A communication method and device

Abstract

The present application relates to a communication method and apparatus. A first network device receives first information from a second terminal device or a third network device, the first information including an identifier of the first terminal device, and the third network device is a network device where the second terminal device resides. The first network device sends the identifier of the first terminal device to the second network device, and the identifier of the first terminal device is used to determine whether the first terminal device is authorized to provide relay services. The first network device receives second information from the second network device, and the second information is used to indicate that the first terminal device is authorized to provide relay services, or to indicate that the first terminal device is not authorized to provide relay services. Even if the first terminal device is in an RRC non-connected state, the first network device can determine whether the first terminal device is authorized to provide relay services through the second network device, thereby improving the success rate of the second terminal device accessing the network.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on November 5, 2020, with application number 202011222778.9 and application name “Path switch method when Relay UE is idle or inactive”, the entire contents of which are incorporated by reference in this application. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a communication method and device. Background Art

[0004] Among the user equipment (UE) relay technologies currently proposed, there is a relay mode in which the remote UE can be visible to the radio access network (RAN). In this relay mode, the remote UE can implement path switching, or link switching. For example, the remote UE can switch from a direct link with the base station to an indirect link that communicates indirectly with the base station. The direct link here refers to the link through which the UE communicates with the base station through the Uu port, and the indirect link is the relay link, that is, the remote UE is connected to the network through the relay UE.

[0005] The current technology mainly considers that the relay UE is in the radio resource control (RRC) connected state, so that the remote UE can switch from the direct link to the indirect link. However, before the remote UE switches to communicate with the network through the relay UE, the relay UE is likely to be in the RRC idle state or the RRC inactive state. Some UEs are authorized to provide relay services, while some UEs are not authorized to provide relay services. UEs that are not authorized to provide relay services cannot provide relay services. If the relay UE is in the RRC connected state, the base station can determine whether the relay UE is authorized to provide relay services. If it is determined that the relay UE is authorized to provide relay services, the base station allows the remote UE to switch to communicate with the network through the relay UE. However, if the relay UE is in the RRC idle state or the RRC inactive state, the base station cannot determine whether the relay UE is authorized to provide relay services. If the remote UE attempts to access the network through a UE that is not authorized to provide relay services, the remote UE will fail to access the network. Summary of the invention

[0006] The embodiments of the present application provide a communication method and apparatus for determining whether a UE in an RRC non-connected state is authorized to provide a relay service, thereby improving the success rate of a remote UE accessing a network.

[0007] In a first aspect, a first communication method is provided, which can be executed by a first network device, or by a chip system, and the chip system can implement the functions of the first network device. Exemplarily, the first network device is an access network device, such as a base station. The method includes: the first network device receives first information from a second terminal device or a third network device, the first information includes an identifier of the first terminal device, and the third network device is a network device where the second terminal device resides; the first network device sends the identifier of the first terminal device to the second network device, and the identifier of the first terminal device is used to determine whether the first terminal device is authorized to provide a relay service; the first network device receives second information from the second network device, and the second information is used to indicate that the first terminal device is authorized to provide a relay service, or indicates that the first terminal device is not authorized to provide a relay service.

[0008] In an embodiment of the present application, even if the first terminal device is in an RRC non-connected state (for example, an RRC idle state or an RRC inactive state), the first network device can determine through the second network device whether the first terminal device is authorized to provide relay services, thereby allowing other terminal devices to access the network through the first terminal device when it is determined that the first terminal device is authorized to provide relay services, thereby improving the success rate of other terminal devices accessing the network.

[0009] In combination with the first aspect, in a first optional implementation of the first aspect, the first information also includes status information of the first terminal device, and the status information of the first terminal device is used to indicate that the first terminal device is in an RRC inactive state or an RRC idle state.

[0010] The first information sent by the second terminal device or the third network device to the first network device may include the status information of the first terminal device, so that the first network device can determine the status of the first terminal device based on the status information of the first terminal device, for example, it can be determined whether the first terminal device is in the RRC idle state or the RRC inactive state. The first network device does not need to take other methods to determine the status of the first terminal device, and the implementation is relatively simple.

[0011] In combination with the first aspect or the first optional implementation of the first aspect, in the second optional implementation of the first aspect, when the second information is used to indicate that the first terminal device is authorized to provide a relay service, the method further includes: the first network device sends a first RRC message, the first RRC message includes first configuration information, and the first configuration information is used to configure the second terminal device to access the network through the first terminal device. If the first terminal device is authorized to provide a relay service, the first network device can configure the second terminal device, for example, the first network device can configure the second terminal device by sending the first configuration information.

[0012] In combination with the second optional implementation of the first aspect, in a third optional implementation of the first aspect, the first RRC message also includes first indication information, and the first indication information is used to indicate triggering the first terminal device to enter an RRC connected state. The first network device knows that the first terminal device is in an RRC non-connected state, and if the second terminal device wants to access the network through the first terminal device, the first terminal device needs to enter an RRC connected state, so the first network device can instruct the second terminal device to trigger the first terminal device to enter an RRC connected state, so that the first terminal device can provide relay services normally.

[0013] In combination with the first aspect or any of the first optional implementation manners to the third optional implementation manners of the first aspect, in a fourth optional implementation manner of the first aspect, the second information is the context of the first terminal device, or the second information is information used to indicate whether the first terminal device is authorized to provide a relay service. For example, the second information is indication information, and the indication information can indicate whether the first terminal device is authorized to provide a relay service. This can reduce the amount of information in the second information and save signaling overhead. For another example, the second information is not indication information, but includes the context of the first terminal device. Whether a terminal device is authorized to provide a relay service, the authorization information is recorded in the context of the terminal device. Therefore, by obtaining the context of the terminal device, it can be determined whether the terminal device is authorized to provide a relay service. The second network device can also send the context of the first terminal device to the first network device, so that the first network device can determine whether the first terminal device is authorized to provide a relay service.

[0014] In combination with the first aspect or any optional implementation manner from the first optional implementation manner to the fourth optional implementation manner of the first aspect, in the fifth optional implementation manner of the first aspect, when the first terminal device is in an RRC inactive state, the second network device is an anchor network device of the first terminal device; when the first terminal device is in an RRC idle state, the second network device is a core network device.

[0015] If the first terminal device is in an RRC inactive state, the context of the first terminal device may be stored in the anchor network device of the first terminal device, so the first network device can determine from the anchor network device of the first terminal device whether the first terminal device is authorized to provide relay services. Alternatively, if the first terminal device is in an RRC idle state, the context of the first terminal device may be stored in a core network device (such as AMF or SMF or PCF, etc.), so the first network device can determine from the core network device whether the first terminal device is authorized to provide relay services.

[0016] In combination with the first aspect or the first optional implementation of the first aspect or the second optional implementation of the first aspect, in the sixth optional implementation of the first aspect, the method further includes: the first network device generates a paging message, and the paging message is used to page the first terminal device; the first network device sends the paging message. Through the scheme of the embodiment of the present application, if the first network device determines that the first terminal device is authorized to provide relay service, then the first network device can instruct the second terminal device to trigger the first terminal device to enter the RRC connection state, or the first network device can also page the first terminal device by itself, so that the first terminal device enters the RRC connection state. If the first network device pages the first terminal device, there is no need for the second terminal device to trigger the first terminal device to enter the RRC connection state, which reduces the operations required for the second terminal device, so that the technical solution of the embodiment of the present application can be applied to terminal devices with lower capabilities.

[0017] In combination with the sixth optional implementation of the first aspect, in a seventh optional implementation of the first aspect, the state of the first terminal device is an RRC inactive state, and the paging message includes the I-RNTI of the first terminal device; the state of the first terminal device is an RRC idle state, and the paging message includes the 5G-S-TMSI of the first terminal device. If the first network device pages the first terminal device, the first network device may carry different information in the paging message to distinguish the first terminal devices in different states.

[0018] In combination with the sixth optional implementation of the first aspect or the seventh optional implementation of the first aspect, in the eighth optional implementation of the first aspect, the first information also includes an identifier of the cell where the first terminal device is located; the first network device sends the paging message, including: the first network device sends the paging message in the cell corresponding to the identifier of the cell. The first network device can perform paging in the cell where the first terminal device resides, without the need to perform paging in a larger range, which also reduces the number of paging messages, saves transmission overhead, and improves paging efficiency.

[0019] In a second aspect, a second communication method is provided, which can be executed by a second terminal device, or by a chip system, and the chip system can realize the functions of the second terminal device. The method includes: the second terminal device measures the first terminal device and determines the state of the first terminal device, the state of the first terminal device is RRC connected state, RRC inactive state, or RRC idle state; the second terminal device sends third information to a third network device, the third information includes the state information of the first terminal device, and the state information of the first terminal device is used to indicate the state of the first terminal device; the second terminal device receives a first RRC message from the third network device, the first RRC message includes first configuration information, and the first configuration information is used to configure the second terminal device to access the network through the first terminal device.

[0020] In combination with the second aspect, in a first optional implementation of the second aspect, the first RRC message also includes first indication information, and the first indication information is used to indicate triggering the first terminal device to enter an RRC connected state.

[0021] In combination with the second aspect or the first optional implementation of the second aspect, in the second optional implementation of the second aspect, the third information also includes a measurement report of the first terminal device, or the third information also includes an identifier of the first terminal device. The second terminal device may send the measurement report of the first terminal device to a third network device, and the network device (e.g., the third network device) may decide which terminal device to select to provide relay service for the second terminal device, or the second terminal device may select a terminal device to provide relay service by itself, for example, if the first terminal device is selected, the second terminal device may send the identifier of the first terminal device to the third network device, without the need for the network device to make another selection.

[0022] In combination with the second aspect or the first optional implementation of the second aspect or the second optional implementation of the second aspect, in a third optional implementation of the second aspect, the method further includes: the second terminal device receives a discovery message from the first terminal device, and the discovery message includes status information of the first terminal device. There are multiple ways for the second terminal device to determine the status of the first terminal device. For example, one way to determine is that the first terminal device includes the status information of the first terminal device in the discovery message, and then the second terminal device can determine the status of the first terminal device by receiving the discovery message from the first terminal device.

[0023] In combination with the third optional implementation of the second aspect, in a fourth optional implementation of the second aspect, the status information of the first terminal device is included in the message body or message header of the discovery message, or the status information of the first terminal device is indicated by the layer 2 destination identifier included in the discovery message. The status information of the first terminal device can be included in the discovery message in different ways, without limitation.

[0024] In combination with the second aspect or the first optional implementation of the second aspect or the second optional implementation of the second aspect, in a fifth optional implementation of the second aspect, the method further includes: the second terminal device receives a discovery message from the first terminal device; the second terminal device determines the state of the first terminal device according to the inclusion of the identification of the first terminal device in the discovery message. There are multiple ways for the second terminal device to determine the state of the first terminal device. For example, another determination method is that the first terminal device can indicate the state of the first terminal device by including the identification of the first terminal device in the discovery message. Then the second terminal device can determine the state of the first terminal device by receiving the inclusion of the identification of the first terminal device in the discovery message from the first terminal device.

[0025] In combination with the fifth optional implementation of the second aspect, in the sixth optional implementation of the second aspect, the second terminal device determines the state of the first terminal device according to the inclusion of the identifier of the first terminal device in the discovery message, including: the second terminal device determines that the state of the first terminal device is the RRC connected state according to the identifier of the first terminal device included in the discovery message as C-RNTI; the second terminal device determines that the state of the first terminal device is the RRC inactive state according to the identifier of the first terminal device included in the discovery message as resume identifier or I-RNTI; the second terminal device determines that the state of the first terminal device is the RRC idle state according to the discovery message not including the identifier of the first terminal device, or including the identifier of the first terminal device as 5G-S-TMSI. The several situations here are just examples and are not limitations to the scheme of the present application.

[0026] In combination with the second aspect or the first optional implementation of the second aspect or the second optional implementation of the second aspect, in the seventh optional implementation of the second aspect, the method further includes: the second terminal device receives a discovery message from the first terminal device through a first resource pool, the first resource pool being used for terminal devices in the RRC inactive state or the RRC idle state; the second terminal device determines that the first terminal device is in the RRC active state or the RRC idle state based on the first resource pool. There are multiple ways for the second terminal device to determine the state of the first terminal device. For example, another way of determination is that the first terminal device can use different resource pools to send discovery messages when it is in different states, so that the second terminal device can determine the state of the first terminal device based on the resource pool that receives the discovery message. In this way, the second terminal device can determine the state of the first terminal device without parsing the discovery message from the first terminal device, which is simpler to implement and more efficient.

[0027] In combination with the second aspect or the first optional implementation of the second aspect or the second optional implementation of the second aspect, in the eighth optional implementation of the second aspect, the method further includes: the second terminal device receives a system message from the first terminal device, and the system message includes the status information of the first terminal device. There are multiple ways for the second terminal device to determine the status of the first terminal device. For example, another determination method is that the first terminal device may include the status information of the first terminal device through a system message, and the second terminal device can determine the status of the first terminal device based on the system message received from the first terminal device, and the system message is, for example, MIB. In this way, the first terminal device can indicate the status of the first terminal device without sending an additional discovery message, which can save signaling overhead.

[0028] Regarding the technical effects brought about by the second aspect or various optional implementations of the second aspect, reference may also be made to the introduction to the technical effects of the first aspect or corresponding implementations.

[0029] In a third aspect, a third communication method is provided, which can be executed by a first terminal device, or by a chip system, and the chip system can implement the function of the first terminal device. The method includes: the first terminal device sends a second message, and the second message is used to indicate the state of the first terminal device, and the state of the first terminal device is RRC connected state, RRC inactive state, or RRC idle state.

[0030] In combination with the third aspect, in a first optional implementation of the third aspect, the first terminal device sends the second message, including: the first terminal device broadcasts the second message; or the first terminal device sends the second message to the second terminal device. The first terminal device can send the second message in a broadcast or unicast manner.

[0031] In combination with the third aspect or the first optional implementation of the third aspect, in a second optional implementation of the third aspect, the second message is a discovery message, and the discovery message includes status information of the first terminal device.

[0032] In combination with the second optional implementation of the third aspect, in a third optional implementation of the third aspect, the status information of the first terminal device is included in the message body or message header of the discovery message, or the status information of the first terminal device is indicated by the layer 2 destination identifier of the discovery message.

[0033] In combination with the third aspect or the first optional implementation of the third aspect, in a fourth optional implementation of the third aspect, the second message is a discovery message, and the discovery message indicates the status of the first terminal device by including an identification of the first terminal device.

[0034] In combination with the fourth optional implementation of the third aspect, in the fifth optional implementation of the third aspect, the identifier of the first terminal device included in the discovery message is C-RNTI, indicating that the state of the first terminal device is the RRC connected state; the identifier of the first terminal device included in the discovery message is a resume identifier or I-RNTI, indicating that the state of the first terminal device is an RRC inactive state; the discovery message does not include the identifier of the first terminal device, or the identifier of the first terminal device included is 5G-S-TMSI, indicating that the state of the first terminal device is an RRC idle state.

[0035] In combination with the third aspect or the first optional implementation of the third aspect, in a sixth optional implementation of the third aspect, the second message is a discovery message, and the discovery message indicates the status of the first terminal device through a resource pool used to send the discovery message.

[0036] In combination with the third aspect or the first optional implementation of the third aspect, in a seventh optional implementation of the third aspect, the second message is a system message, and the system message includes status information of the first terminal device.

[0037] Regarding the technical effects brought about by the third aspect or various optional implementations of the third aspect, reference may be made to the introduction to the technical effects of the first aspect or the corresponding implementations, and / or reference may be made to the introduction to the technical effects of the second aspect or the corresponding implementations.

[0038] In a fourth aspect, a communication device is provided. The communication device may be the first network device described in any one of the first to third aspects. The communication device has the functions of the first network device. The first network device is, for example, a base station, or a baseband device in a base station. In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). The transceiver unit can implement a sending function and a receiving function. When the transceiver unit implements the sending function, it can be called a sending unit, and when the transceiver unit implements the receiving function, it can be called a receiving unit. The sending unit and the receiving unit can be the same functional module, which is called a transceiver unit, and the functional module can implement a sending function and a receiving function; or, the sending unit and the receiving unit can be different functional modules, and the transceiver unit is a general term for these functional modules.

[0039] The receiving unit is used to receive first information from the second terminal device or the third network device, wherein the first information includes an identifier of the first terminal device, and the third network device is a network device where the second terminal device resides;

[0040] The sending unit is used to send the identifier of the first terminal device to the second network device, where the identifier of the first terminal device is used to determine whether the first terminal device is authorized to provide a relay service;

[0041] The receiving unit is further used to receive second information from the second network device, where the second information is used to indicate that the first terminal device is authorized to provide relay service, or indicates that the first terminal device is not authorized to provide relay service.

[0042] or:

[0043] The processing unit is configured to receive first information from a second terminal device or a third network device through the transceiver unit, wherein the first information includes an identifier of the first terminal device, and the third network device is a network device where the second terminal device resides;

[0044] The processing unit is used to send the identification of the first terminal device to the second network device through the transceiver unit, where the identification of the first terminal device is used to determine whether the first terminal device is authorized to provide a relay service;

[0045] The processing unit is further used to receive second information from the second network device through the transceiver unit, where the second information is used to indicate that the first terminal device is authorized to provide relay service, or indicates that the first terminal device is not authorized to provide relay service.

[0046] In another optional implementation, the communication device includes a storage unit and a processing unit, and the processing unit is used to couple with the storage unit and execute the program or instructions in the storage unit to enable the communication device to perform the function of the above-mentioned first network device.

[0047] In a fifth aspect, a communication device is provided. The communication device may be the second terminal device described in any one of the first to third aspects. The communication device has the functions of the second terminal device. In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). The implementation of the transceiver unit can refer to the introduction of the fourth aspect.

[0048] The processing module is used to measure the first terminal device and determine the state of the first terminal device, where the state of the first terminal device is an RRC connected state, an RRC inactive state, or an RRC idle state;

[0049] The transceiver unit is used to send third information to the third network device, where the third information includes the state information of the first terminal device, where the state information of the first terminal device is used to indicate the state of the first terminal device;

[0050] The transceiver unit is used to receive a first RRC message from the third network device, where the first RRC message includes first configuration information, and the first configuration information is used to configure the second terminal device to access the network through the first terminal device.

[0051] or:

[0052] The processing module is used to measure the first terminal device and determine the state of the first terminal device, where the state of the first terminal device is an RRC connected state, an RRC inactive state, or an RRC idle state;

[0053] The sending unit is used to send third information to the third network device, where the third information includes the state information of the first terminal device, and the state information of the first terminal device is used to indicate the state of the first terminal device;

[0054] The receiving unit is used to receive a first RRC message from the third network device, where the first RRC message includes first configuration information, and the first configuration information is used to configure the second terminal device to access the network through the first terminal device.

[0055] or:

[0056] The processing module is used to measure the first terminal device and determine the state of the first terminal device, where the state of the first terminal device is an RRC connected state, an RRC inactive state, or an RRC idle state;

[0057] The processing module is further used to send third information to a third network device through the transceiver unit, where the third information includes state information of the first terminal device, and the state information of the first terminal device is used to indicate a state of the first terminal device;

[0058] The processing module is further used to receive a first RRC message from the third network device through the transceiver unit, where the first RRC message includes first configuration information, and the first configuration information is used to configure the second terminal device to access the network through the first terminal device.

[0059] In another optional implementation, the communication device includes a storage unit and a processing unit, and the processing unit is used to couple with the storage unit and execute the program or instructions in the storage unit to enable the communication device to perform the functions of the above-mentioned second terminal device.

[0060] In a sixth aspect, a communication device is provided. The communication device may be the first terminal device described in any one of the first to third aspects. The communication device has the functions of the first terminal device. In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). The implementation of the transceiver unit can refer to the introduction of the fourth aspect.

[0061] The sending unit is used to send a second message, and the second message is used to indicate the state of the first terminal device, and the state of the first terminal device is RRC connected state, RRC inactive state, or RRC idle state.

[0062] or:

[0063] The processing unit is used to send a second message through the transceiver unit, where the second message is used to indicate the state of the first terminal device, and the state of the first terminal device is RRC connected state, RRC inactive state, or RRC idle state.

[0064] In another optional implementation, the communication device includes a storage unit and a processing unit, and the processing unit is used to couple with the storage unit and execute the program or instructions in the storage unit to enable the communication device to perform the functions of the above-mentioned first terminal device.

[0065] In a seventh aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium is used to store a computer program or instruction, and when the computer-readable storage medium is executed, the method executed by the terminal device or the network device in the above aspects is implemented.

[0066] According to an eighth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the methods described in the above aspects to be implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1A to Figure 1D Several scenario diagrams for path switching for remote terminal devices;

[0068] Figure 2 A flowchart for switching a remote terminal device from a direct link to an indirect link;

[0069] Figure 3 to Figure 17 Flowcharts of several communication methods provided in embodiments of the present application;

[0070] Fig.18 A schematic block diagram of a communication device provided in an embodiment of the present application;

[0071] Fig.19 A schematic block diagram of a terminal device provided in an embodiment of the present application;

[0072] Fig. 20 A schematic block diagram of a network device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0074] Below, some terms in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

[0075] In the embodiment of the present application, the terminal device is a device with wireless transceiver function, which can be a fixed device, a mobile device, a handheld device (such as a mobile phone), a wearable device, a vehicle-mounted device, or a wireless device built into the above device (for example, a communication module, a modem, or a chip system, etc.). The terminal device is used to connect people, objects, machines, etc., and can be widely used in various scenarios, such as but not limited to the following scenarios: cellular communication, device-to-device communication (device-to-device, D2D), vehicle to everything (vehicle to everything, V2X), machine-to-machine / machine-type communication (machine-to-machine / machine-type communications, M2M / MTC), Internet of Things (Internet of Things, IoT), virtual reality (virtual reality, VR), augmented reality (augmented reality, AR), industrial control (industrial control), self-driving, remote medical, smart grid (smart grid), smart furniture, smart office, smart wear, smart transportation, smart city (smart city), drones, robots and other scenarios of terminal devices. The terminal device may sometimes be referred to as user equipment (UE), terminal, access station, UE station, remote station, wireless communication device, or user device, etc. For the convenience of description, the terminal device is described by taking UE as an example in the embodiments of the present application. Among them, remote UE refers to UE that needs other UE to provide relay services to access the network; relay UE refers to UE that provides relay services for other UEs.

[0076] The network device in the embodiment of the present application includes, for example, an access network device and / or a core network device. The access network device is a device with a wireless transceiver function, which is used to communicate with the terminal device. The access network device includes but is not limited to the base station (BTS, Node B, eNodeB / eNB, or gNodeB / gNB) in the above-mentioned communication system, a transmission reception point (TRP), a base station of the subsequent evolution of the third generation partnership project (3GPP), an access node in the wireless fidelity (Wi-Fi) system, a wireless relay node, a wireless backhaul node, etc. The base station can be: a macro base station, a micro base station, a micro-micro base station, a small station, a relay station, etc. Multiple base stations can support the same access technology mentioned above, or they can support the networks of different access technologies mentioned above. The base station may include one or more co-station or non-co-station transmission reception points. The network device may also be a wireless controller, a centralized unit (CU), and / or a distributed unit (DU) in a cloud radio access network (CRAN) scenario. The network device can also be a server, a wearable device, or a vehicle-mounted device. For example, the network device in the vehicle to everything (V2X) technology can be a road side unit (RSU). The following describes the access network device taking the base station as an example. The base station can communicate with the terminal device, or it can communicate with the terminal device through a relay station. The terminal device can communicate with multiple base stations in different access technologies. The core network device is used to implement functions such as mobility management, data processing, session management, policy and billing. The names of the devices that implement the core network functions in systems with different access technologies may be different, and the embodiments of the present application do not limit this. Taking the 5G system as an example, the core network device includes: access and mobility management function (AMF), session management function (SMF), policy control function (PCF) or user plane function (UPF), etc.

[0077] In the embodiment of the present application, the communication device for realizing the function of the network device may be a network device, or may be a device capable of supporting the network device to realize the function, such as a chip system, which may be installed in the network device. In the technical solution provided in the embodiment of the present application, the technical solution provided in the embodiment of the present application is described by taking the device for realizing the function of the network device as an example that the network device is used as the device.

[0078] In the embodiments of the present application, the number of nouns, unless otherwise specified, means "singular noun or plural noun", that is, "one or more". "At least one" means one or more, and "plural" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. For example, A / B means: A or B. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0079] The ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the size, content, order, timing, priority or importance of multiple objects. For example, the first information and the second information can be the same information or different information, and this name does not indicate the difference in the sending order, information volume, content, priority or importance of the two information. In addition, the numbering of the steps in the various embodiments introduced in this application is only to distinguish different steps, and is not used to limit the order of precedence between the steps. For example, step S301 may occur before step S302, or may occur after S302, or may occur at the same time as S302.

[0080] Among the UE relay technologies currently proposed, there is a relay mode in which the remote UE can be visible to the RAN. In this relay mode, the remote UE can implement path switching.

[0081] The path switch process of the remote UE includes the process of switching from a direct link to an indirect link, the process of switching from an indirect link to a direct link, and the process of switching from an indirect link to an indirect link. Figure 1A to Figure 1D .in, Figure 1AA scenario in which a remote UE switches from a non-direct link to a direct link, or a scenario in which a remote UE switches from a direct link to a non-direct link. For example, the remote UE is a smart watch, and the smart watch can be installed with an embedded subscriber identity module (eSIM) card, and the smart watch can communicate directly with the access network device through the eSIM card. The user goes out for a run with a smart watch, but does not bring a mobile phone. When outdoors, the smart watch can communicate directly with the access network device through the Uu port. When the user returns home after running, the smart watch detects the presence of the mobile phone through the sidelink (SL), and the smart watch can automatically switch from a direct link with the access network device to a non-direct link relayed by the mobile phone, or the smart watch can also switch from a direct link with the access network device to a non-direct link relayed by the mobile phone based on the user's operation, so as to use the mobile phone as a relay UE and communicate with the network through the mobile phone to save the power consumption of the smart watch.

[0082] Figure 1B The scenario where the remote UE switches from a non-direct link to another non-direct link. For example, the remote UE is a smart watch, and the user wears the smart watch and a mobile phone. At the beginning, the mobile phone is the relay UE of the smart watch, providing relay services for the smart watch. When the user enters the vehicle, the smart watch can switch from the non-direct link relayed by the mobile phone to the non-direct link relayed by the vehicle, so as to use the vehicle as the new relay UE and communicate with the network through the vehicle, which saves the power consumption of both the smart watch and the mobile phone.

[0083] Figure 1C The scenario in which the remote UE switches from a non-direct link to a direct link, or the scenario in which the remote UE switches from a direct link to a non-direct link. For example, the remote UE is a smart watch. The user is outdoors, and since the smart watch is installed with an eSIM card, the smart watch can communicate directly with access network device A through the eSIM card. Then, the user gets into a vehicle, and the vehicle drives to another city. During the driving of the vehicle, the smart watch automatically (or, based on user operation) switches from a direct link that directly communicates with access network device A to a non-direct link that is relayed through the vehicle to save power consumption of the smart watch. Since the vehicle is in motion, the access network device B and access network device A connected to the vehicle may be different access network devices.

[0084] Figure 1DThe remote UE switches from a non-direct link to a non-direct link. For example, the remote UE is a smart watch. The user takes vehicle A to a certain place. After the user enters vehicle 1, the smart watch can establish a connection with vehicle 1 and use vehicle 1 as the relay UE of the smart watch to communicate with the network through vehicle 1. On the way, the user changed vehicles and entered vehicle 2. During the driving of vehicle 2, the communication quality between the smart watch and vehicle 1 will gradually deteriorate. The smart watch can automatically (or, based on the user's operation) switch from a non-direct link relayed through vehicle 1 to a non-direct link relayed through vehicle 2 to improve the communication quality of the smart watch. In addition, since vehicle 2 is in a driving state, vehicle 1 may also be in a driving state, so the access network device serving vehicle 1 and the access network device serving vehicle 2 may be different access network devices.

[0085] in, Figure 1A and Figure 1B The scenario shown is a handover scenario within a base station (intra-gNB). Figure 1C and Figure 1D The scenario shown is an inter-gNB handover scenario.

[0086] For the case of switching to a non-direct link (including switching from a direct link to a non-direct link, or from a non-direct link to a non-direct link), the mainstream solution currently under discussion is that the base station configures the remote UE to perform measurements, and the remote UE performs measurements based on discovery messages from other UEs. The remote UE sends the measurement results to the base station, and the base station decides whether the remote UE should perform a path switch. If the base station determines that the remote UE is to perform a path switch, the base station sends configuration information to the remote UE and the relay UE respectively for the configuration of the path switch. For example, the process of the remote UE switching from a direct link to a non-direct link can be referred to Figure 2 The process shown.

[0087] S201. A remote UE performs data transmission with a base station.

[0088] S202: The base station sends an RRC message to the remote UE, and the remote UE receives the RRC message from the base station. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0089] S203: The remote UE measures or selects other UEs. For example, the remote UE may trigger other UEs to send discovery messages, so that the remote UE may measure the discovery messages from other UEs to complete the measurement or selection of other UEs.

[0090] S204, the remote UE sends a measurement result to the base station, and the base station receives the measurement result from the remote UE; or, the remote UE sends a selection result to the base station, and the base station receives the selection result from the remote UE. Figure 2 In the example, sending the measurement results is taken.

[0091] The measurement result is, for example, a measurement report. The selection result is, for example, a selection result of the remote UE for the relay UE, including the ID information of the relay UE.

[0092] S205: The base station determines whether the remote UE performs path switch based on the measurement result or the selection result. If the base station determines that the remote UE performs path switch, S206 and S207 are executed; otherwise, S206 and S207 are not executed.

[0093] S206: The base station sends an RRC reconfiguration message to the remote UE, and the remote UE receives the RRC reconfiguration message from the base station. In order to distinguish it from other RRC reconfiguration messages, the RRC reconfiguration message in S206 is referred to as RRC reconfiguration message 1.

[0094] The RRC reconfiguration message 1 may include information configured by the base station for the remote UE, such as configuration information of the Uu port and configuration information of the sidelink (SL). After receiving the RRC reconfiguration message 1, the remote UE may perform configuration according to the information included in the RRC reconfiguration message 1, such as configuring the Uu link and the sidelink.

[0095] Optionally, the RRC reconfiguration message 1 may also include a path switch command for instructing the remote UE to perform a path switch. Alternatively, the RRC reconfiguration message 1 may also include an ID of a relay UE, where the relay UE is a relay UE determined by the base station for the remote UE, which is equivalent to the base station instructing the remote UE to switch to access the network through the relay UE.

[0096] S207: The base station sends an RRC reconfiguration message to the relay UE, and the relay UE receives the RRC reconfiguration message from the base station. In order to distinguish it from other RRC reconfiguration messages, the RRC reconfiguration message in S207 is referred to as RRC reconfiguration message 2.

[0097] The RRC reconfiguration message 2 may include information configured by the base station for the relay UE, such as configuration information of the Uu port and configuration information of the side link, where the side link is a link between the remote UE and the relay UE, and the relay UE provides relay services for the remote UE through the side link. After receiving the RRC reconfiguration message 2, the relay UE may perform configuration according to the information included in the RRC reconfiguration message 2, such as configuring the Uu link and the side link.

[0098] Among them, S206 may occur before S207, or S206 may occur after S207, or S206 and S207 may occur at the same time.

[0099] S208. Direct communication setup is performed between the remote UE and the relay UE.

[0100] S209: The remote UE sends an RRC reconfiguration complete message to the base station through the relay UE, and the base station receives the RRC reconfiguration complete message from the remote UE through the relay UE.

[0101] After the remote UE completes configuration according to the RRC reconfiguration message 1, the remote UE may send an RRC reconfiguration complete message to the base station to indicate that the remote UE has completed the path switching.

[0102] The current technology mainly considers that the relay UE is in the RRC connected state, so that the remote UE can switch from the direct link to the indirect link. However, before the remote UE switches to communicate with the network through the relay UE, the relay UE is likely to be in the RRC idle state or the RRC inactive state. Some UEs are authorized to provide relay services, while some UEs are not authorized to provide relay services. UEs that are not authorized to provide relay services cannot provide relay services. If the relay UE is in the RRC connected state, the base station can determine whether the relay UE is authorized to provide relay services based on the context of the relay UE. If it is determined that the relay UE is authorized to provide relay services, the base station allows the remote UE to switch to communicate with the network through the relay UE. However, if the relay UE is in the RRC idle state or the RRC inactive state, the base station cannot obtain the context of the relay UE, and cannot determine whether the relay UE is authorized to provide relay services. If the remote UE attempts to access the network through a UE that is not authorized to provide relay services, it will cause the remote UE to fail to access the network.

[0103] In view of this, a technical solution of an embodiment of the present application is provided. In an embodiment of the present application, even if the first terminal device is in an RRC non-connected state (e.g., an RRC idle state or an RRC inactive state), the first network device can determine whether the first terminal device is authorized to provide a relay service through a second network device, thereby allowing other terminal devices to access the network through the first terminal device when it is determined that the first terminal device is authorized to provide a relay service, thereby improving the success rate of other terminal devices accessing the network.

[0104] The technical solution provided in the embodiments of the present application can be applied to the fourth generation mobile communication technology (the 4th generation, 4G) system, such as the long term evolution (long term evolution, LTE) system, or can be applied to the 5G system, such as the new radio (new radio, NR) system, or can also be applied to the next generation mobile communication system or other similar communication systems, without specific limitation. In addition, the technical solution provided in the embodiments of the present application can be applied to device-to-device (D2D) scenarios, such as NR-D2D scenarios, etc., or can be applied to V2X scenarios, such as NR-V2X scenarios, etc., for example, it can be applied to the Internet of Vehicles, such as V2X, vehicle-to-vehicle (V2V), etc., or can be used in the fields of intelligent driving, assisted driving, or intelligent networked vehicles.

[0105] Several scenarios of path switch are introduced above. The application scenarios of the embodiments of the present application can mainly refer to the following: Figure 1A or Figure 1C . Figure 1A to Figure 1D The access network device in any of the figures is, for example, a base station. The access network device corresponds to different devices in different systems. For example, in a 4G system, it may correspond to an eNB, and in a 5G system, it may correspond to an access network device in 5G, such as a gNB. Of course, the technical solution provided in the embodiment of the present application can also be applied to future mobile communication systems, so Figure 1A to Figure 1D The access network device in any of the accompanying drawings may also correspond to the network device in a future mobile communication system. Figure 1A to Figure 1D The access network device is taken as a base station as an example. In fact, referring to the introduction in the previous article, the access network device can also be RSU and other devices.

[0106] The method provided by the embodiments of the present application is described below in conjunction with the accompanying drawings. In the accompanying drawings corresponding to the various embodiments of the present application, all steps indicated by dotted lines are optional steps.

[0107] The present application embodiment provides a first communication method, see Figure 3 , which is a flow chart of the method. The method involves a process of switching from a direct link to an indirect link. In the following description, the method is applied to Figure 1A The network architecture shown is taken as an example.

[0108] If the technical solution provided in the embodiment of the present application is applied to Figure 1A The network architecture shown in FIG. 1 , the second terminal device described below may be Figure 1A The remote terminal device shown in the figure, the first terminal device described below may be Figure 1A The relay terminal device in the following description may be Figure 1A The second network device described below is, for example, Figure 1A The core network device not shown, such as AMF or SMF or PCF in the 5G system. In addition, in the following, the second terminal device is described as a remote UE and the first terminal device is a relay UE.

[0109] S301, remote UE and first network device perform data transmission. For example, the third network device is a network device accessed by the remote UE, and the first network device is a network device where the relay UE resides. In the embodiment of the present application, the first network device and the third network device are the same network device.

[0110] S302: The first network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the first network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0111] Alternatively, the first network device may also send broadcast information to the remote UE, and accordingly, the remote UE receives the broadcast information from the first network device. The broadcast information is, for example, included in a system message, or included in other broadcast messages. The broadcast information may include relevant information for the remote UE to select the relay UE, for example, may include measurement configuration information for configuring the remote UE to perform measurements for selecting the relay UE.

[0112] S303: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Figure 3 Take the remote UE measuring one or more UEs as an example. Figure 3 The relay UE shown is, for example, one of the one or more UEs.

[0113] The remote UE may measure other UEs by measuring discovery messages from other UEs, or may measure other information from other UEs, such as data signals from other UEs, etc., which is not limited here. The remote UE may select other UEs based on the measurement results.

[0114] In addition, the remote UE can also obtain the status of other UEs. The status of a UE refers to whether the UE is in RRC connected state, RRC idle state or RRC inactive state. There are many ways for the remote UE to obtain the status of a UE. The following examples are given. In the following introduction, the remote UE obtains the status of the relay UE as an example. The relay UE is Figure 3 The relay UE shown in is a UE measured by the remote UE.

[0115] 1. The first method: the relay UE indicates the status of the relay UE through a discovery message.

[0116] The relay UE sends a discovery message by broadcasting, and the discovery message includes the state information of the relay UE (or called state indication information, etc., without limitation to the name), and the state information of the relay UE can indicate that the state of the relay UE is RRC connected state, RRC idle state or RRC inactive state. After receiving the discovery message from the relay UE, the remote UE can obtain the state information of the relay UE, or in other words, can determine the state of the relay UE.

[0117] For example, the state information of the relay UE is included in the message header of the discovery message, or in the message body of the discovery message. For example, an indication bit is added to the message header or message body of the discovery message, and the indication bit can carry the state information of the relay UE. The message header of the discovery message is, for example, a media access control (MAC) header.

[0118] Alternatively, the status information of the relay UE can also be obtained by using the layer 2 destination ID filled in by the relay UE when sending the discovery message.

[0119] (L2 destination ID) indication. For example, the L2 destination IDs of discovery messages sent by UEs in different states are different. For example, the L2 destination ID filled in by a UE in an RRC connected state is 0000 0000, the L2 destination ID filled in by a UE in an RRC idle state is 0000 0001, and the L2 destination ID filled in by a UE in an RRC inactive state is 0000 0011. Then the remote UE can determine the state of the UE that sent the discovery message through the L2 destination ID of the received discovery message.

[0120] 2. The second method: the relay UE indicates the state of the relay UE by including the identity of the relay UE in the discovery message.

[0121] The relay UE sends a discovery message by broadcasting, and the discovery message can indicate the state of the relay UE by including the identifier of the relay UE. Then, after the remote UE receives the discovery message from the relay UE, it can determine the state of the relay UE according to the identifier of the relay UE included in the discovery message. The identifier of the relay UE is, for example, the ID of the relay UE, and the ID of the UE is, for example, the UE's 5G serving-temporary mobile subscription identifier (5G-S-TMSI), cell radio network temporary identifier (cell-radio network temporary identifier, C-RNTI), 5G globally unique temporary UE identity (5Gglobally unique temporary UE identity, 5G-GUTI), L2 destination ID, resume ID or inactive radio network temporary identifier (inactive RNTI, I-RNTI) or truncated inactive radio network temporary identifier (short inactive RNTI, short-I-RNTI), etc. Among them, the resume ID includes some bits of the I-RNTI.

[0122] For example, if the relay UE is in RRC connected state, the discovery message may include the C-RNTI of the relay UE. If the relay UE is in RRC inactive state, the discovery message may include the resume ID, I-RNTI, or I-RNTI and 5G-S-TMSI of the relay UE. If the relay UE is in RRC idle state, the discovery message may not include the identity of the relay UE, or the discovery message may include the 5G-S-TMSI of the relay UE.

[0123] 3. The third method: the relay UE indicates the status of the relay UE by sending a resource pool of a discovery message.

[0124] UEs in different states use different resource pools when sending discovery messages. For example, the first resource pool is used by UEs in RRC non-connected state. If the relay UE is in RRC idle state or RRC inactive state, the relay UE can send a discovery message through the first resource pool. If the remote UE monitors the discovery message from the relay UE in the first resource pool, it can determine that the relay UE is in the RRC non-connected state.

[0125] The first resource pool is configured by the first network device through a broadcast message, for example, the broadcast message is a system message. Optionally, the broadcast message may also configure a second resource pool, and the second resource pool may be used by a UE in an RRC connected state. Alternatively, the second resource pool is used by a UE in an RRC connected state, and the first network device may configure the second resource pool for the UE in the RRC connected state through a unicast message, and the second resource pools configured for different UEs may be the same or different.

[0126] 4. The fourth method: the relay UE broadcasts the status of the relay UE through a system message.

[0127] For example, the relay UE sends a system message, which may include the status information of the relay UE. After receiving the system message from the relay UE, the remote UE can obtain the status information of the relay UE, or determine the status of the relay UE. The system message is, for example, a master information block (MIB). For example, an indication bit is added to the MIB, and the indication bit can carry the status information of the relay UE.

[0128] The remote UE may determine the state of the relay UE in one or more of the above methods, or the remote UE may determine the state of the relay UE in other methods except the above methods. As for which method the remote UE uses, it may be configured by the first network device or specified by a protocol.

[0129] In addition, the relay UE can also determine the status of the remote UE through any of the above methods, that is, the remote UE in the above method can be replaced by the relay UE, and the relay UE can be replaced by the remote UE. The relay UE can also obtain the status of the remote UE. After the remote UE and the relay UE obtain each other's status, it is conducive to subsequent reasonable processing. For example, the relay UE knows that the remote UE is in the RRC connected state, then the relay UE can immediately enter the RRC connected state to reduce the access delay of the remote UE. For another example, after the remote UE knows that the relay UE is in the RRC idle state or the RRC inactive state, it can choose not to select the relay UE to provide relay service. It should be noted that the scheme here can be applied to all remote UE and relay UE discovery processes, not just limited to the discovery process performed when the remote UE performs path switch. In other words, the scheme here can be used with Figure 3 The embodiments shown may be used in combination or may be used alone.

[0130] S304: The remote UE sends third information to the first network device, and correspondingly, the first network device receives the third information from the remote UE.

[0131] The third information may include, for example, a measurement result or a selection result. The measurement result may be, for example, a measurement report obtained by the remote UE measuring one or more UEs. The selection result may be, for example, a selection result of the remote UE for the relay UE, including the ID of the relay UE. The selection result may include the ID of one UE or may include the IDs of multiple UEs. The UE corresponding to the ID included in the selection result may be, for example, the UE selected by the remote UE based on the measurement report obtained by measuring one or more UEs. For example, Figure 3 The relay UE shown is one of the one or more UEs.

[0132] In addition, the third information may also indicate the status of one or more UEs, which are the UEs corresponding to the measurement result or the UEs corresponding to the selection result. The manner in which the remote UE determines the status of one or more UEs may refer to the introduction of S303. In an embodiment of the present application, the remote UE may inform the first network device of the status of the relay UE, so that the first network device can know the status of the relay UE. For example, in an embodiment of the present application, the relay UE is in an RRC idle state.

[0133] The third information indicates the state of a UE (e.g., a relay UE). For example, one indication method is that the third information includes the state information of the relay UE. Alternatively, if the third information includes a selection result, another indication method is that the third information may indicate the state of the relay UE through the ID of the relay UE. For example, if the ID of the relay UE included in the third information is the L2 destination ID of the relay UE, it indicates that the relay UE is in the RRC idle state; if the ID of the relay UE included in the third information is the I-RNTI or resume ID of the relay UE, it indicates that the relay UE is in the RRC inactive state; if the ID of the relay UE included in the third information is the C-RNTI of the relay UE, it implicitly indicates that the relay UE is in the RRC connected state.

[0134] Optionally, the third information may also include an identifier of a cell where one or more UEs are located, such as an ID of a cell. For example, if the serving cell of the remote UE is the same as the serving cell of one of the one or more UEs, the third information may not include the identifier of the cell to which the UE belongs; or, if the serving cell of the remote UE is different from the serving cell of one of the one or more UEs, the third information may include the identifier of the cell to which the UE belongs.

[0135] S305: The first network device sends first information to the second network device, and correspondingly, the second network device receives the first information from the first network device.

[0136] The first information is obtained by the first network device according to the third information, and the first information may include the identification of one or more UEs. The identification of a UE included in the first information is, for example, the ID of the UE, and the ID of the UE is, for example, 5G-S-TMSI or 5G globally unique temporary UE identity (5G globally unique temporary UE identity, 5G-GUTI). The one or more UEs are the UEs corresponding to the third information, Figure 3 The relay UE shown is one of the one or more UEs. For example, if the third information includes a measurement result, the first network device can obtain the identifier of the UE corresponding to the measurement result, and the first information can include one or more of these identifiers; if the third information includes a selection result, the first network device can include one or more of the UE IDs included in the selection result in the first information. If this is the case, it is also considered that the way in which the first network device obtains the first information is to receive the first information from the remote UE. In an embodiment of the present application, the first information can be understood as being used to request a determination as to whether the one or more UEs are authorized to provide relay services.

[0137] S306. The second network device sends the second information to the first network device, and correspondingly, the first network device receives the second information from the second network device. The second information may indicate whether the one or more UEs are authorized to provide relay services. Among the one or more UEs, some UEs may be authorized to provide relay services, while some UEs may not be authorized to provide relay services. Then, the second information may indicate the one or more UEs respectively.

[0138] For example, the second information is indication information, and the indication information can be used to indicate whether the one or more UEs are authorized to provide relay services. For example, the second information may include one or more sub-indication information, and the number of sub-indication information is the same as the number of UEs to be indicated, and one sub-indication information indicates whether a UE is authorized to provide relay services. For example, the second information includes sub-indication information for indicating a relay UE, and the sub-indication information can indicate that the relay UE is authorized to provide relay services, or indicate that the relay UE is not authorized to provide relay services.

[0139] For another example, the second information is not indication information, but includes the context of the one or more UEs. Whether a UE is authorized to provide a relay service, the authorization information is recorded in the context of the UE. Therefore, by obtaining the context of the UE, it is possible to determine whether the UE is authorized to provide a relay service. The second network device may also send the context of the one or more UEs to the first network device, so that the first network device can determine whether the one or more UEs are authorized to provide a relay service.

[0140] In an embodiment of the present application, if the relay UE requested by the remote UE is in an RRC non-connected state, the first network device may request the second network device to determine whether the relay UE is authorized to provide relay service, so that the first network device selects the remote UE as the target UE for path switching when it is determined that the relay UE is authorized to provide relay service, thereby reducing the situation where the remote UE switches to a UE that is not authorized to provide relay service, and improving the success rate of the remote UE accessing the network.

[0141] S307: The first network device selects a target UE for path switching for the remote UE. In other words, the first network device determines the UE to which the remote UE needs to switch.

[0142] If the second information indicates that a UE is authorized to provide relay service (for example, the second information only indicates the UE, or the second information indicates multiple UEs, but other UEs except the UE are not authorized to provide relay service), or the second information includes the context of a UE, and the context of the UE indicates that the UE is authorized to provide relay service (for example, the second information only includes the context of the UE, or the second information includes the context of multiple UEs, but the context of other UEs except the UE indicates that they are not authorized to provide relay service), the first network device can determine that the UE is the target UE for path switching as the remote UE.

[0143] Alternatively, if the second information indicates that multiple UEs are authorized to provide relay services, or the second information includes the contexts of multiple UEs, and the contexts of some or all of the multiple UEs indicate that they are authorized to provide relay services, then the first network device can determine a UE from the multiple UEs as the target UE for the remote UE to perform path switching.

[0144] If none of the UEs indicated by the second information is provided with relay service, or the contexts of the UEs included in the second information indicate that no relay service is provided, then the first network device cannot perform S307. In this case, the first network device may not perform S307 and subsequent steps, but may send a message to the remote UE, which may instruct the remote UE to continue measuring, or indicate that the relay UE selection fails, etc.

[0145] The target UE selected by the first network device is, for example, Figure 3 The relay UE shown may be in an RRC non-connected state.

[0146] S308: The first network device sends a first message to the remote UE, and correspondingly, the remote UE receives the first message from the first network device. The first message is, for example, an RRC message, so the first message may also be referred to as a first RRC message. For example, the first message is an RRC reconfiguration message.

[0147] The first message may include the first configuration information, and the first configuration information may configure the remote UE to access the network through the relay UE. For example, the first configuration information may also include the ID of the relay UE. For example, the first configuration information may include the configuration information of the second relay link, and the second relay link may include, for example, the side link between the remote UE and the relay UE, through which the remote UE is connected to the relay UE, thereby accessing the network through the relay UE. After receiving the first message, the remote UE may perform configuration according to the first configuration information. Optionally, the first configuration information may also include the configuration information of the side link of the relay UE, that is, the configuration information required for the relay UE and the remote UE to communicate on the PC5 interface. The remote UE may send the configuration information of the side link of the relay UE to the relay UE according to the first configuration information, for the relay UE to configure the PC5 side. Then the network device does not need to send the configuration information of the side link of the relay UE to the relay UE, which can save the air interface signaling overhead.

[0148] Optionally, the first message may further include first indication information, and the first indication information may indicate triggering the relay UE to enter the RRC connected state. The first network device knows that the relay UE is in the RRC non-connected state (for example, the relay UE is in the RRC idle state in the embodiment of the present application), and if the remote UE wants to access the network through the relay UE, the relay UE needs to enter the RRC connected state, so the first network device may instruct the remote UE to trigger the relay UE to enter the RRC connected state, so that the relay UE can provide the relay service normally.

[0149] S309: The remote UE establishes direct communication with the relay UE.

[0150] After completing configuration according to the first configuration information, the remote UE may establish direct communication with the relay UE.

[0151] Alternatively, the remote UE and the relay UE have established a direct communication connection before receiving the first configuration information, and reuse the existing direct communication connection. Step S309 may occur before step S304, and the sequence with step S308 is not limited.

[0152] S310: The relay UE establishes an RRC connection with the first network device.

[0153] For example, when the remote UE is in the process of establishing direct communication with the relay UE, the relay UE may be triggered to enter the RRC connected state. For example, if the remote UE wants to establish direct communication with the relay UE, the remote UE may first send a direct communication request (direction communication request, DCR) message to the relay UE, and the DCR message is used to request the establishment of a direct connection. After receiving the DCR message, the relay UE may send a security establishment request message to the remote UE, and the security establishment request message is used to request the remote UE to perform security verification related operations. After receiving the security establishment request message, the remote UE may perform corresponding security verification. If the security verification is successful, the remote UE may send a security establishment completion message to the relay UE to indicate that the security verification is completed. After receiving the security establishment completion message, the relay UE may send a direct communication establishment completion message (or, referred to as a DCR response message) to the remote UE to indicate that the direct communication between the remote UE and the relay UE is established. After the remote UE receives the direct communication establishment completion message, it can access the network through the relay UE. Of course, the direct communication establishment process between two UEs may also involve other corresponding messages, which are just examples. If this process is adopted, then optionally, the remote UE can trigger the relay UE to enter the RRC connection state through a DCR message or a security establishment completion message. For example, the remote UE can carry trigger information in the DCR message or the security establishment completion message, and the trigger information can be used to trigger the relay UE to enter the RRC connection state. For example, after the remote UE receives the DCR message or the security establishment completion response message, the relay UE can be triggered to enter the RRC connection state due to the receipt of the message.

[0154] Alternatively, after the relay UE establishes direct communication with the remote UE (or, establishes a PC5-signaling (S) connection), the remote UE triggers the relay UE to enter the RRC connected state through a PC5-RRC message. For example, the remote UE may carry trigger information in the PC5-RRC message, and the trigger information may be used to trigger the relay UE to enter the RRC connected state.

[0155] Alternatively, it may be the first RRC message sent by the remote UE to the relay UE to establish a connection with the first network device after the relay UE establishes a PC5-S connection with the remote UE, or it may be the first RRC message sent by the remote UE to the relay UE to inform the first network device that the connection is complete after the relay UE establishes a PC5-S connection with the remote UE. After the relay UE receives the RRC message, it can clearly indicate the need to enter the RRC connection state. The RRC message is, for example, sent by the remote UE through the first signaling radio bearer (SRB) between the remote UE and the relay UE. The first SRB may be, for example, SRB0 or ​​SRB1, or it may be other SRBs.

[0156] After the relay UE is triggered, it may initiate random access after establishing direct communication with the remote UE, or it may initiate random access without completing direct communication with the remote UE, so as to enter the RRC connected state.

[0157] The relay UE enters the RRC connection state after the random access is successful. After the random access is successful, the first network device can send configuration information to the relay UE, such as the second configuration information, and the second configuration information can configure the relay UE to provide relay service for the remote UE. The second configuration information, for example, includes configuration information of the second relay link, and the second relay link, for example, includes the air interface link between the relay UE and the first network device, and can also include the side link between the relay UE and the remote UE. It can be understood that the second configuration information includes the configuration information of the Uu port and the configuration information of the side link, and the side link is the link between the remote UE and the relay UE, and the relay UE provides relay service for the remote UE through the side link.

[0158] S311, the remote UE sends an RRC reconfiguration completion message to the relay UE, and correspondingly, the relay UE receives the RRC reconfiguration completion message from the remote UE; the relay UE sends the RRC reconfiguration completion message to the first network device, and correspondingly, the first network device receives the RRC reconfiguration completion message from the relay UE. That is, the remote UE sends the RRC reconfiguration completion message to the first network device through the relay UE. The RRC reconfiguration completion message can indicate that the remote UE has completed the path switching.

[0159] Through the above process, the remote UE completes the path switch, switching from communicating with the Uu port of the first network device to communicating with the first network device through the relay UE. In the embodiment of the present application, even if the relay UE is in the RRC idle state, the first network device can determine whether the relay UE is authorized to provide relay services through the core network device, so that the remote UE can be allowed to access the network through the relay UE if it is determined that the relay UE is authorized to provide relay services, thereby improving the success rate of the remote UE accessing the network.

[0160] exist Figure 3 In the embodiment shown, the network device accessed by the remote UE and the network device where the relay UE resides are the same network device. Next, a second communication method provided in the embodiment of the present application is introduced. This method involves a process of switching from a direct link to an indirect link. Please refer to Figure 4 , which is a flow chart of the method. In the method, the network device accessed by the remote UE and the network device where the relay UE resides are different network devices.

[0161] The technical solution provided in the embodiments of the present application can be applied to Figure 1C If the technical solution provided in the embodiment of the present application is applied to Figure 1C The network architecture shown in FIG. 1 , the second terminal device described below may be Figure 1C The remote terminal device shown in the figure, the first terminal device described below may be Figure 1C The relay terminal device in the following description may be Figure 1C The access network device 1 in the embodiment, the third network device described below may be Figure 1C The access network device 2 in the embodiment. The second network device described below is, for example, Figure 1C The core network device not shown, such as AMF or SMF or PCF in the 5G system. In addition, in the following, the second terminal device is described as a remote UE and the first terminal device is a relay UE.

[0162] S401, the remote UE performs data transmission with a third network device. For example, the third network device is a network device accessed by the remote UE, and the first network device is a network device where the relay UE resides. In the embodiment of the present application, the first network device and the third network device are different network devices.

[0163] S402: The third network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the third network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0164] For more information about S402, please refer to Figure 3 S302 in the illustrated embodiment.

[0165] S403: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Figure 4 Take the remote UE measuring one or more UEs as an example. Figure 4 The relay UE shown is, for example, one of the one or more UEs.

[0166] For more information about S403, please refer to Figure 3 S303 in the illustrated embodiment.

[0167] S404: The remote UE sends third information to the third network device, and correspondingly, the third network device receives the third information from the remote UE.

[0168] For more information about S404, please refer to Figure 3 S304 in the illustrated embodiment.

[0169] S405: The third network device sends the first information to the second network device, and correspondingly, the second network device receives the first information from the third network device.

[0170] The first information is obtained by the first network device according to the third information, and the first information may include the identification of one or more UEs. The third network device may request the second network device to determine whether the one or more UEs involved in the third information are authorized to provide relay services. For more information about S405, please refer to Figure 3 S305 in the illustrated embodiment.

[0171] S406: The second network device sends second information to the third network device, and correspondingly, the third network device receives the second information from the second network device. The second information may indicate whether the one or more UEs are authorized to provide relay services.

[0172] For more information about S406, please refer to Figure 3S306 in the illustrated embodiment.

[0173] S407: The third network device sends a handover request message to the first network device, and accordingly, the first network device receives the handover request message from the third network device. The handover request message may be used to request to handover the remote UE to the first network device, and in fact, the remote UE is handed over to the relay UE under the first network device.

[0174] S408: The first network device sends a handover acknowledgement message to the third network device, and correspondingly, the third network device receives the handover acknowledgement message from the first network device. The handover acknowledgement message may be used to confirm handover of the remote UE to the first network device.

[0175] Optionally, the switching confirmation message may also include configuration information, such as first configuration information, which may configure the remote UE to access the network through the relay UE. For example, the first configuration information may include configuration information of the second relay link. The second relay link may include a side link between the remote UE and the relay UE, and the remote UE is connected to the relay UE through the side link, thereby accessing the network through the relay UE.

[0176] S409, the third network device sends the information of the relay UE to the first network device, and correspondingly, the third network device receives the information of the relay UE from the third network device. For example, the third network device may send a handover request message to the first network device, and carry the information of the relay UE in the handover request message. The handover request message may be used to request to handover the remote UE to the first network device, or to request to handover the remote UE to the relay UE under the first network device.

[0177] In the method described in S405, the third network device requests the second network device to determine whether one or more UEs involved in the third information are authorized to provide relay services, while in S409, another method is adopted, in which the third network device can determine the network devices where one or more UEs involved in the third information reside, and send the information of one or more UEs to the network devices where these UEs reside, so that the network devices where these UEs reside determine whether the corresponding UEs are authorized to provide relay services. If the network devices where the one or more UEs reside are the same network device, the third network device can send the third information to the network device, and if the network devices where the one or more UEs reside are different network devices, the third network device needs to send the information of one or more UEs to the network devices where they reside respectively.

[0178] For example, if the relay UE resides on the first network device, the third network device may send the information of the relay UE to the first network device. The information of the relay UE may include, for example, an identifier of the relay UE or a measurement result of the relay UE.

[0179] S410: The first network device sends first information to the second network device, and correspondingly, the second network device receives the first information from the third network device.

[0180] The first information is obtained by the first network device according to the information from the third network device. For example, if the first network device receives the identifier of the relay UE from the first network device, the first information may include the identifier of the relay UE. The identifier of the relay UE is, for example, the 5G-S-TMSI or 5G-GUTI of the relay UE.

[0181] S411. The second network device sends second information to the first network device, and correspondingly, the first network device receives the second information from the second network device.

[0182] In this case, the second information may indicate that the relay UE is authorized to provide the relay service, or indicate that the relay UE is not authorized to provide the relay service. For example, the second information includes indication information for indicating whether the relay UE is provided with the authorized service, or the second information includes the context of the relay UE, and the context of the relay UE indicates whether the relay UE is provided with the authorized service.

[0183] S412. The first network device sends the fourth information to the third network device, and correspondingly, the third network device receives the fourth information from the first network device. For example, the first network device sends a handover confirmation message to the third network device, and carries the fourth information in the handover confirmation message. The handover confirmation message can be used to confirm that the remote UE is switched to the first network device, or to confirm that the remote UE is switched to the relay UE under the first network device.

[0184] For example, if the third network device selects the destination UE for path switching for the remote UE, the fourth information and the second information may be the same information, and the fourth information may indicate that the relay UE is authorized to provide relay services, or indicate that the relay UE is not authorized to provide relay services. For another example, if the first network device selects the destination UE for path switching for the remote UE, the fourth information and the second information may be different information, and the fourth information may be obtained based on the second information, for example, the fourth information may indicate that the relay UE is the destination UE, or indicate that the relay UE cannot be the destination UE.

[0185] Optionally, the switching confirmation message may also include configuration information, such as first configuration information, which may configure the remote UE to access the network through the relay UE. For example, the first configuration information may include configuration information of the second relay link. The second relay link may include a side link between the remote UE and the relay UE, and the remote UE is connected to the relay UE through the side link, thereby accessing the network through the relay UE.

[0186] Among them, S405-S408 and S409-S412 are two optional solutions, and only one of them needs to be executed. That is, whether the relay UE is authorized to provide relay service can be confirmed by the third network device accessed by the remote UE or by the first network device where the relay UE resides.

[0187] S413: The first network device or the third network device selects a target UE for path switching for the remote UE, or in other words, the first network device or the third network device determines the UE to which the remote UE needs to switch. Figure 4 In the example, the third network device selects the target UE for path switching for the remote UE.

[0188] If S405 to S408 are executed, S413 may be executed by the third network device, that is, the third network device selects a target UE for path switching for the remote UE. For more information about S413, please refer to Figure 3S307 in the illustrated embodiment.

[0189] If S409 to S412 are executed, S413 may be executed by the third network device, that is, the third network device selects the target UE for path switching for the remote UE, or S413 may be executed by the first network device, that is, the first network device selects the target UE for path switching for the remote UE. For example, if the UE involved in the third information in S404 resides in different network devices, that is, for the UE involved in the third information, the first network devices where they reside are different, then different first network devices will send the fourth information to the third network device. In this case, it is more reasonable for the third network device to select the target UE for path switching for the remote UE. If the UE involved in the third information in S404 resides in the same network device, that is, for the UE involved in the third information, the first network device where they reside is the same device, in this case, it is possible for the third network device or the first network device to select the target UE for path switching for the remote UE.

[0190] S414: The third network device sends a first message to the remote UE, and accordingly, the remote UE receives the first message from the third network device. The first message is, for example, an RRC message, so the first message may also be referred to as a first RRC message. For example, the first message is an RRC reconfiguration message.

[0191] The first message may include the first configuration information. As described above, the first configuration information may be transparently transmitted by the first network device, or configured by the first network device. The first configuration information may configure the remote UE to access the network through the relay UE. The first configuration information may also include the ID of the relay UE. For example, the first configuration information may include the configuration information of the second relay link. Optionally, the first configuration information may also include the ID of the remote UE after switching to the relay UE, for example, the ID is the C-RNTI used by the remote UE after switching to the relay UE. After receiving the first message, the remote UE may perform configuration according to the first configuration information. Optionally, the first configuration information may also include the configuration information of the side link of the relay UE, that is, the configuration information required for the relay UE to communicate with the remote UE on the PC5 interface. The remote UE may send the configuration information of the side link of the relay UE to the relay UE based on the first configuration information, for the relay UE to configure the PC5 side. Then the network device does not need to send the configuration information of the side link of the relay UE to the relay UE, which can save the air interface signaling overhead.

[0192] Optionally, the first message may further include first indication information, and the first indication information may indicate triggering the relay UE to enter the RRC connected state. The first network device knows that the relay UE is in the RRC non-connected state (for example, the relay UE is in the RRC idle state in the embodiment of the present application), and if the remote UE wants to access the network through the relay UE, the relay UE needs to enter the RRC connected state, so the first network device may instruct the remote UE to trigger the relay UE to enter the RRC connected state, so that the relay UE can provide the relay service normally.

[0193] S415: The remote UE establishes direct communication with the relay UE.

[0194] After completing configuration according to the first configuration information, the remote UE may establish direct communication with the relay UE.

[0195] Alternatively, the remote UE and the relay UE have established a direct communication connection before receiving the first configuration information, and reuse the existing direct communication connection. Step S415 may occur before step S404, and the order of step S414 is not limited.

[0196] S416: The relay UE establishes an RRC connection with the first network device.

[0197] For more information about S416, please refer to Figure 3 S310 in the illustrated embodiment.

[0198] S417, the remote UE sends an RRC reconfiguration completion message to the relay UE, and correspondingly, the relay UE receives the RRC reconfiguration completion message from the remote UE; the relay UE sends the RRC reconfiguration completion message to the first network device, and correspondingly, the first network device receives the RRC reconfiguration completion message from the relay UE. That is, the remote UE sends the RRC reconfiguration completion message to the first network device through the relay UE. The RRC reconfiguration completion message can indicate that the remote UE has completed the path switching.

[0199] Through the above process, the remote UE completes the path switch, switching from communicating with the Uu port of the first network device to communicating with the first network device through the relay UE. In the embodiment of the present application, even if the relay UE is in the RRC non-connected state, the first network device can determine whether the relay UE is authorized to provide relay services through the second network device, so that the remote UE can be allowed to access the network through the relay UE when it is determined that the relay UE is authorized to provide relay services, thereby improving the success rate of the remote UE accessing the network. Moreover, whether the relay UE is authorized to provide relay services can be determined by the third network device accessed by the remote UE, or by the first network device where the relay UE resides, which is more flexible.

[0200] exist Figure 3 or Figure 4 In the embodiments shown, the relay UE is in the RRC idle state as an example. The third communication method provided by the embodiment of the present application is introduced below. In this method, the relay UE is in the RRC inactive state as an example. This method involves the process of switching from a direct link to a non-direct link. Please refer to Figure 5 , which is a flow chart of the method.

[0201] The technical solution provided in the embodiments of the present application can be applied to Figure 1A The network architecture shown in the figure. Figure 1A For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 3 The difference is that, Figure 3 The second network device in the illustrated embodiment is a core network device, while the second network device described in the embodiment of the present application is an anchor network device of the relay UE.

[0202] S501, remote UE and first network device perform data transmission. For example, the third network device is a network device accessed by the remote UE, and the first network device is a network device where the relay UE resides. In the embodiment of the present application, the first network device and the third network device are the same network device.

[0203] S502: The first network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the first network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0204] For more information about S502, please refer to Figure 3 S302 in the illustrated embodiment.

[0205] S503: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Figure 5 Take the remote UE measuring one or more UEs as an example. Figure 5 The relay UE shown is, for example, one of the one or more UEs.

[0206] For more information about S503, please refer to Figure 3 S303 in the illustrated embodiment.

[0207] S504: The remote UE sends third information to the first network device, and correspondingly, the first network device receives the third information from the remote UE.

[0208] For more information about S504, please refer to Figure 3 S304 in the illustrated embodiment.

[0209] S505: The first network device sends first information to the second network device, and correspondingly, the second network device receives the first information from the first network device.

[0210] For example, if one or more UEs involved in the third information are in an RRC inactive state, the first network device can determine the anchor network devices of these UEs based on the one or more I-RNTIs or resume IDs, and then send the first information to the corresponding anchor network devices. For example, if the relay UE is one of the one or more UEs, and the first network device determines that the second network device is the anchor network device of the relay UE based on the I-RNTI or resume ID of the relayUE, the first network device sends the first information to the second network device.

[0211] In an embodiment of the present application, the first information is obtained by the first network device according to the third information, and the first information may include the identifier of one or more UEs. The first information may be used to request the context of the relay UE, or to request confirmation of whether the relay UE is authorized to provide relay services. The context saved by the relay UE in the RRC inactive state and the context saved by the anchor network device of the relay UE may include authorization information on whether the relay UE can provide relay services. For more information about S505, such as the content included in the first information, etc., please refer to Figure 3 S305 in the illustrated embodiment. Of course, if the anchor network devices of the one or more UEs are different, the first network device will send the first information to different anchor network devices, and the first information sent by the first network device to different anchor network devices may be different. For example, the first information sent to an anchor network device may include the identifier of the UE of the anchor network device, and the first information sent to the second network device may include the identifier of the relay UE.

[0212] S506: The second network device sends second information to the first network device, and correspondingly, the first network device receives the second information from the second network device.

[0213] If among the UEs involved in the third information, only the anchor network device of the relay UE is the second network device, the first network device may include the identifier of the relay UE in the first information and send it to the second network device. In this case, the second information may indicate whether the relay UE is authorized to provide relay service. Alternatively, if among the UEs involved in the third information, the anchor network devices of at least two UEs are both second network devices, the first network device may carry the identifiers of at least two UEs in the first information and send it to the second network device. In this case, the second information may indicate whether at least two UEs are authorized to provide relay service, and the at least two UEs include the relay UE. Among the at least two UEs, some UEs may be authorized to provide relay service, while some UEs may not be authorized to provide relay service, so the second information may indicate the at least two UEs separately.

[0214] For more information about S506, such as the content of the second information, please refer to Figure 3 S306 in the embodiment shown. It should be noted that if the second network device sends the context of the relay UE to the first network device, the second network device can also trigger the core network device (such as AMF) to perform path switching, where the path switching means that the core network device switches the path for sending data to the relay UE from the second network device to the first network device. After the core network device performs path switching, if the core network device has downlink data that needs to be sent to the relay UE, the core network device will no longer send it to the second network device, but will send it to the first network device.

[0215] S507: The first network device selects a target UE for path switching for the remote UE. In other words, the first network device determines the UE to which the remote UE needs to switch.

[0216] If the anchor network devices of one or more UEs involved in the third information are different, the first network device can receive the second information from different second network devices, and the first network device can select the target UE for path switching for the remoteUE based on the second information. Alternatively, if the anchor network devices of one or more UEs involved in the third information are the same device, the first network device can receive the second information from the second network device, and the first network device can select the target UE for path switching for the remote UE based on the second information. In summary, the first network device can select the target UE for path switching for the remote UE based on one or more second information.

[0217] If one or more second information indicates that a UE is authorized to provide relay service (for example, one second information indicates that the UE is authorized to provide relay service, and the UEs indicated by other second information are not authorized to provide relay service), or one or more second information includes the context of the UE, and only one of the contexts of these UEs indicates that the UE is authorized to provide relay service, while the contexts of other UEs indicate that they are not authorized to provide relay service, then the first network device can determine that the UE is the target UE for path switching as a remote UE.

[0218] Alternatively, if one or more second information indicates that multiple UEs are authorized to provide relay services, or, in the context of the UE included in the one or more second information, the context of multiple UEs indicates that they are authorized to provide relay services, then the first network device can determine a UE from the multiple UEs as the target UE for the remote UE to perform path switching.

[0219] If none of the UEs indicated by the one or more second information is provided with relay service, or the contexts of the UEs included in the one or more second information indicate that no relay service is provided, then the first network device cannot perform S507. In this case, the first network device may not perform S507 and subsequent steps, but may send a message to the remote UE, which may instruct the remote UE to continue measuring, or indicate that the relay UE selection fails, etc.

[0220] The target UE selected by the first network device is, for example, Figure 5 The relay UE shown may be in an RRC non-connected state.

[0221] S508: The first network device sends a first message to the remote UE, and correspondingly, the remote UE receives the first message from the first network device. The first message is, for example, an RRC message, so the first message may also be referred to as a first RRC message. For example, the first message is an RRC reconfiguration message.

[0222] For more information about S508, please refer to Figure 3 S308 in the illustrated embodiment.

[0223] S509: The remote UE establishes direct communication with the relay UE.

[0224] After completing configuration according to the first configuration information, the remote UE may establish direct communication with the relay UE.

[0225] Alternatively, the remote UE and the relay UE have established a direct communication connection before receiving the first configuration information, and reuse the existing direct communication connection. Step S509 may occur before step S504, and the sequence with step S508 is not limited.

[0226] S510: The relay UE establishes an RRC connection with the first network device.

[0227] It should be noted that if the second information includes the context of the relay UE, then during the execution of S510, the first network device no longer needs to request the second network device to obtain the context of the relay UE; and if the second information does not include the context of the relay UE, but includes indication information for indicating whether the relay UE is authorized to provide relay service, then during the execution of S510, the first network device can request the second network device to obtain the context of the relay UE.

[0228] For more information about S510, please refer to Figure 3 S310 in the illustrated embodiment.

[0229] S511, the remote UE sends an RRC reconfiguration completion message to the relay UE, and correspondingly, the relay UE receives the RRC reconfiguration completion message from the remote UE; the relay UE sends the RRC reconfiguration completion message to the first network device, and correspondingly, the first network device receives the RRC reconfiguration completion message from the relay UE. That is, the remote UE sends the RRC reconfiguration completion message to the first network device through the relay UE. The RRC reconfiguration completion message can indicate that the remote UE has completed the path switching.

[0230] Through the above process, the remote UE completes the path switch, switching from communicating with the Uu port of the first network device to communicating with the first network device through the relay UE. In the embodiment of the present application, even if the relay UE is in an RRC inactive state, the first network device can determine whether the relay UE is authorized to provide relay services through the anchor network device of the relay UE, so that the remote UE can be allowed to access the network through the relay UE if it is determined that the relay UE is authorized to provide relay services, thereby improving the success rate of the remote UE accessing the network.

[0231] exist Figure 5 In the embodiment shown, the network device accessed by the remote UE and the network device where the relay UE resides are the same network device. Next, a fourth communication method provided in the embodiment of the present application is introduced. This method involves a process of switching from a direct link to an indirect link. Please refer to Figure 6 , which is a flow chart of the method. In the method, the network device accessed by the remote UE and the network device where the relay UE resides are different network devices.

[0232] The technical solution provided in the embodiments of the present application can be applied to Figure 1C The network architecture shown in the figure. Figure 1C For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 4 The difference is that, Figure 4 The second network device in the illustrated embodiment is a core network device, while the second network device described in the embodiment of the present application is an anchor network device of the relay UE.

[0233] S601: The remote UE performs data transmission with a third network device. For example, the third network device is a network device accessed by the remote UE, and the third network device is a network device where the relay UE resides. In the embodiment of the present application, the first network device and the third network device are different network devices.

[0234] S602: The third network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the third network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0235] For more information about S602, please refer to Figure 3 S302 in the illustrated embodiment.

[0236] S603: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Figure 6 Take the remote UE measuring one or more UEs as an example. Figure 6 The relay UE shown is, for example, one of the one or more UEs.

[0237] For more information about S603, please refer to Figure 3 S303 in the illustrated embodiment.

[0238] S604: The remote UE sends third information to the third network device, and correspondingly, the third network device receives the third information from the remote UE.

[0239] For more information about S604, please refer to Figure 3 S304 in the illustrated embodiment.

[0240] S605: The third network device sends the first information to the second network device, and correspondingly, the second network device receives the first information from the third network device.

[0241] The first information is obtained by the first network device according to the third information, and the first information may include the identification of one or more UEs. The third network device may request the second network device to determine whether the one or more UEs involved in the third information are authorized to provide relay services. For more information about S605, please refer to Figure 5 S505 in the illustrated embodiment.

[0242] S606: The second network device sends second information to the third network device, and correspondingly, the third network device receives the second information from the second network device.

[0243] For more information about S606, please refer to Figure 5 S506 in the illustrated embodiment.

[0244] S607: The third network device sends a handover request message to the first network device, and correspondingly, the first network device receives the handover request message from the third network device. The handover request message can be used to request to handover the remote UE to the first network device, which actually means handing over the remote UE to the relay UE under the first network device.

[0245] S608: The first network device sends a handover confirmation message to the third network device, and correspondingly, the third network device receives the handover confirmation message from the first network device. The handover confirmation message may be used to confirm handover of the remote UE to the first network device.

[0246] Optionally, the switching confirmation message may also include configuration information, such as first configuration information, which may configure the remote UE to access the network through the relay UE. For example, the first configuration information may include configuration information of the second relay link. The second relay link may include a side link between the remote UE and the relay UE, and the remote UE is connected to the relay UE through the side link, thereby accessing the network through the relay UE.

[0247] S609, the third network device sends the information of the relay UE to the first network device, and correspondingly, the third network device receives the information of the relay UE from the third network device. For example, the third network device may send a handover request message to the first network device, and carry the information of the relay UE in the handover request message. The handover request message may be used to request to handover the remote UE to the first network device, or to request to handover the remote UE to the relay UE under the first network device.

[0248] In the method described in S605, the third network device requests the second network device to determine whether one or more UEs involved in the third information are authorized to provide relay services, while in S609, another method is adopted, in which the third network device can determine the network device where one or more UEs involved in the third information reside, and send the information of one or more UEs to the network device where these UEs reside, so that the network device where these UEs reside determines whether the corresponding UE is authorized to provide relay services. If the network device where the one or more UEs reside is the same network device, the third network device can send the third information to the network device, and if the network devices where the one or more UEs reside are different network devices, the third network device needs to send the information of one or more UEs to the network devices where they reside.

[0249] For example, if the relay UE resides on the first network device, the third network device can send the information of the relay UE to the first network device. The information of the relay UE includes, for example, the identifier of the relay UE, such as the I-RNTI or resume ID of the relay UE, so that the first network device can determine the anchor network device of the relay UE.

[0250] S610: The first network device sends first information to the second network device, and correspondingly, the second network device receives the first information from the third network device.

[0251] The first information is obtained by the first network device according to the information from the third network device. For example, if the first network device receives the identifier of the relay UE from the first network device, the first information may include the identifier of the relay UE, and the identifier of the relay UE is, for example, the 5G-S-TMSI or 5G-GUTI of the relay UE. For example, if the relay UE is in an RRC inactive state, and the first network device determines that the second network device is the anchor network device of the relay UE according to the I-RNTI or resume ID of the relay UE, the first network device sends the first information to the second network device.

[0252] S611. The second network device sends second information to the first network device. Correspondingly, the first network device receives the second information from the second network device.

[0253] In this case, the second information may indicate that the relay UE is authorized to provide the relay service, or indicate that the relay UE is not authorized to provide the relay service. For example, the second information includes indication information for indicating whether the relay UE is provided with the authorized service, or the second information includes the context of the relay UE, and the context of the relay UE indicates whether the relay UE is provided with the authorized service.

[0254] It should be noted that if the second network device sends the context of the relay UE to the first network device, the second network device can also trigger the core network device (such as AMF) to perform path switching. Path switching here means that the core network device switches the path for sending data to the relay UE from the second network device to the first network device. After the core network device performs path switching, if the core network device has downlink data that needs to be sent to the relay UE, the core network device will no longer send it to the second network device, but will send it to the first network device.

[0255] S612. The first network device sends the fourth information to the third network device, and correspondingly, the third network device receives the fourth information from the first network device. For example, the first network device sends a handover confirmation message to the third network device, and carries the fourth information in the handover confirmation message. The handover confirmation message can be used to confirm that the remote UE is switched to the first network device, or to confirm that the remote UE is switched to the relay UE under the first network device.

[0256] For example, if the third network device selects the destination UE for path switching for the remote UE, the fourth information and the second information may be the same information, and the fourth information may indicate that the relay UE is authorized to provide relay services, or indicate that the relay UE is not authorized to provide relay services. For another example, if the first network device selects the destination UE for path switching for the remote UE, the fourth information and the second information may be different information, and the fourth information may be obtained based on the second information, for example, the fourth information may indicate that the relay UE is the destination UE, or indicate that the relay UE cannot be the destination UE.

[0257] Optionally, the switching confirmation message may also include configuration information, such as first configuration information, which may configure the remote UE to access the network through the relay UE. For example, the first configuration information may include configuration information of the second relay link. The second relay link may include a side link between the remote UE and the relay UE, and the remote UE is connected to the relay UE through the side link, thereby accessing the network through the relay UE.

[0258] Among them, S605-S608 and S609-S612 are two optional solutions, and only one of them needs to be executed. That is, whether the relay UE is authorized to provide relay service can be confirmed by the third network device accessed by the remote UE or by the first network device where the relay UE resides.

[0259] S613: The first network device or the third network device selects a target UE for path switching for the remote UE, or in other words, the first network device or the third network device determines the UE to which the remote UE needs to switch. Figure 6 Take the example of the first network device selecting a target UE for path switching for the remote UE.

[0260] If S605 to S608 are executed, S613 may be executed by the third network device, that is, the third network device selects a target UE for path switching for the remote UE. For more information about S613, please refer to Figure 3 S307 in the illustrated embodiment.

[0261] If S609 to S612 are executed, S613 may be executed by the third network device, that is, the third network device selects the target UE for path switching for the remote UE, or S613 may be executed by the first network device, that is, the first network device selects the target UE for path switching for the remote UE. For example, if the UE involved in the third information in S604 resides in different network devices, that is, for the UE involved in the third information, the first network devices where they reside are different, then different first network devices will send the fourth information to the third network device. In this case, it is more reasonable for the third network device to select the target UE for path switching for the remote UE. If the UE involved in the third information in S604 resides in the same network device, that is, for the UE involved in the third information, the first network device where they reside is the same device, in this case, it is possible for the third network device or the first network device to select the target UE for path switching for the remote UE.

[0262] S614: The third network device sends a first message to the remote UE, and correspondingly, the remote UE receives the first message from the first network device. The first message is, for example, an RRC message, so the first message may also be referred to as a first RRC message. For example, the first message is an RRC reconfiguration message.

[0263] For the content of the first message, please refer to Figure 4 S414 in the embodiment shown.

[0264] S615: The remote UE establishes direct communication with the relay UE.

[0265] After completing configuration according to the first configuration information, the remote UE may establish direct communication with the relay UE.

[0266] Alternatively, the remote UE and the relay UE have established a direct communication connection before receiving the first configuration information, and reuse the existing direct communication connection. Step S615 may occur before step S604, and the order of step S614 is not limited.

[0267] S616: The relay UE establishes an RRC connection with the first network device.

[0268] For more information about S616, please refer to Figure 3 S310 in the illustrated embodiment.

[0269] S617, the remote UE sends an RRC reconfiguration completion message to the relay UE, and correspondingly, the relay UE receives the RRC reconfiguration completion message from the remote UE; the relay UE sends the RRC reconfiguration completion message to the first network device, and correspondingly, the first network device receives the RRC reconfiguration completion message from the relay UE. That is, the remote UE sends the RRC reconfiguration completion message to the first network device through the relay UE. The RRC reconfiguration completion message can indicate that the remote UE has completed the path switching.

[0270] Through the above process, the remote UE completes the path switch, switching from communicating with the Uu port of the first network device to communicating with the first network device through the relay UE. In the embodiment of the present application, even if the relay UE is in the RRC non-connected state, the first network device can determine whether the relay UE is authorized to provide relay services through the anchor network device of the relay UE, so that the remote UE can be allowed to access the network through the relay UE when it is determined that the relay UE is authorized to provide relay services, thereby improving the success rate of the remote UE accessing the network. Moreover, whether the relay UE is authorized to provide relay services can be determined by the third network device accessed by the remote UE, or by the first network device where the relay UE resides, which is more flexible.

[0271] In the previous embodiment, it is introduced that the remote UE can trigger the relay UE to enter the RRC connected state. Next, the fifth communication method provided in the embodiment of the present application is introduced, through which it is introduced how the remote UE triggers the relay UE to enter the RRC connected state. This method involves the process of switching from a direct link to a non-direct link. Please refer to Figure 7 , which is a flow chart of the method.

[0272] The technical solution provided in the embodiments of the present application can be applied to Figure 1A The network architecture shown in the figure. Figure 1A For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 3 Description of the illustrated embodiment.

[0273] S701, remote UE and first network device perform data transmission. For example, the third network device is a network device accessed by the remote UE, and the first network device is a network device where the relay UE resides. However, the embodiment of the present application takes the first network device and the third network device as the same network device as an example.

[0274] S702: The first network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the first network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0275] For more information about S702, please refer to Figure 3 S302 in the illustrated embodiment.

[0276] S703: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Figure 7 Take the remote UE measuring one or more UEs as an example. Figure 7 The relay UE shown is, for example, one of the one or more UEs.

[0277] For more information about S703, please refer to Figure 3 S303 in the illustrated embodiment.

[0278] S704: The remote UE sends third information to the first network device, and correspondingly, the first network device receives the third information from the remote UE.

[0279] For more information about S704, please refer to Figure 3 S304 in the illustrated embodiment.

[0280] S705: The first network device sends a first message to the remote UE, and correspondingly, the remote UE receives the first message from the first network device. The first message is, for example, an RRC message, so the first message may also be referred to as a first RRC message. For example, the first message is an RRC reconfiguration message.

[0281] The first message may include first indication information, and the first indication information may be used to indicate that some or all UEs involved in the triggering third information enter the RRC connected state, for example Figure 7 The relay UE shown is one of the UEs triggered by the first indication information.

[0282] That is, after obtaining the third information, the first network device can instruct the remote UE to trigger the UE that may provide the relay service for the remote UE to enter the RRC connected state. If this method is adopted, the first network device can obtain the context of these UEs according to the normal process after these UEs enter the RRC connected state to determine whether these UEs are authorized to provide relay services, without the need to additionally confirm whether these UEs are authorized to provide relay services because these UEs are in the RRC non-connected state, so that the process executed by the first network device is more compatible with existing technologies.

[0283] Among them, S705 is an optional step.

[0284] S706: The remote UE sends a third message, and correspondingly, the relay UE receives the third message from the remote UE. The third message may indicate entering the RRC connected state.

[0285] The first message in S705 may indicate that the remote UE triggers one or more UEs to enter the RRC connection state. The triggering methods of the remote UE for these UEs are similar, so here we take the remote UE triggering the relay UE to enter the RRC connection state as an example. In addition, if a UE is triggered to enter the RRC connection state, the remote UE can send a third message to the UE. For example, the third message can carry the L2 destination ID of the UE. In this case, the third message can be regarded as a unicast message. If multiple UEs are to be triggered to enter the RRC connection state, the remote UE can unicast the third message to different UEs respectively, or the remote UE can also broadcast the third message to reduce the sending process of the remote UE.

[0286] Optionally, the third message is a PC5-S message, an RRC message or a PC5-RRC message. Among them, the PC5-RRC message is a message transmitted after the remote UE and the relay UE establish direct communication, and the PC5-S message is, for example, a message transmitted when the direct communication between the remote UE and the relay UE has not yet been established. The PC5-S message that can be used as the third message includes, for example, a discovery message, a DCR message or a security establishment completion message, or may also include other messages in the process of establishing direct communication between the remote UE and the relay UE, or may also include other messages except for the messages involved in the process of establishing direct communication, or may also be a message newly added in the embodiment of the present application.

[0287] For example, if the third message is a PC5-S message, then the third message is to indicate entering the RRC connected state. One indication method is that the third message includes second indication information, and the second indication information can be used to indicate entering the RRC connected state. Then the relay UE that receives the third message can determine to enter the RRC connected state according to the second indication information. For example, the second indication information can be included in the message body of the third message, or can also be included in the MAC header of the third message.

[0288] For another example, if the third message is a PC5-S message, then the third message is to indicate entering the RRC connected state. Another indication method is that the third message does not include the second indication information. Not including the second indication information is used to indicate entering the RRC connected state. In this case, if the third message includes the second indication information, it is used to indicate not entering the RRC connected state. For example, if the remote UE is relayed through the relay UE and it is hoped that the relay UE will monitor paging for the remote UE, then the relay UE may not have to enter the RRC connected state to monitor paging for the remote UE, so the third message may include the second indication information to indicate not entering the RRC connected state; or, if the remote UE is relayed through the relay UE in order to perform a path switch, that is, the remote UE needs to communicate with the network through the relay UE, then the relay UE needs to enter the RRC connected state, and at this time the third message may not include the second indication information to indicate entering the RRC connected state.

[0289] For another example, if the third message is a PC5-S message, then the third message is to indicate entering the RRC connected state. Another indication method is that the third message indicates entering the RRC connected state through the identifier of the remote UE included. For example, if the third message includes the C-RNTI of the remote UE, it indicates that the remote UE is to perform a path switch, which can also be considered as an implicit indication of entering the RRC connected state; or, if the third message does not include the identifier of the remote UE, it indicates that the remote UE is to access the network for the first time through the relay UE, which can also be considered as an implicit indication of entering the RRC connected state; or, if the third message includes the 5G-S-TMSI of the remote UE, it indicates that the remote UE needs to monitor paging through the relay UE, which can also be considered as an implicit indication of not entering the RRC connected state.

[0290] For another example, if the third message is an RRC message, one implementation method is that the third message is the first RRC message sent by the remote UE to the relay UE to establish a connection with the first network device after the relay UE establishes a PC5-S connection with the remote UE. After the relay UE receives the RRC message, it can clearly know that it needs to enter the RRC connection state. The RRC message is, for example, sent by the remote UE through the first SRB between the remote UE and the relay UE, and the first SRB is, for example, SRB0 or ​​SRB1, or it can also be other SRBs.

[0291] For another example, if the third message is a PC5-RRC message, the third message may include indication information, such as third indication information, and the third indication information may be used to indicate entering the RRC connected state.

[0292] In addition to the above implementation methods, the third message may also have other implementation methods, which are not limited in the embodiments of the present application, as long as the third message can be used to trigger the relay UE to enter the RRC connected state.

[0293] S707, the relay UE sends a fourth message to the remote UE, and correspondingly, the remote UE receives the fourth message from the relay UE. After receiving the third message, the relay UE may enter the RRC connected state. After entering the RRC connected state, the relay UE may send a fourth message to the remote UE, and the fourth message may indicate that the RRC connected state has been entered. Alternatively, if the relay UE fails to enter the RRC connected state, the relay UE may also send a fourth message to the remote UE, and the fourth message may indicate that the RRC connected state has failed to be entered. In the embodiment of the present application, the fourth message indicating that the RRC connected state has been entered is taken as an example.

[0294] The fourth message is, for example, a PC5-S message, or may also be a PC5-RRC message, or the fourth message may also be a data packet. The PC5-S message that can be used as the fourth message includes, for example, a discovery message, a DCR response message, or a security establishment request message, or may also include other messages in the process of establishing direct communication between the remote UE and the relay UE, or may also include other messages other than the messages involved in the process of establishing direct communication, or may also be a new message added in the embodiment of the present application. The PC5-RRC message that can be used as the fourth message includes, for example, a PC5 configuration message (RRC reconfiguration sidelink) or a PC5 configuration completion message (RRC reconfiguration complete sidelink) or a PC5 capability interaction message (UE capability enquiry sidelink, UE capability information sidelink) or a master information block (MIB) on PC5, etc. For example, the fourth message may include indication information, such as fourth indication information, and the fourth indication information may be used to indicate that the RRC connection state has been entered, or to indicate that the entry into the RRC connection state has failed. The fourth indication information may be carried in a message header (e.g., MAC header) of the fourth message, or may be carried in a message body of the fourth message. For example, by including an indication of the UE status in the discovery message, such as indicating that the UE has entered the RRC connected state; or, for another example, by indicating the UE status through the MIB on the SL.

[0295] Afterwards, the remote UE may, for example, further send an RRC reconfiguration completion message to the first network device to indicate whether the remote UE has successfully or failed to perform path switching.

[0296] The relay UE may not necessarily send the fourth message to the remote UE, that is, the fourth message may not be sent, so S707 is an optional step.

[0297] S708: The first network device selects a target UE for path switching for the remote UE.

[0298] The embodiment of the present application may not execute S705. Then, after executing S704, the following steps may be executed: Figure 3 S305 and S306 of the illustrated embodiment, that is, if the UE involved in the third information is not triggered to enter the RRC connected state, the first network device can determine whether the UE involved in the third information is authorized to provide relay services. In addition, if S705 is not performed, S706 and S707 may occur after S709.

[0299] If S705 is executed, the first network device can obtain the context of the UE involved in the third information, and can determine whether these UEs are authorized to provide relay services based on the context of these UEs, so that the first network device can select a target UE for the remote UE from the UEs authorized to provide relay services.

[0300] If S705 is not executed, but S305 and S306 are executed, then the first network device has also determined whether the UE involved in the third information is authorized to provide relay services, so that the first network device can select a target UE for the remote UE from the UEs authorized to provide relay services. Figure 3 S307 in the illustrated embodiment.

[0301] The target UE selected by the first network device is, for example, Figure 7 The relay UE shown may be in an RRC non-connected state.

[0302] S709: The first network device sends an RRC reconfiguration message to the remote UE. Correspondingly, the remote UE receives the RRC reconfiguration message from the first network device.

[0303] If S705 is executed, then in S709, the first network device sends a common RRC reconfiguration message to the remote UE. The RRC reconfiguration message may include first configuration information, and the first configuration information may configure the remote UE to access the network through the relay UE. For example, the first configuration information may include configuration information of the second relay link, and the second relay link may include, for example, a side link between the remote UE and the relay UE, and the remote UE is connected to the relay UE through the side link, thereby accessing the network through the relay UE. After receiving the RRC reconfiguration message, the remote UE may perform configuration according to the first configuration information.

[0304] If S705 is not executed, but S305 and S306 are executed, then the RRC reconfiguration message in S709 may also be referred to as the first message. The first message is, for example, an RRC message, so the first message may also be referred to as the first RRC message. The RRC reconfiguration message is only one implementation of the first message. At this time, the first message may also include the first configuration information. Optionally, the first message at this time may also include first indication information, and the first indication information may indicate triggering the relay UE (i.e., the target UE selected by the first network device in S708) to enter the RRC connected state. The first network device knows that the relay UE is in the RRC non-connected state (for example, the relay UE is in the RRC idle state or the RRC inactive state), and if the remote UE wants to access the network through the relay UE, the relay UE needs to enter the RRC connected state, so the first network device may instruct the remote UE to trigger the relay UE so that the relay UE can provide relay services normally.

[0305] If S705 is executed, the execution order of the above steps is, for example, S701-S702-S703-S704-705-S706-S707-S708-S709; if S705 is not executed, the execution order of the above steps is, for example, S701-S702-S703-S704-S708-S709-S706-S707. Of course, S305 and S306 can also be executed before executing S708.

[0306] In the embodiment of the present application, the remote UE can trigger the relay UE to enter the RRC connection state, so that the relay UE is configured to provide relay services. Moreover, if the process is performed before the first network device selects a target UE for the remote UE, it can help the first network device select a target UE from multiple UEs in the RRC connection state, without the need to additionally determine whether these UEs are authorized to provide relay services, thereby reducing the execution process of the first network device.

[0307] In the previous article, it is introduced that the remote UE can trigger the relay UE to enter the RRC connected state, and the relay UE may succeed or fail to enter the RRC connected state. Therefore, the sixth communication method provided by the embodiment of the present application is introduced below, and the processing method for the case where the relay UE fails to enter the RRC connected state is introduced through this method. This method involves the process of switching from a direct link to a non-direct link, please refer to Figure 8 , which is a flow chart of the method.

[0308] The technical solution provided in the embodiments of the present application can be applied to Figure 1AThe network architecture shown in the figure. Figure 1A For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 3 Description of the illustrated embodiment.

[0309] S801, the remote UE sends a third message, and correspondingly, the relay UE receives the third message from the remote UE. The third message may indicate entering the RRC connection state. Optionally, the third message may also indicate the reason why the remote UE requests to establish a connection with the relay UE, for example, the reason is that the remote UE needs to access the network for the first time through the relay UE, or the remote UE needs to perform a path switch, or the remote UE needs to monitor paging through the relay UE, etc.

[0310] S801 is equivalent to Figure 7 S706 in the embodiment shown, so for more information about S801, please refer to S706. Figure 7 The embodiment shown.

[0311] S802: The relay UE does not perform a unified access control (UAC) process, or the relay UE performs a UAC process and sets an access category to "0".

[0312] The so-called UAC process means that when the relay UE has a service and wants to enter the RRC connected state from the RRC idle state, it needs to perform the UAC process in the cell where the relay UE resides. The UAC process is: the UE determines the access category and access identity based on the service, and the base station configures the access control parameters for different access types through broadcast messages; the UE randomly generates a random number between 0 and 1 according to the access type to which the UE belongs. If the generated random number is within a certain range determined by the access control parameters, the UE can initiate random access. If the generated random number is not within a certain range determined by the access control parameters, the UE cannot initiate random access temporarily, but needs to wait for a period of time before generating a random number again to determine whether it can initiate random access.

[0313] For example, the relay UE can directly access the network without UAC access control based on the service of the remote UE. That is, if the restoration or establishment of the RRC connection of the relay UE is triggered by the service of the remote UE, it is considered that the access is allowed.

[0314] For another example, if the third message indicates that the reason why the remote UE establishes a connection with the relay UE is that the remote UE needs to access the network for the first time through the relay UE, or the remote UE needs to perform a path switch, etc., the relay UE may not perform the UAC process to save time and improve the efficiency of the relay UE's random access. Alternatively, regardless of the reason why the third message indicates that the remote UE establishes a connection with the relay UE, or the third message does not indicate the reason why the remote UE establishes a connection with the relay UE, the relay UE may not perform the UAC process.

[0315] For another example, the relay UE may set the access category of the remote UE to 0 according to the service of the remote UE. That is, if the restoration or establishment of the RRC connection of the relay UE is triggered by the service of the remote UE, the RRC sets the access category to 0.

[0316] For another example, the relay UE may set the access category to 0 or allocate a new access category according to the service of the remote UE, so that the relay UE can perform unified access control by itself. That is, if the restoration or establishment of the RRC connection of the relay UE is triggered by the service of the remote UE, the relay UE receives the instruction of the upper layer (such as the NAS layer) and sets the access category to 0, for example.

[0317] Among them, S802 is an optional step, and the relay UE may optionally perform it.

[0318] S803: The relay UE sends a random access preamble to the first network device, and correspondingly, the first network device receives the preamble from the relay UE. The first network device is the network device where the relay UE resides.

[0319] The preamble may be a common preamble, or the preamble may be pre-set, and the pre-setting method may be, for example, configured by the first network device through broadcast information, or specified by the protocol. If the preamble is pre-set, then the preamble may be used to indicate the reason why the relay UE enters the RRC connected state, for example, the reason is for other UEs to perform path switching, or the reason is for other UEs to access the network for the first time, or the reason is for other UEs to monitor paging and request resources that need to reply to connection establishment requests or discovery messages, etc.

[0320] S804: The first network device sends a random access response (RAR) message to the relay UE. Correspondingly, the relay UE receives the RAR message from the first network device.

[0321] S805, the relay UE sends an RRC setup request message to the first network device, and correspondingly, the first network device receives the RRC setup request message from the relay UE. Alternatively, the relay UE sends an RRC resume request message to the first network device, and correspondingly, the first network device receives the RRC resume request message from the relay UE. Figure 8 Take the RRC setup request message as an example. The RRC setup request message or the RRC recovery request message is also the third message (Msg3) in the random access process. It should be noted that the third message in S801 does not refer to the third message in the random access process, so the Msg3 here is not the same message as the third message in S801.

[0322] Optionally, Msg3 may include cause information, which is used to indicate the reason why the relay UE enters the RRC connected state. For example, the reason is for other UEs to perform path switching, or the reason is for other UEs to access the network for the first time, or the reason is for other UEs to monitor paging and request resources for communicating with other UEs, etc. For example, if the preamble is pre-configured, then Msg3 does not include cause information; or, if the preamble is a common preamble and is not used to indicate the reason why the relay UE enters the RRC connected state, then Msg3 may include cause information. For another example, regardless of whether the preamble is pre-configured, Msg3 may include cause information.

[0323] If the relay UE performs random access to enter the RRC connected state from the RRC idle state, Msg3 may be an RRC setup request message, and S805 takes this as an example; if the relay UE performs random access to enter the RRC connected state from the RRC inactive state, Msg3 may be an RRC resume request message, or Msg3 may be other RRC messages; if the relay UE performs random access to restore the RRC connection with the first network device, that is, the relay UE is in the connection recovery state, Msg3 may be an RRC reestablishment request message.

[0324] S806. If the relay UE sends an RRC setup request message to the first network device in S805, the first network device sends an RRC setup message to the relay UE, and accordingly, the relay UE receives the RRC setup message from the first network device. Alternatively, if the relay UE sends an RRC resume request message to the first network device in S805, the first network device sends an RRC resume message to the relay UE, and accordingly, the relay UE receives the RRC resume message from the first network device. Figure 8 Take the example that the message is an RRC establishment message. The RRC establishment message or the RRC recovery message may indicate that the RRC connection is successfully established. If the first network device refuses to establish the RRC connection, S806 may be replaced by the first network device sending an RRC reject message to the relay UE, and accordingly, the relay UE receives the RRC reject message from the first network device, and the RRC reject message may indicate that the RRC connection establishment failed, or indicate that the RRC connection establishment is refused. If the relay UE receives the RRC reject message, it is determined that the RRC connection establishment failed. The RRC reject message may also carry time information to indicate the length of time the relay UE needs to wait.

[0325] S807. If the relay UE receives an RRC setup message from the first network device in S806, the relay UE sends an RRC setup complete message to the first network device, and accordingly, the first network device receives the RRC setup complete message from the relay UE. Alternatively, if the relay UE receives an RRC resume message from the first network device in S806, the relay UE sends an RRC resume complete message to the first network device, and accordingly, the first network device receives the RRC resume complete message from the relay UE. Figure 8 Take the RRC setup complete message as an example. The RRC setup complete message may indicate that the RRC connection has been established, or the RRC recovery complete message may indicate that the RRC connection has been restored. The RRC setup complete message or the RRC recovery complete message may also be understood as the fifth message (Msg5) in the random access process.

[0326] S808. The relay UE sends a fourth message to the remote UE, and correspondingly, the remote UE receives the fourth message from the relay UE. The fourth message may indicate that the relay UE has entered the RRC connected state (or, indicates that the relay UE has entered the RRC connected state), or indicates that the relay UE has failed to enter the RRC connected state. If the fourth message indicates that the relay UE has failed to enter the RRC connected state, then optionally, the fourth message may also indicate the reason why the relay UE failed to enter the RRC connected state, or the fourth message may also include time information to indicate the length of time the relay UE needs to wait for retrying access. If the remote UE accesses the network for the first time through the relay UE or requests the relay UE to monitor paging, the remote UE may choose to continue waiting or trigger reselection of the relay UE based on the information.

[0327] For example, the RRC layer of the relay UE may send an indication to the PC5-S layer of the relay UE to indicate whether the relay UE has successfully or failed to enter the RRC connection state. After receiving the indication, the PC5-S layer of the relay UE may send a fourth message to the PC5-S layer of the remote UE. For example, the fourth message is a PC5-S message or a PC5-RRC message, or the fourth message may also be a data packet, and the PC5-S message that may be the fourth message may be, for example, a discovery message or a DCR response message.

[0328] If the fourth message indicates that the RRC connection state has been entered, the corresponding content can refer to Figure 7If the fourth message indicates that the entry into the RRC connected state fails, the relay UE may continue to perform the following steps.

[0329] S809: The remote UE reestablishes the RRC connection. The remote UE may have received the first configuration information from the first network device (for an introduction to this step, refer to Figure 7 In the embodiment shown in the figure), the first configuration information is used to configure the remote UE to access the network through the relay UE. However, the relay UE fails to enter the RRC connection state and cannot provide relay service for the remote UE. Therefore, the remote UE is equivalent to being unable to continue to apply the first configuration information, and the remote UE can initiate RRC connection re-establishment. For example, the remote UE can initiate RRC connection re-establishment under a fourth network device, and the fourth network device and the first network device are, for example, the same network device, or the fourth network device and the first network device can also be different network devices. That is, the remote UE can initiate RRC connection re-establishment under the network device to which the remote UE accesses, or it can also initiate RRC connection re-establishment under a new network device. For another example, the remote UE can trigger the reselection of the relay, and initiate RRC connection re-establishment to the network through the newly selected relay UE.

[0330] S810, the remote UE sends a failure reason to the fourth network device, and accordingly, the fourth network device receives the failure reason from the remote UE. The failure reason may indicate the reason why the remote UE fails to perform path switching, such as the relay UE connection establishment failure, or the reason is the reason why the relay UE fails to enter the RRC connection state, that is, the reason is known by the remote UE through the fourth message. Figure 8 In the example, the fourth network device and the first network device are the same network device.

[0331] The failure cause may be sent by the remote UE to the fourth network device during the process of reestablishing the RRC connection, for example, the remote UE may carry the failure cause in an RRC reestablishment request message and send it to the fourth network device. Alternatively, the failure cause may also be sent by the remote UE to the fourth network device after completing the RRC connection reestablishment.

[0332] Alternatively, the remote UE may not execute S809, but directly send the failure reason to the fourth network device. Alternatively, the remote UE may not send the failure reason to the fourth network device. Therefore, S809 and S810 are both optional steps.

[0333] The embodiment of the present application provides a method for handling the situation where the relay UE fails to enter the RRC connection, and the embodiment of the present application can enable the first network device to know the reason why the relay UE enters the RRC connection state, and can enable the relay UE to quickly enter the RRC connection state, thereby improving the communication continuity of the remote UE.

[0334] exist Figure 3 to Figure 6 It can be seen from the embodiments shown in any of the accompanying drawings that the remote UE can send an RRC reconfiguration completion message to the first network device through the relay UE to instruct the remote UE to complete the path switch. However, since the remote UE cannot know whether the relay UE has completed the configuration according to the configuration information from the first network device, if the remote UE sends an RRC reconfiguration completion message to the first network device when the relay UE has not yet completed the configuration, it may cause the relay UE to be unable to forward the RRC reconfiguration completion message to the first network device. Therefore, the seventh communication method provided in the embodiment of the present application is introduced next. Through this method, the remote UE can send an RRC reconfiguration completion message to the first network device after knowing that the relay UE configuration is completed. This method involves a process of switching from a direct link to a non-direct link, please refer to Fig. 9 , which is a flow chart of the method.

[0335] The technical solution provided in the embodiments of the present application can be applied to Figure 1A The network architecture shown in the figure. Figure 1A For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 3 Description of the illustrated embodiment.

[0336] S901, remote UE performs data transmission with a first network device. For example, the third network device is a network device accessed by the remote UE, and the first network device is a network device where the relay UE resides. In the embodiment of the present application, the first network device and the third network device are the same network device.

[0337] S902: The first network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the first network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0338] For more information about S902, please refer to Figure 3 S302 in the illustrated embodiment.

[0339] S903: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Fig. 9 Take the remote UE measuring one or more UEs as an example. Fig. 9 The relay UE shown is, for example, one of the one or more UEs.

[0340] For more information about S903, please refer to Figure 3 S303 in the illustrated embodiment.

[0341] S904: The remote UE sends third information to the first network device, and correspondingly, the first network device receives the third information from the remote UE.

[0342] For more information about S904, please refer to Figure 3 S304 in the illustrated embodiment.

[0343] S905. The first network device sends first information to the second network device. Correspondingly, the second network device receives the first information from the first network device.

[0344] The first information is obtained by the first network device according to the third information, and the first information may include the identification of one or more UEs. The first network device may request the second network device to determine whether the one or more UEs involved in the third information are authorized to provide relay services. For more information about S905, please refer to Figure 3 S305 in the illustrated embodiment.

[0345] S906: The second network device sends second information to the first network device, and correspondingly, the first network device receives the second information from the second network device. The second information may indicate whether the one or more UEs are authorized to provide relay services.

[0346] For more information about S906, please refer to Figure 3S306 in the illustrated embodiment.

[0347] In the embodiment of the present application, S905 and S906 are optional steps.

[0348] S907: The first network device selects a target UE for path switching for the remote UE.

[0349] For more information about S907, please refer to Figure 3 S307 in the illustrated embodiment.

[0350] S908: The first network device sends a first message to the remote UE, and correspondingly, the remote UE receives the first message from the first network device. The first message is, for example, an RRC message, so the first message may also be referred to as a first RRC message. For example, the first message is an RRC reconfiguration message.

[0351] For more information about S908, please refer to Figure 3 S308 in the illustrated embodiment.

[0352] S909, the remote UE sends a fifth message to the relay UE, and correspondingly, the relay UE receives the fifth message from the remote UE. After completing the configuration according to the first configuration information, the remote UE may send a fifth message to the relay UE, and the fifth message may indicate entering the RRC connected state. In addition, after receiving the fifth message, the relay UE can also determine that the remote UE has completed the configuration for the second relay link.

[0353] The fifth message is, for example, a PC5-S message. The PC5-S message that can be used as the fifth message is, for example, a DCR message or a security establishment completion message, or may be other PC5-S messages.

[0354] S910: The relay UE sends a preamble to the first network device. Correspondingly, the first network device receives the preamble from the relay UE.

[0355] For more information about S910, please refer to Figure 8 S803 in the embodiment shown.

[0356] S911. The first network device sends a RAR message to the relay UE. Correspondingly, the relay UE receives the RAR message from the first network device.

[0357] S912: The relay UE sends an RRC establishment request message to the first network device, and correspondingly, the first network device receives the RRC establishment request message from the relay UE. Alternatively, the relay UE sends an RRC recovery request message to the first network device, and correspondingly, the first network device receives the RRC recovery request message from the relay UE. Fig. 9 For example, the message is an RRC establishment request message. The RRC establishment request message or the RRC recovery request message is also Msg3 in the random access process.

[0358] For more information about S912, please refer to Figure 8 S805 in the embodiment shown.

[0359] S913. If in S912, the relay UE sends an RRC establishment request message to the first network device, the first network device sends an RRC establishment message to the relay UE, and correspondingly, the relay UE receives the RRC establishment message from the first network device. Alternatively, if in S912, the relay UE sends an RRC recovery request message to the first network device, the first network device sends an RRC recovery (RRC resume) message to the relay UE, and correspondingly, the relay UE receives the RRC recovery message from the first network device. Fig. 9 Take the example that the message is an RRC establishment message. The RRC establishment message or the RRC recovery message may indicate that the RRC connection establishment is successful. If the first network device refuses to establish the RRC connection, S906 may be replaced by the first network device sending an RRC reject message to the relay UE, and accordingly, the relay UE receives the RRC reject message from the first network device, and the RRC reject message may indicate that the RRC connection establishment failed, or indicate that the RRC connection establishment is refused. If the relay UE receives the RRC reject message, it is determined that the RRC connection establishment failed.

[0360] S914. If the relay UE receives an RRC establishment message from the first network device in S913, the relay UE sends an RRC establishment completion message to the first network device, and accordingly, the first network device receives the RRC establishment completion message from the relay UE. Alternatively, if the relay UE receives an RRC recovery message from the first network device in S913, the relay UE sends an RRC recovery completion message to the first network device, and accordingly, the first network device receives the RRC recovery completion message from the relay UE. Fig. 9Take the RRC setup complete message as an example. The RRC setup complete message may indicate that the RRC connection has been established, or the RRC recovery complete message may indicate that the RRC connection has been restored. The RRC setup complete message or the RRC recovery complete message may also be understood as the fifth message (Msg5) in the random access process. It should be noted that Msg5 is not the same message as the fifth message in S909.

[0361] S915. The first network device sends third configuration information to the relay UE. Correspondingly, the relay UE receives the third configuration information from the first network device.

[0362] If the preamble in S910 does not indicate the reason why the relay UE requests to enter the RRC connection state, and the RRC establishment request message in S912 does not include the reason information, then the first network device may not be able to learn the reason why the relay UE enters the RRC connection state through the random access process of the relay UE. In this case, the first network device can configure the relay UE normally, for example, the first network device sends the third configuration information to the relay UE, and the third configuration information may include the Uu configuration between the relay UE and the first network device. The third configuration information is used to configure the communication between the relay UE and the first network device, and is not used to configure the relay UE to provide relay services for other UEs.

[0363] S916. The relay UE sends a sidelink UE information (SUI) message to the first network device. Correspondingly, the first network device receives the SUI message from the relay UE.

[0364] If the preamble in S910 does not indicate the reason why the relay UE requests to enter the RRC connected state, and the RRC establishment request message in S912 does not include the reason information, then the first network device may not be able to learn the reason why the relay UE enters the RRC connected state through the random access process of the relay UE. In order to let the first network device know the reason why the relay UE enters the RRC connected state, the relay UE can send a SUI message to the first network device, and the SUI message may include the identifier of the remote UE, for example, the C-RNTI of the remote UE. Optionally, the SUI message can also request to configure the side link between the remote UE and the relay UE to support the relay UE to provide relay services for the remote UE.

[0365] If the preamble in S910 indicates the reason why the relay UE requests to enter the RRC connected state, or the RRC establishment request message in S912 includes the reason information, S915 and S916 may not be performed. Therefore, S915 and S916 are both optional steps.

[0366] S917: The first network device sends second configuration information to the relay UE, and correspondingly, the relay UE receives the second configuration information from the first network device. For example, the first network device includes the second configuration information in an RRC reconfiguration message and sends it to the relay UE.

[0367] The second configuration information can configure the relay UE to provide a relay service for the remote UE. The second configuration information includes, for example, configuration information of a second relay link, and the second relay link includes, for example, an air interface link between the relay UE and the first network device, and may also include a side link between the relay UE and the remote UE. It can be understood that the second configuration information includes configuration information of the Uu port and configuration information of the side link, and the side link is a link between the remote UE and the relay UE, and the relay UE provides a relay service for the remote UE through the side link.

[0368] S918, the relay UE sends an RRC reconfiguration completion message to the first network device, and correspondingly, the first network device receives the RRC reconfiguration completion message from the relay UE. After receiving the second configuration information, the relay UE may send an RRC reconfiguration completion message to the first network device to indicate that the relay UE has received the second configuration information; or, after completing the configuration according to the second configuration information, the relay UE may send an RRC reconfiguration completion message to the first network device to indicate that the relay UE has completed the configuration.

[0369] S919, the relay UE sends the sixth message to the remote UE, and correspondingly, the remote UE receives the sixth message from the relay UE. After completing the configuration according to the second configuration information, the relay UE may send the sixth message to the remote UE, and the sixth message may indicate that the relay UE has completed the configuration for the first relay link. Through this process, the remote UE can learn that the relay UE has completed the configuration for the first relay link, and determine that the relay UE can provide relay services normally. For example, the fifth message is a DCR message, and the sixth message may be a DCR response message.

[0370] S920, the remote UE sends an RRC reconfiguration completion message to the relay UE, and correspondingly, the relay UE receives the RRC reconfiguration completion message from the remote UE; the relay UE sends the RRC reconfiguration completion message to the first network device, and correspondingly, the first network device receives the RRC reconfiguration completion message from the relay UE. That is, the remote UE sends the RRC reconfiguration completion message to the first network device through the relay UE. The RRC reconfiguration completion message can indicate that the remote UE has completed the path switching.

[0371] Through the technical solution provided in the embodiment of the present application, the relay UE and the remote UE can know when each other's configuration is completed, reducing the probability of transmission loss caused by one UE being configured but the other UE not being configured.

[0372] Next, an eighth communication method provided by an embodiment of the present application is introduced. Through this method, the remote UE can also send an RRC reconfiguration completion message to the first network device when it is informed that the relay UE configuration is completed. This method involves a process of switching from a direct link to an indirect link. Please refer to Fig.10 , which is a flow chart of the method.

[0373] The technical solution provided in the embodiments of the present application can be applied to Figure 1A The network architecture shown in the figure. Figure 1A For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 3 Description of the illustrated embodiment.

[0374] S1001. The remote UE performs data transmission with the first network device. For example, the third network device is the network device accessed by the remote UE, and the first network device is the network device where the relay UE resides. In the embodiment of the present application, the first network device and the third network device are the same network device.

[0375] S1002: The first network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the first network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0376] For more information about S1002, please refer to Figure 3 S302 in the illustrated embodiment.

[0377] S1003: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Fig.10 Take the remote UE measuring one or more UEs as an example. Fig.10 The relay UE shown is, for example, one of the one or more UEs.

[0378] For more information about S1003, please refer to Figure 3 S303 in the illustrated embodiment.

[0379] S1004: The remote UE sends third information to the first network device, and correspondingly, the first network device receives the third information from the remote UE.

[0380] For more information about S1004, please refer to Figure 3 S304 in the illustrated embodiment.

[0381] S1005. The first network device sends first information to the second network device. Correspondingly, the second network device receives the first information from the first network device.

[0382] The first information is obtained by the first network device according to the third information, and the first information may include the identification of one or more UEs. The first network device may request the second network device to determine whether the one or more UEs involved in the third information are authorized to provide relay services. For more information about S1005, please refer to Figure 3 S305 in the illustrated embodiment.

[0383] S1006: The second network device sends second information to the first network device, and correspondingly, the first network device receives the second information from the second network device. The second information may indicate whether the one or more UEs are authorized to provide relay services.

[0384] For more information about S1006, please refer to Figure 3 S306 in the illustrated embodiment.

[0385] In the embodiment of the present application, S1005 and S1006 are optional steps.

[0386] S1007. The first network device selects a target UE for path switching for the remote UE.

[0387] For more information about S1007, please refer to Figure 3 S307 in the illustrated embodiment.

[0388] S1008. The first network device sends a first message to the remote UE, and correspondingly, the remote UE receives the first message from the first network device. The first message is, for example, an RRC message, so the first message may also be referred to as a first RRC message. For example, the first message is an RRC reconfiguration message.

[0389] The first message may include first indication information, and the first indication information may indicate triggering the relay UE to enter the RRC connected state. The first network device knows that the relay UE is in the RRC non-connected state, and if the remote UE wants to access the network through the relay UE, the relay UE needs to enter the RRC connected state, so the first network device may instruct the remote UE to trigger the relay UE to enter the RRC connected state, so that the relay UE can provide the relay service normally.

[0390] However, in the embodiment of the present application, the first message does not include the first configuration information (for an introduction to the first configuration information, refer to Figure 3 In other words, the remote UE cannot be configured according to the first message. Furthermore, the first message may not instruct the remote UE to switch to the relay UE.

[0391] S1009, the remote UE sends a DCR message to the relay UE, and correspondingly, the relay UE receives the DCR message from the remote UE; or, the remote UE sends a security establishment completion message to the relay UE, and correspondingly, the relay UE receives the security establishment completion message from the remote UE. The DCR message or the security establishment completion message can be used to trigger the relay UE to enter the RRC connected state. Because the first message in the embodiment of the present application does not include the first configuration information, neither the DCR message nor the security establishment completion message can implicitly indicate that the remote UE has been configured.

[0392] S1010: The relay UE sends a preamble to the first network device. Correspondingly, the first network device receives the preamble from the relay UE.

[0393] For more information about S1010, please refer to Figure 8 S803 in the illustrated embodiment.

[0394] S1011. The first network device sends a RAR message to the relay UE. Correspondingly, the relay UE receives the RAR message from the first network device.

[0395] S1012, the relay UE sends an RRC establishment request message to the first network device, and accordingly, the first network device receives the RRC establishment request message from the relay UE. Alternatively, the relay UE sends an RRC recovery request message to the first network device, and accordingly, the first network device receives the RRC recovery request message from the relay UE. The RRC establishment request message or the RRC recovery request message is also Msg3 in the random access process.

[0396] For more information about S1012, please refer to Figure 8 S805 in the embodiment shown.

[0397] S1013. If the relay UE sends an RRC establishment request message to the first network device in S1012, the first network device sends an RRC establishment message to the relay UE, and accordingly, the relay UE receives the RRC establishment message from the first network device. Alternatively, if the relay UE sends an RRC recovery request message to the first network device in S1012, the first network device sends an RRC recovery (RRC resume) message to the relay UE, and accordingly, the relay UE receives the RRC recovery message from the first network device. Fig.10 Take the example that the message is an RRC establishment message. The RRC establishment message or the RRC recovery message may indicate that the RRC connection establishment is successful. If the first network device refuses to establish the RRC connection, S1006 may be replaced by the first network device sending an RRC reject message to the relay UE, and accordingly, the relay UE receives the RRC reject message from the first network device, and the RRC reject message may indicate that the RRC connection establishment failed, or indicate that the RRC connection establishment is refused. If the relay UE receives the RRC reject message, it is determined that the RRC connection establishment failed.

[0398] S1014. If the relay UE receives an RRC establishment message from the first network device in S1013, the relay UE sends an RRC establishment completion message to the first network device, and accordingly, the first network device receives the RRC establishment completion message from the relay UE. Alternatively, if the relay UE receives an RRC recovery message from the first network device in S1013, the relay UE sends an RRC recovery completion message to the first network device, and accordingly, the first network device receives the RRC recovery completion message from the relay UE. Fig.10Take the RRC setup complete message as an example. The RRC setup complete message may indicate that the RRC connection has been established, or the RRC recovery complete message may indicate that the RRC connection has been restored. The RRC setup complete message or the RRC recovery complete message may also be understood as Msg5 in the random access process.

[0399] S1015. The first network device sends third configuration information to the relay UE. Correspondingly, the relay UE receives the third configuration information from the first network device.

[0400] For more information about S1015, please refer to Fig. 9 S915 in the embodiment shown.

[0401] S1016. The relay UE sends a SUI message to the first network device. Correspondingly, the first network device receives the SUI message from the relay UE.

[0402] For more information about S1016, please refer to Fig. 9 S916 in the embodiment shown.

[0403] S1017: The first network device sends second configuration information to the relay UE, and correspondingly, the relay UE receives the second configuration information from the first network device. For example, the first network device includes the second configuration information in an RRC reconfiguration message and sends it to the relay UE.

[0404] For more information about S1017, please refer to Fig. 9 S917 in the embodiment shown.

[0405] S1018, the relay UE sends a DCR response message to the remote UE, and correspondingly, the remote UE receives the DCR response message from the relay UE. This is based on the example of the remote UE sending a DCR message to the relay UE in S1009. If the remote UE sends a security establishment request message to the relay UE in S1009, S1018 can be replaced by the relay UE sending a security establishment completion message to the remote UE, and correspondingly, the remote UE receives the security establishment completion message from the relay UE.

[0406] If the relay UE has resources for sending a DCR response message (or a security establishment complete message) without entering the RRC connection state, then S1018 may occur after S1009 and is not affected by the relay UE initiating a random access procedure. If the relay UE needs to enter the RRC connection state to obtain resources for sending a DCR response message (or a security establishment complete message), then S1018 may occur after S1017.

[0407] S1019, the relay UE sends an RRC reconfiguration completion message to the first network device, and correspondingly, the first network device receives the RRC reconfiguration completion message from the relay UE. After receiving the second configuration information, the relay UE may send an RRC reconfiguration completion message to the first network device to indicate that the relay UE has received the second configuration information; or, after completing the configuration according to the second configuration information, the relay UE may send an RRC reconfiguration completion message to the first network device to indicate that the relay UE has completed the configuration.

[0408] S1020, the relay UE sends the sixth message to the remote UE, and correspondingly, the remote UE receives the sixth message from the relay UE. After completing the configuration according to the second configuration information, the relay UE may send the sixth message to the remote UE, and the sixth message may indicate that the relay UE has completed the configuration for the first relay link. Through this process, the remote UE can know that the relay UE has completed the configuration for the first relay link, and determines that the relay UE can provide relay services normally. For example, the sixth message is a PC5-RRC message. After receiving the sixth message, the remote UE may reply to the relay UE to confirm the receipt of the message, or may not reply to confirm the receipt of the message.

[0409] S1021, the remote UE sends a seventh message to the relay UE, and correspondingly, the relay UE receives the seventh message from the remote UE. The seventh message may indicate that the remote UE has completed configuration of the second relay link, for example, the seventh message is a PC5-RRC message.

[0410] In an embodiment of the present application, the first message sent by the first network device in S1008 does not include the first configuration information. Then after S1008, the first network device may send the first configuration information to the remote UE, for example, the first network device may send the first configuration information to the remote UE through an RRC configuration message or other message. After receiving the first configuration information, the remote UE may be configured according to the first configuration information. After the configuration is completed, the remote UE may send the seventh message to the relay UE so that the relay UE can also clearly know that the remote UE has been configured.

[0411] After receiving the seventh message, the relay UE may reply to the remote UE with a message confirming receipt, or may not reply with a message confirming receipt. Optionally, the sixth message and the seventh message may be response messages to each other.

[0412] S1022, the remote UE sends an RRC reconfiguration completion message to the relay UE, and correspondingly, the relay UE receives the RRC reconfiguration completion message from the remote UE; the relay UE sends the RRC reconfiguration completion message to the first network device, and correspondingly, the first network device receives the RRC reconfiguration completion message from the relay UE. That is, the remote UE sends the RRC reconfiguration completion message to the first network device through the relay UE. The RRC reconfiguration completion message can indicate that the remote UE has completed the path switching.

[0413] Through the technical solution provided in the embodiment of the present application, the relay UE and the remote UE can know when each other's configuration is completed, reducing the probability of transmission loss caused by one UE being configured but the other UE not being configured.

[0414] In the embodiments shown above, the remote UE triggers the relay UE to enter the RRC connected state. Next, the ninth communication method provided in the embodiment of the present application is introduced. Through this method, the network device can wake up the relay UE without the remote UE triggering the relay UE to enter the RRC connected state. This method involves the process of switching from a direct link to a non-direct link. Please refer to Fig.11 , which is a flow chart of the method.

[0415] The technical solution provided in the embodiments of the present application can be applied to Figure 1A The network architecture shown in the figure. Figure 1A For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 3 Description of the illustrated embodiment.

[0416] S1101, remote UE performs data transmission with a first network device. For example, the third network device is a network device accessed by the remote UE, and the first network device is a network device where the relay UE resides. In the embodiment of the present application, the first network device and the third network device are the same network device.

[0417] S1102: The first network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the first network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0418] For more information about S1102, please refer to Figure 3 S302 in the illustrated embodiment.

[0419] S1103: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Fig.11 Take the remote UE measuring one or more UEs as an example. Fig.11 The relay UE shown is, for example, one of the one or more UEs.

[0420] For more information about S1103, please refer to Figure 3 S303 in the illustrated embodiment.

[0421] S1104: The remote UE sends third information to the first network device, and correspondingly, the first network device receives the third information from the remote UE.

[0422] For more information about S1104, such as the content of the third information, please refer to Figure 3 S304 in the embodiment shown. For example, in the embodiment of the present application, the third information includes the identifier of the cell where one or more UEs involved in the third information are located, for example, the third information includes the identifier of the cell where the relay UE is located.

[0423] In addition, the first network device may obtain fourth information based on the third information, for example, the fourth information includes the identifiers of some UEs (or all UEs) involved in the third information, and may also include the status information of some UEs (or all UEs) involved in the third information, for example, the fourth information includes the identifier of the relay UE, and includes the status information of the relay UE. The status information of a UE may indicate that the state of the UE is an RRC connected state or an RRC non-connected state, for example, the status information of the relay UE may indicate that the relay UE is in an RRC non-connected state. In an embodiment of the present application, for example, the relay UE is in an RRC idle state or an RRC inactive state.

[0424] S1105: The first network device generates a paging message, where the paging message is used to page the relay UE. The first network device may page some or all of the UEs involved in the fourth information, and paging the relay UE is taken as an example here.

[0425] In an embodiment of the present application, regardless of whether the relay UE is in an RRC idle state or an RRC inactive state, it can be paged by the first network device without being paged by the core network device, thereby reducing the interaction process between the first network device and the core network device. The paging message may include an identifier of the relay UE to page the relay UE. For example, if the relay UE is in an RRC idle state, the identifier of the relay UE included in the paging message may be the 5G-S-TMSI of the relay UE, and if the relay UE is in an RRC inactive state, the identifier of the relay UE included in the paging message may be the I-RNTI of the relay UE to distinguish different states of the relay UE.

[0426] Optionally, before generating a paging message, the first network device may first send first information to the core network device, and the first information may be used to determine whether the relay UE is authorized to provide relay service. The core network device may send second information to the first network device to indicate whether the relay UE is authorized to provide relay service. If the relay UE is authorized to provide relay service, the first network device may generate a paging message to page the relay UE, and if the relay UE is not authorized to provide relay service, the first network device does not need to generate a paging message. For example, the first network device may instruct the remote UE to continue measuring, or the first network device may re-select the target UE for path switching for the remote UE, etc. For an introduction to concepts such as first information and second information, please refer to Figure 3 The embodiment shown.

[0427] S1106: The first network device sends a paging message, and correspondingly, the relay UE receives the paging message. For example, the first network device sends the paging message in the cell where the relay UE resides.

[0428] After receiving the paging message, the relay UE can initiate random access to the first network device to enter the RRC connected state. If the first network device pages multiple UEs, multiple UEs can enter the RRC connected state. After multiple UEs enter the RRC connected state, the first network device selects one UE from the multiple UEs as the target UE for the remote UE to perform path switching.

[0429] In the embodiment of the present application, because the first network device can know the cell where the relay UE is located, no matter whether the relay UE is in the RRC idle state or the RRC inactive state, the first network device can generate a paging message to perform paging in the cell, which is equivalent to changing the paging mechanism and reducing the paging process of the core network device. Moreover, because the first network device can perform paging in the cell where the relay UE resides, it is not necessary to perform paging in a larger range, which also reduces the number of paging messages, saves transmission overhead, and improves paging efficiency.

[0430] Next, the tenth communication method provided by the embodiment of the present application is introduced. Through this method, the network device can also wake up the relay UE without the remote UE triggering the relay UE to enter the RRC connection state. This method involves the process of switching from a direct link to a non-direct link. Please refer to Fig.12 , which is a flow chart of the method.

[0431] The technical solution provided in the embodiments of the present application can be applied to Figure 1C The network architecture shown in the figure. Figure 1C For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 4 Description of the illustrated embodiment.

[0432] S1201: The remote UE performs data transmission with a third network device. For example, the third network device is a network device accessed by the remote UE, and the first network device is a network device where the relay UE resides. In the embodiment of the present application, the first network device and the third network device are different network devices.

[0433] S1202: The third network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the third network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0434] For more information about S1202, please refer to Figure 3 S302 in the illustrated embodiment.

[0435] S1203: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Fig.12 Take the remote UE measuring one or more UEs as an example. Fig.12 The relay UE shown is, for example, one of the one or more UEs.

[0436] For more information about S1203, please refer to Figure 3 S303 in the illustrated embodiment.

[0437] S1204: The remote UE sends third information to the third network device, and correspondingly, the third network device receives the third information from the remote UE.

[0438] For more information about S1204, such as the content of the third information, please refer to Figure 3 S304 in the embodiment shown. For example, in the embodiment of the present application, the third information includes the identifier of the cell where one or more UEs involved in the third information are located, for example, the third information includes the identifier of the cell where the relay UE is located.

[0439] S1205: The third network device sends fourth information to the first network device, and correspondingly, the first network device receives the fourth information from the third network device. For example, the third network device may send the fourth information to the first network device via an Xn message between base stations.

[0440] For example, the fourth information includes the identifiers of some UEs (or all UEs) involved in the third information, and may also include the status information of some UEs (or all UEs) involved in the third information, for example, the fourth information includes the identifier of the relay UE, and includes the status information of the relay UE. The status information of a UE may indicate that the state of the UE is an RRC connected state or an RRC non-connected state. For example, the status information of the relay UE may indicate that the relay UE is in an RRC non-connected state. In an embodiment of the present application, for example, the relay UE is in an RRC idle state or an RRC inactive state. In addition, the fourth information may also include the identifiers of some UEs (or all UEs) involved in the third information, and may also include the identifiers of the cells where some UEs (or all UEs) involved in the third information are located. For example, the fourth information includes the ID of the cell where the relay UE resides.

[0441] S1206: The first network device generates a paging message, and the paging message is used to page the relay UE. The first network device may page some or all UEs involved in the fourth information, and paging the relay UE is taken as an example here.

[0442] In an embodiment of the present application, regardless of whether the relay UE is in an RRC idle state or an RRC inactive state, it can be paged by the first network device where the relay UE resides, without the need for paging by the core network device, thereby reducing the interaction process between the first network device and the core network device. The paging message may include an identifier of the relay UE to page the relay UE. For example, if the relay UE is in an RRC idle state, the identifier of the relay UE included in the paging message may be the 5G-S-TMSI of the relay UE, and if the relay UE is in an RRC inactive state, the identifier of the relay UE included in the paging message may be the I-RNTI of the relay UE to distinguish different states of the relay UE.

[0443] S1207: The first network device sends a paging message, and correspondingly, the relay UE receives the paging message. For example, the first network device sends the paging message in the cell where the relay UE resides.

[0444] After receiving the paging message, the relay UE can initiate random access to the first network device to enter the RRC connection state. If the first network device pages multiple UEs, multiple UEs can enter the RRC connection state. After multiple UEs enter the RRC connection state, the first network device or the third network device selects one UE from the multiple UEs as the target UE for the remote UE to perform path switching.

[0445] Optionally, before generating a paging message, the first network device may first determine whether the relay UE is authorized to provide relay services according to the context of the relay UE. If the relay UE is authorized to provide relay services, the first network device may generate a paging message to page the relay UE, and if the relay UE is not authorized to provide relay services, the first network device does not need to generate a paging message, for example, the first network device may send a failure message to the third network device to indicate that the relay UE cannot be paged, or to indicate the reason why the relay UE cannot be paged.

[0446] In the embodiment of the present application, because the first network device can know the cell where the relay UE is located, no matter whether the relay UE is in the RRC idle state or the RRC inactive state, the first network device can generate a paging message to perform paging in the cell, which is equivalent to changing the paging mechanism and reducing the paging process of the core network device. Moreover, because the first network device can perform paging in the cell where the relay UE resides, it is not necessary to perform paging in a larger range, which also reduces the number of paging messages, saves transmission overhead, and improves paging efficiency.

[0447] exist Fig.11 or Fig.12 In the embodiment shown, no matter whether the relay UE is in the RRC idle state or the RRC inactive state, it is paged by the access network device, which is equivalent to changing the paging mechanism to a certain extent. Next, the eleventh communication method provided in the embodiment of the present application is introduced. Through this method, the relay UE can be woken up by the network device without the remote UE triggering the relay UE to enter the RRC connected state, and this method does not require changing the paging mechanism. This method involves the process of switching from a direct link to a non-direct link. Please refer to Fig.13 , which is a flow chart of the method.

[0448] The technical solution provided in the embodiments of the present application can be applied to Figure 1A The network architecture shown in the figure. Figure 1A For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 3 Description of the illustrated embodiment.

[0449] S1301, remote UE and third network device perform data transmission. For example, the third network device is a network device accessed by remote UE, and the embodiment of the present application also involves a first network device, which is a core network device, such as AMF or SMF or PCF.

[0450] S1302: The third network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the third network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0451] For more information about S1302, please refer to Figure 3 S302 in the illustrated embodiment.

[0452] S1303: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Fig.13 Take the remote UE measuring one or more UEs as an example. Fig.13 The relay UE shown is, for example, one of the one or more UEs.

[0453] For more information about S1303, please refer to Figure 3 S303 in the illustrated embodiment.

[0454] S1304: The remote UE sends third information to the third network device, and correspondingly, the third network device receives the third information from the remote UE.

[0455] For more information about S1304, such as the content of the third information, please refer to Figure 3 S304 in the embodiment shown. For example, in the embodiment of the present application, the third information includes the identifier of the cell where one or more UEs involved in the third information are located, for example, the third information includes the identifier of the cell where the relay UE is located.

[0456] S1305. The third network device sends fourth information to the first network device, and correspondingly, the first network device receives the fourth information from the third network device. For example, the third network device may send the fourth information to the first network device via an Xn message between base stations. The fourth information may be used to indicate (or request) paging one or more UEs, where the one or more UEs include some or all of the UEs involved in the third information, and the one or more UEs are in an RRC idle state. For example, the one or more UEs include a relay UE.

[0457] For example, the fourth information includes the identifiers of some UEs (or all UEs) involved in the third information, and may also include the status information of some UEs (or all UEs) involved in the third information, for example, the fourth information includes the identifier of the relay UE, and includes the status information of the relay UE. The status information of a UE may indicate that the status of the UE is an RRC connected state or an RRC non-connected state, for example, the status information of the relay UE may indicate that the relay UE is in an RRC non-connected state. In an embodiment of the present application, for example, the relay UE is in an RRC idle state or an RRC inactive state. Optionally, the fourth information may also include the identifiers of the cells where some UEs (or all UEs) involved in the third information are located, for example, the fourth information includes the ID of the cell where the relay UE resides.

[0458] S1306: The first network device generates a paging message, and the paging message is used to page the relay UE. The first network device may page some or all UEs involved in the fourth information, and paging the relay UE is taken as an example here.

[0459] In the embodiment of the present application, the UE in the RRC idle state can be paged by the core network device, so there is no need to change the existing paging mechanism, making the technical solution of the embodiment of the present application more compatible with the existing technology. The paging message may include the identifier of the relay UE to page the relay UE.

[0460] Optionally, before generating a paging message, the first network device may first determine whether the relay UE is authorized to provide relay services according to the context of the relay UE. If the relay UE is authorized to provide relay services, the first network device may generate a paging message to page the relay UE, and if the relay UE is not authorized to provide relay services, the first network device does not need to generate a paging message, for example, the first network device may send a failure message to the third network device to indicate that the relay UE cannot be paged, or to indicate the reason why the relay UE cannot be paged.

[0461] S1307: The first network device sends a paging message, and correspondingly, the relay UE receives the paging message. For example, the first network device sends the paging message in the cell where the relay UE resides.

[0462] After receiving the paging message, the relay UE can initiate random access to the first network device to enter the RRC connected state. If the first network device pages multiple UEs, multiple UEs can enter the RRC connected state. After multiple UEs enter the RRC connected state, the first network device selects one UE from the multiple UEs as the target UE for the remote UE to perform path switching.

[0463] In the embodiment of the present application, the first network device can learn the cell where the relay UE is located, so the first network device can page the relay UE in the cell without paging in a larger range, thereby reducing the number of paging messages, saving transmission overhead, and improving paging efficiency.

[0464] Next, the twelfth communication method provided by the embodiment of the present application is introduced. Through this method, the network device can wake up the relay UE without the remote UE triggering the relay UE to enter the RRC connected state, and this method does not need to change the paging mechanism. This method involves the process of switching from a direct link to a non-direct link. Please refer to Fig.14 , which is a flow chart of the method.

[0465] The technical solution provided in the embodiments of the present application can be applied to Figure 1C The network architecture shown in the figure. Figure 1C For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 4 Description of the illustrated embodiment.

[0466] S1401, remote UE performs data transmission with a third network device. For example, the third network device is a network device accessed by the remote UE, and the embodiment of the present application also involves a first network device and a second network device, the first network device is a core network device, such as AMF or SMF or PCF, and the second network device is a network device where the relay UE resides.

[0467] S1402: The third network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the third network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0468] For more information about S1402, please refer to Figure 3 S302 in the illustrated embodiment.

[0469] S1403: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Fig.14 Take the remote UE measuring one or more UEs as an example. Fig.14 The relay UE shown is, for example, one of the one or more UEs.

[0470] For more information about S1403, please refer to Figure 3 S303 in the illustrated embodiment.

[0471] S1404: The remote UE sends third information to the third network device, and correspondingly, the third network device receives the third information from the remote UE.

[0472] For more information about S1404, such as the content of the third information, please refer to Figure 3 S304 in the embodiment shown. For example, in the embodiment of the present application, the third information includes the identifier of the cell where one or more UEs involved in the third information are located, for example, the third information includes the identifier of the cell where the relay UE is located.

[0473] S1405. The third network device sends the identifier of the relay UE to the second network device, and correspondingly, the second network device receives the identifier of the relay UE from the third network device. For example, the third network device may send the identifier of the relay UE to the second network device via an Xn message between base stations. Optionally, the third network device may also send the identifier of the cell where the relay UE resides to the second network device. Since the third network device is not the network device where the relay UE resides, the third network device may send the identifier of the relay UE to the second network device where the relay UE resides.

[0474] S1406: The second network device sends fourth information to the first network device, and correspondingly, the first network device receives the fourth information from the second network device. The fourth information can be used to instruct (or request) paging the relay UE.

[0475] For example, the fourth information includes an identifier of the relay UE and may also include the state information of the relay UE. The state information of a UE may indicate that the state of the UE is an RRC connected state or an RRC non-connected state. For example, the state information of the relay UE may indicate that the relay UE is in an RRC non-connected state. In an embodiment of the present application, for example, the relay UE is in an RRC idle state. Optionally, the fourth information may also include an identifier of the cell where the relay UE is located. For example, the fourth information includes the ID of the cell where the relay UE resides.

[0476] S1407: The first network device generates a paging message, where the paging message is used to page the relay UE.

[0477] For more information about S1407, please refer to Fig.13 S1306 in the illustrated embodiment.

[0478] S1408: The first network device sends a paging message, and correspondingly, the second network device receives the paging message from the first network device. Because the first network device is a core network device, the core network device first sends the paging message to the second network device where the relay UE resides.

[0479] S1409, the second network device sends a paging message, and correspondingly, the relay UE receives the paging message from the second network device. For example, the first network device sends a paging message in the cell where the relay UE resides. For example, the first network device sends a paging message in the cell where the relay UE resides.

[0480] For more information about S1409, please refer to Fig.13 S1307 in the embodiment shown.

[0481] In the embodiment of the present application, the first network device can learn the cell where the relay UE is located, so the first network device can page the relay UE in the cell without paging in a larger range, thereby reducing the number of paging messages, saving transmission overhead, and improving paging efficiency.

[0482] exist Fig.13 or Fig.14 In the embodiment shown, the relay UE is in the RRC idle state. Next, the thirteenth communication method provided by the embodiment of the present application is introduced. In this method, the relay UE is in the RRC inactive state, and the anchor network device of the relay UE can page the relay UE, which is equivalent to the method also not needing to change the paging mechanism. This method involves the process of switching from a direct link to a non-direct link, please refer to Fig.15 , which is a flow chart of the method.

[0483] The technical solution provided in the embodiments of the present application can be applied to Figure 1A The network architecture shown in the figure. Figure 1A For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 3 Description of the illustrated embodiment.

[0484] S1501, remote UE performs data transmission with a first network device. For example, the first network device is a network device accessed by the remote UE and is also a network device where the relay UE resides. In addition, the embodiment of the present application also involves a third network device, which is an anchor network device of the relay UE. In the embodiment of the present application, the first network device and the third network device are different network devices.

[0485] S1502: The first network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the first network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0486] For more information about S1502, please refer to Figure 3 S302 in the illustrated embodiment.

[0487] S1503: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Fig.15 Take the remote UE measuring one or more UEs as an example. Fig.15 The relay UE shown is, for example, one of the one or more UEs.

[0488] For more information about S1503, please refer to Figure 3 S303 in the illustrated embodiment.

[0489] S1504: The remote UE sends third information to the first network device, and correspondingly, the first network device receives the third information from the remote UE.

[0490] For more information about S1504, such as the content of the third information, please refer to Figure 3 S304 in the embodiment shown. For example, in the embodiment of the present application, the third information includes information of one or more UEs involved in the third information, wherein the information of one UE may include one or more of the following: resume ID of the UE, I-RNTI of the UE, or short-I-RNTI of the UE. For example, the third information includes information of the relay UE, and the information of the relay UE includes one or more of the following: resume ID of the relay UE, I-RNTI of the relay UE, or short-I-RNTI of the relay UE.

[0491] In addition, the first network device may obtain fourth information based on the third information, for example, the fourth information includes the identifiers of some UEs (or all UEs) involved in the third information, and may also include the status information of some UEs (or all UEs) involved in the third information, for example, the fourth information includes the identifier of the relay UE, and includes the status information of the relay UE. The status information of a UE may indicate that the state of the UE is an RRC connected state or an RRC non-connected state, for example, the status information of the relay UE may indicate that the relay UE is in an RRC non-connected state. In an embodiment of the present application, for example, the relay UE is in an RRC idle state or an RRC inactive state.

[0492] S1505: The first network device sends first information to the third network device, and correspondingly, the third network device receives the first information from the first network device. The first information can be used to determine whether the relay UE is authorized to provide relay services, or the first information can request to obtain the context of the relay UE for context migration.

[0493] If the first network device is not the anchor network device of the relay UE, the first network device may determine the anchor network device of the relay UE, such as the third network device, based on one or more of the resume ID of the relay UE, the I-RNTI of the relay UE, or the short-I-RNTI of the relay UE, thereby sending the first information to the third network device, for example, the first information includes the identifier of the relay UE. For one or more UEs involved in the third information, if the first network device is not the anchor network device of these UEs, the first network device may send the first information to the anchor network devices of these UEs accordingly, and the first information sent to different anchor network devices may be different. Here, the example of the first network device sending the first information to the third network device is taken.

[0494] S1506: The third network device determines whether the relay UE is authorized to provide relay service.

[0495] The third network device may determine whether the relay UE is authorized to provide the relay service according to the context of the relay UE. If the relay UE is authorized to provide the relay service, S1506 may be executed; if the relay UE is not authorized to provide the relay service, S1506 and subsequent steps do not need to be executed, for example, the third network device may send a rejection message to the first network device to indicate the rejection of providing the context of the relay UE, or indicate the reason for the rejection of providing the context of the relay UE.

[0496] S1506: The third network device sends the context of the relay UE to the first network device. Correspondingly, the first network device receives the context of the relay UE from the third network device.

[0497] It should be noted that if the third network device sends the context of the relay UE to the first network device, the third network device can also trigger the core network device (such as AMF) to perform path switching. Path switching here means that the core network device switches the path for sending data to the relay UE from the third network device to the first network device. After the core network device performs path switching, if the core network device has downlink data that needs to be sent to the relay UE, the core network device will no longer send it to the third network device, but will send it to the first network device.

[0498] S1507: The first network device selects a target UE for path switching for the remote UE. In other words, the first network device determines the UE to which the remote UE needs to switch.

[0499] For example, the target UE selected by the first network device is a relay UE.

[0500] S1508. The first network device sends a paging message, and the relay UE receives the paging message accordingly. The paging message is used to page the relay UE. The first network device may page some or all UEs involved in the fourth information, and paging the relay UE is taken as an example here. For example, the first network device sends a paging message in the cell where the relay UE resides.

[0501] S1509. The relay UE enters the RRC connected state.

[0502] After receiving the paging message, the relay UE can initiate random access to the first network device to enter the RRC connection state. If the first network device pages multiple UEs, multiple UEs can enter the RRC connection state. After multiple UEs enter the RRC connection state, the first network device selects one UE from the multiple UEs as the target UE for the remote UE to perform path switching. For example, the target UE determined by the first network device is the relay UE.

[0503] S1510: The first network device sends an RRC reconfiguration message to the remote UE, and correspondingly, the remote UE receives the RRC reconfiguration message from the first network device. For the sake of distinction, the RRC reconfiguration message is referred to as RRC reconfiguration message 1.

[0504] The RRC reconfiguration message 1 may include first configuration information, and the first configuration information may configure the remote UE to access the network through the relay UE. For example, the first configuration information may include configuration information of the second relay link, and the second relay link is, for example, a side link between the remote UE and the relay UE, and the remote UE is connected to the relay UE through the side link, thereby accessing the network through the relay UE. After receiving the RRC reconfiguration message 1, the remote UE may perform configuration according to the first configuration information.

[0505] S1511. The first network device sends an RRC reconfiguration message to the relay UE. Correspondingly, the relay UE receives the RRC reconfiguration message from the first network device. For the sake of distinction, the RRC reconfiguration message is referred to as RRC reconfiguration message 2.

[0506] RRC reconfiguration message 2 may include second configuration information, and the second configuration information may configure the relay UE to provide relay service for the remote UE. The second configuration information may include, for example, configuration information of the first relay link, and the first relay link may include, for example, an air interface link between the relay UE and the first network device, and may also include a side link between the remote UE and the relay UE. It may be understood that the configuration information of the first relay link includes configuration information of the Uu port and configuration information of the side link, and the side link is a link between the remote UE and the relay UE, and the relay UE provides relay service for the remote UE through the side link. After receiving RRC reconfiguration message 2, the relay UE may be configured according to the second configuration information.

[0507] For example, S1510 may occur before S1511, or S1510 may occur after S1511, or S1510 and S1511 may occur simultaneously.

[0508] S1512: The remote UE establishes direct communication with the relay UE.

[0509] If the remote UE selects the relay UE by itself, S1512 may also occur before S1504.

[0510] S1513, the remote UE sends an RRC reconfiguration completion message to the relay UE, and accordingly, the relay UE receives the RRC reconfiguration completion message from the remote UE; the relay UE sends the RRC reconfiguration completion message to the first network device, and accordingly, the first network device receives the RRC reconfiguration completion message from the relay UE. That is, the remote UE sends the RRC reconfiguration completion message to the first network device through the relay UE. The RRC reconfiguration completion message can indicate that the remote UE has completed the path switching.

[0511] In the embodiment of the present application, the first network device can learn the cell where the relay UE is located, so the first network device can page the relay UE in the cell without paging in a larger range, thereby reducing the number of paging messages, saving transmission overhead, and improving paging efficiency.

[0512] Next, the fourteenth communication method provided by the embodiment of the present application is introduced. In this method, the relay UE is in the RRC inactive state, and the relay UE can be paged by the anchor network device of the relay UE, which is equivalent to the method also not needing to change the paging mechanism. This method involves the process of switching from a direct link to an indirect link, please refer to Fig.16 , which is a flow chart of the method.

[0513] The technical solution provided in the embodiments of the present application can be applied to Figure 1C The network architecture shown in the figure. Figure 1C For the corresponding relationship between the devices in the network architecture shown, please refer to Figure 4 Description of the illustrated embodiment.

[0514] S1601, remote UE and second network device perform data transmission. For example, the second network device is a network device accessed by remote UE. In addition, the embodiment of the present application also involves a first network device and a third network device, the first network device is a network device where relay UE resides, and the third network device is an anchor network device of relay UE. In the embodiment of the present application, the first network device, the second network device and the third network device are different network devices.

[0515] S1602: The second network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the second network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0516] For more information about S1602, please refer to Figure 3 S302 in the illustrated embodiment.

[0517] S1603: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Fig.16 Take the remote UE measuring one or more UEs as an example. Fig.16 The relay UE shown is, for example, one of the one or more UEs.

[0518] For more information about S1603, please refer to Figure 3 S303 in the illustrated embodiment.

[0519] S1604: The remote UE sends third information to the second network device, and correspondingly, the second network device receives the third information from the remote UE.

[0520] For more information about S1604, such as the content of the third information, please refer to Figure 3 S304 in the embodiment shown. For example, in the embodiment of the present application, the third information includes information of one or more UEs involved in the third information, wherein the information of one UE may include one or more of the following: resume ID of the UE, I-RNTI of the UE, or short-I-RNTI of the UE. For example, the third information includes information of the relay UE, and the information of the relay UE includes one or more of the following: resume ID of the relay UE, I-RNTI of the relay UE, or short-I-RNTI of the relay UE.

[0521] Optionally, the second network device may obtain fourth information based on the third information, for example, the fourth information includes the identifiers of some UEs (or all UEs) involved in the third information, and may also include the status information of some UEs (or all UEs) involved in the third information, for example, the fourth information includes the identifier of the relay UE, and includes the status information of the relay UE. The status information of a UE may indicate that the status of the UE is an RRC connected state or an RRC non-connected state, for example, the status information of the relay UE may indicate that the relay UE is in an RRC non-connected state. In an embodiment of the present application, for example, the relay UE is in an RRC idle state or an RRC inactive state.

[0522] S1605: The second network device sends first information to the third network device, and correspondingly, the third network device receives the first information from the second network device. The first information can be used to determine whether the relay UE is authorized to provide relay service.

[0523] If the second network device is not the anchor network device of the relay UE, the second network device may determine the anchor network device of the relay UE, such as the third network device, according to the resume ID and / or I-RNTI of the relay UE, thereby sending the first information to the third network device, for example, the first information includes the identifier of the relay UE. For one or more UEs involved in the third information, if the second network device is not the anchor network device of these UEs, the second network device may send the first information to the anchor network devices of these UEs accordingly, and the first information sent to different anchor network devices may be different. Here, the second network device sending the first information to the third network device is taken as an example.

[0524] S1606: The third network device determines whether the relay UE is authorized to provide relay service.

[0525] The third network device may determine whether the relay UE is authorized to provide the relay service according to the context of the relay UE. If the relay UE is authorized to provide the relay service, S1606 may be executed; if the relay UE is not authorized to provide the relay service, S1606 and subsequent steps do not need to be executed, for example, the third network device may send a rejection message to the second network device to indicate the rejection of providing the context of the relay UE, or indicate the reason for rejecting the provision of the context of the relay UE.

[0526] S1607: The third network device sends second information to the second network device, and correspondingly, the first network device receives the second information from the third network device.

[0527] The second information may indicate that the relay UE is authorized to provide relay service, or indicate that the relay UE is not authorized to provide relay service. For example, the second information is indication information, which may be used to indicate that the relay UE is authorized to provide relay service, or indicate that the relay UE is not authorized to provide relay service.

[0528] S1608: The second network device selects a target UE for path switching for the remote UE. In other words, the second network device determines the UE to which the remote UE needs to switch.

[0529] For more information about S1608, please refer to Figure 3 S307 in the illustrated embodiment.

[0530] S1609: The second network device sends a handover request message to the first network device, and correspondingly, the first network device receives the handover request message from the second network device. The handover request message can be used to request to handover the remote UE to the first network device, and of course, actually handover the remote UE to the relay UE under the first network device.

[0531] S1610: The first network device sends a handover confirmation message to the third network device, and correspondingly, the third network device receives the handover confirmation message from the first network device. The handover confirmation message may be used to confirm handover of the remote UE to the first network device.

[0532] Optionally, the switching confirmation message may also include configuration information, such as first configuration information, which may configure the remote UE to access the network through the relay UE. For example, the first configuration information may include configuration information of the second relay link, and the second relay link includes a side link between the relay UE and the remote UE. The remote UE is connected to the relay UE through the side link, thereby accessing the network through the relay UE.

[0533] S1611. The second network device sends fourth information to the first network device, and correspondingly, the first network device receives the fourth information from the second network device. The fourth information may be used to indicate (or request) paging the relay UE. For example, the second network device may send a handover request message to the first network device, and carry the fourth information in the handover request message. The handover request message may be used to request that the remote UE be handed over to the first network device, or to request that the remote UE be handed over to the relay UE under the first network device.

[0534] For example, the fourth information includes an identifier of the relay UE, such as a resume ID and / or I-RNTI of the relay UE. In addition, the fourth information may also include status information of the relay UE. The status information of a UE may indicate that the status of the UE is an RRC connected state or an RRC non-connected state. For example, the status information of the relay UE may indicate that the relay UE is in an RRC non-connected state. In an embodiment of the present application, for example, the relay UE is in an RRC idle state. Optionally, the fourth information may also include an identifier of the cell where the relay UE is located. For example, the fourth information includes the ID of the cell where the relay UE resides.

[0535] The second network device may determine the network device where one or more UEs involved in the third information reside, and send the information of the one or more UEs to the network device where the UEs reside, so that the network device where the UEs reside pages the corresponding UEs. If the network device where the one or more UEs reside is the same network device, the second network device may send the fourth information to the network device, and if the network devices where the one or more UEs reside are different network devices, the second network device needs to send the information of the one or more UEs to the respective network devices where they reside.

[0536] For example, if the relay UE resides on the first network device, the second network device may send the fourth information to the first network device.

[0537] S1612: The first network device sends first information to the third network device, and correspondingly, the third network device receives the first information from the first network device. The first information can be used to determine whether the relay UE is authorized to provide relay service, or the first information can request to obtain the context of the relay UE.

[0538] The first network device may determine the anchor network device of the relay UE, such as the third network device, according to the resume ID and / or I-RNTI of the relay UE, thereby sending the first information to the third network device. For example, the first information includes the identifier of the relay UE. The identifier of the relay UE is, for example, the 5G-S-TMSI or 5G-GUTI of the relay UE.

[0539] S1613. The third network device sends second information to the first network device. Correspondingly, the first network device receives the second information from the third network device.

[0540] The second information may indicate that the relay UE is authorized to provide the relay service, or indicate that the relay UE is not authorized to provide the relay service. For example, the second information includes the context of the relay UE, and the context of the relay UE indicates whether the relay UE is provided with the authorized service.

[0541] S1614: The second network device or the first network device selects a target UE for path switching for the remote UE, or in other words, the second network device or the first network device determines the UE to which the remote UE needs to switch. Fig.16 Take the example of the first network device selecting a target UE for path switching for the remote UE.

[0542] If the target UE is selected by the second network device, the first network device may send information indicating whether the relay UE is authorized to provide relay services to the second network device. The second network device may receive the information from one or more first network devices, so that the second network device may select a UE as the target UE from the UEs authorized to provide relay services. The selection method and other contents can be referred to Figure 3 S307 in the embodiment shown. If the first network device selects the target UE, the selection method and other contents may also refer to Figure 3 S307 in the illustrated embodiment.

[0543] Among them, S1605-S1610 and S1611-S1614 are two optional solutions, and only one of them needs to be executed. That is, whether the relay UE is authorized to provide relay service can be confirmed by the third network device accessed by the remote UE or by the second network device where the relay UE resides.

[0544] S1615. The first network device sends a paging message, and the relay UE receives the paging message accordingly. The paging message is used to page the relay UE. The first network device may page some or all UEs involved in the fourth information, and paging the relay UE is taken as an example here. For example, the first network device sends a paging message in the cell where the relay UE resides.

[0545] If the target UE is selected by the second network device, then after selecting the target UE, the second network device may send the identifier of the target UE to the first network device, so that the first network device can page the target UE.

[0546] S1616. The relay UE enters the RRC connected state.

[0547] After receiving the paging message, the relay UE can initiate random access to the first network device to enter the RRC connection state. If the first network device pages multiple UEs, multiple UEs can enter the RRC connection state. After multiple UEs enter the RRC connection state, the first network device selects one UE from the multiple UEs as the target UE for the remote UE to perform path switching. For example, the target UE determined by the first network device is the relay UE.

[0548] S1617: The first network device sends an RRC reconfiguration message to the remote UE. Correspondingly, the remote UE receives the RRC reconfiguration message from the first network device. For easy distinction, the RRC reconfiguration message is referred to as RRC reconfiguration message 1.

[0549] For more information about S1617, please refer to Fig.15 S1509 in the embodiment shown.

[0550] S1618: The first network device sends an RRC reconfiguration message to the relay UE, and correspondingly, the relay UE receives the RRC reconfiguration message from the first network device. For the sake of distinction, the RRC reconfiguration message is referred to as RRC reconfiguration message 2.

[0551] For more information about S1618, please refer to Fig.15 S1510 in the illustrated embodiment.

[0552] S1619: The remote UE establishes direct communication with the relay UE.

[0553] If the remote UE selects the relay UE by itself, S1619 may also occur before S1604.

[0554] S1620, the remote UE sends an RRC reconfiguration completion message to the relay UE, and accordingly, the relay UE receives the RRC reconfiguration completion message from the remote UE; the relay UE sends the RRC reconfiguration completion message to the first network device, and accordingly, the first network device receives the RRC reconfiguration completion message from the relay UE. That is, the remote UE sends the RRC reconfiguration completion message to the first network device through the relay UE. The RRC reconfiguration completion message may indicate that the remote UE has completed the path switching.

[0555] In the embodiment of the present application, the first network device can learn the cell where the relay UE is located, so the first network device can page the relay UE in the cell without paging in a larger range, thereby reducing the number of paging messages, saving transmission overhead, and improving paging efficiency.

[0556] Next, a fifteenth communication method provided in an embodiment of the present application is introduced. The method may include: Figure 3 The embodiment shown to Fig.16 Part or all of the steps in any one or more of the embodiments shown in the embodiment, that is, through this method, it can be explained Figure 3 The embodiment shown to Fig.16 How one or more of the embodiments shown can be combined for application. Fig.17 , which is a flow chart of the method.

[0557] S1701: The remote UE performs data transmission with a network device. For example, the network device is a network device accessed by the remote UE.

[0558] S1702: The network device sends an RRC message to the remote UE, and correspondingly, the remote UE receives the RRC message from the network device. The RRC message includes, for example, measurement configuration information, and the measurement configuration information is used by the remote UE to measure other UEs or select other UEs.

[0559] For more information about S1702, please refer to Figure 3 S302 in the illustrated embodiment.

[0560] S1703: The remote UE measures or selects one or more UEs. For example, the remote UE may trigger one or more UEs to send discovery messages, so that the remote UE may measure the discovery messages from the one or more UEs to complete the measurement or selection of the one or more UEs. Fig.17 Take the remote UE measuring one or more UEs as an example. Fig.17 The relay UE shown is, for example, one of the one or more UEs.

[0561] For more information about S1703, please refer to Figure 3 S303 in the illustrated embodiment.

[0562] S1704: The remote UE sends third information to the network device, and correspondingly, the network device receives the third information from the remote UE.

[0563] For more information about S1704, please refer to Figure 3 S304 in the illustrated embodiment.

[0564] S1705: The network device determines whether the relay UE is authorized to provide relay service.

[0565] If the relay UE is in RRC idle state, more information about S1705 can be found in Figure 3 S305-S306 in the embodiment shown, or refer to Figure 4 S405 to S408 in the embodiment shown, or refer to Figure 4 Alternatively, if the relay UE is in the RRC inactive state, more details of S1705 can be found in Figure 5 S505-S506 in the embodiment shown, or refer to Figure 6S605 to S608 in the embodiment shown, or refer to Figure 6 S609 to S612 in the embodiment shown.

[0566] According to the introduction of the above embodiments, the network device that determines whether the relay UE is authorized to provide the relay service may be the network device accessed by the remote UE, or may not be the network device accessed by the remote UE. Fig.17 For example, if the network device that the relay UE is authorized to provide relay services is the network device that the remote UE accesses, which network device should it actually be? Figure 3 The embodiment shown to Figure 6 An introduction to any of the illustrated embodiments.

[0567] S1706. The remote UE triggers the relay UE to enter the RRC connected state.

[0568] For more information about S1706, please refer to Figure 7 S705 to S707 in the embodiment shown. In addition, for the process of relay UE entering RRC connected state, etc., please refer to Figure 8 S802 to S810 in the embodiment shown.

[0569] S1707. The network device pages the relay UE.

[0570] For more information about S1707, please refer to Fig.11 The embodiment shown to Fig.16 An introduction to some or all of the steps of any one of the illustrated embodiments.

[0571] Among them, S1706 and S1707 are two optional solutions, and you only need to implement one of them.

[0572] In addition, according to the introduction of the above-mentioned embodiment, the network device for paging the relay UE may be the network device accessed by the remote UE, or may not be the network device accessed by the remote UE. Fig.17 For example, to determine which network device the paging relay UE is connected to, you can refer to Fig.11 The embodiment shown to Fig.16 An introduction to any of the illustrated embodiments.

[0573] S1708. The remote UE and the relay UE notify each other that the configuration is completed.

[0574] That is, if the remote UE completes the configuration of the second relay link, it can inform the relay UE, and if the relay UE completes the configuration of the first relay link, it can also inform the remote UE. Fig. 9 S908-920 in the embodiment shown, or refer to Fig.10 S1008 to S1021 in the embodiment shown.

[0575] In addition, S1708 may also occur during the execution of S1706, or may occur after the execution of S1706 is completed, or may occur after the execution of S1707 is completed.

[0576] Figure 3 The embodiment shown to Fig.16 One or more of the embodiments shown in the embodiments may be combined for application. For example, the embodiments of the present application provide Figure 3 The embodiment shown to Fig.16 The embodiments shown are combined with examples of applications. Alternatively, Figure 3 The embodiment shown to Fig.16 The illustrated embodiments may not be combined but may be used individually.

[0577] Fig.18 A schematic diagram of the structure of a communication device provided in an embodiment of the present application is given. The communication device 1800 may be Figure 3 The embodiment shown to Fig.17 The relay UE described in any one of the embodiments shown in the embodiment is used to implement the method performed by the relay UE in the above method embodiment. Alternatively, the communication device 1800 may be Figure 3 The embodiment shown to Fig.17 The remote UE described in any one of the embodiments shown in the embodiment is used to implement the method executed by the remote UE in the above method embodiment. The communication device may also be Figure 3 The embodiment shown to Fig.17 The network device (eg, the first network device) described in any one of the embodiments shown is used to implement the method corresponding to the network device (eg, the first network device) in the above method embodiment. For specific functions, please refer to the description in the above method embodiment.

[0578] The communication device 1800 includes one or more processors 1801. The processor 1801 may also be referred to as a processing unit, which may implement certain control functions. The processor 1801 may be a general-purpose processor or a dedicated processor, etc. For example, it may include: a baseband processor, a central processing unit, an application processor, a modem processor, a graphics processor, an image signal processor, a digital signal processor, a video codec processor, a controller, a memory, and / or a neural network processor, etc. The baseband processor may be used to process communication protocols and communication data. The central processing unit may be used to control the communication device 1800, execute software programs and / or process data. Different processors may be independent devices, or they may be integrated into one or more processors, for example, integrated into one or more dedicated integrated circuits.

[0579] Optionally, the communication device 1800 includes one or more memories 1802 for storing instructions 1804, and the instructions can be executed on the processor so that the communication device 1800 performs the method described in the above method embodiment. Optionally, data can also be stored in the memory 1802. The processor and the memory can be set separately or integrated together.

[0580] Optionally, the communication device 1800 may include instructions 1803 (sometimes also referred to as codes or programs), and the instructions 1803 may be executed on the processor so that the communication device 1800 executes the method described in the above embodiment. The processor 1801 may store data.

[0581] Optionally, the communication device 1800 may further include a transceiver 1805 and an antenna 1806. The transceiver 1805 may be referred to as a transceiver unit, a transceiver, a transceiver circuit, a transceiver, an input / output interface, etc., and is used to implement the transceiver function of the communication device 1800 through the antenna 1806.

[0582] Optionally, the communication device 1800 may also include one or more of the following components: a wireless communication module, an audio module, an external memory interface, an internal memory, a universal serial bus (USB) interface, a power management module, an antenna, a speaker, a microphone, an input / output module, a sensor module, a motor, a camera, or a display screen, etc. It is understood that in some embodiments, the communication device 1800 may include more or fewer components, or some components may be integrated, or some components may be separated. These components may be implemented in hardware, software, or a combination of software and hardware.

[0583] The processor 1801 and the transceiver 1805 described in the embodiments of the present application may be implemented in an integrated circuit (IC), an analog IC, a radio frequency integrated circuit (RFID), a mixed signal IC, an application specific integrated circuit (ASIC), a printed circuit board (PCB), or an electronic device, etc. The communication device described herein may be an independent device (e.g., an independent integrated circuit, a mobile phone, etc.), or may be a part of a larger device (e.g., a module that can be embedded in other devices). For details, please refer to the aforementioned description of the terminal device and the network device, which will not be repeated here.

[0584] The present application embodiment provides a terminal device, which can be used in the above embodiments (for the convenience of description, referred to as UE). The terminal device includes a Figures 3 to 17 The corresponding means (means), units and / or circuits of the UE functions described in the embodiments shown in any one or more of the figures. For example, the terminal device includes a transceiver module to support the terminal device to implement the transceiver function, and a processing module to support the terminal device to process the signal.

[0585] Fig.19 A schematic diagram of the structure of a terminal device provided in an embodiment of the present application is given.

[0586] The terminal device 1900 can be applied to Figure 1A to Figure 1D In the architecture shown in any of the accompanying drawings. For ease of explanation, Fig.19 Only the main components of the terminal device 1900 are shown. Fig.19 As shown, the terminal device 1900 includes a processor, a memory, a control circuit, an antenna, and an input-output device. The processor is mainly used to process the communication protocol and communication data, and to control the entire terminal device 1900, execute the software program, and process the data of the software program. The memory is mainly used to store software programs and data. The control circuit is mainly used for converting baseband signals and radio frequency signals and processing radio frequency signals. The antenna is mainly used to send and receive radio frequency signals in the form of electromagnetic waves. The input-output device, such as a touch screen, a display screen, a microphone, a keyboard, etc., is mainly used to receive data input by the user and output data to the user.

[0587] Taking the terminal device 1900 as a mobile phone as an example, when the terminal device 1900 is turned on, the processor can read the software program in the storage unit, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be sent wirelessly, the processor performs baseband processing on the data to be sent, and outputs the baseband signal to the control circuit. The control circuit performs radio frequency processing on the baseband signal and then sends the radio frequency signal outward through the antenna in the form of electromagnetic waves. When data is sent to the terminal device 1900, the control circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor. The processor converts the baseband signal into data and processes the data.

[0588] Those skilled in the art will appreciate that for ease of description, Fig.19 Only one memory and processor are shown. In some embodiments, the terminal device 1900 may include multiple processors and memories. The memory may also be referred to as a storage medium or a storage device, etc., which is not limited in the embodiments of the present invention.

[0589] As an optional implementation method, the processor may include a baseband processor and a central processing unit. The baseband processor is mainly used to process the communication protocol and communication data, and the central processing unit is mainly used to control the entire terminal device 1900, execute software programs, and process software program data. Fig.19 The processor in integrates the functions of the baseband processor and the central processing unit. Those skilled in the art can understand that the baseband processor and the central processing unit can also be independent processors, which are interconnected through technologies such as buses. The terminal device 1900 may include multiple baseband processors to adapt to different network standards, and the terminal device 1900 may include multiple central processing units to enhance its processing capabilities. The various components of the terminal device 1900 can be connected through various buses. The baseband processor can also be described as a baseband processing circuit or a baseband processing chip. The central processing unit can also be described as a central processing circuit or a central processing chip. The function of processing the communication protocol and communication data can be built into the processor, or it can be stored in the storage unit in the form of a software program, and the processor executes the software program to realize the baseband processing function.

[0590] In one example, the antenna with transceiver functions and the control circuit can be regarded as the transceiver unit 1910 of the terminal device 1900, and the processor with processing function can be regarded as the processing unit 1920 of the terminal device 1900. Fig.19As shown, the terminal device 1900 includes a transceiver unit 1910 and a processing unit 1920. The transceiver unit may also be referred to as a transceiver, a transceiver, a transceiver device, etc. Optionally, the device used to implement the receiving function in the transceiver unit 1910 may be regarded as a receiving unit, and the device used to implement the sending function in the transceiver unit 1910 may be regarded as a sending unit, that is, the transceiver unit 1910 includes a receiving unit and a sending unit. Exemplarily, the receiving unit may also be referred to as a receiver, a receiver, a receiving circuit, etc., and the sending unit may be referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

[0591] The present application also provides a network device, which can be used in the above embodiments. The network device includes a Figures 3 to 17 The means, units and / or circuits for implementing the functions of the network device (e.g., the first network device) described in any one or more of the embodiments shown in the accompanying drawings. For example, the network device includes a transceiver module to support the network device to implement the transceiver function, and a processing module to support the network device to process the signal.

[0592] Fig. 20 A schematic diagram of the structure of a network device provided in an embodiment of the present application is given. Fig. 20 As shown, the network equipment can be applied to Figure 1A to Figure 1D The network device includes: a baseband device 2001, a radio frequency device 2002, and an antenna 2003. In the uplink direction, the radio frequency device 2002 receives information sent by the terminal device through the antenna 2003, and sends the information sent by the terminal device to the baseband device 2001 for processing. In the downlink direction, the baseband device 2001 processes the information of the terminal device and sends it to the radio frequency device 2002, and the radio frequency device 2002 processes the information of the terminal device and sends it to the terminal device through the antenna 2003.

[0593] The baseband device 2001 includes one or more processing units 20011, a storage unit 20012 and an interface 20013. The processing unit 20011 is used to support the network device to perform the functions of the network device in the above method embodiment. The storage unit 20012 is used to store software programs and / or data. The interface 20013 is used to exchange information with the radio frequency device 2002, and the interface includes an interface circuit for inputting and outputting information. In one implementation, the processing unit is an integrated circuit, such as one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits can be integrated together to form a chip. The storage unit 20012 and the processing unit 20011 can be located in the same chip, that is, an on-chip storage element. Alternatively, the storage unit 20012 can also be on a different chip from the processing unit 20011, that is, an off-chip storage element. The storage unit 20012 can be a memory, or a general term for multiple memories or storage elements.

[0594] The network device may implement some or all of the steps in the above method embodiment in the form of one or more processing unit schedulers. Figures 3 to 17 The one or more processing units may support the same wireless access technology or different wireless access technologies.

[0595] Those of ordinary skill in the art will appreciate that the units and steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0596] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0597] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned computer-readable storage medium can be any available medium that can be accessed by a computer. By way of example and not limitation, computer-readable media may include random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), universal serial bus flash disk, mobile hard disk, or other optical disk storage, magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer. In addition, by way of example but not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), or direct rambus RAM (DR RAM).

[0598] The above is only a specific implementation of the present application, but the protection scope of the embodiments of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the embodiments of the present application, which should be included in the protection scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application should be based on the protection scope of the claims.

[0599] In combination with the above, the present application also provides the following embodiments:

[0600] Embodiment 1: A communication method, comprising:

[0601] The first network device receives first information from the second terminal device or the third network device, where the first information includes an identification of the first terminal device, and the third network device is a network device where the second terminal device resides;

[0602] The first network device sends an identifier of the first terminal device to the second network device, where the identifier of the first terminal device is used to determine whether the first terminal device is authorized to provide a relay service;

[0603] The first network device receives second information from the second network device, where the second information is used to indicate that the first terminal device is authorized to provide a relay service, or indicates that the first terminal device is not authorized to provide a relay service.

[0604] Embodiment 2: According to the method described in Embodiment 1, the first information also includes status information of the first terminal device, and the status information of the first terminal device is used to indicate that the first terminal device is in an RRC inactive state or an RRC idle state.

[0605] Embodiment 3: According to the method of embodiment 1 or embodiment 2, when the second information is used to indicate that the first terminal device is authorized to provide a relay service, the method further includes:

[0606] The first network device sends a first RRC message, where the first RRC message includes first configuration information, where the first configuration information is used to configure a second terminal device to access a network through the first terminal device.

[0607] Embodiment 4: According to the method described in Embodiment 3, the first RRC message also includes first indication information, and the first indication information is used to indicate triggering the first terminal device to enter an RRC connection state.

[0608] Embodiment 5: According to the method described in any one of Embodiments 1 to 4, the second information is the context of the first terminal device, or the second information is information used to indicate whether the first terminal device is authorized to provide relay service.

[0609] Embodiment 6: The method according to any one of Embodiments 1 to 5,

[0610] When the first terminal device is in an RRC inactive state, the second network device is an anchor network device of the first terminal device;

[0611] When the first terminal device is in the RRC idle state, the second network device is a core network device.

[0612] Embodiment 7: The method according to any one of Embodiments 1 to 3, further comprising:

[0613] The first network device generates a paging message, where the paging message is used to page the first terminal device;

[0614] The first network device sends the paging message.

[0615] Embodiment 8: The method according to embodiment 7,

[0616] The state of the first terminal device is an RRC inactive state, and the paging message includes the I-RNTI of the first terminal device;

[0617] The state of the first terminal device is an RRC idle state, and the paging message includes the 5G-S-TMSI of the first terminal device.

[0618] Embodiment 9: According to the method of embodiment 7 or embodiment 8, the first information further includes an identifier of a cell where the first terminal device is located; and the first network device sending the paging message includes:

[0619] The first network device sends the paging message in the cell corresponding to the identifier of the cell.

[0620] Embodiment 10: A communication method, comprising:

[0621] The second terminal device measures the first terminal device and determines a state of the first terminal device, where the state of the first terminal device is an RRC connected state, an RRC inactive state, or an RRC idle state;

[0622] The second terminal device sends third information to the third network device, where the third information includes the state information of the first terminal device, where the state information of the first terminal device is used to indicate the state of the first terminal device;

[0623] The second terminal device receives a first RRC message from the third network device, where the first RRC message includes first configuration information, and the first configuration information is used to configure the second terminal device to access the network through the first terminal device.

[0624] Embodiment 11: According to the method described in Embodiment 10, the first RRC message also includes first indication information, and the first indication information is used to indicate triggering the first terminal device to enter an RRC connection state.

[0625] Embodiment 12: According to the method described in Embodiment 10 or Embodiment 11, the third information further includes a measurement report of the first terminal device, or the third information further includes an identifier of the first terminal device.

[0626] Embodiment 13: The method according to any one of Embodiments 10 to 12, further comprising:

[0627] The second terminal device receives a discovery message from the first terminal device, where the discovery message includes status information of the first terminal device.

[0628] Embodiment 14: According to the method described in Embodiment 13, the status information of the first terminal device is included in the message body or message header of the discovery message, or the status information of the first terminal device is indicated by a layer 2 destination identifier included in the discovery message.

[0629] Embodiment 15: The method according to any one of Embodiments 10 to 12, further comprising:

[0630] The second terminal device receives a discovery message from the first terminal device;

[0631] The second terminal device determines the state of the first terminal device according to the inclusion of the identifier of the first terminal device in the discovery message.

[0632] Embodiment 16, according to the method of embodiment 15, the second terminal device determines the state of the first terminal device according to the inclusion of the identifier of the first terminal device in the discovery message, including:

[0633] The second terminal device determines, according to the identification of the first terminal device included in the discovery message as C-RNTI, that the state of the first terminal device is the RRC connected state;

[0634] The second terminal device determines, according to the identification of the first terminal device included in the discovery message as a resume identification or an I-RNTI, that the state of the first terminal device is an RRC inactive state;

[0635] The second terminal device determines that the state of the first terminal device is an RRC idle state based on the fact that the discovery message does not include the identifier of the first terminal device, or that the identifier of the first terminal device included is 5G-S-TMSI.

[0636] Embodiment 17: The method according to any one of Embodiments 10 to 12, further comprising:

[0637] The second terminal device receives a discovery message from the first terminal device through a first resource pool, where the first resource pool is used by a terminal device in the RRC inactive state or the RRC idle state;

[0638] The second terminal device determines whether the first terminal device is in the RRC activated state or the RRC idle state based on the first resource pool.

[0639] Embodiment 18: The method according to any one of Embodiments 10 to 12, further comprising:

[0640] The second terminal device receives a system message from the first terminal device, where the system message includes status information of the first terminal device.

[0641] Embodiment 19: A communication method, comprising:

[0642] The first terminal device sends a second message, where the second message is used to indicate a state of the first terminal device, where the state of the first terminal device is an RRC connected state, an RRC inactive state, or an RRC idle state.

[0643] Embodiment 20: According to the method described in Embodiment 19, the first terminal device sends a second message, including:

[0644] The first terminal device broadcasts the second message; or,

[0645] The first terminal device sends the second message to the second terminal device.

[0646] Embodiment 21: According to the method described in Embodiment 19 or Embodiment 20, the second message is a discovery message, and the discovery message includes status information of the first terminal device.

[0647] Embodiment 22: According to the method described in Embodiment 21, the status information of the first terminal device is included in the message body or message header of the discovery message, or the status information of the first terminal device is indicated by the layer 2 destination identifier of the discovery message.

[0648] Embodiment 23: According to the method described in Embodiment 19 or Embodiment 20, the second message is a discovery message, and the discovery message indicates the status of the first terminal device by including an identification of the first terminal device.

[0649] Embodiment 24: The method according to embodiment 23,

[0650] The identifier of the first terminal device included in the discovery message is C-RNTI, indicating that the state of the first terminal device is the RRC connected state;

[0651] The identifier of the first terminal device included in the discovery message is a resume identifier or an I-RNTI, indicating that the state of the first terminal device is an RRC inactive state;

[0652] The discovery message does not include the identifier of the first terminal device, or the included identifier of the first terminal device is 5G-S-TMSI, indicating that the state of the first terminal device is RRC idle state.

[0653] Embodiment 25: According to the method described in Embodiment 19 or Embodiment 20, the second message is a discovery message, and the discovery message indicates the status of the first terminal device through a resource pool used to send the discovery message.

[0654] 26. According to the method described in Example 19 or Example 20, the second message is a system message, and the system message includes status information of the first terminal device.

[0655] Embodiment 27: A communication method, comprising:

[0656] The second terminal device sends a third message, where the third message is used to instruct the first terminal device to enter an RRC connection state, wherein the second terminal device requests the first terminal device to provide a relay service.

[0657] Embodiment 28: According to the method of embodiment 27, the second terminal device sends a third message, including:

[0658] The second terminal device broadcasts the third message; or,

[0659] The second terminal device sends the third message to the first terminal device.

[0660] Embodiment 29: The method according to embodiment 27 or embodiment 28, further comprising:

[0661] The second terminal device receives a fourth message from the first terminal device, where the fourth message is used to indicate that the first terminal device has entered the RRC connection state, or is used to indicate that the first terminal device has failed to enter the RRC connection state.

[0662] Embodiment 30: According to the method described in Embodiment 27 or Embodiment 28, the third message further includes the reason why the second terminal device requests to establish a connection with the first terminal device.

[0663] Embodiment 31, according to the method of embodiment 30, the reason why the second terminal device requests to establish a connection with the first terminal device is:

[0664] The second terminal device requests to access the network for the first time through the first terminal device; or,

[0665] The second terminal device requests to switch to a path for accessing the network through the first terminal device; or,

[0666] The second terminal device requests to monitor paging through the first terminal device.

[0667] Embodiment 32: According to the method described in any one of Embodiments 27 to 31, the third message is a discovery message, a DCR message or a security establishment completion message.

[0668] Embodiment 33: According to the method of embodiment 32, the third message is used to indicate entering the RRC connected state, including:

[0669] The third message includes second indication information, where the second indication information is used to indicate entering the RRC connected state; or,

[0670] The third message does not include second indication information, and is used to indicate entering the RRC connected state.

[0671] Embodiment 34: According to the method of embodiment 32, the third message is used to indicate entering the RRC connected state, including:

[0672] The third message includes the C-RNTI of the first terminal device, or the third message does not include the identifier of the second terminal device, indicating that the first terminal device enters the RRC connected state.

[0673] Embodiment 35: According to the method described in any one of Embodiments 27 to 31, the third message is a PC5-RRC message after the second terminal device establishes a PC5-S connection with the first terminal device.

[0674] Embodiment 36: According to the method described in any one of Embodiments 27 to 31, the third message is the first RRC message for establishing a connection with the first network device after the second terminal device establishes a PC5-S connection with the first terminal device.

[0675] Embodiment 37: According to the method described in any one of Embodiments 27 to 36, the fourth message is a discovery message, a DCR response message or a PC5-RRC message, or the fourth message is a data packet.

[0676] Embodiment 38: According to the method according to any one of Embodiments 27 to 37, when the fourth message is used to indicate that the first terminal device fails to enter the RRC connected state, the method further includes:

[0677] The second terminal device initiates an RRC re-establishment process;

[0678] After the RRC re-establishment is successful, or during the RRC re-establishment process, the second terminal device sends a failure reason to the fourth network device, where the failure reason is used to indicate the reason why the second terminal device failed to perform path switching, and the path switching is that the second terminal device switches to a path that is relayed through the first terminal device.

[0679] Embodiment 39: According to the method described in any one of Embodiments 27 to 38, before the second terminal device sends the third message, the method further includes:

[0680] The second terminal device receives a first RRC message from a third network device, where the first RRC message includes first indication information, and the first indication information is used to indicate a trigger for the first terminal device to enter an RRC connection state.

[0681] Embodiment 40: A communication method, comprising:

[0682] The first terminal device receives a third message from the second terminal device, where the third message is used to indicate entering an RRC connected state, wherein the second terminal device needs to request the first terminal device to provide a relay service;

[0683] The first terminal device performs a random access process to enter the RRC connection state.

[0684] Embodiment 41: The method according to embodiment 40, further comprising:

[0685] The first terminal device sends a fourth message to the second terminal device, where the fourth message is used to indicate that the first terminal device has entered the RRC connection state, or is used to indicate that the first terminal device has failed to enter the RRC connection state.

[0686] Embodiment 42: According to the method described in Embodiment 40 or Embodiment 41, the third message further includes the reason why the second terminal device requests to establish a connection with the first terminal device.

[0687] Embodiment 43: The method according to any one of Embodiments 40 to 42, further comprising:

[0688] Before the first terminal device performs a random access process, the first terminal device does not perform a UAC process.

[0689] Embodiment 44: According to the method described in any one of Embodiment 40 to Embodiment 43, the first terminal device performs a random access process, including:

[0690] The first terminal device sends a random access preamble code to the first network device;

[0691] The first terminal device receives a random access response message from the first network device;

[0692] The first terminal device sends an RRC establishment request message to the first network device;

[0693] The first terminal device receives an RRC establishment completion message from the first network device, where the RRC establishment completion message is used to indicate that the RRC connection is successfully established, or to indicate a rejection of establishing the RRC connection.

[0694] Embodiment 45, the method according to embodiment 44,

[0695] The random access preamble is preconfigured, and the random access preamble is used to indicate that the reason why the first terminal device enters the RRC connected state is to provide a path switch for other terminal devices; or,

[0696] The RRC establishment request message includes reason information for the first terminal device to enter the RRC connection state.

[0697] Embodiment 46: According to the method described in any one of Embodiments 40 to 45, the third message is a discovery message, a DCR message or a security establishment completion message.

[0698] Embodiment 47: According to the method of embodiment 46, the third message is used to indicate entering the RRC connected state, including:

[0699] The third message includes second indication information, where the second indication information is used to indicate entering the RRC connected state; or,

[0700] The third message does not include second indication information, and is used to indicate entering the RRC connected state.

[0701] Embodiment 48: According to the method of embodiment 46, the third message is used to indicate entering the RRC connected state, including:

[0702] The third message includes the C-RNTI of the first terminal device, or the third message does not include the identifier of the first terminal device, indicating that the first terminal device enters the RRC connected state.

[0703] Embodiment 49: According to the method described in any one of Embodiments 40 to 45, the third message is a PC5-RRC message after the second terminal device establishes a PC5-S connection with the first terminal device.

[0704] Embodiment 50: According to the method described in any one of Embodiments 40 to 45, the third message is the first RRC message for establishing a connection with the first network device after the second terminal device establishes a PC5-S connection with the first terminal device.

[0705] Embodiment 51: According to the method described in any one of Embodiments 40 to 50, the fourth message is a discovery message, a DCR response message or a PC5-RRC message, or the fourth message is a data packet.

[0706] Embodiment 52: A communication method, comprising:

[0707] The second terminal device sends a fifth message to the first terminal device, where the fifth message is used to indicate entering the RRC connected state, wherein the second terminal device requests the first terminal device to provide a relay service;

[0708] The second terminal device receives a sixth message from the first terminal device, where the sixth message is used to indicate that the first terminal device has completed configuration of a first relay link, and the first relay link is used to provide a relay service for the second terminal device.

[0709] Embodiment 53: The method according to embodiment 52, further comprising:

[0710] The second terminal device receives a first RRC message from a third network device, where the first RRC message includes first indication information, and the first indication information is used to indicate a trigger for the first terminal device to enter the RRC connection state.

[0711] Embodiment 54: According to the method described in Embodiment 52 or Embodiment 53, the first RRC message also includes first configuration information, and the first configuration information is used to configure the second terminal device to access the network through the first terminal device.

[0712] Embodiment 55: According to the method described in Embodiment 54, the fifth message is also used to indicate that the second terminal device has completed configuration of a second relay link, and the second relay link is used to access the network through the first terminal device.

[0713] Embodiment 56: The method according to any one of Embodiments 52 to 55,

[0714] The fifth message is a PC5-S message, or a DCR message, or a security establishment completion message.

[0715] Embodiment 57: The method according to any one of Embodiments 52 to 56,

[0716] The sixth message is a DCR response message.

[0717] Embodiment 58: The method according to embodiment 52 or embodiment 53, further comprising:

[0718] The second terminal device receives first configuration information from a third network device, where the first configuration information is used to configure the second terminal device to access a network through the first terminal device;

[0719] The second terminal device is configured according to the first configuration information;

[0720] After the configuration is completed, the second terminal device sends a seventh message to the first terminal device, where the seventh message is used to indicate that the second terminal device has completed the configuration of the second relay link, and the second relay link is used to access the network through the first terminal device.

[0721] Embodiment 59, the method according to embodiment 58,

[0722] The sixth message is a PC5-RRC message.

[0723] Embodiment 60, the method according to embodiment 58 or embodiment 59,

[0724] The seventh message is a PC5-RRC message.

[0725] Embodiment 61: A communication method, comprising:

[0726] The first terminal device receives a fifth message from the second terminal device, where the fifth message is used to indicate entering an RRC connected state;

[0727] The first terminal device is configured according to second configuration information from a third network device, where the second configuration information is used to configure the first terminal device to provide a relay service for the second terminal device;

[0728] After the configuration is completed, the first terminal device sends a sixth message to the second terminal device, where the sixth message is used to indicate that the first terminal device has completed the configuration of the first relay link, and the first relay link is used to provide relay service for the second terminal device.

[0729] Embodiment 62: According to the method described in Embodiment 61, the fifth message is also used to indicate that the second terminal device has completed configuration of a second relay link, and the second relay link is used to access the network through the first terminal device.

[0730] Embodiment 63, the method according to embodiment 62,

[0731] The fifth message is a PC5-S message, or a DCR message, or a security establishment completion message.

[0732] Embodiment 64: According to the method described in Embodiment 62 or Embodiment 63, the sixth message is a DCR response message.

[0733] Embodiment 65: The method according to embodiment 61, further comprising:

[0734] The first terminal device receives a seventh message from the second terminal device, where the seventh message is used to indicate that the second terminal device has completed configuration of a second relay link, and the second relay link is used to access a network through the first terminal device.

[0735] Embodiment 66: The method according to embodiment 65,

[0736] The sixth message is a PC5-RRC message.

[0737] Embodiment 67, the method according to embodiment 65 or embodiment 66,

[0738] The seventh message is a PC5-RRC message.

[0739] Embodiment 68: A communication method, comprising:

[0740] The first network device acquires fourth information, where the fourth information includes an identifier of the first terminal device, and the fourth information also includes status information of the first terminal device, or the fourth information is further used to indicate paging the first terminal device, where the status information of the first terminal device is used to indicate that the state of the first terminal device is an RRC inactive state or an RRC idle state;

[0741] The first network device generates a paging message, where the paging message is used to page the first terminal device;

[0742] The first network device sends the paging message.

[0743] Embodiment 69: According to the method of embodiment 68, the first network device obtains the fourth information, including:

[0744] The first network device receives third information from the second terminal device, and acquires the fourth information according to the third information, wherein the third information includes status information of the first terminal device and an identifier of the first terminal device or a measurement report of the first terminal device, wherein the second terminal device requests the first terminal device to provide a relay service; or

[0745] The first network device receives the fourth information from the second network device.

[0746] Embodiment 70, the method according to embodiment 68 or embodiment 69,

[0747] The state of the first terminal device is an RRC inactive state, and the paging message includes the I-RNTI of the first terminal device;

[0748] The state of the first terminal device is an RRC idle state, and the paging message includes the 5G-S-TMSI of the first terminal device.

[0749] Embodiment 71: The method according to any one of Embodiments 68 to 70, further comprising:

[0750] The first network device sends first information to a third network device, where the first information is used to determine whether the first terminal device is authorized to provide a relay service;

[0751] The first network device receives second information from the third network device, where the second information is used to indicate that the first terminal device is authorized to provide a relay service.

[0752] Embodiment 72: According to the method described in Embodiment 71, the second information is the context of the first terminal device.

[0753] Embodiment 73: According to the method of Embodiment 68 or Embodiment 69, the fourth information further includes an identifier of a cell where the first terminal device is located; and the first network device sends the paging message, including:

[0754] The first network device sends the paging message in the cell corresponding to the identifier of the cell.

[0755] Embodiment 74: The method according to embodiment 68, embodiment 69 or embodiment 73, further comprising:

[0756] The first network device determines, based on the context of the first terminal device, that the first terminal device is authorized to provide a relay service.

[0757] Embodiment 75, a communication device, wherein the communication device comprises a processing unit and a transceiver unit, the processing unit and the transceiver unit are coupled, and can execute the method as described in any one of embodiments 1 to 9, or execute the method as described in any one of embodiments 68 to 74.

[0758] Embodiment 76. A communication device, wherein the communication device comprises a processing unit and a transceiver unit, the processing unit and the transceiver unit are coupled and capable of executing a method as described in any one of embodiments 10 to 18, or executing a method as described in any one of embodiments 19 to 26, or executing a method as described in any one of embodiments 27 to 39, or executing a method as described in any one of embodiments 40 to 51, or executing a method as described in any one of embodiments 52 to 60, or executing a method as described in any one of embodiments 61 to 67.

[0759] Embodiment 77, a communication device, wherein the communication device comprises a processor and a transceiver, the processor and the transceiver are coupled and can execute the method as described in any one of embodiments 1 to 9, or execute the method as described in any one of embodiments 68 to 74.

[0760] Embodiment 78. A communication device, wherein the communication device comprises a processor and a transceiver, the processor and the transceiver are coupled and capable of executing the method described in any one of embodiments 10 to 18, or executing the method described in any one of embodiments 19 to 26, or executing the method described in any one of embodiments 27 to 39, or executing the method described in any one of embodiments 40 to 51, or exe...

Claims

1. A communication method, characterized in that: include: The first network device receives first information from the second terminal device or the third network device, where the first information includes an identification of the first terminal device, and the third network device is a network device where the second terminal device resides; The first network device sends an identifier of the first terminal device to the second network device, where the identifier of the first terminal device is used to determine whether the first terminal device is authorized to provide a relay service, wherein when the first terminal device is in an RRC inactive state, the second network device is an anchor network device of the first terminal device, and when the first terminal device is in an RRC idle state, the second network device is a core network device; The first network device receives second information from the second network device, where the second information is used to indicate that the first terminal device is authorized to provide a relay service, or indicates that the first terminal device is not authorized to provide a relay service.

2. The method according to claim 1, characterized in that: The first information also includes status information of the first terminal device, and the status information of the first terminal device is used to indicate that the first terminal device is in an RRC inactive state or an RRC idle state.

3. The method according to claim 1 or 2, characterized in that: In a case where the second information is used to indicate that the first terminal device is authorized to provide a relay service, the method further includes: The first network device sends a first RRC message, where the first RRC message includes first configuration information, where the first configuration information is used to configure a second terminal device to access a network through the first terminal device.

4. The method according to claim 3, characterized in that The first RRC message also includes first indication information, and the first indication information is used to indicate triggering the first terminal device to enter an RRC connected state.

5. The method according to any one of claims 1, 2 and 4, characterized in that: The second information is the context of the first terminal device, or the second information is information used to indicate whether the first terminal device is authorized to provide a relay service.

6. The method according to claim 1 or 2, characterized in that: The method further comprises: The first network device generates a paging message, where the paging message is used to page the first terminal device; The first network device sends the paging message.

7. The method according to claim 6, characterized in that The state of the first terminal device is an RRC inactive state, and the paging message includes the I-RNTI of the first terminal device; The state of the first terminal device is an RRC idle state, and the paging message includes the 5G-S-TMSI of the first terminal device.

8. The method according to claim 7, characterized in that The first information further includes an identifier of a cell where the first terminal device is located; and the first network device sending the paging message includes: The first network device sends the paging message in the cell corresponding to the identifier of the cell.

9. A communication method, characterized in that: include: The second terminal device measures the first terminal device and determines a state of the first terminal device, where the state of the first terminal device is an RRC connected state, an RRC inactive state, or an RRC idle state; The second terminal device sends third information to the third network device, the third information including status information of the first terminal device, the status information of the first terminal device being used to indicate the status of the first terminal device, wherein the third information is used by the third network device to request the second network device to determine whether one or more terminal devices involved in the third information are authorized to provide a relay service, the first terminal device is one of the one or more terminal devices, wherein when the first terminal device is in an RRC inactive state, the second network device is an anchor network device of the first terminal device, and when the first terminal device is in an RRC idle state, the second network device is a core network device; The second terminal device receives a first RRC message from the third network device, where the first RRC message includes first configuration information, and the first configuration information is used to configure the second terminal device to access the network through the first terminal device.

10. The method according to claim 9, characterized in that The first RRC message also includes first indication information, and the first indication information is used to indicate triggering the first terminal device to enter an RRC connected state.

11. The method according to claim 9 or 10, characterized in that: The third information also includes a measurement report of the first terminal device, or the third information also includes an identifier of the first terminal device.

12. The method according to claim 9 or 10, characterized in that: The method further comprises: The second terminal device receives a discovery message from the first terminal device, where the discovery message includes status information of the first terminal device.

13. The method according to claim 12, characterized in that The status information of the first terminal device is included in the message body or message header of the discovery message, or the status information of the first terminal device is indicated by a layer 2 destination identifier included in the discovery message.

14. The method according to claim 9 or 10, characterized in that The method further comprises: The second terminal device receives a discovery message from the first terminal device; The second terminal device determines the state of the first terminal device according to the inclusion of the identifier of the first terminal device in the discovery message.

15. The method according to claim 14, characterized in that The second terminal device determines the state of the first terminal device according to the inclusion of the identifier of the first terminal device in the discovery message, including: The second terminal device determines, according to the identification of the first terminal device included in the discovery message as C-RNTI, that the state of the first terminal device is the RRC connected state; The second terminal device determines, according to the identification of the first terminal device included in the discovery message as a resume identification or an I-RNTI, that the state of the first terminal device is an RRC inactive state; The second terminal device determines that the state of the first terminal device is an RRC idle state based on the fact that the discovery message does not include the identifier of the first terminal device, or that the identifier of the first terminal device included is 5G-S-TMSI.

16. The method according to claim 9 or 10, characterized in that The method further comprises: The second terminal device receives a discovery message from the first terminal device through a first resource pool, where the first resource pool is used by a terminal device in the RRC inactive state or the RRC idle state; The second terminal device determines whether the first terminal device is in the RRC activated state or the RRC idle state based on the first resource pool.

17. The method according to claim 9 or 10, characterized in that The method further comprises: The second terminal device receives a system message from the first terminal device, where the system message includes status information of the first terminal device.

18. A communication device, characterized in that: The method comprises a transceiver unit and a processing unit, wherein the transceiver unit and the processing unit are coupled and can execute the method according to any one of claims 1 to 8, or execute the method according to any one of claims 9 to 17.

19. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store a computer program, and when the computer program is run on a computer, the computer executes the method according to any one of claims 1 to 8, or the computer executes the method according to any one of claims 9 to 17.

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