Communication method and device

Abstract

Disclosed are a communication method and device, in which a first terminal device establishes a connection with a second terminal device, and the second terminal device is a relay for communication between the first terminal device and a network device. In response to the first terminal device being in the non-RRC connected state, the first terminal device sends first information to the second terminal device, the first information being used for requesting establishment of an RRC connection between the first terminal device and the network device. The method is beneficial to reducing the time delay of waiting for the first terminal device to be converted into the RRC connection state when there is service data transmission, thereby reducing the transmission time delay of the service data and improving the service quality.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0002] In terminal-to-network relay communication, if the terminal and the base station are far apart, indirect communication is achieved through relays. When the terminal needs to transmit service data, both the terminal and the relay must be in a radio resource control (RRC) connected state. That is, both the terminal and the relay need to establish an RRC connection with the base station before the terminal begins transmitting service data. This process incurs latency. If there are many relays between the terminal and the base station, it can lead to significant latency in terminal service data transmission, affecting service quality. Summary of the Invention

[0003] This application provides a communication method and apparatus that helps reduce data transmission latency and improve service quality.

[0004] In a first aspect, embodiments of this application provide a communication method. The method includes: establishing a connection between a first terminal device and a second terminal device, wherein the second terminal device is a relay for communication between the first terminal device and a network device. In response to the first terminal device being in a non-RRC connected state, the first terminal device sends first information to the second terminal device, the first information being used to request the establishment of an RRC connection between the first terminal device and the network device.

[0005] As can be seen, in this method, after the first terminal device establishes a connection with the second terminal device, if the first terminal device is in a non-RRC connection state, the first terminal device initiates an RRC connection request through the second terminal device so that an RRC connection can be established between the first terminal device and the network device, thereby causing the first terminal device to switch to an RRC connection state.

[0006] In this way, when other terminal devices need to transmit service data and choose to initiate an RRC connection establishment request through the first terminal device, the first terminal device, which is in the RRC connection state, can directly forward the RRC establishment request message from the other terminal devices. This reduces the latency of waiting for the first terminal device to switch to the RRC connection state, thereby reducing the transmission latency of service data and improving service quality. Alternatively, when the first terminal device subsequently needs to transmit service data, it can directly send service data to the second terminal device, reducing the latency of waiting for the first terminal device to switch to the RRC connection state, thereby reducing the transmission latency of service data and improving service quality.

[0007] In an optional implementation, the first information is further used to trigger the second terminal device to send second information to the network device or the third terminal device in response to the second terminal device being in a non-RRC connected state. The second information is used to request the establishment of an RRC connection between the second terminal device and the network device. The third terminal device is a relay for communication between the second terminal device and the network device.

[0008] It is evident that this method also facilitates the second terminal device initiating an RRC connection establishment request after receiving the first information, even when the second terminal device is in a non-RRC connection state. This allows the second terminal device to switch to an RRC connection state, enabling it to forward the first information and assist the first terminal device in establishing an RRC connection with the network device. This method is beneficial for the successful establishment of an RRC connection between the first terminal device and the network device.

[0009] In an optional implementation, the method further includes: after the first terminal device and the network device complete the establishment of an RRC connection, acquiring service data and sending the service data to the second terminal device.

[0010] In one optional implementation, the first terminal device serves as a relay for communication between the fourth terminal device and the network device. Before acquiring service data, the method further includes: the first terminal device establishing a connection with the fourth terminal device; the first terminal device receiving third information from the fourth terminal device, the third information being used to request the establishment of an RRC connection between the fourth terminal device and the network device; and the first terminal device sending the third information to the second terminal device.

[0011] It is evident that when the fourth terminal device initiates an RRC connection establishment request through the first terminal device, the first terminal device, which is already in the RRC connection state, can directly forward the third information from the fourth terminal device, reducing the latency of waiting for the first terminal device to switch to the RRC connection state, and thus reducing the latency of the fourth terminal device establishing an RRC connection with the network device.

[0012] In one alternative implementation, the service data is uplink data to be sent by the first terminal device in RRC connection state.

[0013] It is evident that when the first terminal device has service data transmission, the first terminal device and the network device have already completed the establishment of an RRC connection, that is, the first terminal device is already in the RRC connection state. The first terminal device in the RRC connection state can directly send service data to the second terminal device, reducing the latency of waiting for the first terminal device to switch to the RRC connection state, thereby reducing the latency of service data transmission.

[0014] In an optional implementation, the method further includes: in response to a connection failure between the first terminal device and the second terminal device, establishing a connection between the first terminal device and a fifth terminal device, wherein the fifth terminal device is a relay for communication between the first terminal device and the network device, and the fifth terminal device is different from the second terminal device. The first terminal device sends fourth information to the fifth terminal device, the fourth information being used to request the re-establishment of the RRC connection between the first terminal device and the network device.

[0015] It is evident that, in the event of a connection failure between the first terminal device and the second terminal device, the first terminal device establishes a connection with other relays and initiates an RRC connection re-establishment through these other relays, which helps ensure the reliability of the RRC connection between the first terminal device and the network device.

[0016] Optionally, the fourth information is also used to trigger the fifth terminal device to switch to an RRC connection state in response to the fifth terminal device being in a non-RRC connection state.

[0017] The above scheme facilitates the transition of the fifth terminal device from a non-RRC connection state to an RRC connection state after receiving the fourth information. The fifth terminal device, then in the RRC connection state, forwards the fourth information to assist the first terminal device and the network device in re-establishing the RRC connection.

[0018] Secondly, embodiments of this application provide a communication method. The method includes: a terminal device receiving fifth information from a network device, the fifth information indicating conditions for the terminal device to become a relay. In response to the terminal device meeting the conditions and being in a non-RRC connected state, the terminal device establishes an RRC connection with the network device.

[0019] As can be seen, in this method, when the terminal device meets the conditions to become a relay and is not in an RRC connection state, the terminal device establishes an RRC connection with the network device, thereby enabling the terminal device to switch to an RRC connection state. This method helps other terminal devices establish RRC connections with the network device through the relay, reducing the latency of waiting for the relay to switch to an RRC connection state, thus reducing the latency of other terminal devices establishing RRC connections with the network device. This, in turn, reduces the latency of transmitting service data when other terminal devices are in an RRC connection state, improving service quality.

[0020] In one alternative implementation, the fifth information includes a first threshold and / or a second threshold. The condition for the terminal device to become a relay is that the RSRP between the terminal device and the network device is greater than or equal to the first threshold, and / or, the RSRP between the terminal device and the network device is less than or equal to the second threshold.

[0021] Thirdly, embodiments of this application provide a communication method. The method includes: a network device sending fifth information, the fifth information indicating conditions for a terminal device to become a relay; and the network device establishing an RRC connection with a terminal device that meets the conditions and is in a non-RRC connection state.

[0022] As can be seen, in this method, the network device configures the terminal device to become a relay, so that when the terminal device meets the conditions for becoming a relay and is not in an RRC connection state, it establishes an RRC connection with the network device, thereby enabling the terminal device to switch to an RRC connection state. This method helps other terminal devices establish RRC connections with the network device through the relay, reducing the latency of waiting for the relay to switch to an RRC connection state, thus reducing the latency of other terminal devices establishing RRC connections with the network device. This, in turn, reduces the latency of transmitting service data when other terminal devices are in an RRC connection state, improving service quality.

[0023] In one alternative implementation, the fifth information includes a first threshold and / or a second threshold. The condition for the terminal device to become a relay is that the RSRP between the terminal device and the network device is greater than or equal to the first threshold, and / or, the RSRP between the terminal device and the network device is less than or equal to the second threshold.

[0024] Fourthly, embodiments of this application provide a communication device, the communication device comprising:

[0025] The communication unit is used to establish a connection with the second terminal device, which is a relay for communication between the communication device and the network device.

[0026] The communication unit is also configured to send first information to the second terminal device in response to the communication device being in a non-RRC connection state, the first information being used to request the establishment of an RRC connection between the communication device and the network device.

[0027] In addition, other alternative implementations of the communication device in this regard can be found in the relevant content of the first aspect above, and will not be described in detail here.

[0028] Fifthly, embodiments of this application provide a communication device, the communication device comprising:

[0029] The communication unit is used to receive fifth information from the network device, which indicates the conditions under which the communication device becomes a relay.

[0030] The processing unit is used to establish an RRC connection with the network device in response to the communication device meeting the conditions and the communication device being in a non-RRC connection state.

[0031] In addition, other alternative implementations of the communication device in this regard can be found in the relevant content of the second aspect above, and will not be described in detail here.

[0032] Sixthly, embodiments of this application provide a communication device, the communication device comprising:

[0033] The communication unit is used to send a fifth message, which indicates the conditions under which the terminal device becomes a relay.

[0034] The processing unit is used to establish an RRC connection with a terminal device that meets the conditions and is not in an RRC connection state.

[0035] In addition, other alternative implementations of the communication device in this regard can be found in the relevant content of the third aspect described above, and will not be detailed here.

[0036] In a seventh aspect, embodiments of this application provide a communication device, which includes a memory and a processor; optionally, the communication device further includes a communication interface.

[0037] Memory, used to store computer programs;

[0038] A communication interface used to receive or send data;

[0039] A processor is used to call program instructions stored in memory.

[0040] In one alternative implementation, the processor invokes a computer program to perform the following operations:

[0041] Establish a connection with a second terminal device, which is a relay used for communication between the communication device and the network device;

[0042] In response to the communication device being in a non-RRC connection state, a first message is sent to the second terminal device, the first message being used to request the establishment of an RRC connection between the communication device and the network device.

[0043] In addition, other optional implementations of the communication device in this manner can be found in the relevant content of the first aspect above, and will not be described in detail here.

[0044] In another alternative implementation, the processor invokes a computer program to perform the following operations:

[0045] Receive a fifth message from the network device, which indicates the conditions under which the communication device becomes a relay;

[0046] In response to the communication device meeting the conditions and the communication device being in a non-RRC connection state, an RRC connection is established with the network device.

[0047] In addition, other optional implementations of the communication device in this manner can be found in the relevant content of the second aspect above, and will not be described in detail here.

[0048] In another alternative implementation, the processor invokes a computer program to perform the following operations:

[0049] Send the fifth message, which indicates the conditions under which the terminal device becomes a relay;

[0050] Establish an RRC connection with a terminal device that meets the conditions and is not in an RRC connection state.

[0051] In addition, other optional implementations of the communication device in this manner can be found in the relevant content of the third aspect above, and will not be described in detail here.

[0052] Eighthly, embodiments of this application provide a chip, the chip including a processor and a communication interface, the communication interface being used to receive or send data.

[0053] In one alternative implementation, the processor is configured to cause the chip to perform:

[0054] Establish a connection with a second terminal device, which is a relay for communication between the chip and the network device;

[0055] In response to the chip being in a non-RRC connection state, a first message is sent to the second terminal device. The first message is used to request the establishment of an RRC connection between the chip and the network device.

[0056] In addition, other optional implementation methods of the chip in this approach can be found in the relevant content of the first aspect above, and will not be described in detail here.

[0057] In another alternative implementation, the processor is configured to cause the chip to perform:

[0058] Receive fifth information from the network device, which indicates the conditions for the chip to become a relay;

[0059] In response to the chip meeting the conditions and the chip being in a non-RRC connection state, an RRC connection is established with the network device.

[0060] In addition, other optional implementation methods of the chip in this approach can be found in the relevant content of the second aspect above, and will not be described in detail here.

[0061] In another alternative implementation, the processor is configured to cause the chip to perform:

[0062] Send the fifth message, which indicates the conditions under which the terminal device becomes a relay;

[0063] Establish an RRC connection with a terminal device that meets the conditions and is not in an RRC connection state.

[0064] In addition, other optional implementation methods of the chip in this approach can be found in the relevant content of the third aspect above, and will not be described in detail here.

[0065] Ninthly, embodiments of this application provide a module device, the module device including a communication module, a power module, a storage module, and a chip, wherein:

[0066] The power module is used to provide electrical energy to the module device;

[0067] The storage module is used to store data and instructions;

[0068] The communication module is used for internal communication within the module device, or for communication between the module device and external devices.

[0069] The chip is used to perform the method described in the first, second, or third aspect above.

[0070] In a tenth aspect, embodiments of this application provide a computer-readable storage medium for storing computer software instructions used by the aforementioned terminal, including a program for executing the methods described in the first, second, or third aspects.

[0071] Eleventhly, embodiments of this application also provide a computer program product, which, when run on a processor, enables the implementation of the method flow described in the first, second, or third aspect above. Attached Figure Description

[0072] Figure 1 A schematic diagram of a single-hop U2N relay communication provided in an embodiment of this application;

[0073] Figure 2 This is a schematic diagram of a two-hop U2N relay communication provided in an embodiment of this application;

[0074] Figure 3 This is a schematic diagram of a three-hop U2N relay communication provided in an embodiment of this application;

[0075] Figure 4 This is a schematic diagram illustrating the establishment of an RRC connection between an edge terminal device and a network device according to an embodiment of this application.

[0076] Figure 5 This is a flowchart illustrating a communication method provided in an embodiment of this application;

[0077] Figure 6 This is a schematic diagram of another communication method provided in an embodiment of this application;

[0078] Figure 7 This is a schematic diagram of another communication method provided in an embodiment of this application;

[0079] Figure 8 This is a flowchart illustrating another communication method provided in an embodiment of this application;

[0080] Figure 9 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0081] Figure 10 This is a schematic diagram of another communication device provided in an embodiment of this application;

[0082] Figure 11 This is a schematic diagram of the structure of a module device provided in an embodiment of this application. Detailed Implementation

[0083] The embodiments of this application will now be described in conjunction with the accompanying drawings.

[0084] In this application, the terms "first" and "second," etc., used in the specification, claims, and drawings are used to distinguish different objects, not to describe a specific order. "First" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature. In the description of this embodiment, unless otherwise stated, "a plurality of" means two or more.

[0085] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0086] It should be understood that in this application, "multiple" refers to two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0087] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0088] First, the system architecture involved in the embodiments of this application will be introduced:

[0089] This application is applicable to third-generation mobile communication (3G) systems, fourth-generation mobile communication (4G) systems, and fifth-generation mobile communication (5G) systems, as well as to various new communication systems in the future, such as sixth-generation (6G) mobile communication systems and seventh-generation (7G) mobile communication systems. However, the embodiments of this application are not limited in this respect.

[0090] This application's embodiments can also be applied to user equipment to network (U2N) relay communication scenarios. U2N relay communication is suitable for communication between remote terminal devices and network devices, where the edge terminal devices and network devices are far apart or located at the edge of the network device's coverage area. Based on U2N relay communication, the edge terminal devices and network devices achieve indirect communication through relay terminal devices. In this application's embodiments, the relay terminal device can also be simply referred to as a relay.

[0091] like Figure 1 As shown, Figure 1 This is a schematic diagram of a single-hop U2N relay communication according to an embodiment of this application. In a single-hop U2N relay communication scenario, the edge terminal device and the network device communicate indirectly through a relay. The edge terminal device and the relay are connected via a PC5 link, and the relay and the network device are connected via a Uu link. In this embodiment, the PC5 link is a link implemented based on interface 5 in proximity services (ProSe) communication, and the Uu link is a link implemented based on a universal user-to-network interface.

[0092] In multi-hop U2N relay communication scenarios, edge terminal devices and network devices communicate indirectly through at least two relays. Of these at least two relays, the relay directly connected to the edge terminal device can be referred to as the first relay UE, which is the relay closest to the edge terminal device among the at least two relays. The relay directly connected to the network device can be referred to as the last relay UE, which is also the relay closest to the network device among the at least two relays.

[0093] like Figure 2 As shown, Figure 2 This is a schematic diagram of a two-hop U2N relay communication according to an embodiment of this application. In the two-hop U2N relay communication scenario, the edge terminal device and the network device communicate indirectly through a first relay terminal and a last relay terminal. Specifically, the edge terminal device is connected to the first relay terminal via a PC5 link. The first relay terminal is connected to the last relay terminal via a PC5 link. The last relay terminal is connected to the network device via a Uu link.

[0094] like Figure 3 As shown, Figure 3 This is a schematic diagram of a three-hop U2N relay communication according to an embodiment of this application. In the three-hop U2N relay communication scenario, the edge terminal device and the network device communicate indirectly through three relays. These three relays include: a first relay terminal, a last relay terminal, and a relay located between the first relay terminal and the last relay terminal. The relay located between the first relay terminal and the last relay terminal can also be called an intermediate relay UE. The edge terminal device is connected to the first relay terminal via a PC5 link. The first relay terminal communicates with the intermediate relay terminal via a PC5 link. The intermediate relay terminal communicates with the last relay terminal via a PC5 link. The last relay terminal is connected to the network device via a Uu link.

[0095] The embodiments of this application are also applicable to U2N relay communication scenarios with three or more hops, such as four-hop U2N relay communication, five-hop U2N relay communication, etc. In U2N relay communication scenarios with three or more hops, there are multiple intermediate relay terminals between the first relay terminal and the last relay terminal. Different intermediate relay terminals communicate with each other via PC5 links.

[0096] It should be noted that the above Figure 1 , Figure 2 and Figure 3 The forms of the devices described are merely examples and do not represent any limitation on the form of the devices.

[0097] In this embodiment, the network device can be a network equipment or a module / unit / chip / module device capable of implementing some or all of the functions of a network equipment. For example, a network equipment can be a base station (BS), also known as a base station device, which is a device deployed in a wireless access network (RAN) to provide wireless communication functions. For example, in 2G networks, devices providing base station functions include base transceiver stations (BTS). In 3G networks, devices providing base station functions include NodeBs (NodeBs). In 4G networks, devices providing base station functions include evolved NodeBs (eNBs). In wireless local area networks (WLANs), devices providing base station functions are access points (APs). In 5G new radio (NR), the device gNB provides base station functionality, and the evolved Node B (ng-eNB) further evolves into a Node B. The gNB communicates with the terminal device using NR technology, while the ng-eNB communicates with the terminal using evolved universal terrestrial radio access (E-UTRA) technology. Both the gNB and ng-eNB can connect to the 5G core network. The base station in this embodiment also includes devices that provide base station functionality in future new communication systems, such as base stations in 6G mobile communication systems. It should be noted that this embodiment does not limit the type of network device.

[0098] In the embodiments of this application, the terminal device (e.g., edge terminal device, relay, the first terminal device, second terminal device, third terminal device, fourth terminal device, fifth terminal device, and sixth terminal device mentioned below) may be a terminal equipment, or it may be a module / unit / chip / module device that can realize some or all of the functions of the terminal equipment. Terminal devices can be mobile phones, tablet personal computers, laptop computers (also known as notebook computers), personal digital assistants (PDAs), handheld computers, netbooks, ultra-mobile personal computers (UMPCs), mobile internet devices (MIDs), augmented reality (AR) / virtual reality (VR) devices, robots, wearable devices, vehicle user equipment (VUEs), pedestrian user equipment (PUEs), smart home devices (home appliances with wireless communication capabilities, such as refrigerators, televisions, washing machines, or furniture), game consoles, personal computers (PCs), ATMs, or self-service machines, etc. Wearable devices include: smartwatches, smart bracelets, smart headphones, smart glasses, smart jewelry (smart bracelets, smart chains, smart rings, smart necklaces, smart anklets, smart anklets, etc.), smart wristbands, smart clothing, etc. It should be noted that the embodiments of this application do not limit the type of terminal device.

[0099] The relevant concepts involved in the embodiments of this application will be explained below.

[0100] 1. The edge terminal device establishes an RRC connection with the network device.

[0101] In U2N relay communication scenarios, edge terminal devices and relays may be in any RRC state, including: RRC idle, RRC inactive, and RRC connected.

[0102] The edge terminal device establishes an RRC connection with the network device to put it into an RRC connected state. For example, the edge terminal device sends an RRC setup request message to the relay. After receiving the RRC setup request message from the edge terminal device, if the relay is in an RRC idle state or an RRC inactive state, the relay needs to first switch to an RRC connected state (i.e., establish an RRC connection with the network device) before forwarding the edge terminal device's RRC setup request message to the network device to assist the edge terminal device in establishing an RRC connection with the network device.

[0103] Currently, when an edge terminal device has service data to transmit to a network device, if it is in an RRC idle or RRC inactive state, it sends an RRC establishment request message to the relay, which then converts the relay-assisted edge terminal device to an RRC connected state. Therefore, the presence of service data to be transmitted triggers the edge terminal device to transition from an RRC idle or RRC inactive state to an RRC connected state. Conversely, if the edge terminal device has no service data to transmit (e.g., no data to send / receive, or no service), it can be in any RRC state; for example, to save energy, it can be in an RRC idle or RRC inactive state.

[0104] For example, consider a single-hop U2N relay communication scenario. Combined with... Figure 4 After the edge terminal device discovers and selects a relay, it establishes a PC5 connection with the relay. When the edge terminal device has service data to be transmitted (e.g., service data to be sent or service data to be received), if the edge terminal device is in RRC idle state or RRC inactive state, it sends an RRC setup request message #1 to the relay. The RRC setup request message #1 is used to request the establishment of an RRC connection between the edge terminal device and the network device.

[0105] After receiving RRC Establishment Request Message #1, if the relay is in an RRC idle state or an RRC inactive state, the relay sends an RRC Establishment Request Message #2 to the network device. The RRC Establishment Request Message #2 is used to request the establishment of an RRC connection between the relay and the network device.

[0106] After receiving RRC setup request message #2, the network device establishes an RRC connection with the relay, causing the relay to switch to RRC connected state. The establishment of the RRC connection between the relay and the network device includes: after receiving the RRC setup request message #2, the network device sends an RRC setup response message to the relay, which carries the specific configuration for establishing the RRC connection. The relay establishes signaling radiobearer 1 (SRB1) according to the configuration carried in the RRC setup response message, including establishing a radio link control (RLC) channel for the Uu interface of SRB1. The relay sends an RRC setup complete message to the network device. After switching to RRC connected state, the relay sends an RRC setup request message #1 to the network device.

[0107] After receiving RRC Establishment Request Message #1, the network device establishes an RRC connection with the edge terminal device through a relay in RRC connection state, thereby enabling the edge terminal device to switch to RRC connection state. The establishment of the RRC connection between the edge terminal device and the network device includes: after receiving RRC Establishment Request Message #1, the network device sends an RRC Establishment Response Message to the edge terminal device through a relay. The RRC Establishment Response Message carries the specific configuration for establishing the RRC connection. The edge terminal device establishes SRB1 according to the configuration carried in the RRC Establishment Response Message, including: establishing RLC channels for the PC5 and Uu interfaces of SRB1. The edge terminal device sends an RRC Establishment Complete Message to the network device through a relay.

[0108] Since the edge terminal device has service data to be transmitted, after the RRC connection between the edge terminal device and the network device is established, the network device sends a security mode command to the edge terminal device via a relay to ensure the security of service data transmission between the edge terminal device and the network device. The edge terminal device sends a security mode complete message to the network device via a relay. The network device sends an RRC reconfiguration message to the edge terminal device via a relay to instruct the edge terminal device to establish a data channel with the network device and complete the SRB configuration. The edge terminal device sends an RRC reconfiguration complete message to the network device via a relay. Based on the RRC reconfiguration message, the edge terminal device establishes a signaling radio bearer 2 (SRB2) and a data radio bearer (DRB) with the network device, including: establishing an RLC channel for SRB2 / DRB using PC5 and Uu interfaces. Among them, the signaling radio bearers (SRB1, SRB2) are used to transmit signaling, and the data radio bearers are used to transmit data.

[0109] After the edge terminal device establishes SRB2 and DRB with the network device, the edge terminal device and the network device transmit service data through relay.

[0110] As can be seen, in U2N relay communication scenarios, if a terminal device needs to transmit service data and initiates an RRC connection establishment request, it must wait for the relay to switch to RRC connection state before the relay-assisted terminal device in RRC connection state can establish the RRC connection and begin transmitting service data. This process incurs latency. If there are many relays between the terminal device and the network device (e.g., in a multi-hop U2N relay communication scenario), it will lead to significant latency in service data transmission, affecting service quality.

[0111] Therefore, embodiments of this application provide a communication method that can reduce the latency of business data transmission and improve service quality.

[0112] The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0113] Please see Figure 5 , Figure 5 This is a flowchart illustrating a communication method provided in an embodiment of this application. The communication method includes the following steps.

[0114] S501. The first terminal device establishes a connection with the second terminal device, wherein the second terminal device is a relay for communication between the first terminal device and the network device.

[0115] Optionally, in this embodiment, the connection established between different terminal devices is a PC5 connection. For example, establishing a connection between the first terminal device and the second terminal device includes establishing a PC5 connection between the first terminal device and the second terminal device. Based on this, a PC5 link can be established between the first terminal device and the second terminal device, and then the first terminal device and the second terminal device can communicate through the PC5 link.

[0116] Additionally, by way of example, in the embodiments of this application, the first terminal device can be a relay. For instance, in a two-hop U2N relay communication scenario, the first terminal device is the first relay terminal, and the second terminal device is the last relay terminal. As another example, in a U2N relay communication scenario with more than two hops, the first terminal device is the first relay terminal, and the second terminal device is an intermediate relay terminal connected to the first relay terminal.

[0117] Alternatively, the first terminal device can also be an edge terminal device. For example, in a single-hop U2N relay communication scenario, the first terminal device is an edge terminal device, and the second terminal device is a relay used to realize indirect communication between the edge terminal device and the network device. As another example, in a multi-hop U2N relay communication scenario, the first terminal device is an edge terminal device, and the second terminal device is the first relay terminal.

[0118] In one alternative implementation, the second terminal device is a relay selected by the first terminal device. Understandably, the first terminal device selects the second terminal device and performs the operation of establishing a connection with the second terminal device.

[0119] This application does not limit the implementation method of the first terminal device selecting the second terminal device. For example, the second terminal device broadcasts information about its ability to act as a relay and / or its specific hop number as a relay. The first terminal device selects the second terminal device to establish a connection based on the acquired information about the second terminal device. Another example is that the first terminal device sends an instruction to obtain relay information. After receiving this instruction, the second terminal device sends its own information to the first terminal device, so that the first terminal device can select the second terminal device to establish a connection based on this information.

[0120] S502, In response to the first terminal device being in a non-RRC connection state, the first terminal device sends first information to the second terminal device, the first information being used to request the establishment of an RRC connection between the first terminal device and the network device. Accordingly, the second terminal device receives the first information.

[0121] Understandably, when the connection between the first terminal device and the second terminal device is established and the first terminal device is in a non-RRC connection state, the first terminal device is triggered to send the first information to the second terminal device, that is, the first terminal device is triggered to initiate an RRC connection establishment request.

[0122] In addition, in step S502, the first terminal device sending the first information to the second terminal device in response to the first terminal device being in a non-RRC connection state can also be understood as: if the first terminal device is in a non-RRC connection state, the first terminal device sends the first information to the second terminal device; or it can also be understood as: when the first terminal device is in a non-RRC connection state, the first terminal device sends the first information to the second terminal device.

[0123] Optionally, the non-RRC connected state includes the RRC idle state and the RRC inactive state. For example, the first terminal device being in a non-RRC connected state includes: the first terminal device being in the RRC idle state or the RRC inactive state. Other terminal devices mentioned below (e.g., the second terminal device, the third terminal device, the fourth terminal device, etc.) are similarly in a non-RRC connected state, and will not be described further below.

[0124] Alternatively, the first information could be an RRC establishment request message, which is used to request the establishment of an RRC connection between the first terminal device and the network device.

[0125] In an optional implementation, the method further includes: after receiving the first information, the second terminal device, in response to being in a non-RRC connection state, sends second information to the network device or the third terminal device. The second information is used to request the establishment of an RRC connection between the second terminal device and the network device; the third terminal device is a relay for communication between the second terminal device and the network device. Therefore, the first information also triggers the second terminal device to send the second information to the network device or the third terminal device in response to being in a non-RRC connection state.

[0126] The statement that the second terminal device sends the second information to the network device or the third terminal device in response to the second terminal device being in a non-RRC connection state can also be understood as: if the second terminal device is in a non-RRC connection state, the second terminal device sends the second information to the network device or the third terminal device; or, it can also be understood as: when the second terminal device is in a non-RRC connection state, the second terminal device sends the second information to the network device or the third terminal device.

[0127] Furthermore, "the second terminal device is in a non-RRC connected state" can also be understood as: the second terminal device is not in an RRC connected state. For example, "the second terminal device is in a non-RRC connected state" includes: the second terminal device is in an RRC idle state or an RRC inactive state.

[0128] Alternatively, the second information could be an RRC establishment request message, which is used to request the establishment of an RRC connection between the second terminal device and the network device.

[0129] The following provides exemplary descriptions of two scenarios: the second terminal device sending the second information to the network device and the second terminal device sending the second information to the third terminal device, as described in optional implementation methods 1.1 and 1.2.

[0130] In implementation method 1.1, the situation where the second terminal device sends second information to the network device can be applied to scenarios where the second terminal device can communicate directly with the network device, for example, in scenarios where the second terminal device and the network device are connected via a Uu link.

[0131] For example, such as Figure 1 As shown, this embodiment of the application is applied to a single-hop U2N relay communication scenario. The first terminal device is an edge terminal device, and the second terminal device is a relay used to realize indirect communication between the edge terminal device and the network device. After receiving the second information, if the second terminal device is in a non-RRC connection state, the second terminal device sends the second information to the network device.

[0132] For example, such as Figure 2 As shown, this embodiment of the application is applied to a two-hop U2N relay communication scenario, where the first terminal device is the first relay terminal and the second terminal device is the last relay terminal. After receiving the second information, if the second terminal device is in a non-RRC connection state, the second terminal device sends the second information to the network device.

[0133] Optionally, in the case where the second terminal device sends the second information to the network device, the method further includes: after the second terminal device and the network device complete the establishment of an RRC connection (i.e., the second terminal device switches to the RRC connection state), the second terminal device forwards the first information to the network device to assist the first terminal device in establishing an RRC connection with the network device, thereby enabling the first terminal device to switch to the RRC connection state.

[0134] In implementation method 1.2, the second terminal device sends the second information to the third terminal device. This can be applied to scenarios where the second terminal device and the network device need to communicate indirectly through one or more relays, and the third terminal device is one of the one or more relays.

[0135] For example, this application embodiment is applied to a multi-hop U2N relay communication scenario, where the first terminal device is an edge terminal device and the second terminal device is the first relay terminal. After receiving the second information, if the second terminal device is in a non-RRC connection state, the second terminal device sends the second information to the third terminal device. In a two-hop U2N relay communication scenario, such as... Figure 2 As shown, the third terminal device is the last relay terminal. In U2N relay communication scenarios with more than two hops, the third terminal device is an intermediate relay terminal connected to the first relay terminal.

[0136] For example, in a U2N relay communication scenario with two or more hops, the first terminal device is the first relay terminal, and the second terminal device is an intermediate relay terminal connected to the first relay terminal. After receiving the second information, if the second terminal device is in a non-RRC connection state, the second terminal device sends the second information to the third terminal device. In a three-hop U2N relay communication scenario, such as... Figure 3 As shown, the third terminal device is the last relay terminal. In U2N relay communication scenarios with more than three hops, the third terminal device is an intermediate relay terminal connected to the second terminal device.

[0137] Optionally, in the case where the second terminal device sends the second information to the third terminal device, the method further includes: after receiving the second information, the third terminal device, in response to being in a non-RRC connection state, sends a sixth message to the network device or the sixth terminal device. The sixth message is used to request the establishment of an RRC connection between the third terminal device and the network device; the sixth terminal device is a relay for communication between the third terminal device and the network device. Therefore, the second message also triggers the third terminal device to send the sixth message to the network device or the sixth terminal device in response to being in a non-RRC connection state.

[0138] The process of the third terminal device sending the sixth information to the network device or the sixth terminal device is similar to the process of the second terminal device sending the second information to the network device or the third terminal device. Please refer to the relevant descriptions for further details.

[0139] In response to the third terminal device being in a non-RRC connection state, the third terminal device sends the sixth information to the network device or the sixth terminal device. This is similar to the second terminal device sending the second information to the network device or the third terminal device in response to the second terminal device being in a non-RRC connection state. Please refer to the relevant descriptions, which will not be repeated here.

[0140] Furthermore, the operations performed by the sixth terminal device after receiving the sixth information are similar to those performed by the second terminal device after receiving the first information and by the third terminal device after receiving the second information, and will not be described in detail here.

[0141] Understandably, for the first terminal device to establish an RRC connection with the network device, it needs to wait for the second terminal device to complete its RRC connection with the network device (i.e., the second terminal device is in RRC connection state). Then, the second terminal device in RRC connection state forwards the first information to assist the first terminal device in establishing the RRC connection with the network device. Similarly, for the second terminal device to establish an RRC connection with the network device, it needs to wait for the third terminal device to complete its RRC connection with the network device (i.e., the third terminal device is in RRC connection state). Then, the third terminal device in RRC connection state forwards the second information to assist the second terminal device in establishing the RRC connection with the network device. The process for the third terminal device to establish an RRC connection with the network device is similar and will not be elaborated further.

[0142] It can be seen that, for any relay between the first terminal device and the network device, after receiving the information for requesting the establishment of an RRC connection, if it is in an RRC connection state, it can directly forward the received information for requesting the establishment of an RRC connection; if it is not in an RRC connection state, it switches to an RRC connection state and then forwards the received information for requesting the establishment of an RRC connection.

[0143] For the first terminal device, after sending the first information in order to establish an RRC connection with the network device, it needs to wait for all the relays between the first terminal device and the network device to switch to the RRC connection state before the relays in the RRC connection state assist the first terminal device in establishing an RRC connection with the network device.

[0144] In an optional implementation, the method further includes: after the first terminal device and the network device complete the RRC connection establishment, the first terminal device establishes a connection with the fourth terminal device. The fourth terminal device sends third information to the first terminal device, the third information being used to request the establishment of an RRC connection between the fourth terminal device and the network device. The first terminal device sends the third information to the second terminal device. This implementation can be applied to a scenario where the first terminal device is a relay for communication between the fourth terminal device and the network device. For example, in the U2N relay communication scenario, the first terminal device is the first relay terminal, and the fourth terminal device is an edge terminal device.

[0145] Understandably, before the fourth terminal device selects the first terminal device to establish a connection, the first terminal device has already completed the RRC connection establishment with the network device, meaning the first terminal device is already in the RRC connection state. Thus, after the fourth terminal device establishes a connection with the first terminal device and sends the third information to the first terminal device, the first terminal device can directly send the third information to the second terminal device, reducing the latency of waiting for the first terminal device to transition from a non-RRC connection state to an RRC connection state, thereby reducing the latency of the fourth terminal device establishing an RRC connection with the network device.

[0146] Furthermore, in one approach, the establishment of an RRC connection between the first terminal device and the network device is achieved by the relays already in the RRC connection state after all relays between the first terminal device and the network device have switched to the RRC connection state. Therefore, the establishment of an RRC connection between the first terminal device and the network device also means that all relays between the first terminal device and the network device are in the RRC connection state. It is evident that when the first terminal device forwards the third information, the first terminal device, and all relays between the first terminal device and the network device, are in the RRC connection state. Any relay between the first terminal device and the network device can directly forward the third information after receiving it. The method provided in this application reduces the latency of waiting for the relays between the fourth terminal device and the network device to switch from a non-RRC connection state to an RRC connection state, thereby reducing the latency of establishing an RRC connection between the fourth terminal device and the network device.

[0147] Optionally, the third information is sent by the fourth terminal device when there is service data to be transmitted. Understandably, the fact that the fourth terminal device has service data to be transmitted triggers it to send the third information when it is determined to be in a non-RRC connection state, thereby enabling the fourth terminal device to establish an RRC connection with the network device and switch to an RRC connection state. Optionally, after the fourth terminal device completes the RRC connection establishment with the network device, it sends service data to the first terminal device, the first terminal device sends service data to the second terminal device, and the second terminal device directly or indirectly sends service data to the network device. Since the method provided in this embodiment can reduce the latency of establishing an RRC connection between the fourth terminal device and the network device, it can reduce the transmission latency of service data and improve service quality.

[0148] In an optional implementation, the method further includes: after the first terminal device and the network device complete the establishment of an RRC connection, sending service data to the second terminal device, wherein the service data is uplink data to be sent by the first terminal device while it is in an RRC connection state.

[0149] Optionally, after establishing a connection with the second terminal device, even if the first terminal device has no service or service data to transmit, if the first terminal device is in a non-RRC connection state, the first terminal device sends first information to switch to an RRC connection state. Understandably, this method allows the first terminal device to complete the RRC connection establishment before any service data transmission occurs, meaning the first terminal device is already in an RRC connection state. This allows the first terminal device to directly send service data when it has data to transmit, reducing the latency of waiting for the first terminal device to establish an RRC connection with the network device, thereby reducing the transmission latency of service data.

[0150] In an optional implementation, the method further includes: in response to a connection failure between the first terminal device and the second terminal device, establishing a connection between the first terminal device and a fifth terminal device, wherein the fifth terminal device is a relay for communication between the first terminal device and the network device, and the fifth terminal device is different from the second terminal device. The first terminal device sends fourth information to the fifth terminal device, the fourth information being used to request the re-establishment of the RRC connection between the first terminal device and the network device.

[0151] The phrase "in response to the failure of the connection between the first terminal device and the second terminal device, the first terminal device establishes a connection with the fifth terminal device" can be understood as: if the connection between the first terminal device and the second terminal device fails, the first terminal device establishes a connection with the fifth terminal device; or it can also be understood as: in the case of the failure of the connection between the first terminal device and the second terminal device, the first terminal device establishes a connection with the fifth terminal device.

[0152] Additionally, for example, a connection failure between the first terminal device and the second terminal device includes: a PC5 connection failure between the first terminal device and the second terminal device.

[0153] Optionally, the fourth information is also used to trigger the fifth terminal device to switch to an RRC connection state in response to the fifth terminal device being in a non-RRC connection state. For example, the fifth terminal device switching to an RRC connection state in response to the fifth terminal device being in a non-RRC connection state can also be understood as: if the fifth terminal device is in a non-RRC connection state, the fifth terminal device switches to an RRC connection state; or it can also be understood as: if the fifth terminal device is in a non-RRC connection state, the fifth terminal device switches to an RRC connection state.

[0154] For example, after receiving the fourth information, if the fifth terminal device is in a non-RRC connection state, it establishes an RRC connection with the network device to switch to an RRC connection state. Then, the fifth terminal device in the RRC connection state directly forwards the fourth information to the network device, or indirectly sends the fourth information to the network device through a relay between the fifth terminal device and the network device, to assist in re-establishing the RRC connection between the first terminal device and the network device.

[0155] Optionally, the fifth terminal device is a relay selected by the first terminal device. Understandably, if the connection between the first terminal device and the second terminal device fails, the first terminal device will reselect a relay to establish a connection and send the fourth information to the reselected relay. Furthermore, this application does not limit the implementation method of how the first terminal device selects the fifth terminal device; for example, it can be similar to the aforementioned selection of the second terminal device by the first terminal device, and will not be elaborated further.

[0156] Furthermore, the above description addresses the scenario where the connection between the first and second terminal devices fails. Similarly, if the second terminal device and the network device communicate indirectly via a third terminal device, and the connection between the second and third terminal devices fails, the second terminal device can re-select another relay to establish a connection and send a request to the newly selected relay to re-establish the RRC connection between the second terminal device and the network device. The scenario where the third terminal device and the network device communicate indirectly via a relay is similar and will not be elaborated further.

[0157] In summary, in this communication method, a connection is established between a first terminal device and a second terminal device, with the second terminal device acting as a relay for communication between the first terminal device and the network device. In response to the first terminal device being in a non-RRC connected state, the first terminal device sends first information to the second terminal device, the first information being used to request the establishment of an RRC connection between the first terminal device and the network device.

[0158] As can be seen, in this method, after the first terminal device establishes a connection with the second terminal device, if the first terminal device is in a non-RRC connection state, the first terminal device initiates an RRC connection request through the second terminal device so that an RRC connection can be established between the first terminal device and the network device, thereby causing the first terminal device to switch to an RRC connection state.

[0159] In this way, when other terminal devices need to transmit service data and choose to initiate an RRC connection establishment request through the first terminal device, the first terminal device, which is in the RRC connection state, can directly forward the RRC establishment request message from the other terminal devices. This reduces the latency of waiting for the first terminal device to switch to the RRC connection state, thereby reducing the transmission latency of service data and improving service quality. Alternatively, when the first terminal device subsequently needs to transmit service data, it can directly send service data to the second terminal device, reducing the latency of waiting for the first terminal device to switch to the RRC connection state, thereby reducing the transmission latency of service data and improving service quality.

[0160] based on Figure 5 The communication method described herein will be illustrated below using a two-hop U2N relay communication scenario as an example.

[0161] Example 1: The first terminal device is the first relay terminal, and the second terminal device is the last relay terminal.

[0162] like Figure 6 As shown, in the communication method of Example 1, the first terminal device and the second terminal device establish a PC5 connection. In response to the first terminal device being in a non-RRC connection state, the first terminal device sends first information to the second terminal device, the first information being used to request the establishment of an RRC connection between the first terminal device and the network device. After receiving the first information, in response to the second terminal device being in a non-RRC connection state, the second terminal device sends second information to the network device, the second information being used to request the establishment of an RRC connection between the second terminal device and the network device.

[0163] After receiving the second information, the network device establishes an RRC connection with the second terminal device, causing the second terminal device to switch to an RRC connected state. The establishment of the RRC connection between the network device and the second terminal device includes: after receiving the second information, the network device sends an RRC establishment response message #1 to the second terminal device, which carries the specific configuration for establishing the RRC connection; the second terminal device establishes SRB1 according to the configuration carried in the RRC establishment response message #1, including: the second terminal device and the network device establishing RLC channels for the PC5 and Uu interfaces for SRB1; and the second terminal device sending an RRC establishment completion message #1 to the network device.

[0164] After the second terminal device switches to RRC connection state, it forwards the first information to the network device.

[0165] After receiving the first information, the network device establishes an RRC connection with the first terminal device through the second terminal device, thereby causing the first terminal device to switch to an RRC connected state. The establishment of the RRC connection between the network device and the first terminal device includes: the network device sending an RRC establishment response message #2 to the first terminal device through the second terminal device, the RRC establishment response message #2 carrying the specific configuration for the first terminal device to establish the RRC connection; the first terminal device establishing SRB1 according to the configuration carried in the RRC establishment response message #2, including: the first terminal device and the network device establishing RLC channels for the PC5 and Uu interfaces for SRB1; and the first terminal device sending an RRC establishment completion message #2 to the network device through the second terminal device.

[0166] The edge terminal device discovers and selects the first terminal device, and establishes a PC5 connection with the first terminal device. When the edge terminal device has service data to be transmitted (e.g., service data to be sent or received), in response to the edge terminal device being in a non-RRC connection state, it sends an RRC establishment request message #1 to the first terminal device. The RRC establishment request message #1 is used to request the establishment of an RRC connection between the edge terminal device and the network device. The first terminal device, which has already switched to an RRC connection state, forwards the RRC establishment request message #1 to the second terminal device. The second terminal device, which has also switched to an RRC connection state, forwards the RRC establishment request message #1 to the network device.

[0167] After receiving RRC Establishment Request Message #1, the network device establishes an RRC connection and a data channel with the edge terminal device through the first terminal device and the second terminal device. Then, the edge terminal device and the network device transmit service data through the first terminal device and the second terminal device.

[0168] The process of establishing an RRC connection and data channel between the network device and the edge terminal device includes: After receiving the RRC establishment request message #1, the network device sends an RRC establishment response message #3 to the edge terminal device through the second terminal device and the first terminal device. The RRC establishment response message #3 carries the specific configuration for establishing the RRC connection by the edge terminal device. The edge terminal device establishes SRB1 according to the configuration carried in the RRC establishment response message #3, including: the edge terminal device and the network device establishing RLC channels for the PC5 and Uu interfaces of SRB1. The edge terminal device sends an RRC establishment completion message #3 to the network device through the first terminal device and the second terminal device. The network device sends a security mode command to the edge terminal device through the second terminal device and the first terminal device to ensure the security of service data transmission between the edge terminal device and the network device. The edge terminal device sends a security mode completion message to the network device through the first terminal device and the second terminal device. The network device sends an RRC reconfiguration message to the edge terminal device through the second terminal device and the first terminal device to instruct the edge terminal device to establish a data channel with the network device and complete the SRB configuration. The edge terminal device sends an RRC reconfiguration complete message to the network device through the first terminal device and the second terminal device. Based on the RRC reconfiguration message, the edge terminal device establishes SRB2 and DRB with the network device, including: the edge terminal device and the network device establishing RLC channels with PC5 and Uu interfaces for SRB2 or DRB.

[0169] For a more detailed explanation of the method described in Example 1, please refer to the foregoing. Figure 5 The relevant explanations of the method will not be repeated here.

[0170] Example 2: The first terminal device is an edge terminal device, the second terminal device is the first relay terminal, and the third terminal device is the last relay terminal.

[0171] like Figure 7 As shown, in the communication method of Example 2, the first terminal device establishes a PC5 connection with the second terminal device. In response to the first terminal device being in a non-RRC connection state, the first terminal device sends a first message to the second terminal device, the first message requesting the establishment of an RRC connection between the first terminal device and the network device. After receiving the first message, in response to the second terminal device being in a non-RRC connection state, the second terminal device sends a second message to the third terminal device, the second message requesting the establishment of an RRC connection between the second terminal device and the network device. After receiving the second message, in response to the third terminal device being in a non-RRC connection state, the third terminal device sends a sixth message to the network device, the sixth message requesting the establishment of an RRC connection between the third terminal device and the network device.

[0172] After receiving the sixth information, the network device establishes an RRC connection with the third terminal device, causing the third terminal device to switch to an RRC connected state. The establishment of the RRC connection between the network device and the third terminal device includes: after receiving the third information, the network device sends an RRC establishment response message #1 to the third terminal device, which carries the specific configuration for establishing the RRC connection; the third terminal device establishes SRB1 according to the configuration carried in the RRC establishment response message #1, including: the third terminal device and the network device establishing RLC channels for the PC5 and Uu interfaces for SRB1; and the third terminal device sending an RRC establishment completion message #1 to the network device.

[0173] After the third terminal device switches to RRC connection state, it forwards the second information to the network device.

[0174] After receiving the second information, the network device establishes an RRC connection with the second terminal device through the third terminal device, thereby causing the second terminal device to switch to an RRC connected state. The establishment of the RRC connection between the network device and the second terminal device includes: after receiving the second information, the network device sends an RRC establishment response message #2 to the second terminal device through the third terminal device. The RRC establishment response message #2 carries the specific configuration for the second terminal device to establish the RRC connection; the second terminal device establishes SRB1 according to the configuration carried in the RRC establishment response message #2, including: the second terminal device and the network device establishing RLC channels for the PC5 and Uu interfaces of SRB1; and the second terminal device sending an RRC establishment completion message #2 to the network device.

[0175] After the second terminal device switches to RRC connection state, it forwards the first information to the third terminal device. The third terminal device, which has already switched to RRC connection state, then forwards the first information to the network device.

[0176] After receiving the first information, the network device establishes an RRC connection with the first terminal device through the third and second terminal devices, thereby causing the first terminal device to switch to an RRC connected state. The establishment of the RRC connection between the network device and the first terminal device includes: the network device sending an RRC establishment response message #3 to the first terminal device through the third and second terminal devices, whereby the RRC establishment response message #3 carries the specific configuration for the first terminal device to establish the RRC connection; the first terminal device establishing SRB1 according to the configuration carried in the RRC establishment response message #3, including: the first terminal device and the network device establishing RLC channels for the PC5 and Uu interfaces of SRB1; and the first terminal device sending an RRC establishment completion message #3 to the network device through the second and third terminal devices.

[0177] When the first terminal device has service data to be sent, it sends indication information to the network device through a second terminal device and a third terminal device that have both switched to RRC connection state. After receiving the indication information, the network device sends a security mode command to the first terminal device through the third and second terminal devices to ensure the security of service data transmission between the first terminal device and the network device. In another scenario, when the first terminal device has service data to receive and the network device has service data to send to the first terminal device, the first terminal device does not need to send indication information to the network device. Instead, the network device directly sends a security mode command to the first terminal device through the third and second terminal devices when it has service data to send to the first terminal device.

[0178] The first terminal device sends a security mode completion message to the network device through the second and third terminal devices. The network device sends an RRC reconfiguration message to the first terminal device through the third and second terminal devices to instruct the first terminal device to establish a data channel with the network device and complete the SRB configuration. The first terminal device sends an RRC reconfiguration completion message to the network device through the second and third terminal devices. Based on the RRC reconfiguration message, the first terminal device establishes SRB2 and DRB with the network device, including: the first terminal device and the network device establishing an RLC channel with PC5 and Uu interfaces for SRB2 or DRB. Then, the first terminal device and the network device transmit service data through the second and third terminal devices.

[0179] For a more detailed explanation of the method described in Example 2, please refer to the foregoing. Figure 5 The relevant explanations of the method will not be repeated here.

[0180] Please see Figure 8 , Figure 8 This is a flowchart illustrating another communication method provided in an embodiment of this application, which includes the following steps.

[0181] S801. The network device sends a fifth message, which indicates the conditions for the terminal device to become a relay. Accordingly, the terminal device receives the fifth message.

[0182] In this embodiment of the application, the terminal device becomes a relay, which can be understood as: the terminal device can act as a relay for realizing indirect communication between other terminal devices and network devices.

[0183] S802. In response to the terminal device meeting the conditions to become a relay and the terminal device being in a non-RRC connection state, the terminal device establishes an RRC connection with the network device. For information on the non-RRC connection state, please refer to [link to relevant documentation]. Figure 5 The methods described herein will not be repeated here.

[0184] Specifically, the establishment of an RRC connection between the terminal device and the network device in response to the terminal device meeting the conditions for becoming a relay and the terminal device being in a non-RRC connection state can be understood as: if the terminal device meets the conditions for becoming a relay and the terminal device is in a non-RRC connection state, the terminal device establishes an RRC connection with the network device; or it can also be understood as: when the terminal device meets the conditions for becoming a relay and the terminal device is in a non-RRC connection state, the terminal device establishes an RRC connection with the network device.

[0185] Additionally, it should be noted that the method described in step S801 is merely an exemplary method for the terminal device to obtain the conditions for becoming a relay. This application embodiment does not limit the implementation method of the terminal device obtaining the conditions for becoming a relay. For example, the conditions for the terminal device to become a relay can also be pre-configured in the terminal device.

[0186] This application does not impose any restrictions on the conditions under which a terminal device can act as a relay. The conditions for a terminal device to act as a relay are illustrated below.

[0187] Example 1: The conditions for a terminal device to become a relay are: the reference signal receiving power (RSRP) between the terminal device and the network device is greater than or equal to a first threshold, and / or, the RSRP between the terminal device and the network device is less than or equal to a second threshold. The second threshold and / or the first threshold may be pre-configured in the terminal device, or they may be carried in the fifth information. This application embodiment does not limit the implementation method of the terminal device obtaining the first threshold and the second threshold.

[0188] For example, the condition for a terminal device to become a relay is that the RSRP between the terminal device and the network device is greater than or equal to L1. If the RSRP between the terminal device and the network device is greater than or equal to L1, and the terminal device is in a non-RRC connection state, then the terminal device and the network device establish an RRC connection.

[0189] For example, the condition for a terminal device to become a relay is that the RSRP between the terminal device and the network device is less than or equal to L2. If the RSRP between the terminal device and the network device is less than or equal to L2, and the terminal device is not in an RRC connection state, then the terminal device and the network device establish an RRC connection.

[0190] For example, the conditions for a terminal device to become a relay are: the RSRP between the terminal device and the network device is greater than or equal to L1, and the RSRP is less than or equal to L2; where L1 is less than L2. If the RSRP between the terminal device and the network device is greater than or equal to L1, and the RSRP is less than or equal to L2, and the terminal device is not in an RRC connection state, then the terminal device and the network device establish an RRC connection.

[0191] Example 2: The condition for a terminal device to become a relay is that the terminal device can receive relay discovery information broadcast by relay #1. Relay #1 is another relay different from the terminal device. In this example, if the terminal device can receive relay discovery information broadcast by another relay, it means that the terminal device can become a relay. For example, the relay discovery information broadcast by a relay is information used to indicate whether it can act as a relay and / or specifically which hop relay it is.

[0192] Example 3: The condition for a terminal device to become a relay is that the terminal device can receive relay request information from the edge terminal device. In this example, if the terminal device can receive relay request information sent by the edge terminal device, it means that the terminal device can become a relay.

[0193] Example 4: The condition for a terminal device to become a relay is that the RSRP between the terminal device and relay #1 is greater than or equal to the third threshold. Here, relay #1 is another relay different from the terminal device. For example, the RSRP between the terminal device and relay #1 is the RSRP corresponding to the PC5 link between the terminal device and relay #1. Furthermore, the third threshold may be pre-configured in the terminal device, or it may be carried in the fifth information. This application embodiment does not limit the implementation method of the terminal device obtaining the third threshold.

[0194] Example 5: The condition for a terminal device to become a relay is that the RSRP between the terminal device and the edge terminal device is greater than or equal to the fourth threshold. For example, the RSRP between the terminal device and the edge terminal device is the RSRP corresponding to the PC5 link between the terminal device and the edge terminal device. In addition, the fourth threshold may be pre-configured in the terminal device, or it may be carried in the fifth information. This application embodiment does not limit the implementation method of the terminal device obtaining the fourth threshold.

[0195] In one alternative implementation, the conditions under which a terminal device becomes a relay of a different type can be the same or different.

[0196] For example, the types of relays include: a first relay, a second relay, and a third relay. The first relay is a relay directly connected to the edge terminal device (such as the first relay terminal mentioned above), the second relay is a relay directly connected to the network device (such as the last relay terminal mentioned above), and the third relay is a relay that is not directly connected to either the edge terminal device or the network device (such as the intermediate relay terminal mentioned above). Any two or more of the conditions for a terminal device to become a first relay, the conditions for a terminal device to become a second relay, and the conditions for a terminal device to become a third relay can be the same or different.

[0197] For example, the condition for a terminal device to become the first relay terminal is that the RSRP between the terminal device and the edge terminal device is greater than or equal to the fourth threshold.

[0198] The conditions for a terminal device to become the last relay terminal are: the RSRP between the terminal device and the network device is greater than or equal to L1, and the RSRP between the terminal device and the network device is less than or equal to L2; where L1 is less than L2.

[0199] The condition for a terminal device to become an intermediate relay terminal is that the RSRP between the terminal device and other relays is greater than or equal to the third threshold.

[0200] In summary, in this communication method, the network device sends a fifth piece of information, which indicates the conditions for the terminal device to become a relay. In response to the terminal device meeting the conditions for becoming a relay and being in a non-RRC connected state, the terminal device establishes an RRC connection with the network device. Therefore, when the terminal device meets the conditions for becoming a relay and is in a non-RRC connected state, the terminal device establishes an RRC connection with the network device, thus enabling the terminal device to switch to an RRC connected state. This method helps reduce the latency of waiting for the relay to switch to an RRC connected state when subsequent edge terminal devices establish RRC connections with the network device via relays, thereby reducing the latency of establishing RRC connections between the edge terminal devices and the network device.

[0201] In addition, if the edge terminal device initiates the establishment of an RRC connection with the network device when there is service data to be transmitted, this communication method reduces the latency of the edge terminal device establishing an RRC connection with the network device, thereby reducing the latency of the edge terminal device transmitting service data and improving service quality.

[0202] See Figure 9 , Figure 9This is a schematic diagram of a communication device according to an embodiment of the present invention. The communication device 900 can be a terminal device, or a component of a terminal device (e.g., an integrated circuit, a chip, etc.); or, the communication device 900 can be a network device, or a component of a network device (e.g., an integrated circuit, a chip, etc.). The communication device 900 may include a processing unit 901. Optionally, the communication device 900 may further include a communication unit 902, and the processing unit 901 can be used to control the communication unit 902 to perform data / signaling transmission and reception. Optionally, the communication device 900 may further include a storage unit.

[0203] In one implementation, the communication device 900 is used to perform the functions of the first terminal device in the aforementioned method embodiments:

[0204] The communication unit 902 is used to establish a connection with the second terminal device, which is a relay for communication between the communication device 900 and the network device.

[0205] The communication unit 902 is also configured to send first information to the second terminal device in response to the communication device 900 being in a non-RRC connection state. The first information is used to request the establishment of an RRC connection between the communication device 900 and the network device.

[0206] In another implementation, the communication device 900 is used to perform the functions of the terminal device in the aforementioned method embodiments:

[0207] The communication unit 902 is used to receive fifth information from the network device, which indicates the conditions for the communication device 900 to become a relay.

[0208] The processing unit 901 is configured to establish an RRC connection with the network device in response to the communication device 900 meeting the conditions and the communication device 900 being in a non-RRC connection state.

[0209] In another implementation, the communication device 900 is used to perform the functions of the network device in the aforementioned method embodiments:

[0210] The communication unit 902 is used to send fifth information, which is used to indicate the conditions for the terminal device to become a relay.

[0211] The processing unit 901 is used to establish an RRC connection with a terminal device that meets the conditions and is in a non-RRC connection state.

[0212] The embodiments of this application and the above-described method embodiments are based on the same concept and have the same technical effects. For the specific principles, please refer to the description of the above-described method embodiments, which will not be repeated here.

[0213] Please see Figure 10 , Figure 10This is a schematic diagram of another communication device provided in an embodiment of this application. The communication device 1000 can be used to perform related operations of the aforementioned network device or terminal device. The communication device 1000 may include a memory 1001 and a processor 1002. Optionally, it may also include a communication interface 1003. The memory 1001, processor 1002, and communication interface 1003 are connected via one or more communication buses. The communication interface 1003 is controlled by the processor 1002 for sending and receiving information.

[0214] Memory 1001 may include read-only memory and random access memory, and provides instructions and data to processor 1002. A portion of memory 1001 may also include non-volatile random access memory.

[0215] Communication interface 1003 is used to receive or send data.

[0216] Processor 1002 can be a central processing unit (CPU), but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor; optionally, processor 1002 can also be any conventional processor. Wherein:

[0217] Memory 1001 is used to store program instructions.

[0218] Processor 1002 is used to call program instructions stored in memory 1001.

[0219] In one optional implementation, when the processor 1002 invokes the computer program, it is used to perform the functions of the first terminal device in the aforementioned method embodiments:

[0220] Establish a connection with the second terminal device, which is a relay for communication between the communication device 1000 and the network device;

[0221] In response to the communication device 1000 being in a non-RRC connection state, a first message is sent to the second terminal device. The first message is used to request the establishment of an RRC connection between the communication device 1000 and the network device.

[0222] In another optional implementation, when the processor 1002 invokes the computer program, it performs the functions of the terminal device in the foregoing method embodiments:

[0223] Receive fifth information from the network device, the fifth information being used to indicate the conditions for the communication device 1000 to become a relay;

[0224] In response to the communication device 1000 meeting the conditions and being in a non-RRC connection state, an RRC connection is established with the network device.

[0225] In another optional implementation, when the processor 1002 invokes the computer program, it performs the functions of the network device in the foregoing method embodiments:

[0226] Send the fifth message, which indicates the conditions under which the terminal device becomes a relay;

[0227] Establish an RRC connection with a terminal device that meets the conditions and is not in an RRC connection state.

[0228] The embodiments of this application and the above-described method embodiments are based on the same concept and have the same technical effects. For the specific principles, please refer to the description of the above-described method embodiments, which will not be repeated here.

[0229] This application also provides a chip that can perform the relevant steps of the terminal device or network device in the foregoing method embodiments. The chip includes a processor and a communication interface, the communication interface being used to receive or send data.

[0230] In one embodiment, the chip performs the relevant steps of the first terminal device in the aforementioned method embodiments:

[0231] The processor is configured to cause the chip to perform the following operations: establish a connection with a second terminal device, which is a relay for communication between the chip and a network device; and send a first message to the second terminal device in response to the chip being in a non-RRC connection state, the first message being used to request the establishment of an RRC connection between the chip and the network device.

[0232] In another approach, the chip performs the relevant steps of the terminal device in the aforementioned method embodiments:

[0233] The processor is configured to cause the chip to perform the following operations: receive fifth information from the network device, the fifth information indicating the conditions for the chip to become a relay; and establish an RRC connection with the network device in response to the chip meeting the conditions and the chip being in a non-RRC connected state.

[0234] In another embodiment, the chip performs the relevant steps of the network device in the aforementioned method embodiments:

[0235] The processor is configured to cause the chip to perform the following operations: send a fifth message indicating the conditions under which a terminal device becomes a relay; and establish an RRC connection with a terminal device that meets the conditions and is in a non-RRC connection state.

[0236] The embodiments of this application and the above-described method embodiments are based on the same concept and have the same technical effects. For the specific principles, please refer to the description of the above-described method embodiments, which will not be repeated here.

[0237] For each device or product applied to or integrated into a chip, each of its modules can be implemented using hardware methods such as circuits, or at least some modules can be implemented using software programs that run on a processor integrated inside the chip, while the remaining (if any) modules can be implemented using hardware methods such as circuits.

[0238] like Figure 11 As shown, Figure 11 This is a schematic diagram of the structure of a module device provided in an embodiment of this application. The module device 1100 can perform the relevant steps of the terminal device or network device in the aforementioned method embodiments. The module device 1100 includes: a communication module 1101, a power module 1102, a storage module 1103, and a chip 1104.

[0239] The power module 1102 is used to provide power to the module device; the storage module 1103 is used to store data and instructions; and the communication module 1101 is used for internal communication within the module device or for communication between the module device and external devices.

[0240] In one embodiment, chip 1104 is used to perform the method executed by the first terminal device in the above method embodiment: establishing a connection with a second terminal device, the second terminal device being a relay for communication between chip 1104 and a network device; in response to chip 1104 being in a non-RRC connection state, sending first information to the second terminal device, the first information being used to request the establishment of an RRC connection between chip 1104 and the network device.

[0241] In another embodiment, chip 1104 is used to perform the method executed by the terminal device in the above method embodiment: receiving fifth information from the network device, the fifth information being used to indicate the conditions for chip 1104 to become a relay; and in response to chip 1104 meeting the conditions and chip 1104 being in a non-RRC connection state, establishing an RRC connection with the network device.

[0242] In another embodiment, chip 1104 is used to perform the method executed by the network device in the above method embodiment: sending fifth information, the fifth information being used to indicate the conditions for the terminal device to become a relay; and establishing an RRC connection with a terminal device that meets the conditions and is in a non-RRC connection state.

[0243] The implementation method of this module device can be found in the relevant content of the above method embodiments, and will not be described in detail here.

[0244] The embodiments of this application and the above-described method embodiments are based on the same concept and have the same technical effects. For the specific principles, please refer to the description of the above-described method embodiments, which will not be repeated here.

[0245] This application also provides a computer-readable storage medium storing instructions that, when executed on a processor, enable the implementation of the method flow described in the above method embodiments.

[0246] This application also provides a computer program product, which, when run on a processor, enables the implementation of the method flow described in the above method embodiments.

[0247] Regarding the modules / units included in the various devices and products described in the above embodiments, they can be software modules / units, hardware modules / units, or a combination of both. For example, for various devices and products applied to or integrated into a chip, all of their modules / units can be implemented using hardware methods such as circuits, or at least some modules / units can be implemented using software programs that run on the chip's integrated processor, while the remaining (if any) modules / units can be implemented using hardware methods such as circuits. For various devices and products applied to or integrated into a chip module, all of their modules / units can be implemented using hardware methods such as circuits. Different modules / units can be located in the same part (e.g., chip, circuit module, etc.) or different components of the chip module, or at least some modules / units... It can be implemented using software programs that run on the processor integrated within the chip module. The remaining (if any) modules / units can be implemented using hardware methods such as circuits. For various devices and products applied to or integrated into the terminal, the modules / units they contain can all be implemented using hardware methods such as circuits. Different modules / units can be located in the same component (e.g., chip, circuit module, etc.) or in different components within the terminal. Alternatively, at least some modules / units can be implemented using software programs that run on the processor integrated within the terminal, while the remaining (if any) modules / units can be implemented using hardware methods such as circuits.

[0248] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some operations can be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0249] The descriptions of the various embodiments provided in this application can be referenced mutually. Each embodiment has its own emphasis, and parts not described in detail in a certain embodiment can be referred to the relevant descriptions of other embodiments. For the sake of convenience and brevity, for example, the functions and operations of the various devices and equipment provided in the embodiments of this application can be referred to the relevant descriptions of the method embodiments of this application. The method embodiments and the device embodiments can also be referenced, combined or cited from each other.

[0250] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A communication method, characterized in that, Applied to a first terminal device, the method includes: Establish a connection with a second terminal device, which is a relay for communication between the first terminal device and the network device; In response to the first terminal device being in a non-Radio Resource Control (RRC) connection state, a first message is sent to the second terminal device, the first message being used to request the establishment of an RRC connection between the first terminal device and the network device.

2. The method according to claim 1, characterized in that, The first information is also used to trigger the second terminal device to send the second information to the network device or the third terminal device in response to the second terminal device being in a non-RRC connection state; The second information is used to request the establishment of an RRC connection between the second terminal device and the network device; The third terminal device is a relay used for communication between the second terminal device and the network device.

3. The method according to claim 1, characterized in that, The method further includes: After the first terminal device establishes an RRC connection with the network device, it acquires service data and sends the service data to the second terminal device.

4. The method according to claim 3, characterized in that, The first terminal device is a relay for communication between the fourth terminal device and the network device; before acquiring service data, the method further includes: Establish a connection with the fourth terminal device; Receive third information from the fourth terminal device, the third information being used to request the establishment of an RRC connection between the fourth terminal device and the network device; The third information is sent to the second terminal device.

5. The method according to claim 3, characterized in that, The service data is the uplink data to be sent by the first terminal device when it is in RRC connection state.

6. The method according to any one of claims 1 to 5, characterized in that, The method further includes: In response to a connection failure between the first terminal device and the second terminal device, a connection is established with a fifth terminal device, which is a relay for communication between the first terminal device and the network device, and the fifth terminal device is different from the second terminal device. A fourth message is sent to the fifth terminal device, the fourth message being used to request the re-establishment of the RRC connection between the first terminal device and the network device.

7. A communication method, characterized in that, Applied to a terminal device, the method includes: Receive fifth information from a network device, the fifth information being used to indicate the conditions under which the terminal device becomes a relay; In response to the terminal device meeting the conditions and the terminal device being in a non-Radio Resource Control (RRC) connection state, an RRC connection is established with the network device.

8. The method according to claim 7, characterized in that, The fifth piece of information includes a first threshold and / or a second threshold; The conditions for the terminal device to become a relay are: the reference signal received power (RSRP) between the terminal device and the network device is greater than or equal to the first threshold, and / or the RSRP between the terminal device and the network device is less than or equal to the second threshold.

9. A communication method, characterized in that, Applied to a network device, the method includes: Send a fifth message, which indicates the conditions under which the terminal device becomes a relay; Establish an RRC connection with a terminal device that meets the conditions and is in a non-Radio Resource Control (RRC) connection state.

10. The method according to claim 9, characterized in that, The fifth piece of information includes a first threshold and / or a second threshold; The conditions for the terminal device to become a relay are: the reference signal received power (RSRP) between the terminal device and the network device is greater than or equal to the first threshold, and / or the RSRP between the terminal device and the network device is less than or equal to the second threshold.

11. A communication device, characterized in that, The apparatus includes modules or units for implementing the method of any one of claims 1 to 6, or modules or units included in implementing the method of claim 7 or 8, or modules or units included in implementing the method of claim 9 or 10.

12. A communication device, characterized in that, The communication device includes a processor and a memory interconnected thereto, wherein the memory is used to store a computer program, the computer program including program instructions, and the processor is configured to invoke the program instructions to perform the method as claimed in any one of claims 1 to 6, or to perform the method as claimed in claim 7 or 8, or to perform the method as claimed in claim 9 or 10.

13. A chip, characterized in that, The device includes a processor and a communication interface, wherein the processor is configured to cause the chip to perform the method as claimed in any one of claims 1 to 6, or the method as claimed in claim 7 or 8, or the method as claimed in claim 9 or 10.

14. A module device, characterized in that, The module device includes a communication module, a power module, a storage module, and a chip, wherein: The power module is used to provide electrical energy to the module device; The storage module is used to store data and instructions; The communication module is used for internal communication within the module device, or for communication between the module device and external devices. The chip is used to perform the method as described in any one of claims 1 to 6, or to perform the method as described in claim 7 or 8, or to perform the method as described in claim 9 or 10.

15. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-readable instructions that, when executed on a communication device, cause the communication device to perform the method according to any one of claims 1 to 6, or cause the communication device to perform the method according to claim 7 or 8, or cause the communication device to perform the method according to claim 9 or 10.

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