terminal; In the terminal-to-network relay scenario, modify the configuration parameters related to the PC5 relay RLC channel between the layer 2 relay terminal and the remote terminal; Reconfiguration of NR sidelink measurement reporting related parameters; Reconfiguration of sidelink CSI reference signal resources and CSI reporting delay boundaries; Reconfiguration of line link DRX on the opposite terminal side. 3. Terminal to Network Relay The remote terminal performs measurement reporting, and includes information such as the relay terminal identifier, serving cell identifier, and reference signal received power (RSRP) measurement results in the measurement reporting information. When the link quality of the serving relay terminal is lower than the configured threshold value, and, optionally, the link quality of the adjacent cell is higher than the configured threshold value, the remote terminal performs measurement reporting. Event 2 When the link quality of the serving cell is lower than the configured threshold value, and the link quality of the optional relay terminal is higher than the configured threshold value, the remote terminal performs measurement reporting. In addition, in order to assist the remote terminal in performing the switching from the direct link to the indirect link, a new timer is introduced. When the remote terminal receives an RRC reconfiguration message indicating the switching from the direct link to the indirect link, the remote terminal starts the timer. When the timer times out, the remote terminal performs RRC reestablishment. In the terminal-to-network relay, the network side will configure the bearer ID for the remote terminal and the relay terminal for end-to-end data transmission of the relay terminal. In addition, the network side will additionally configure the bearer parameters on the PC5 interface between the relay terminal and the remote terminal. In the configuration of the Sidelink Relay Adaptation Protocol (SRAP) layer, the network will map the bearer ID with the PC5 RLC channel ID. The relay terminal can learn the specific configuration information used by the remote terminal through the RLC channel ID. However, the relay terminal cannot learn the specific information of the quality of service (QoS) of the corresponding service transmitted by the remote terminal using this configuration information. In the embodiments of the present application, the backward compatibility problem after the introduction of multi-hop relay can be solved, and the problem of remote users who only support single-hop relay accessing the multi-hop relay network can be avoided. FIG3 is a schematic flow chart of a relay communication method according to an embodiment of the present application. The method 300 may optionally be applied to the system shown in FIG1 , FIG2A or FIG2B , but is not limited thereto. The method includes at least part of the following contents. S310. The first terminal sends the first information, and the first information is used to indicate the relay status information. In an embodiment of the present application, the first terminal may send the first information to the second terminal. For example, the first terminal is a relay terminal, and the second terminal is a remote terminal, a source terminal, or a target terminal. The first information may indicate the relay status information of the first terminal. The relay status information may include relay capability information, such as whether the first terminal supports relaying, the currently working relay type, the specific number of relay hops, etc. In the relay scenario, the relay status information indicated by the first information can be used to select a suitable relay for the terminal to improve the communication quality. For example, it can avoid that a remote user or target that only supports single-hop relay is used to access a multi-hop relay network, reduce unnecessary network access operations, and improve the overall communication quality of the communication network. In one implementation, the second terminal is a remote terminal or a target terminal. In one implementation, the first terminal is a relay terminal. In one implementation, the relay state information is used to indicate at least one of the following: Works in single-hop relay mode; Working in multi-hop relay state; The number of hops for the current job. For example, the first information may indicate the relay type in which the relay terminal is currently working, such as working in a single-hop relay state or working in a multi-hop relay state. The first information may also indicate the number of relay hops in which the relay terminal is currently working, for example, a hop number of 1 indicates that the relay is working in a single-hop relay state, and a hop number of 3 indicates that the relay is working in a multi-hop relay state and is at the third hop. In one implementation, the first information is in a first message. In an embodiment of the present application, the first terminal may send a first message to the second terminal, and the first message carries the first information to explicitly or implicitly indicate the relay state information of the first terminal. In one embodiment, the first information is indicated by one or more indicator bits in the first message. In an embodiment of the present application, the relay state information of the first terminal can be explicitly indicated by the indicator bit in the first message. For example, the value of the indicator bit in the first message is 1, which can indicate that the first terminal is operating in a single-hop relay state. If the value of the indicator bit in the first message is 0, it can indicate that the first terminal is operating in a multi-hop relay state. Alternatively, if the value of the indicator bit in the first message is 11, it can indicate that the first terminal is operating in a multi-hop relay state and is at the third hop. In one implementation, the first information is at least one of the following in the first message: Layer 2 identification; Relay Service Code (RSC), also known as relay service code; Business logo; Physical layer parameters. In the embodiment of the present application, the relay state information of the first terminal may be implicitly indicated by other identifiers, codes or parameters in the first message. For example, if the layer 2 identifier in the first message is an odd number, it indicates that the relay state information is working in a single-hop relay state, and if it is an even number, it indicates that the relay state information is working in a multi-hop relay state. For another example, if the layer 2 identifier in the first message is an odd number, it indicates that the relay state information is working in a multi-hop relay state, and if it is an even number, it indicates that the relay state information is working in a single-hop relay state. For another example, the RSC or service ID can be divided into several value ranges. If the RSC or service ID in the first message is in the first value range, it indicates that the relay state information is working in a single-hop relay state; if the RSC or service ID in the first message is in the second value range, it indicates that the relay state information is working in a multi-hop relay state. In relay state. In one embodiment, the physical layer parameters include at least one of a relay service reference signal sequence and a reference signal cyclic shift. For example, a correspondence between the physical layer parameters and the relay state information can be set. For example, among 128 reference signal sequences, the first 64 reference signal sequences correspond to a single hop, and the last 64 reference signal sequences correspond to multiple hops. For another example, among the 128 reference signal sequences, the first 32 reference signal sequences correspond to a single hop, followed by 32 reference signal sequences correspond to 2 hops, followed by 32 reference signal sequences correspond to 3 hops, and the last 32 reference signal sequences correspond to 4 hops. For another example, the number of bits of the reference signal cyclic shift is an odd number corresponding to a single hop, and an even number corresponding to multiple hops. Fig. 4 is a schematic flow chart of a relay communication method 400 according to another embodiment of the present application. The method may include one or more features of the above method. In one implementation, the first message includes a discovery message. In one implementation, the discovery message includes a discovery announcement message. S310: The first terminal sends first information, including: S410, the first terminal broadcasts a discovery notification message to the second terminal, the discovery notification message is used to indicate the relay state information of the first terminal. For example, the first terminal, such as a relay terminal, indicates the relay state information of the relay terminal by broadcasting the discovery notification message. The second terminal, such as a remote terminal or a target terminal, that receives the discovery notification message can determine whether it can be accessed through the relay terminal. For example, if the relay state information of the relay terminal is that it is working in a multi-hop relay state, and the remote terminal or the target terminal only supports working in a single-hop relay state, the remote terminal or the target terminal does not use the relay terminal for access. If the relay state information of the relay terminal is that it is working in a multi-hop relay state, and the remote terminal or the target terminal supports working in a multi-hop relay state, the remote terminal or the target terminal can use the relay terminal for access. For another example, if the relay state information of the relay terminal indicates that it is working in a single-hop relay state, and the remote terminal or the target terminal only supports working in a single-hop relay state, the remote terminal or the target terminal uses the relay terminal for access. If the relay state information of the relay terminal indicates that it is working in a single-hop relay state, and the remote terminal or the target terminal supports working in a multi-hop relay state, if a terminal that only supports multi-hop relay cannot access a single-hop relay, the remote terminal or the target terminal cannot use the relay terminal for access, otherwise it can use the relay terminal for access. FIG5 is a schematic flow chart of a relay communication method 500 according to another embodiment of the present application. The method may include one or more features of the above method. In one embodiment, as shown in FIG5, the method further includes: S510: A first terminal receives a discovery request message sent by a second terminal, where the discovery request message is used to indicate relay state information of the second terminal. For example, the second terminal indicates the relay state information supported by the second terminal by sending a discovery request message. After receiving the discovery request message, the first terminal can determine whether the second terminal can be accessed through the first terminal based on the relay state information of the second terminal. For example, the discovery request message may indicate that the second terminal, such as a remote terminal or a target terminal, supports working in a multi-hop relay state. If the first terminal, such as a relay terminal, works in a multi-hop relay state, the first terminal may determine that the second terminal can be accessed through the first terminal. If the first terminal, such as a relay terminal, works in a single-hop relay state, if a terminal that only supports multi-hop relay cannot access a single-hop relay, the first terminal may determine that the second terminal cannot be accessed through the first terminal; if a terminal that supports multi-hop relay can access a single-hop relay, the first terminal may also determine that the second terminal can be accessed through the first terminal. For example, the discovery request message may indicate that the second terminal, such as a remote terminal or a target terminal, supports working in a single-hop relay state. If the first terminal, such as a relay terminal, works in a single-hop relay state, the first terminal may determine that the second terminal can be accessed through the first terminal. If the first terminal, such as a relay terminal, works in a multi-hop relay state, the first terminal may determine that the second terminal cannot be accessed through the first terminal. In one implementation, as shown in FIG. 5 , the discovery message includes a discovery response message. S310: The first terminal sends first information, including: S520: The first terminal sends a discovery response message to the second terminal, where the discovery response message is used to indicate relay state information of the first terminal. For example, the discovery response message sent by the first terminal to the second terminal indicates the relay status information of the first terminal, that is, the relay terminal. The second terminal, such as a remote terminal or a target terminal, can determine whether the second terminal can access through the relay terminal based on the relay status information of the relay terminal. If the first terminal works in a multi-hop relay state, and the second terminal also supports working in a multi-hop relay state, the second terminal can access the communication system, such as a sideline communication system or an uplink and downlink communication system, through the first terminal as a relay. If the first terminal works in a multi-hop relay state, but the second terminal only supports working in a single-hop relay state, the second terminal cannot access the communication system through the first terminal as a relay. Fig. 6 is a schematic flow chart of a relay communication method 600 according to another embodiment of the present application. The method may include one or more features of the above method. In one embodiment, the first message includes a PC5 signaling (PC5-S) message. In one embodiment, as shown in FIG6 , the method further includes: S610: A first terminal receives a connection establishment request message sent by a second terminal, where the connection establishment request message is used to indicate relay state information of the second terminal. In one embodiment, the connection establishment request message is a ProSe direct link establishment request message. For example, the connection establishment request message sent by the second terminal to the first terminal may be a direct communication request (DCR) message such as a ProSe direct link establishment request message. The first terminal that receives the ProSe direct link establishment request message may determine whether the second terminal can access the communication system through the first terminal based on the relay type supported by the second terminal. For example, if the proximity service direct link establishment request message indicates that the relay state information of the second terminal supports working in a multi-hop relay state, and the first terminal is currently working in a single-hop relay state, if the terminal that only supports multi-hop relay cannot access the single-hop relay, the second terminal does not choose to use the first terminal as the relay for the second terminal; if the terminal that only supports multi-hop relay can access the single-hop relay, the second terminal may also choose to use the first terminal as the relay for the second terminal; if the first terminal is currently working in a multi-hop relay state, the second terminal may choose to use the first terminal as the relay for the second terminal. For example, if the proximity service direct link establishment request message indicates that the relay state information of the second terminal supports working in a single-hop relay state, and the first terminal is currently working in a single-hop relay state, the first terminal is selected to be used as the relay for the second terminal; if the first terminal is currently working in a multi-hop relay state, the first terminal is not selected to be used as the relay for the second terminal. In one implementation, the PC5 signaling message includes a security mode configuration message and / or a connection establishment response message. S310: The first terminal sends first information, including: S620: The first terminal sends a security mode configuration message and / or a connection establishment response message to the second terminal, where the security mode configuration message and / or the connection establishment response message is used to indicate relay state information of the first terminal. In one implementation, the security mode configuration message is a ProSe direct link security mode command message. For example, the security mode configuration message sent by the first terminal to the second terminal may include a security mode command (Safe Mode Command, SMC) message. The second terminal that receives the security mode command message may choose whether to access the communication system through the first terminal according to the relay type supported by itself. For example, if the proximity service direct link security mode command message indicates that the relay state information of the first terminal is working in a multi-hop relay state, and the second terminal does not support working in a multi-hop relay state, the second terminal may not choose to use the first terminal as a relay for the second terminal; if the second terminal supports working in a multi-hop relay state, the second terminal may choose to use the first terminal as a relay for the second terminal. For another example, if the proximity service direct link security mode command message indicates that the relay state information of the first terminal is working in a single-hop relay state, and the second terminal supports working in a single-hop relay state, the second terminal chooses to use the first terminal as the relay for the second terminal; if the second terminal supports working in a multi-hop relay state, if the terminal that only supports multi-hop relay cannot access the single-hop relay, the second terminal does not choose to use the first terminal as the relay for the second terminal; if the terminal that supports multi-hop relay can access the single-hop relay, the second terminal may also choose to use the first terminal as the relay for the second terminal. In one embodiment, the connection establishment response message is a proximity service direct link establishment acceptance message. For example, the connection establishment response message sent by the first terminal to the second terminal may include a direct communication acceptance (Direct Communication Accept, DCA) message. Specifically, for example, the DCA message may be a proximity service direct link establishment acceptance (ProSe direct link establishment accept) message. The proximity service direct link establishment acceptance message sent by the first terminal to the second terminal may include relay status information indicating the first terminal. The second terminal that receives the proximity service direct link establishment acceptance message can choose whether to access the communication system through the first terminal according to the relay type supported by itself. For example, if the proximity service direct link establishment acceptance message indicates that the relay state information of the first terminal is working in a multi-hop relay state, and the second terminal does not support working in a multi-hop relay state, the second terminal does not choose to use the first terminal as a relay for the second terminal; if the second terminal supports working in a multi-hop relay state, the second terminal chooses to use the first terminal as a relay for the second terminal. For another example, if the proximity service direct link establishment acceptance message indicates that the relay state information of the first terminal is working in a single-hop relay state, and the second terminal supports working in a single-hop relay state, the second terminal chooses to use the first terminal as the relay for the second terminal; if the second terminal supports working in a multi-hop relay state, if the terminal that only supports multi-hop relay cannot access the single-hop relay, the second terminal does not choose to use the first terminal as the relay for the second terminal; if the terminal that supports multi-hop relay can access the single-hop relay, the second terminal may also choose to use the first terminal as the relay for the second terminal. Fig. 7 is a schematic flow chart of a relay communication method 700 according to another embodiment of the present application. The method may include one or more features of the above method. In one implementation, the first message includes a PC5 radio resource control layer message. In one implementation, the PC5 radio resource control layer message includes a capability-related message, and the method further includes: S710. A first terminal receives a first capability-related message sent by a second terminal, where the first capability-related message is used to indicate relay state information of the second terminal. For example, after the second terminal sends a first capability-related message to the first terminal, the first terminal that receives the first capability-related message can determine whether the second terminal can access the communication system through the first terminal based on the relay type supported by the second terminal. For example, if the first capability-related message indicates that the relay state information of the second terminal is working in a multi-hop relay state, and the first terminal is currently working in a single-hop relay state, if the terminal that only supports multi-hop relay cannot access the single-hop relay, the first terminal can determine not to use the second capability-related message. A terminal acts as a relay for a second terminal; if a terminal supporting multi-hop relay can access a single-hop relay, the first terminal can also determine to use the first terminal as a relay for the second terminal; if the first terminal currently works in a multi-hop relay state, the first terminal determines that the first terminal can be used as a relay for the second terminal. For example, if the first capability-related message indicates that the relay state information of the second terminal is working in a single-hop relay state, and the first terminal is currently working in a single-hop relay state, the first terminal can determine to use the first terminal as a relay for the second terminal; if the first terminal is currently working in a multi-hop relay state, the first terminal determines that the first terminal cannot be used as a relay for the second terminal. In one implementation, as shown in FIG. 7 , S310: the first terminal sends first information, including: S720: The first terminal sends a second capability-related message to the second terminal, where the second capability-related message is used to indicate relay state information of the first terminal. For example, after the first terminal sends the second capability-related message to the second terminal, the second terminal that receives the second capability-related message can choose whether to access the communication system through the first terminal according to the relay type supported by the second terminal. For example, if the second capability-related message indicates that the relay state information of the first terminal is working in a multi-hop relay state, and the second terminal does not support working in a multi-hop relay state, the second terminal does not choose to use the first terminal as a relay for the second terminal; if the second terminal supports working in a multi-hop relay state, the second terminal chooses to use the first terminal as a relay for the second terminal. For another example, if the second capability-related message indicates that the relay status information of the first terminal is working in a single-hop relay state, and the second terminal supports working in a single-hop relay state, the second terminal chooses to use the first terminal as the relay of the second terminal; if the second terminal supports working in a multi-hop relay state, if the terminal that only supports multi-hop relay cannot access the single-hop relay, the second terminal does not choose to use the first terminal as the relay of the second terminal; if the terminal that supports multi-hop relay can access the single-hop relay, the second terminal may also choose to use the first terminal as the relay of the second terminal. FIG8 is a schematic flow chart of a relay communication method according to an embodiment of the present application. The method 800 may optionally be applied to the system shown in FIG1 , FIG2A or FIG2B , but is not limited thereto. The method includes at least part of the following contents. S810. The second terminal receives first information, where the first information is used to indicate relay state information. In one implementation, the first information is in a first message. In one implementation, the first information is indicated by one or more indication bits in the first message. In one implementation, the first information is at least one of the following in the first message: Layer 2 identification; Relay Service Code RSC; Business logo; Physical layer parameters. In one embodiment, the physical layer parameter includes at least one of a relay service reference signal sequence and a reference signal cyclic shift. In one implementation, the relay state information is used to indicate at least one of the following: Works in single-hop relay mode; Working in multi-hop relay state; The number of hops for the current job. In one embodiment, the first message includes a discovery message. FIG9 is a schematic flow chart of a relay communication method 900 according to another embodiment of the present application. The method may include one or more features of the above method. In one embodiment, the discovery message includes a discovery notification message, S810 the second terminal receives the first information, including: S910: The second terminal receives a discovery notification message broadcast by the first terminal, where the discovery notification message is used to indicate relay state information of the first terminal. FIG10 is a schematic flow chart of a relay communication method 1000 according to another embodiment of the present application. The method may include one or more features of the above method. In one embodiment, the method further includes: S1010: The second terminal sends a discovery request message to the first terminal, where the discovery request message is used to indicate relay state information of the second terminal. In one implementation, as shown in FIG. 10 , the discovery message includes a discovery response message, and S810 the second terminal receives first information, including: S1020: The second terminal receives a discovery response message sent by the first terminal, where the discovery response message is used to indicate relay state information of the first terminal. Fig. 11 is a schematic flow chart of a relay communication method 1100 according to another embodiment of the present application. The method may include one or more features of the above method. In one embodiment, the first message includes a PC5 signaling message. In one embodiment, as shown in FIG11 , the method further includes: S1110. The second terminal sends a connection establishment request message to the first terminal. The connection establishment request message is used to indicate the second terminal's Following status information. In one implementation, the connection establishment request message is a proximity service direct link establishment request message. In one implementation, the PC5 signaling message includes a security mode configuration message and / or a connection establishment response message. S810 The second terminal receives the first information, including: S1120: The second terminal receives a security mode configuration message and / or a connection establishment response message sent by the first terminal, where the security mode configuration message and / or the connection establishment response message is used to indicate relay state information of the first terminal. In one implementation, the security mode configuration message is a proximity based service direct link security mode command message, and / or the connection establishment response message is a proximity based service direct link establishment accept message. Fig. 12 is a schematic flow chart of a relay communication method 1200 according to another embodiment of the present application. The method may include one or more features of the above method. In one implementation, the first message includes a PC5 radio resource control layer message. In one implementation, the PC5 radio resource control layer message includes a capability-related message, and the method further includes: S1210. The second terminal sends a first capability-related message to the first terminal, where the first capability-related message is used to indicate relay state information of the second terminal. In one implementation, as shown in FIG. 12 , S810, the second terminal receives first information, including: S1220. The second terminal receives a second capability-related message sent by the first terminal, where the second capability-related message is used to indicate relay state information of the first terminal. In one implementation, the first terminal is a relay terminal. In one implementation, the second terminal is a remote terminal or a target terminal. For specific examples of the second terminal executing the relay communication methods 800 to 1200 of this embodiment, reference may be made to the relevant descriptions about the second terminal in the above-mentioned embodiments of the first terminal executing the relay communication methods 300 to 700, which will not be repeated here for the sake of brevity. The embodiments of the present application can be used in a multi-hop terminal-to-terminal relay scenario. In order to prevent a traditional UE that only supports single-hop relay from connecting to a multi-hop relay, the embodiments of the present application can provide a specific signaling interaction process. The following are several specific examples. Example 1: Indicated by discovery message In this example, the manner in which different types of relays (including but not limited to single-hop and multi-hop) are indicated by the discovery message may include at least one of the following: 1. Explicit indication: The above indication is explicitly delivered through signaling. 2. Implicit indication: Indicated by at least one of the following information: a) Layer 2 ID: Different access control modes are reserved with different IDs, which are distinguished by the Layer 2 ID. For example, an odd-numbered Layer 2 ID indicates a single hop, and an even-numbered Layer 2 ID indicates multiple hops. b) RSC, service ID: Different RSC and / or service ID are reserved for different access control modes, and are distinguished by RSC and / or service ID. For example, the first value range of RSC and / or service ID indicates a single hop, and the second value range indicates multiple hops. c) Physical layer parameters (such as reference signal (RS) sequence, RS cyclic shift): Different physical layer parameters are reserved for different access control modes, and are distinguished by physical layer parameters. For example, among 128 reference signal sequences, the first 64 indicate single hop and the last 64 indicate multi-hop. As shown in FIG. 13A , the process of finding an indication includes (only case 1 is shown) Case 1. Discovery model-A, the relay UE (e.g., relay 1 or relay 2) indicates the relay capabilities supported by the relay UE by broadcasting a discovery announcement message. For example, in multiple ultimate scenarios from the network to relay 1 to relay 2, the discovery message sent by relay 1 to the remote UE indicates that relay 1 works in a single-hop relay state, and the discovery message sent by relay 2 to the remote UE indicates that relay 2 works in a multi-hop relay state. The remote UE decides whether to access relay 2 based on the ability management. Case 2. Discovery model-B, including: a) The remote UE indicates the relay capabilities supported by the remote UE by sending a discovery solicitation message, so that the relay UE can determine whether it can access through itself, and / or, b) The relay UE indicates the relay capabilities supported by the relay UE by sending a discovery response message, so that the remote UE can determine whether it can access through the relay. Specifically, the content indicated in the message exchanged between the relay UE and / or the remote UE may include: 1. The relay UE may indicate whether it supports access by a single-hop remote UE and / or whether it supports access by a multi-hop relay UE. 2. The remote UE can indicate whether it supports access to the multi-hop relay UE. The multi-hop in this example may be more than 1 hop. Figure 13A shows a scenario of network relay (relay between the network and the terminal). As shown in Figure 13B, in the scenario of device relay (relay between terminals), the process is similar. Example 2: Indication via PC5-S message In this example, the manner in which different types of relays (including but not limited to single-hop and multi-hop) are indicated by the PC5-S message may include: At least one of the following: 1. Explicit indication: The above indication is explicitly transmitted through PC5-S signaling. 2. Implicit indication: Indicated by at least one of the following information: a) Layer 2 ID: Different IDs are reserved for different access control modes, and are distinguished by Layer 2 IDs. b) Service ID: Different service IDs are reserved for different access control modes, and they are distinguished by service IDs. c) Physical layer parameters (such as RS sequence, RS cyclic shift): Different physical layer parameters are reserved for different access control modes, and are distinguished by physical layer parameters. As shown in FIG. 14A , the process indicated by PC5-S includes: 1. The remote UE indicates the relay capabilities supported by the remote UE by sending a DCR message, so that the relay UE can determine whether it can access through itself, and / or, 2. The relay UE indicates the relay capabilities supported by the relay UE by sending SMC and / or DCA messages, thereby facilitating the remote UE to determine whether it can access through the relay. Specifically, the content indicated in the message exchanged between the relay UE and / or the remote UE may include: 1. The relay UE may indicate whether it supports access by traditional single-hop remote UEs and / or whether it supports access by multi-hop relay UEs. 2. The remote UE can indicate whether it supports access to the multi-hop relay UE. The multi-hop in this example may be more than 1 hop. Figure 14A shows a scenario of network relay (relay between the network and the terminal). As shown in Figure 14B, in the scenario of device relay (relay between terminals), the process is similar. Example 3: Indication via PC5-RRC In this example, the manner in which different types of relays (including but not limited to single-hop and multi-hop) are indicated by the PC5-RRC message may include at least one of the following: 1. Explicit indication: The above indication is explicitly delivered via PC5-RRC signaling. 2. Implicit indication: Indicated by at least one of the following information: a) Layer 2 ID: Different IDs are reserved for different access control modes, and are distinguished by Layer 2 IDs. b) Physical layer parameters (such as RS sequence, RS cyclic shift): Different physical layer parameters are reserved for different access control modes, and are distinguished by physical layer parameters. As shown in FIG. 15A , the process indicated by PC5-RRC includes: 1. The remote UE indicates the relay capabilities supported by the remote UE by sending a capability-related message, so that the relay UE can determine whether it can access through itself, and / or, 2. The relay UE indicates the relay capabilities supported by the relay UE by sending a capability-related message, thereby facilitating the remote UE to determine whether it can access through the relay. Specifically, the content indicated in the message exchanged between the relay UE and / or the remote UE may include: 1. The relay UE may indicate whether it supports access by traditional single-hop remote UEs and / or whether it supports access by multi-hop relay UEs. 2. The remote UE can indicate whether it supports access to the multi-hop relay UE. The multi-hop in this example may be more than 1 hop. Figure 15A shows a scenario of network relay (relay between the network and the terminal). As shown in Figure 15B, in the scenario of device relay (relay between terminals), the process is similar. Through the solution of the embodiment of the present application, in the relay scenario, through the specific signaling interaction process in the above example, a suitable relay terminal can be selected to access the network according to the relay types supported by the relay terminal, the remote terminal, the target terminal, etc., thereby solving the backward compatibility problem. For example, it is prevented that a UE that only supports single-hop relay is connected to a multi-hop relay UE. FIG16 is a schematic block diagram of a first terminal 1600 according to an embodiment of the present application. The first terminal 1600 may include: The first sending unit 1601 is used to send first information, where the first information is used to indicate relay state information. In one implementation, the first information is in a first message. In one implementation, the first information is indicated by one or more indication bits in the first message. In one implementation, the first information is at least one of the following in the first message: Layer 2 identification; Relay Service Code RSC; Business logo; Physical layer parameters. In one embodiment, the physical layer parameter includes at least one of a relay service reference signal sequence and a reference signal cyclic shift. In one implementation, the relay state information is used to indicate at least one of the following: Works in single-hop relay mode; Working in multi-hop relay state; The number of hops for the current job. In one embodiment, the first message includes a discovery message. Figure 17 is a schematic flow chart of a first terminal 1700 according to another embodiment of the present application. The first terminal may include one or more features of the above-mentioned first terminal. In one embodiment, the discovery message includes a discovery notification message, and the first sending unit 1601 is further used to broadcast the discovery notification message to the second terminal, and the discovery notification message is used to indicate the relay state information of the first terminal. In one implementation, as shown in FIG17 , the first terminal 1700 further includes: The first receiving unit 1701 is configured to receive a discovery request message sent by a second terminal, where the discovery request message is used to indicate relay state information of the second terminal. In one implementation, as shown in FIG. 17 , the discovery message includes a discovery response message, and the first sending unit 1601 is further configured to send a discovery response message to the second terminal, where the discovery response message is configured to indicate relay status information of the first terminal. In one implementation, as shown in FIG. 17 , the first message includes a PC5 signaling message. In one implementation, as shown in FIG17 , the first terminal 1700 further includes: The second receiving unit 1702 is configured to receive a connection establishment request message sent by a second terminal, where the connection establishment request message is used to indicate relay state information of the second terminal. In one implementation, the connection establishment request message is a proximity service direct link establishment request message. In one embodiment, the PC5 signaling message includes a security mode configuration message and / or a connection establishment response message, and the first sending unit 1601 is also used to send a security mode configuration message and / or a connection establishment response message to the second terminal, and the security mode configuration message and / or the connection establishment response message is used to indicate the relay status information of the first terminal. In one implementation, the security mode configuration message is a proximity based service direct link security mode command message, and / or the connection establishment response message is a proximity based service direct link establishment accept message. In one implementation, the first message includes a PC5 radio resource control layer message. In one implementation, as shown in FIG. 17 , the PC5 radio resource control layer message includes a capability-related message, and the first terminal 1700 further includes: The third receiving unit 1703 is configured to receive a first capability-related message sent by a second terminal, where the first capability-related message is used to indicate relay state information of the second terminal. In an implementation manner, the first sending unit is further used to send a second capability-related message to the second terminal, where the second capability-related message is used to indicate the relay state information of the first terminal. In one implementation, the second terminal is a remote terminal or a target terminal. In one implementation, the first terminal is a relay terminal. FIG18 is a schematic block diagram of a second terminal 1800 according to an embodiment of the present application. The second terminal 1800 may include: The first receiving unit 1801 is used to receive first information, where the first information is used to indicate relay state information. In one implementation, the first information is in a first message. In one implementation, the first information is indicated by one or more indication bits in the first message. In one implementation, the first information is at least one of the following in the first message: Layer 2 identification; Relay Service Code RSC; Business logo; Physical layer parameters. In one embodiment, the physical layer parameter includes at least one of a relay service reference signal sequence and a reference signal cyclic shift. In one implementation, the relay state information is used to indicate at least one of the following: Works in single-hop relay mode; Working in multi-hop relay state; The number of hops for the current job. In one embodiment, the first message includes a discovery message. Figure 19 is a schematic flow chart of a second terminal 1900 according to another embodiment of the present application. The second terminal may include one or more features of the above-mentioned terminal. In one embodiment, the discovery message includes a discovery notification message, and the first receiving unit 1801 is also used to receive a discovery notification message broadcast by the first terminal, and the discovery notification message is used to indicate the relay state information of the first terminal. In an implementation manner, the discovery message includes a discovery response message, and the first receiving unit 1801 is further configured to receive a discovery response message sent by the first terminal, where the discovery response message is used to indicate relay state information of the first terminal. FIG19 is a schematic flow chart of a second terminal 1900 according to another embodiment of the present application. The second terminal may include one or more features of the second terminal described above. In one implementation, the second terminal 1900 further includes: The first sending unit 1901 is configured to send a discovery request message to the first terminal, where the discovery request message is used to indicate relay state information of the second terminal. In one implementation, as shown in FIG. 19 , the discovery message includes a discovery response message, and the first receiving unit 1801 is further used to receive a discovery response message sent by the first terminal, where the discovery response message is used to indicate relay status information of the first terminal. In one embodiment, the first message includes a PC5 signaling message. In one implementation, as shown in FIG19 , the second terminal 1900 further includes: The second sending unit 1902 is configured to send a connection establishment request message to the first terminal, where the connection establishment request message is used to indicate the relay state information of the second terminal. In one implementation, the connection establishment request message is a proximity service direct link establishment request message. In one embodiment, the PC5 signaling message includes a security mode configuration message and / or a connection establishment response message, and the first receiving unit 1801 is also used to receive a security mode configuration message and / or a connection establishment response message sent by the first terminal, and the security mode configuration message and / or the connection establishment response message is used to indicate the relay status information of the first terminal. In one implementation, the security mode configuration message is a proximity based service direct link security mode command message, and / or the connection establishment response message is a proximity based service direct link establishment accept message. In one implementation, the first message includes a PC5 radio resource control layer message. In one implementation, as shown in FIG. 19 , the PC5 radio resource control layer message includes a capability-related message, and the second terminal 1900 further includes: The third sending unit 1903 is used to send a first capability-related message to the first terminal, where the first capability-related message is used to indicate the relay state information of the second terminal. In an implementation manner, the first receiving unit 1801 is further configured to receive a second capability-related message sent by the first terminal, where the second capability-related message is used to indicate relay state information of the first terminal. In one implementation, the first terminal is a relay terminal. In one implementation, the second terminal is a remote terminal or a target terminal. The second terminal 1800, 1900 of the embodiment of the present application can implement the corresponding functions of the second terminal in the aforementioned method embodiment. The processes, functions, implementation methods and beneficial effects corresponding to each module (submodule, unit or component, etc.) in the second terminal can be found in the corresponding description in the above method embodiment, which will not be repeated here. It should be noted that the functions described by each module (submodule, unit or component, etc.) in the second terminal of the application embodiment can be implemented by different modules (submodule, unit or component, etc.), or by the same module (submodule, unit or component, etc.). Fig. 20 is a schematic structural diagram of a communication device 2000 according to an embodiment of the present application. The communication device 2000 includes a processor 2010, and the processor 2010 can call and run a computer program from a memory to enable the communication device 2000 to implement the method in the embodiment of the present application. In one implementation, the communication device 2000 may further include a memory 2020. The processor 2010 may call and run a computer program from the memory 2020, so that the communication device 2000 implements the method in the embodiment of the present application. The memory 2020 may be a separate device independent of the processor 2010 , or may be integrated into the processor 2010 . In one implementation, the communication device 2000 may further include a transceiver 2030, and the processor 2010 may control the transceiver 2030 to communicate with other devices, specifically, may send information or data to other devices, or receive information or data sent by other devices. The transceiver 2030 may include a transmitter and a receiver. The transceiver 2030 may further include an antenna, and the number of antennas may be one or more. In one implementation, the communication device 2000 may be the first terminal of the embodiment of the present application, and the communication device 2000 may implement the corresponding processes implemented by the first terminal in each method of the embodiment of the present application, which will not be described here for the sake of brevity. In one implementation, the communication device 2000 may be the second terminal of the embodiment of the present application, and the communication device 2000 may implement the corresponding processes implemented by the second terminal in each method of the embodiment of the present application, which will not be described here for the sake of brevity. Fig. 21 is a schematic structural diagram of a chip 2100 according to an embodiment of the present application. The chip 2100 includes a processor 2110, and the processor 2110 can call and run a computer program from a memory to implement the method in the embodiment of the present application. In one implementation, the chip 2100 may further include a memory 2120. The processor 2110 may call and run a computer program from the memory 2120 to implement the method executed by the first terminal or the second terminal in the embodiment of the present application. The memory 2120 may be a separate device independent of the processor 2110 , or may be integrated into the processor 2110 . In one implementation, the chip 2100 may further include an input interface 2130. The processor 2110 may control the input interface 2130 to communicate with other devices or chips, and specifically, may obtain information or data sent by other devices or chips. In one implementation, the chip 2100 may further include an output interface 2140. The processor 2110 may control the output interface 2140 to communicate with other devices or chips, and specifically, may output information or data to other devices or chips. In one implementation, the chip can be applied to the first terminal in the embodiment of the present application, and the chip can implement the corresponding processes implemented by the first terminal in each method of the embodiment of the present application, which will not be described here for brevity. In one implementation, the chip can be applied to the second terminal in the embodiments of the present application, and the chip can implement the corresponding processes implemented by the second terminal in each method of the embodiments of the present application, which will not be described in detail here for the sake of brevity. The chip applied to the first terminal and the second terminal may be the same chip or different chips. It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc. The processor mentioned above may be a general-purpose processor, a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC) or other programmable logic devices, transistor logic devices, discrete hardware components, etc. Among them, the general-purpose processor mentioned above may be a microprocessor or any conventional processor, etc. The memory mentioned above may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable ROM (PROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM) or a flash memory. The volatile memory may be a random access memory (RAM). It should be understood that the above-mentioned memory is exemplary but not restrictive. For example, the memory in the embodiments of the present application may also be static random access memory (static RAM, SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchronous link dynamic random access memory (synch link DRAM, SLDRAM) and direct memory bus random access memory (Direct Rambus RAM, DR RAM), etc. That is to say, the memory in the embodiments of the present application is intended to include but not limited to these and any other suitable types of memory. FIG22 is a schematic block diagram of a communication system 2200 according to an embodiment of the present application. The communication system 2200 includes a first terminal 2210 and a second terminal 2220 . The first terminal 2210 is used to send first information, where the first information is used to indicate relay state information. The second terminal 2220 is used to receive first information, where the first information is used to indicate relay status information. The first terminal 2210 may be used to implement the corresponding functions implemented by the first terminal in the above method, and the second terminal 2220 may be used to implement the corresponding functions implemented by the second terminal in the above method. For the sake of brevity, they will not be described in detail here. In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function in accordance with the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions can be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server, data center, etc. that contains one or more available media integrations. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)). It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application. Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here. The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A relay communication method, comprising: The first terminal sends first information, where the first information is used to indicate relay state information.

2. The method according to claim 1, wherein: The first information is in a first message. 3 . The method according to claim 2 , wherein the first information is indicated by one or more indication bits in the first message.

4. The method according to claim 2, wherein: The first information is at least one of the following in the first message: Layer 2 identification; Relay Service Code RSC; Business logo; Physical layer parameters.

5. The method according to claim 4, wherein: The physical layer parameter includes at least one of a relay service reference signal sequence and a reference signal cyclic shift.

6. The method according to any one of claims 2 to 5, wherein: The relay state information is used to indicate at least one of the following: Works in single-hop relay mode; Working in multi-hop relay state; The number of hops for the current job.

7. The method according to any one of claims 2 to 6, wherein: The first message comprises a discovery message.

8. The method according to claim 7, wherein: The discovery message includes a discovery notification message, and the first terminal sends the first information, including: The first terminal broadcasts a discovery notification message to the second terminal, where the discovery notification message is used to indicate relay state information of the first terminal.

9. The method according to claim 8, wherein: The discovery message includes a discovery response message, and the first terminal sends first information including: The first terminal sends a discovery response message to the second terminal, where the discovery response message is used to indicate relay state information of the first terminal.

10. The method according to claim 9, wherein: The method further comprises: The first terminal receives a discovery request message sent by the second terminal, where the discovery request message is used to indicate relay state information of the second terminal.

11. The method according to any one of claims 2 to 6, wherein: The first message includes a PC5 signaling message.

12. The method according to claim 11, wherein: The PC5 signaling message includes a security mode configuration message and / or a connection establishment response message, and the first terminal sends the first information, including: The first terminal sends a security mode configuration message and / or a connection establishment response message to the second terminal, where the security mode configuration message and / or the connection establishment response message is used to indicate the relay state information of the first terminal.

13. The method according to claim 12, wherein: The security mode configuration message is a proximity based service direct link security mode command message, and / or the connection establishment response message is a proximity based service direct link establishment accept message.

14. The method according to claim 12 or 13, wherein: The method further comprises: The first terminal receives a connection establishment request message sent by the second terminal, where the connection establishment request message is used to indicate relay state information of the second terminal.

15. The method according to any one of claims 12 to 14, wherein: The connection establishment request message is a proximity service direct link establishment request message.

16. The method according to any one of claims 2 to 6, wherein: The first message includes a PC5 radio resource control layer message.

17. The method according to claim 16, wherein: The PC5 radio resource control layer message includes a capability-related message, and the method further includes: The first terminal receives a first capability-related message sent by a second terminal, where the first capability-related message is used to indicate relay state information of the second terminal.

18. The method according to claim 17, wherein: The first terminal sends first information, including: The first terminal sends a second capability-related message to the second terminal, where the second capability-related message is used to indicate relay state information of the first terminal.

19. The method according to any one of claims 8 to 10, 12 to 15, 17, 18, wherein: The second terminal is a remote terminal or a target terminal.

20. The method according to any one of claims 1 to 19, wherein: The first terminal is a relay terminal.

21. A relay communication method, comprising: The second terminal receives first information, where the first information is used to indicate relay state information.

22. The method according to claim 21, wherein: The first information is in a first message.

23. The method according to claim 22, wherein the first information is indicated by one or more indication bits in the first message.

24. The method according to claim 22, wherein: The first information is at least one of the following in the first message: Layer 2 identification; Relay Service Code RSC; Business logo; Physical layer parameters.

25. The method according to claim 24, wherein: The physical layer parameter includes at least one of a relay service reference signal sequence and a reference signal cyclic shift.

26. The method according to any one of claims 22 to 25, wherein: The relay state information is used to indicate at least one of the following: Works in single-hop relay mode; Working in multi-hop relay state; The number of hops for the current job.

27. The method according to any one of claims 22 to 26, wherein: The first message comprises a discovery message.

28. The method according to claim 27, wherein: The discovery message includes a discovery notification message, and the second terminal receives the first information, including: The second terminal receives a discovery notification message broadcast by the first terminal, where the discovery notification message is used to indicate relay state information of the first terminal.

29. The method according to claim 28, wherein: The discovery message includes a discovery response message, and the second terminal receives the first information, including: The second terminal receives a discovery response message sent by the first terminal, where the discovery response message is used to indicate relay state information of the first terminal.

30. The method of claim 29, wherein: The method further comprises: The second terminal sends a discovery request message to the first terminal, where the discovery request message is used to indicate relay state information of the second terminal.

31. The method according to any one of claims 22 to 26, wherein: The first message includes a PC5 signaling message.

32. The method according to claim 31, wherein: The PC5 signaling message includes a security mode configuration message and / or a connection establishment response message, and the second terminal receives the first information, including: The second terminal receives a security mode configuration message and / or a connection establishment response message sent by the first terminal, where the security mode configuration message and / or the connection establishment response message is used to indicate relay state information of the first terminal.

33. The method of claim 32, wherein: The security mode configuration message is a proximity based service direct link security mode command message, and / or the connection establishment response message is a proximity based service direct link establishment accept message.

34. The method according to claim 32 or 33, wherein: The method further comprises: The second terminal sends a connection establishment request message to the first terminal, where the connection establishment request message is used to indicate relay state information of the second terminal.

35. The method according to any one of claims 32 to 34, wherein: The connection establishment request message is a proximity service direct link establishment request message.

36. The method according to any one of claims 22 to 26, wherein: The first message includes a PC5 radio resource control layer message.

37. The method of claim 36, wherein: The PC5 radio resource control layer message includes a capability-related message, and the method further includes: The second terminal sends a first capability-related message to the first terminal, where the first capability-related message is used to indicate relay state information of the second terminal.

38. The method of claim 37, wherein: The second terminal receives the first information, including: The second terminal receives a second capability-related message sent by the first terminal, where the second capability-related message is used to indicate relay state information of the first terminal.

39. The method according to any one of claims 28 to 30, 32 to 35, 37, 38, wherein: The first terminal is a relay terminal.

40. The method according to any one of claims 21 to 39, wherein: The second terminal is a remote terminal or a target terminal.

41. A first terminal, comprising: The first sending unit is used to send first information, where the first information is used to indicate relay state information.

42. The first terminal according to claim 41, wherein: The first information is in a first message.

43. The first terminal according to claim 42, wherein the first information is indicated by one or more indication bits in the first message.

44. The first terminal according to claim 42, wherein: The first information is at least one of the following in the first message: Layer 2 identification; Relay Service Code RSC; Business logo; Physical layer parameters.

45. The first terminal according to claim 44, wherein: The physical layer parameter includes at least one of a relay service reference signal sequence and a reference signal cyclic shift.

46. ​​The first terminal according to any one of claims 42 to 45, wherein: The relay state information is used to indicate at least one of the following: Works in single-hop relay mode; Working in multi-hop relay state; The number of hops for the current job.

47. The first terminal according to any one of claims 42 to 46, wherein: The first message comprises a discovery message.

48. The first terminal according to claim 47, wherein: The discovery message includes a discovery notification message, and the first sending unit is further configured to broadcast the discovery notification message to the second terminal, where the discovery notification message is used to indicate relay state information of the first terminal.

49. The first terminal according to claim 48, wherein: The discovery message includes a discovery response message, and the first sending unit is further used to send a discovery response message to the second terminal, where the discovery response message is used to indicate relay state information of the first terminal.

50. The first terminal according to claim 49, wherein: The first terminal further includes: The first receiving unit is configured to receive a discovery request message sent by a second terminal, where the discovery request message is used to indicate relay state information of the second terminal.

51. The first terminal according to any one of claims 42 to 46, wherein: The first message includes a PC5 signaling message.

52. The first terminal according to claim 51, wherein: The PC5 signaling message includes a security mode configuration message and / or a connection establishment response message, and the first sending unit is also used to send a security mode configuration message and / or a connection establishment response message to the second terminal, and the security mode configuration message and / or the connection establishment response message is used to indicate the relay status information of the first terminal.

53. The first terminal according to claim 52, wherein: The security mode configuration message is a proximity based service direct link security mode command message, and / or the connection establishment response message is a proximity based service direct link establishment accept message.

54. The first terminal according to claim 52 or 53, wherein: The first terminal further includes: The second receiving unit is used to receive a connection establishment request message sent by a second terminal, where the connection establishment request message is used to indicate the relay state information of the second terminal.

55. The first terminal according to any one of claims 52 to 54, wherein: The connection establishment request message is a proximity service direct link establishment request message.

56. The first terminal according to any one of claims 42 to 46, wherein: The first message includes a PC5 radio resource control layer message.

57. The first terminal according to claim 56, wherein: The PC5 radio resource control layer message includes a capability-related message, and the first terminal further includes: The third receiving unit is used to receive a first capability-related message sent by a second terminal, where the first capability-related message is used to indicate relay state information of the first terminal.

58. The first terminal according to claim 57, wherein: The first sending unit is further used to send a second capability-related message to the second terminal, where the second capability-related message is used to indicate relay state information of the first terminal.

59. The first terminal according to any one of claims 48 to 50, 52 to 55, 57, and 58, wherein: The second terminal is a remote terminal or a target terminal.

60. The first terminal according to any one of claims 41 to 59, wherein: The first terminal is a relay terminal.

61. A second terminal, comprising: The first receiving unit is used to receive first information, where the first information is used to indicate relay state information.

62. The second terminal according to claim 61, wherein: The first information is in a first message.

63. The second terminal according to claim 62, wherein the first information is indicated by one or more indication bits in the first message.

64. The second terminal according to claim 62, wherein: The first information is at least one of the following in the first message: Layer 2 identification; Relay Service Code RSC; Business logo; Physical layer parameters.

65. The second terminal according to claim 64, wherein: The physical layer parameter includes at least one of a relay service reference signal sequence and a reference signal cyclic shift.

66. The second terminal according to claim 62, wherein: The relay state information is used to indicate at least one of the following: Works in single-hop relay mode; Working in multi-hop relay state; The number of hops for the current job.

67. The second terminal according to any one of claims 62 to 66, wherein: The first message comprises a discovery message.

68. The second terminal according to claim 67, wherein: The discovery message includes a discovery notification message. The first receiving unit is further configured to receive a discovery notification message broadcast by the first terminal. The discovery notification message is configured to indicate relay status information of the first terminal.

69. The second terminal according to claim 68, wherein: The discovery message includes a discovery response message, and the first receiving unit is further configured to receive a discovery response message sent by the first terminal, wherein the discovery response message is used to indicate relay state information of the first terminal.

70. The second terminal according to claim 69, wherein: The second terminal further includes: The first sending unit is used to send a discovery request message to the first terminal, where the discovery request message is used to indicate the relay state information of the second terminal.

71. The second terminal according to any one of claims 62 to 66, wherein: The first message includes a PC5 signaling message.

72. The second terminal according to claim 71, wherein: The PC5 signaling message includes a security mode configuration message and / or a connection establishment response message. The first receiving unit is also used to receive a security mode configuration message and / or a connection establishment response message sent by the first terminal. The security mode configuration message and / or the connection establishment response message is used to indicate the relay status information of the first terminal.

73. The second terminal according to claim 72, wherein: The security mode configuration message is a proximity based service direct link security mode command message, and / or the connection establishment response message is a proximity based service direct link establishment accept message.

74. The second terminal according to claim 72 or 73, wherein: The second terminal further includes: The second sending unit is used to send a connection establishment request message to the first terminal, where the connection establishment request message is used to indicate the relay state information of the second terminal.

75. The second terminal according to any one of claims 72 to 74, wherein: The connection establishment request message is a proximity service direct link establishment request message.

76. The second terminal according to any one of claims 62 to 66, wherein: The first message includes a PC5 radio resource control layer message.

77. The second terminal according to claim 76, wherein: The PC5 radio resource control layer message includes a capability-related message, and the second terminal further includes: The third sending unit is used to send a first capability-related message to the first terminal, where the first capability-related message is used to indicate the relay state information of the second terminal.

78. The second terminal according to claim 77, wherein: The first receiving unit is further used to receive a second capability-related message sent by the first terminal, where the second capability-related message is used to indicate relay state information of the first terminal.

79. The second terminal according to any one of claims 68 to 70, 72 to 75, 77, and 78, wherein: The first terminal is a relay terminal.

80. The second terminal according to any one of claims 61 to 79, wherein: The second terminal is a remote terminal or a target terminal.

81. A terminal device, comprising: A processor and a memory, the memory being used to store a computer program, the processor being used to call and run the computer program stored in the memory so that the terminal device executes the method as described in any one of claims 1 to 20 or any one of claims 21 to 40.

82. A chip, comprising: A processor, configured to call and run a computer program from a memory, so that a device equipped with the chip executes a method as claimed in any one of claims 1 to 20 or any one of claims 21 to 40.

83. A computer-readable storage medium for storing a computer program, which, when executed by a device, causes the device to perform the method as claimed in any one of claims 1 to 20 or any one of claims 21 to 40.

84. A computer program product comprising computer program instructions for causing a computer to perform the method of any one of claims 1 to 20 or any one of claims 21 to 40.

85. A computer program causing a computer to perform the method of any one of claims 1 to 20 or any one of claims 21 to 40.

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